00:00
We have a new class of drugs,
the prototypical drug of which
is griseofulvin.
00:06
Now it is not active topically.
00:09
It actually an orally ingested
agent for skin infections.
00:14
So that's sometimes kind of
confusing to a lot of medical
students.
00:18
It's a skin drug but
it's not used topically.
00:20
It's distributed to
the stratum corneum
where it binds to various proteins.
00:27
It should not be used in
patients with porphyria
because you can actually precipitate a porphyria crisis
with this agent.
00:35
In terms of how it works, it
actually inhibits microtubule
formation in the dermatophytes.
00:41
It's a fungistatic so it's
absorbed into fungal cells
through an active transporter.
00:46
The toxicity of this agent
includes, headache
and GI distress, fever, rash and
flushing from the histamine
release that you sometimes get.
00:55
Now the other thing that's
really important with this agent
is that it will interfere
with warfarin levels.
01:00
So be careful of your warfarin
dosing in your INR's when you
start this medication.
01:07
Terbinafine is available both
in oral and in topical forms.
01:13
Like griseofulvin it is
distributed to the stratum
corneum where it binds
to various proteins.
01:19
It's actually much more
effective then griseofulvin.
01:23
And we see it all the time
used in fungal infections.
01:29
In terms of how it works, it
inhibits squalene epoxidase.
01:35
It accumulates, there's an
accumulation of squalene
and this interferes with
ergosterol synthesis.
01:43
And this is actually
a fungicidal activity.
01:45
Toxicity once again
same as the other ones.
01:48
Headache, GI distress, fever,
rash and flushing
from histamine release.
01:53
And once again this drug also
will interfere with warfarin
dosing and levels.