Pharmacology Question Set 3

A 24-year-old man has just been shifted to the post-operative unit, after undergoing an appendectomy following two episodes of acute appendicitis. Eight hours after the surgery, he complains of nausea and vomiting. On physical examination, his temperature is 98.4º F, the pulse rate is 96/minute, the blood pressure is 122/80 mm Hg, and the respiratory rate is 14/minute. His abdomen is soft on palpation and intestinal peristaltic sounds are heard normally on auscultation. The surgeon adds intravenous ondansetron to his post-operative medication orders, after which the patient reports relief from nausea and vomiting. Which of the following best explains the mechanism of action of this drug?

Following a gastric surgery, a 45-year-old woman complains of severe nausea and vomiting on the second post-operative day. On physical examination, her vitals are stable and examination of the abdomen reveals no significant abnormality. As she is already receiving an appropriate dosage of ondansetron, the surgeon adds metoclopramide to her treatment orders. Following addition of the drug, she experiences significant relief from nausea and vomiting. Which of the following mechanisms best explains the action of this drug?

Following a gastric surgery, a 45-year-old woman complains of severe nausea and vomiting on the second post-operative day. On physical examination, her vitals are stable and examination of the abdomen reveals no significant abnormality. As she is already receiving an appropriate dosage of ondansetron, the surgeon adds metoclopramide to her treatment orders. Following addition of the drug, she experiences significant relief from nausea and vomiting. Which of the following mechanisms best explains the action of this drug?

A 65-year-old man presents with a small painless ulcer with a raised border on his right forearm which has persisted over the last three weeks. His past history is significant for three occurrences of basal cell carcinoma on different areas of the body during the last four years, all having been surgically excised. The morphology of the present lesion is also highly suggestive of basal cell carcinoma. He tells the physician that if the lesion is a basal cell carcinoma, he does not want to undergo biopsy and surgery, if possible to avoid it. The physician then suggests the use of a cream, which is FDA-approved for the treatment of small superficial basal cell carcinomas in low-risk areas. The cream contains a chemotherapeutic agent, which is an antimetabolite and an S-phase-specific anticancer drug. Which of the following mechanisms best explains its action?

A 72-year-old man has been recently diagnosed with stage III squamous cell carcinoma of the oral cavity. After the necessary laboratory work-up, concurrent chemoradiation therapy has been planned. Radiation therapy is planned to take place over 7 weeks and he will receive radiation doses daily, from Monday to Friday, in 2.0 Gy fractions. For concurrent chemotherapy, he will receive intravenous cisplatin at a dosage of 50 mg/m^2 weekly for 7 weeks. Which of the following best explains the mechanism of action of the antineoplastic drug that the patient will receive?

An 11-year-old boy is brought to a pediatrician by his parents for the routine Tdap immunization booster dose around adolescence. Going through his medical records, the pediatrician notes that the child has been immunized as per CDC recommendations except that he had received catch-up Tdap immunization at age of 8 years. When the parents were asked about this delay, they inform the pediatrician that they immigrated to this country three years ago from a developing country where the child had not been immunized against diphtheria, tetanus, and pertussis. Therefore, he received catch-up series at 8 years of age, which included the first dose of Tdap vaccine. Which of the following options should the pediatrician choose to continue the immunization schedule of the boy?

A young researcher who recently joined an immunology research center knows that capsular polysaccharides are important antigens for bacteria such as Hemophilus influenzae type b (Hib), Neisseria meningitidis, and Streptococcus pneumoniae. As a member of a research team working on Hib vaccine, he asks his senior colleague why capsular polysaccharides are conjugated with protein carriers such as tetanus toxoid. In reply, he is told it is because of the advantages of conjugation. Which of the following might be the reason for this answer?

A 52-year-old man presents to the emergency department with a history of nausea, vomiting, palpitation, and lightheadedness after consuming a drink prepared from the leaves of yellow oleander (Thevetia peruviana). He had read somewhere that such a drink is healthy. As he liked the taste, he consumed three glasses of the drink before developing the present symptoms. There is no past medical history suggestive of any significant medical condition. On physical examination, he is disoriented. His temperature is 97.8 ºF, the pulse rate is 140/minute and irregular, the blood pressure is 94/58 mm Hg, and the respiratory rate is 14/minute. Auscultation of the heart reveals an irregularly irregular heartbeat and auscultation of the lungs does not reveal any significant abnormality. His abdomen is soft and the pupillary reflexes are intact. His electrocardiogram has peaked T waves. A botanist confirms that yellow oleander leaves contain cardiac glycosides. In addition to control of airway, breathing, and circulation, and supportive treatment, which of the following medications is indicated?

A 20-year-old man presents to the physician complaining of a tremor involving both upper limbs for the last three weeks. His past medical history is significant for two episodes of undiagnosed jaundice over the last one year. On physical examination, his temperature is 98.4 ºF, the pulse rate is 82/minute, the blood pressure is 116/78 mm Hg, and the respiratory rate is 12/minute. The physician notes the presence of excessive salivation and a mask-like face. Examination of the central nervous system reveals ataxic gait accompanied by asymmetric resting and kinetic tremors. Examination of the abdomen reveals the presence of hepatomegaly. Ocular examination reveals the presence of a greenish-gold limbal ring in both corneas. After necessary laboratory workup, the physician prescribes a drug, warning the patient that it may worsen his tremors. The physician also mentions that it is important to assess complete blood counts and monitor for the presence of urinary protein during initial drug therapy, as the drug is known to cause nephrotic syndrome and pancytopenia. Which of the following is another known adverse effects of the drug prescribed for this patient?

A 5-year-old boy is brought to the emergency department with altered sensorium and dyspnea. His father, a mechanic, informs the physician that the boy accidentally ingested an unknown amount of radiator fluid. On examination, the boy’s temperature is 98.8 ºF, the pulse rate is 116/minute, the blood pressure is 98/78 mm Hg, and the respiratory rate is 42/minute. Examination of the chest reveals deep and rapid respirations with absence of any wheeze, rhonchi or crepitations. An acid-base evaluation reveals his blood pH to be 7.2 and the anion gap 16 mEq/L. Examination of his urine shows the presence of oxalate crystals. Which of the following is most appropriate antidote for the poisoning that the boy has developed?

A 62-year-old man, who is known to have recurrent thromboembolic strokes, visits his physician for routine follow up. While assessing for drug compliance, the physician realizes that he has inadvertently doubled his dose of warfarin a month ago. When he is asked about any new complaints, he denies any new symptoms, including any bleeding. His physical examination also does not show any sign of bleeding. Based on the lifestyle of the patient, the physician does not consider him to be at increased risk for bleeding. The physician orders an INR for this patient, which turns out to be 9.5. In addition to temporarily stopping warfarin, which of the following drugs is indicated for this patient’s treatment?

A 17-year-old adolescent female is brought to the emergency department six hours after she attempted suicide by consuming 16 tablets of acetaminophen (500 mg of acetaminophen per tablet). Her friend informs the physician that she broke up with her boyfriend a few days ago, and she was acting very depressed for the last two days. At present, she does not have any complaints nor symptoms. On physical examination, her vitals and physical examination are normal. The physician orders laboratory investigations including a serum acetaminophen level. When the physician plots the serum acetaminophen level on the Rumack-Matthew nomogram, it suggests “probable hepatic toxicity”. After interpreting the normogram, the physician starts her treatment with a drug which is a precursor of glutathione and is a specific antidote for acetaminophen poisoning. Which of the following is an additional beneficial mechanism of action of the drug in this case?

A 25-year-old female presents to the doctor's office feeling low on energy for the last two weeks and sometimes feels like staying home all day. She works for a technology startup and is attending graduate school part-time in the evening. She is very concerned about her health and tries to eat a balanced diet. She goes running daily and takes yoga classes three times a week. She gets together with her friends every weekend and has continued to do so the last few weeks. Her schedule is quite hectic and she is always "on the go". There have been no changes in her sleep, appetite, and daily routine. She denies having flu-like symptoms, headaches, body aches, indigestion, weight loss, agitation, or restlessness. She admits to moderate drinking and marijuana use but has never smoked cigarettes. Her medical history does not reveal anything significant and she takes no medications, other than vitamin C pills for cold prevention. A friend suggested she take a herbal product containing Ginseng and St. John's wort for her decreased energy levels. Her Body Mass Index (BMI) is 22 kg/m^2. Physical examination reveals no findings and labs show: Serum Electrolytes Sodium: 138 mEq/L Potassium: 3.9 mEq/L Chloride: 101 mEq/L Thyroid Stimulating Hormone: 3.5 μU/mL Hemoglobin (Hb%): 13.5 g/dL Mean Corpuscular Hemoglobin (MCH): 31 pg Mean Corpuscular Volume (MCV): 85 fl Leucocyte count: 5000 /mm^3 Platelet count: 250,000 /mm^3 The doctor advises her to cut down on her drinking and marijuana use. What else should she be advised?

A 74-year-old man is brought by paramedics to the emergency department for slurred speech and weakness in the left arm and leg for one hour. The patient was playing with his grandson when the symptoms started and his wife immediately called an ambulance. There is no history of head trauma or recent surgery. The patient takes captopril for hypertension. Vitals are pulse: 110 /min, respiration: 22/min, and blood pressure: 200/105 mmHg. Physical examination the patient is alert and conscious but speech is impaired. Muscle strength is 0/5 in the left arm and leg and 5/5 in the right arm and leg. A non-contrast CT of the head shows no evidence of intracranial bleeding. Labs show: Serum Glucose: 90 mg/dL Serum Electrolytes: Sodium: 140 mEq/L Potassium: 4.1 mEq/L Chloride: 100 mEq/L Serum Creatinine: 1.3 mg/dl Blood Urea Nitrogen: 20 mg/dl Cholesterol, total: 240 mg/dL HDL-cholesterol: 38 mg/dL LDL-cholesterol: 100 mg/dL Triglycerides: 190 mg/dL Hemoglobin (Hb%): 15.3 g/dL Mean Corpuscular Volume (MCV): 83 fl Reticulocyte count: 0.8 % Erythrocyte count: 5.3 million/mm^3 Platelet count: 130,000/mm^3 Partial Thromboplastin Time (aPTT): 30 seconds Prothrombin Time (PT): 12 seconds. Although he is within the time frame of the standard therapy for his most likely condition, he cannot be started on it because of which of the following contraindications?

A 9-month-old male infant is brought to a pediatrician by his parents for routine immunization. The pediatrician comes to know that the family has recently migrated to United States from a developing country, where the infant has received immunization as per national immunization schedule for that country. The pediatrician prepares a plan for the infant’s immunization as per standard guidelines. Looking at the plan, the parents ask him with surprise why the infant needs to be vaccinated with injectable polio vaccine, as he had received an oral polio vaccines earlier. The pediatrician explains them that as per recommended immunization schedule for children and adolescents in United States, it is important to complete schedule of immunization using injectable polio vaccine (IPV). He also mentions that IPV is considered safer than OPV and IPV has some distinct advantages over OPV. Which of the following statements best explain the pediatrician’s suggestions?

A public health researcher is invited to participate in a government meeting on immunization policies. Other participants in the meeting include physicians, pediatricians, representatives of vaccine manufacturers, persons from the health ministry, etc. For a specific viral disease, there are two vaccines – one is a live attenuated vaccine (LAV) and the other is a subunit vaccine. Manufacturers of both the vaccines promote their own vaccines in the meeting. Non-medical persons in the meeting ask the public health researcher to compare the two. The public health researcher clearly explains pros and cons of the two types of the vaccines. Which of the following statements is most likely to have been made by the researcher in his presentation?

An 38-year-old woman visits the doctor's office for progressive weakness and pallor for the last few weeks. She also complains of shortness of breath during her yoga class. She denies fever, cough, runny nose, changes in appetite or bowel and bladder habit. Previously, she had no complaints except for an occasional migraine which was relieved by acetaminophen. For the last month, she has been having more frequent attacks of migraines and was started on prophylactic aspirin. Vitals reveal a pulse of 102 bpm, respirations 18/min, and blood pressure 130/84 mmHg. Her blood pressure on previous visits has been 110/76 mmHg, 120/78 mmHg, and 114/80 mmHg. Physical examination is otherwise unremarkable. Stool for occult blood is positive. Besides a low hemoglobin concentration, which other lab finding is expected in this patient?

A 7-year-old girl is referred to the hematology clinic by her pediatrician. She has had low-grade fever for a week but a source of infection could not be detected. The child also complained of leg pain for a couple of weeks. The mother also noticed increasing lethargy and easy fatigability but attributed it to longer school hours as she has started first grade recently. The girl was born at term by a normal vaginal delivery and was healthy previously. Physical examination is significant for pallor and cervical lymphadenopathy. Further investigations including bone marrow aspiration and cytology confirms the diagnosis of acute lymphoblastic leukemia (ALL). The patient is started on a chemotherapy regimen consisting of vincristine, daunorubicin, L-asparginase and prednisolone for induction followed by intrathecal methotrexate for maintenance. Following the fourth cycle of chemotherapy, she develops bilateral ptosis. Physical examination shows normal pupillary reflex and eye movement. She is started on pyridoxine and pyridostigmine and in seven days she has complete resolution of the ptosis in 7 days. Which of the following drugs is most likely associated with this adverse reaction?

A middle-aged homeless man is found lying unresponsive on the streets by the police, and is rushed to the emergency department. His blood pressure is 110/80 mm Hg, pulse rate is 100 per minute, and his respirations are 10 per minute and shallow. His extremities are cold and clammy and the pupils are constricted and non-reactive. His blood glucose is 55 mg/dL. IV access is established immediately, with the administration of dextrose and naloxone. In half an hour, the patient is fully conscious, alert and responsive. He denies any medical illnesses, hospitalizations, or surgeries in the past. Physical examination reveals injection track marks along both arms. He admits to the use of cocaine and heroin. He smokes cigarettes and consumes alcohol. His vital signs are now stable. A urine sample is sent for toxicology screening. Which of the following is the most likely cause of his respiratory depression?

A 38-year-old female patient is diagnosed with a stage IIIa infiltrating ductal carcinoma involving the left breast. The tumor is ER/PR positive, HER- 2 negative, poorly differentiated Bloom-Richardson grade 3 and extending to the margins. 4/20 nodes are positive. She undergoes a lumpectomy with axillary lymph node dissection, followed by chemotherapy and radiation therapy to the left breast and axilla. Her chemotherapy regimen involves doxorubicin, cyclophosphamide and paclitaxel. Following completion of the intensive phase, she is started on tamoxifen as an adjuvant therapy. Six months later, she presents with increasing fatigue, orthopnea and paroxysmal nocturnal dyspnea. Physical examination reveals the presence of an S3 gallop, jugular venous distension, pedal edema and ascites. She is diagnosed with congestive cardiac failure and admitted for further management. An echocardiogram confirms the diagnosis of dilated cardiomyopathy with severe diastolic dysfunction and an ejection fraction of 10%. Her medical history prior to the diagnosis of breast cancer is negative for any cardiac conditions. The baseline echocardiogram prior to starting chemotherapy and a 12-lead electrocardiogram were normal. Which of the following is probably responsible for her current cardiac condition?

A 20-year-old college student is found lying unconscious on the floor of his room by his roommate. The paramedics arrive at the site and find him lying unresponsive, with cold, clammy extremities and constricted, non-reactive pupils. He smells of alcohol, his blood pressure is 110/80 mm Hg, the pulse rate is 100 per minute, the respirations are 10 per minute and shallow. Intravenous access is established and dextrose is administered. The roommate suggests the possibility of drug abuse by the patient. He says he has seen the patient sniff a powdery substance, and injects himself often, but has never confronted him about it. The patient is brought to the emergency department. The doctor performs a quick examination and orders the administration of a particular drug. Within 5-10 minutes of administration, the patient regains consciousness and his breathing improves. He is alert and cooperative within the next few minutes. Physical examination reveals injection track marks on both arms. He denies any past medical, surgical or psychiatric history or suicidal ideation. He says that he was smoking a cigarette in his room and does not know what happened thereafter. He smokes a pack of cigarettes daily and drinks alcohol on weekends, about 4-5 drinks at a time, but denies using drugs. Urine toxicology is positive for heroin. He is admitted to the hospital for further treatment. Which of the following may have helped antagonize the state of acute overdose in this patient?

A 23-year-old primigravid presents to her obstetrician at 28 weeks of gestation for a scheduled visit. Except for occasional headaches, she generally feels well. She reports regular fetal movements and mild abdominal pain at times. Her medical history is unremarkable. A prenatal multivitamin and the occasional acetaminophen are her only medications. Blood pressure is 148/110 mmHg today. On her last visit at 24 weeks of gestation, her blood pressure was 146/96 mmHg. Fundus measures 28 cm above the pubic symphysis. Labs show: Serum Glucose (fasting): 88 mg/dL Serum Electrolytes: Sodium: 142 mEq/L Potassium: 3.9 mEq/L Chloride: 101 mEq/L Serum Creatinine: 0.9 mg/dl Blood Urea Nitrogen: 10 mg/dl Alanine aminotransferase (ALT): 18 U/L Aspartate aminotransferase (AST): 16 U/L Hemoglobin (Hb%): 15 g/dL Mean Corpuscular Volume (MCV): 85 fl Reticulocyte count: 1% Erythrocyte count: 5.1 million/mm^3 Platelet count: 95,000/mm^3 Urinalysis: Proteins: 2+ Glucose: Negative Ketones: Negative Leucocytes: Negative Nitrites: Negative Red Blood Cells (RBC): Negative Casts: Negative Which of the following medications should she be started on?

A 28-year-old woman comes to the physician for a follow-up visit. She was diagnosed with allergic rhinitis and bronchial asthma at the age of 11 years. Her regular controller medications include daily high-dose inhaled corticosteroids and montelukast but she still needs to use rescue inhaler three to four times a week following exercise. She also mentions that she gets breathless with moderate exertion. After a thorough evaluation, the physician explains that her medications dosage have to be increased. She refuses to take oral corticosteroids daily due to concerns about side effects. The physician prescribes him omalizumab, which is administered every three weeks subcutaneously. Which of the following best explains the mechanism of action of the new medication that has been added to the woman’s ongoing controller medications?

An 8-year-old boy is brought to the pediatrician with the complaints of recurrent episodes of wheezing for last two years. He uses salbutamol inhaler for relief from wheezing but his symptoms are worsening recently. He often coughs during nights, which awakens him from sleep almost every alternate day. He is not able to play football because he starts coughing after 10-15 minutes of play. At present, his physical examination is completely normal and auscultation of his chest does not reveal any abnormal breath sounds. His peak expiratory flow rate (PEFR) is 75% of expected for his age, sex, and height. After a complete diagnostic evaluation, the pediatrician prescribes him low-dose inhaled fluticasone daily for at least three months. He also mentions that the boy may require continuing inhaled corticosteroid (ICS) therapy for a few years if symptoms recur after discontinuation of ICS. However, the parents are concerned about side effects of corticosteroids. Which of the following corticosteroid-related adverse effects is most likely to be experienced by the child?

An 11-year-old girl presents to a pediatrician with the complaints of recurrent wheezing for last three years. After a detailed history, complete physical examination, and thorough diagnostic evaluation, the pediatrician informs her that she has mild persistent asthma, which will be most effectively treated with an inhaled corticosteroids (ICS). However, her parents firmly object to the use of corticosteroids in any form, despite being told about the side-effects associated with ICS are negligible. Therefore the pediatrician suggests her regular use of a drug that does not contain a corticosteroid. He mentions that the drug is used as prophylaxis only and will not be useful to treat an acute bronchospasm. Which of the following drugs is most likely suggested by the pediatrician?

An 18-year-old male adolescent presents to the clinic with shortness of breath and fever for last 2 days. He also has a cough for the same duration. He is asthmatic and uses inhaled albuterol for symptom relief when required. He used it today three times at 10-minute intervals but has not experienced relief yet. On physical examination, his temperature is 101ºF (38ºC), the pulse rate is 130/minute, the blood pressure is 116/80 mm Hg, and the respiratory rate is 28/minute. Auscultation of chest reveals bilateral crackles. Considering that he has already taken inhaled albuterol and that he has tachycardia, the doctor nebulizes him with inhaled ipratropium bromide, which significantly improves his symptoms. Which of the following is the mechanism of action of this drug?

A 36-year-old man presents to a physician after he had a transient loss of consciousness while he was resting after dinner on the previous night. His symptoms lasted only for a few seconds and resolved spontaneously. This is the third time he experienced such episode. He says that he recently started having nightmares. His father died of sudden cardiac death at the age of 45 without any history of hypertension or any chronic cardiac disorder. A complete physical examination is normal. A 12-lead electrocardiogram shows ST-segment elevations in V1, V2 and V3, and presence of incomplete right bundle branch block (RBBB). After a complete diagnostic evaluation, a diagnosis of Brugada syndrome is made. He is prescribed a class I antiarrhythmic drug, which is a sodium channel blocker that slows phase 0 depolarization in ventricular muscle fibers. The drug also blocks potassium channel and prolongs action potential duration, but it does not shorten phase 3 repolarization. It also has mild anticholinergic and alpha-blocking activity. If taken in high doses, which of the following are the most likely side effects of the drug?

A 53-year-old man presents to the physician with a history of repeated episodes of joint pain and fever for the last three months. The joints involved are knee joints on both sides and small joints of both hands. He recorded his temperature at home and says that it never went above 100F. His vitals are pulse: 88/min, blood pressure: 134/88 mmHg, respiratory rate: 13/min and temperature: 99F. On physical examination, he has mild joint swelling. However, radiological evaluation of the involved joints does not suggest osteoarthritis or rheumatoid arthritis. Past medical history is significant for acute myocardial infarction one year ago, with sustained ventricular tachycardia as a complication. He has been taking procainamide since then as an antiarrhythmic agent. After necessary laboratory evaluation, the physician suspects that his joint pain and fever may be due to the use of procainamide. Which of the following serological findings is most likely to be present in this patient based on the clinical presentation?

A 55-year-old man presents to his physician with the complaint of recurrent episodes of palpitation over the past two weeks. He also mentions that he tends fatigue easily these days. He denies chest pain, breathlessness, dizziness or syncope at the moment but has a history of ischemic heart disease. He smokes a pack of cigarettes every day and drinks occasionally. On physical examination, his temperature is 98.4ºF (38ºC), pulse rate is 124/minute and is irregularly irregular, blood pressure is 142/86 mm Hg, and respiratory rate is 16/minute. Auscultation of his chest is normal with an absence of rales over both lung fields. After an ECG showing fibrillatory waves and irregular RR interval, the physician concludes that his symptoms are due to atrial fibrillation. The patient is prescribed oral diltiazem. Which of the following side-effects should the physician warn the patient about?

A 46-year-old farmer is brought by his neighbor to the emergency department after he accidentally got splashed with a liquid insecticide that was stored in a bucket in the store room. He is coughing violently with severe breathing difficulty and runny nose. He is massaging his thigh muscles saying that the pain is unbearable. He says that his vision is blurry. There is vomit on his sweater. On physical examination, he is pale, his temperature is 98.2 ºF (36.7 ºC), pulse rate is 130/minute, blood pressure is 144/92 mm Hg and respiratory rate is 20/minute. Auscultation of chest reveals bilateral crepitations and rhonchi. He is perspiring and salivating excessively, pinpoint pupils are present. His neighbor informs the doctor that he uses malathion as an insecticide in his farm. After securing the airway atropine and pralidoxime are administered in appropriate doses in addition to supportive treatment. Which of the following signs is most likely to improve with atropine?

A team of researchers is synthesis of a drug that would potentially reduce blood pressure in hypertensive patients by a novel mechanism of action. The drug A is an inactive prodrug and enters hepatocytes, reacts with reactant B, a native material in the cell, and creates products C and D. D has blood pressure lowering effects. The reaction requires presence of enzyme E. The researcher observes that, for the above chemical reaction, ΔG is less than zero in normal hepatocytes whereas in hepatocytes of patients with fatty liver, ΔG is more than zero due to some unknown reason. Based on this knowledge, provided the concentration and actions of reactant B and enzyme E are same in both normal hepatocytes and hepatocytes of fatty liver patients, which of the following is the most likely possibility, if drug A is administered to hypertensive patients with fatty liver?

A drug discovery team is conducting a research to observe characteristics of a novel drug under different experimental conditions. The drug is converted into the inactive metabolites by action of an enzyme E. After multiple experiments, the team concludes that as compared to physiologic pH, affinity of the enzyme E for the drug decreases markedly in acidic pH. Co-administration of an antioxidant A increases value of Michaelis-Menten constant (Km) for the enzyme reaction, while co-administration of a drug B decreases value of Km. If metabolism of the novel drug follows Michaelis-Menten kinetics at the therapeutic dose, in which of the following conditions, metabolism of the drug will be the slowest? Consider that effects of different factors on metabolism of the drug are linearly additive/subtractive and not complex.

While studying metabolism of a novel drug, a researcher identifies molecule which inhibits metabolism of the drug by binding with enzyme E. Molecule A inhibits the enzyme E by binding at the same active site on the enzyme where the drug binds. Which of the following statements best describes effects of the molecule A on Vmax and Km of the enzymatic reaction?

A 28-year-old woman presents to a psychiatrist with a history of unexplained anxiety symptoms for the last ten years. Till date, she has not visited any psychiatrist because she believes that she should not take medicines to change her emotions or thoughts. However, after explaining nature of her disorder, the psychiatrist prescribes daily alprazolam to her. When she comes for her first follow-up, she reports excellent relief from her symptoms without any side-effects. The psychiatrist encourages her to continue her medication for next three months and calls her for a follow-up visit after three months. After three months, she tells her psychiatrist that she has been experiencing excessive sedation and drowsiness over the last few weeks. The psychiatrist finds that she is taking alprazolam in correct dosage and she is not taking any other medication that causes sedation. Upon asking her about any recent changes in her lifestyle, she mentions that for last two months, she has made a diet change. The psychiatrist tells her that the diet change may be the reason why she is experiencing excessive sedation and drowsiness. Which of the following is the most likely diet change the psychiatrist is talking about?

A student studying pharmacology is a member of a team that is conducting a research related to elimination of anticoagulant medications. His duty as a member of the team is to collect serum samples of the subjects every four hours and send them for analysis of serum drug levels. He is also supposed to collect, document and analyze the data. For one of the subjects, he notices that the subject is eliminating 0.5 mg of the drug every 4 hours. Which of the following anticoagulants is most likely consumed by the subject?

A 48-year-old man presents to the emergency department with the complaints of substernal chest pain since one hour. The pain is crushing in nature and radiates to his neck and left arm. He rates the pain as 7/10. He gives a history of similar episodes in the past that resolved with rest. He is a non-smoker and drinks alcohol occasionally. On physical examination, his temperature is 98.6 ºF (37 ºC), the pulse rate is 130/minute and is irregular, the blood pressure is 148/92 mm Hg, and the respiratory rate is 18/minute. The physician immediately orders an electrocardiogram, which suggests an acute Q-wave myocardial infarction (MI). After appropriate emergency management, he is admitted to the medical floor. He develops atrial fibrillation on the second day of admission. He is given a β-adrenergic blocking agent for his arrhythmia. On discharge, he is advised to continue the medication for at least two years. Which of the following β-adrenergic blocking agents was most likely prescribed to this patient?

A 59-year-old man presents to the emergency department with the complaint of palpitations for last 30 minutes. He denies any chest pain, breathlessness, or loss of consciousness. His medical history is negative for hypertension or ischemic heart disease. On physical examination, his temperature is 98.4ºF (38ºC), pulse rate is 146/minute and irregular, blood pressure is 118/80 mm Hg, and the respiratory rate is 15/minute. A 12-lead electrocardiogram reveals an absence of normal P waves and presence of saw tooth appearing waves. The doctor treats him with a single intravenous infusion of ibutilide under continuous electrographic monitoring, which successfully converts the abnormal rhythm to sinus rhythm. Which of the following mechanisms best explains the therapeutic action of this drug in this patient?

A 26-year-old woman presents to a gynecologist as she has missed a period. After performing complete physical examination and screening test for pregnancy, her gynecologist informs her that she is pregnant. She is very surprised as she has been taking oral contraceptives regularly. When the gynecologist asks her about consumption of any other drug, she mentions that she has been put on treatment for pulmonary tuberculosis for the last two months. Her current anti-tubercular regimen includes rifampin, isoniazid, pyrazinamide, and ethambutol. Which of the following mechanisms best explains the failure of oral contraceptives in case of the woman?

A 24-year-old man presents to a physician with history of intermittent fever for the last two days. His episodes of fever are accompanied by rigors and chills. On physical examination, his temperature is 102 °F, pulse rate is 110/minute, blood pressure is 116/80 mm Hg, and respiratory rate is 18/minute. Examination of his abdomen reveals splenomegaly. His blood sample is sent for examination of peripheral smear, which confirms diagnosis of Plasmodium falciparum malaria. He mentions that his father has been recently recovered from chloroquine-resistant P. falciparum malaria, which was treated successfully with quinine. Based on this history, considering possibility of chloroquine resistance, the physician prescribes oral quinine to the patient. After five days, the patient returns with improved symptoms of malaria but with complaints of headache, tinnitus, nausea, and dizziness. The physician confirms if he had taken quinine in correct dosage. Upon asking, he mentions that he had been taking a drug for last three months to control his dyspepsia symptoms. Which of the following drugs is most likely to have caused above mentioned symptoms in the patient?

A 66-year-old man presents to the emergency department due to palpitation, syncope and difficulty breathing. He has a past medical history of stroke and his current medication includes warfarin. The on-duty physician performs a complete physical examination and suspects cardiac arrhythmia. The urgent bedside electrocardiogram suggests ventricular tachycardia. He responds well to amiodarone. At the time of discharge, his medications include warfarin and amiodarone. His physician advises him to monitor his prothrombin time regularly for the next six months. Which of the following mechanisms best explains the basis for this advice?

A 56-year-old man is brought to the emergency department with breathlessness and altered sensorium. His daughter informs the physician that he has been having high fever and cough for last three days. She also mentions that he was discharged from hospital five days before, following a successful coronary artery bypass grafting (CABG). In the post-operative period, he was in an intensive care unit (ICU) for six days, including 12 hours of mechanical ventilation. On physical examination, his temperature is 103° F, pulse rate is 110/minute, blood pressure is 104/78 mm Hg, and respiratory rate is 30/minute. Signs of respiratory distress and cyanosis are present. On chest auscultation, crepitation are present in right lung. He is confused and gives inappropriate verbal responses to painful stimuli. He is immediately started on oxygen therapy, intravenous fluids, and supportive care. After collection of appropriate samples for bacteriological culture, treatment with empirical intravenous antibiotics are started. After 24 hours of treatment, the microbiology results indicate Pseudomonas aeruginosa infection. The physician changes the antibiotics to a combination of aztreonam and tobramycin, as the patient has known hypersensitivity to penicillin antibiotics. Which of the following best describes the rationale behind the combination that was preferred by the physician?

A 66-year-old man was recently admitted to the intensive care unit for management of laboratory-confirmed septic shock. His current management includes appropriate management of airway and breathing, intravenous antibiotics, fluid resuscitation, and supportive care. After the administration of adequate intravenous isotonic fluids, his temperature is 99° F, pulse rate is 120/minute, blood pressure is 90/50 mm Hg, and respiratory rate is 22/minute. His extremities are warm and capillary refill time is normal. The physician starts vasopressor therapy with norepinephrine. A resident physician asks the physician why norepinephrine is preferred over epinephrine as a vasopressor for this patient. Which of the following characteristics of norepinephrine best explains this choice?

A drug research team has synthesized a novel oral drug that acts as an adrenergic agonist at multiple adrenergic receptors. When administered in animals, it has been shown to produce urinary retention at therapeutic doses with the absence of other manifestations of adrenergic stimulation. The researchers are interested in understanding signal transduction and molecular mechanisms behind the action of the novel drug. Which of the following receptors will most likely transduce signals across plasma membrane following administration of the novel drug?

A 77-year-old man with refractory shock has been under treatment in an intensive care unit for last seven days. Despite the best possible management by the team of physicians and intensivists, he fails to show improvement. After discussion with his relatives and obtaining informed consent from them, the team administers to him a novel drug, an adrenergic agonist that produces positive chronotropic effects and inotropic effects, and stimulates the release of renin from the kidneys. The drug does not have any other adrenergic effects. Which of the following second messengers is most likely to be responsible for the actions of the novel drug?

A 7-year-old boy is brought to a pediatrician by his parents. The parents say that the boy accidentally instilled a drop from a bottle of medicated eye drops into his right eye. According to them, the boy’s grandfather uses the eye drops which were prescribed for him by an ophthalmologist. The parents have also brought the eye drops with them. The pediatrician notes that the eye drops contain an α1-adrenergic agonist drug. He examines the boy’s eye and finds that the eye drops have produced their effects. He reassures the parents about the self-limiting effect of the drug and the absence of any risk of long-term complications. Which of the following effects are most likely to have occurred in the child’s eye?

A 58-year-old woman presents to her physician complaining of a headache in the occipital region for one week. She is a known case of essential hypertension and has been taking a combination of two anti-hypertensive drugs for the last six months. She is also following life-style modification measures that help to reduce the blood pressure. The physician performs a complete physical examination and notes that her blood pressure is 150/90 mm Hg. Neurological examination is normal. He tells her that uncontrolled hypertension could lead to headache. He adds an antihypertensive drug that acts as a selective α2-adrenergic receptor agonist. On follow-up, she reports that she does not have any symptom and her blood pressure is 124/82 mm Hg. Which of the following mechanisms best explains the therapeutic effect of the drug which was added by the physician?

A 17-year-old female is rushed into the emergency department by her father who found her collapsed in her bedroom 15 mins before their arrival of the ambulance.There was an empty bottle of clomipramine in her bedroom which her mother takes for her depression. The father says that his daughter recently broke up with her boyfriend and was quite upset. Vitals show respirations: 8/min, pulse: 130/min and blood pressure: 100/60 mmHg. On examination, the patient is unresponsive to vocal and tactical stimulus. Her oral mucosa and tongue are dry and the bladder is palpable. A bedside electrocardiogram (ECG) shows QRS widening. Which of the following would most benefit the patient at this time?

A 58-year-old female presents to the clinic for frequent headaches for the past few months. The pain in her head starts at random and is unrelated to any stimulus. Further inquiry reveals the patient has difficulty falling asleep and has had problems concentrating at work for several months. She reports regreting about her past mistakes feels guilty about having hurt people in her life. While she occasionally thinks about committing suicide, she denies any suicidal plans. Her appetite is diminished. There is no family history of depression or psychiatric illness. Physical exam is unremarkable. Thyroid stimulating hormone (TSH) level is 3.5 uU/mL. The patient is started on amitriptyline and asked to follow-up in two weeks. During her follow-up visit, the patient reports slight improvement in her mood and has no more headaches, but she complains lightheadedness when she rises out of bed in the morning or stands up from her desk at work. Which of the following pharmacological effects of her medication is responsible for her new complaint?

A 38-year-old male presents to his primary care physician for a follow-up visit. Two weeks back, he presented with fatigue and weight loss for four months. He felt tired all the time, which he blamed on waking up early in the morning and being unable to fall back asleep. Although he is a successful web developer with lots of ongoing projects, he no longer feels interested in his work. He lost weight and says," I just don't want to eat". A diagnosis of major depression was made and sertraline started. His past medical history is unremarkable and he takes no other medications. For the last two weeks, he has been compliant with his medications and is now getting a full night's sleep with no early morning awakenings. Since starting the medication, he has had mild nausea but no other complaints. Despite regaining his appetite, he hasn't regained any lost weight and he still feels fatigued. He believes the medication is not working and asks to be started on something else. Which of the following is most appropriate for this patient?

A 75-years-old female presents to the emergency department with sudden onset of weakness and difficulty walking. She also complains of nausea and palpitations. She was working in her garden about an hour ago when her problems started. The patient is feeling warm even though the ER is airconditioned. She was diagnosed with depression 5 years back and, after failing to respond to various antidepressants, was started on venlafaxine to which she responded well. Since then she has had no depressive symptoms. Besides her psychiatric conditions, her medical history is significant for hypertension and osteoporosis. Her current medications are aspirin, lisinopril, alendronate, calcium and vitamin D supplements, and venlafaxine. She is a retired school teacher and recently celebrated 50th marriage anniversary. Her pulse is 110 bpm, respirations are 22/min, and blood pressure is 160/100 mmHg. On examination the patient is irritable but no findings are elicited. A CT scan of the head, electrocardiogram (ECG), and blood tests are all normal. Which of the following most likely accounts for this patient's symptoms?

A 30-year-old male presents to the physician for 'feeling down' and tired on most days for the last 3 years. Over this period, she also had difficulty concentrating and has been sleeping excessively. She denies any manic or hypomanic symptoms. She also denies any suicidal ideation or preoccupation with death. A physical examination is unremarkable and labs show: Serum Glucose (fasting): 88 mg/dL; Serum Electrolytes: Sodium: 42 mEq/L Potassium: 3.9 mEq/L Chloride: 101 mEq/L; Serum Creatinine: 0.8 mg/dl; Blood Urea Nitrogen: 10 mg/dl; Hemoglobin (Hb %): 15 g/dL; Mean Corpuscular Volume (MCV): 85 fl; Reticulocyte count: 1 %; Erythrocyte count: 5.1 million/mm^3; Thyroid Stimulating Hormone: 3.5 μU/mL. The physician decides to prescribe a medication that increases norepinephrine nerve stimulation. The patient comes back 2 weeks later complaining of dizziness, dry mouth, and constipation. Which of the following was most likely prescribed to this patient?

A 50-year-old female presents to the emergency department accompanied by her husband for a severe headache and vomiting after attending a wine tasting at the local brewery. She tells you that her headache is mostly at the back of her head. Her husband adds that she vomited twice today. She is complaining of nausea. Her past medical history is significant for depression diagnosed 20 years but is now well-controlled with medication. She also has significant vitamin D deficiency. Currently, she takes phenelzine and a vitamin D supplement. She is a non-smoker and denies the use of recreational drugs. Her pupils are dilated and she is sweating profusely in the ER which is air conditioned. Which of the following is most likely to be raised?

A 22-year-old female comes to her physician with complaints of low energy levels for six months. She feels as if she has no energy to do anything and has lost interest in photography which she was previously passionate about. Feelings of hopelessness occupy her mind and she can no longer focus at work as an architect. She forces herself to hang out with her friends on the weekend but says that she would rather just stay home. She denies any suicidal ideation. Her past medical history shows she was treated with Cognitive Behavioral Therapy (CBT) for bulimia nervosa in her teens but she no longer is concerned about her weight. She also has gastroesophageal reflux which is being treated with esomeprazole. A few weeks back she decided to quit smoking and succeeded in cutting down the number of cigarettes smoked per day. She does not drink alcohol or use recreational drugs. Her Body Mass Index (BMI) is 24 kg/m^2 and the physical examination is unremarkable. Which aspect of this patient's presentation is a contraindication to using bupropion as an antidepressant?

A 32-year-old male presents to the physician with difficulty sleeping and "feeling low" for the past three months. He has difficulty falling asleep and frequently wakes up early in the morning for no apparent reason. Although he denies any suicidal thoughts, he admits he to occasional feeling of hopelessness and loss of concentration at work. For the last 2 months, he has made excuses to avoid meeting his friends for their regular poker game on Thursdays. He got married a year ago and plans on having a child next year. His past medical history reveals nothing significant. He currently takes a daily multivitamin. Physical examination is unremarkable and laboratory studies, including Thyroid Stimulating Hormone (TSH), are within normal limits. Which of the following drugs will be the most appropriate for this patient?

A 20-year-old female presents to the physician with the complaint of persistent sadness for the last 2 months. She says she is always feeling tired and nothing seems to cheer her up. Previously a top student at her college, she did not register for classes this term because she does not feel like going to school anymore. Her friends complain that she does not want to 'hang out' with them anymore. She is sleeping more than usual and often does not want to leave the bed in morning. No suicidal ideation or preoccupation with death is reported. Concerned about her weight, she has maintained a calorie restricted diet for the last several years but admits to a junk food binge every once in a while. Her past medical history is unremarkable. She currently takes a daily multivitamin. Her pulse is 64 bpm, respirations are 12/min, blood pressure is 110/70 mmHg, and temperature is 36.9°C (98.5°F). Examination reveals a pale young female with a dry oral cavity and multiple dental caries. Her Body Mass Index (BMI) is 17.5 kg/m^2. She has some calluses on the knuckles of her left hand. Which of the following medications is most likely to benefit this patient?

A 40-year-old woman presents to the physician's clinic with difficulty falling asleep and tiredness for past 6 weeks. Despite going to bed early at night she is unable to fall asleep. She denies feeling anxious or having disturbing thoughts while in bed. Even when she manages to fall asleep, she wakes up early in the morning and is unable to fall back asleep. She was forced to find a new job several months back due to her employer going bankrupt and has had difficulty adjusting to her new position. She has grown increasingly irritable and feels hopeless more and more. Her concentration and interest at work have diminished. She denies thoughts of suicide or death. Because of her diminished appetite, she has lost 4 kg (8.8 lbs) in the last few weeks and has started drinking a glass of wine every night instead of eating dinner. She has no significant past medical history and takes no medications at the moment. Which of the following is the best medication for her?

A 57-year-old female presents to the physician's clinic complaining of feeling sleepy all the time. She reports having an uncontrollable urge to take multiple naps during the day and sometimes sees strange shadows in front of her before falling asleep. Although she awakens feeling refreshed and energized, she often finds herself 'stuck' and cannot move for a while after waking up. She is overweight and has failed to lose weight despite multiple attempts of diet control and exercise programs. She denies smoking, alcohol consumption, and recreational drug usage. Family history reveals that both her parents were overweight and her father was hypertensive. She is a former school teacher and lives with her husband. Her vitals are pulse: 84 /min, respirations: 16/min, and blood pressure: 128/84 mmHg. Examination reveals an obese lady with a Body Mass Index (BMI) of 36 kg/m^2 with remaining of the examination unremarkable. Which of the following should be prescribed for this patient's condition?

A 26-year-old female presents to the physician's clinic due to increased anxiety for the last couple of weeks despite taking her medication. She previously presented one month back with an 8-month history of insomnia and feeling of impending doom due to her precarious financial situation. At that time, she was started on an anxiolytic medication and advised to follow-up after 8 weeks. She came a couple of weeks early for her follow-up appointment as she ran out of her anti-anxiety medication. Due to ever increasing anxiety levels she started taking, of her own accord, extra doses of her medication to achieve a similar anxiolytic effect. Which medication was she most likely prescribed?

An 11-year-old male is brought to the clinic by his parents for poor academic performance. His teacher told the parents that their kid may have to repeat a grade due to his lack of progress. The child has no known learning disabilities and has had good grades in the past but now, his teacher says, the boy does not pay attention to the lessons, tends to fidget about in his seat, and often blurts out comments when it is someone else's turn to speak. Furthermore, his after school karate coach says the boy no longer listens to instructions and has a hard time focussing on the activity at hand. The parents are vehemently opposed to using any medication with the potential for addiction. Which of the following is the most suitable medication for treating this child?