Okay, this is chapter four immune, sulfonamides, fluoroquinolones and metronidazole.
The four drugs we're going to use are the first combination drug sulfamethoxazole-trimethoprim,
abbreviated SMZ/TMP, and we'll use that abbreviation throughout. Brand, Bactrim DS and Septra.
These are folic acid inhibitors, and
the bottom line is that the bacteria needs to make its own folic acid,
so if we stop that ability then we can continue to take in folic acid from food, but the bacteria can't.
The fluoroquinolones ciprofloxacin and levofloxacin,
brand Cipro and Levaquin, respectively, and then the nitroimidazoles, which is metronidazole.
It's not really an antibiotic. It's an anti-protozoal, but we don't need to split hairs.
Practice question one. When I see the drug classes and the drugs themselves, I start thinking
immediately about some side-effects and
things like that, but let's start with our first question.
'Which drug classes commonly treat a urinary tract infection? Select all that apply'
When I think of sulfa drug in the folic acid inhibitor trimethoprim, I immediately think
Stevens-Johnson syndrome with the sulfa drug, or
drinking a lot of water to make sure you don't get crystalluria, or
bilirubin in the brain in
young
infants. With the trimethoprim, I think of
hyperkalemia,
struggles to get renal excretion of the potassium.
Those are the four that I think of when we're talking about side effects with those drugs.
The fluoroquinolones, first thing I think with Cipro is that you have to take it to twice a day
versus Levaquin, which you take once a day, but with both I immediately think of chelation,
that binding that I talked about the tetracyclines where you have aluminum or magnesium or calcium
and
you have these divalent
cations where we've got a couple of pluses and they bind to the
drug itself making it inert.
I think of photosensitivity, so being out in the sun and burning very easily, and then I think of Achilles tendon
rupture,
which is a very graphic thing to think of, but this tendon tissue has actually
caused the FDA to make a change
and I'll go over that a little bit later. The nitroimidazole, and I said antibiotics and antiprotozoal, but
peptic ulcer disease,
usually in quad therapy,
treatment for Clostridium difficile, and then that
disulfiram effect where somebody takes in metronidazole and then
alcohol at the same time, they're going to possibly have severe nausea and vomiting to the point of projectile vomiting, something like that.
Here are the answers:
the common drug classes for UTIs are the sulfa/
folic acid inhibitor combination and then the fluoroquinolones, but let's go to that FDA
notice.
I've just highlighted the key points that
fluoroquinolones
should be reserved when you have an uncomplicated urinary tract infection because of serious side effects and they outweigh the benefits.
Basically saying that for a long time the Cipro and levo would have been
pretty readily dispensed for a urinary tract infection.
Now I think prescribers are going to be quite a bit more cautious with this FDA
mandate that's gone out.
Here are the drug names so what drug classes
or what drugs commonly treat a urinary tract infection? SMZ/TMP, the sulfamethoxazole
trimethoprim
the ciprofloxacin, and then the levofloxacin.
Now we're going to be
under this new FDA guideline, we're really thinking, okay,
that's going to change from the uncomplicated UTI to
something that might be complicated where there's maybe kidney involvement or something like that.
Practice question 3, make B) correct: 'Which medication might cause achilles tendon rupture or, and what I've done here
is that test makers can ask
the same exact question and just replace photosensitivity or chelation
for this question, so 'What medication might cause achilles tendon rupture or
Photosensitivity or chelation as an adverse effect?' and in this case you would say ciprofloxacin and levofloxacin.
I have seen before that
sulfamethoxazole
can also cause a bit of further sensitivity, but I've also seen articles to the contrary,
so I'm not going to say sulfa drugs for right now.
Question 4, makes C) correct: 'Which medication is once daily dosing?' The sulfa drugs you'll probably use twice a day,
Cipro twice a day, levofloxacin is the one that's once daily dosing which really makes a difference when you're a patient
And you know you're busy. So, like a Z-Pack, you only have to take one a day. Metronidazole,
this one's actually every six hours so quite often to take something like this.
'Which medication is a drug of choice for C-Diff?'
Metronidazole, definitely. Vancomycin, metronidazole, as soon as you hear C. Diff those are the two you want to really think about.
'Which medication would be a preferred treatment for peptic ulcer disease - select all that apply?'
It's a little bit tricky. A
fluoroquinolone, sure, would work for peptic ulcer disease, but you want to think okay, well levofloxacin, it's
only taken once a day that's better than having to take something twice a day,
so if given the choice and a preferred treatment, I would prefer levofloxacin over ciprofloxacin. Then metronidazole again,
often added as a fourth in quad therapy for peptic ulcer disease.
'Which medication can cause the disulfiram like reaction when a patient takes with alcohol?' Disulfiram itself
is something that patients who are alcoholics who are are trying to get off of alcohol would take so that
If they did drink the alcohol, it make them really sick, and they would hopefully remember that experience and not do it again.
Obviously the patient can stop taking it. It's kind of similar I guess to
putting
that lacquer on someone's nails when you don't want them to bite their nails
and it just tastes so bad and then you start to remember 'Oh, I shouldn't be doing that'.
What happens with metronidazole is that if you take that with alcohol and -
Really? Why is anyone taking an antibiotic with alcohol,
you suppress the immune system a little bit,
so this is just one of those unusual oddball unique side effects that a lot of the test makers like to test on.