Kaplan-4 (Anitmicrobials) Flashcards
What is the DOC of treating listeria?
Ampicillin
What is the preferred antimicrobial for treating H.pylori and B. Burgdofery
Amoxocillin
What are the drugs that are B-lactamase resistant?
Nafcillin, Methicillin, oxacillin. They treat Gram(+), staphylococci but not MRSA, there is no B-lactam useful for MRSA
What is the drug that blocks secretion of penicillin, increasing plasma levels and increasing half-life?
Probenecid. (Decreases clearance)
what are the 1st generation Cephalosporins?
Cefazolin, cephalexin
What are the 2nd gen ceph?
Cefotetan, Cefaclor, Cefuroxime
What are 3rd gen ceph?
Ceftriaxone, and cefotaxime. Treats N. Gonorrhea and crosses BBB, hence can be used in the empiric treatment of meningitis.
What do we give patients that are allergic to Penicillin?
For Gram +: Macrolides
For Gram -: Azreonam, aminoglycosides; SMX-TMP, Floxacin
What drugs are indicated for life threatening infections pending cultures results?
Imipenem/Meropenem. Empiric management, same as penicillin ; resistant to beta-lactamases. They have a large spectrum.
What drug must be administered with Imipenem?
What is a major SE of Imipenem?
Cilastatin; because cilastating is a renal dihydropeptidase inhibitor preventing formation of nephrotoxic metabolite.
SE: seizures
What is the MOA of vancomycin?
Binding to D-ala-D-ala on pentapeptide to inhibit transglycosylation, preventing elongation of peptidoglycan chains.
DOC: MRSA, Enterococci, C.Diff (back up)
Altered peptidoglycan structure (D-ALA-D-LAC) confers resistance to what medication?
Vancomycin
What are SE of Vancomycin?
Histamine release: “red-man / red-neck” syndrome.
Ototoxicity
Nephrotoxicity.
What kind of drugs do you treat immunocompromised pts with gram (-) aerobe infections?
Bactericidal drugs, can’t give bacteriostatic. Aminoglycosides cause misreading of the codon, hence why they are bactericidal. (for Step-1, it is the only bacterial protein inhibitor that is bactericidal)
What bacteria are resistant to aminoglycosides?
Anaerobes because aminoglycosides are bactericidal, accumulated intracellularly via ocygen dependent uptake, so anaerobes innately resistant.
What are the Aminoglycosides?
Gentamicin, Amikacin and Streptomycin.
What are the SE of aminoglycosides?
Similar to Vancomycin , nephrotoxicity, otoxicity, but it is different from vanco cause it causes neuromuscular blockade due to decrease Ach release.
(Vanco causes histamine release “Red neck” which is different than aminoglycosides, also vanco is only for Gram (+) bugs)
What is the preferred drug for treating syphillis and back up drug?
Penicillin G
Back up: tetracyclines (Doxycycline and minocycline)
SE of Tetracyclines?
- Tooth enamel dysplasia and possible decrease of bone growth.
- Phototoxicity
- Liver dysfunction during pregnancy
What is the cause of Grey Baby syndrome?
Its cause neonates lack glucuronyl transferase, and chloramphenicol is metabolized via hepatic glucuronidation; Hence we have to decrease dose in liver dysfunction and neonates.
SE: it also causes aplastic anemia.
What can we treat Legionella pneumophila with?
Macrolides: Erythromycin / Azithromycin / Clarithromycin
What class of drugs inhibit dihydropteroate synthetase?
Sulfonamides
What class of drugs inhibit dihydrofolate reductase?
Trimethoprim and Pyrimethamine
What do we use to treat Pneumocystis Jiroveci and Toxoplasmosis gondii?
TMP-SMX
Back-up for Pne. Jiro. : Pentamidine or Atovaquone
What are MOA of sulfasalazine? What does this drug treats?
Sulfasalazine is a prodrug used in Ulcerative colitis and rheumatoid arthritis. This drug is composed of 5-ASA double bonded to sulfa pyridine (SP)
What drug is the most common cause of Steven Johnson syndrome?
Sulfonamides
What drug can cause kernicterus in neonates by displacing bilirubin from albumin?
Sulfonamides, due to high albumin binding.
Sulfonamides SE?
Hypersensitivity (SJS)
Hemolysis in G6PD deficiency
Photosensitivity
Kernicterus in neonates
What is a side effect unique of Trimethoprim or pyrimethamine?
They are sulfonamides and can cause bone marrow suppression.
What is the MOA of flouroquinolones?
Quinolones are bactericidal and interfere with DNA synthesis. Inhibit toposisomerase II (DNA gyrase) and topoisomerase IV (responsible for separation of replicated DNA during cell division)
What are quinolones indicated for?
UTIs
STIs/ PIDs
Diarrhea to : shigella, salmonella, E. coli, Campylobacter.
What drug causes inhibition of chondrogenesis?
Flouroquinolones, which are contraindicated in pregnancy and in children.
Other SE include:
Tendonitis, tendon rupture
Phototoxicity
CNS effect (Insomnia, dizqziness, headache)
What is the regimen for H.Pylori?
Amoxicillin or Metronidazole
Omeprazole Omeprazole
Clarithromycin Clarithromycin
What is the MOA of Metronidazole and what organisms are they indicated for?
Metronidazole are indicated for anaerobes, it is converted to free dradicals by ferredoxin, binds to DNA and other macromalecules, bactericidal.
What drug decreases visual acuity and red-green discrimination?
Ethambutol
What drug produces these combination of SE? Hepatitis, Induction of P450, Red-orange metabolites.
Rifampin, inhibits DNA-dependent RNA polymerase. All body fluids are orange with this drug.
What is the MOA of “Azoles” antifungals?
It inhibits 14-alpha-demethylase prevents lanosterol conversion to ergosterol.
What is the only Azole antifungal that crosses BBB and treat meningeal infections?
Flucanazole, it penetrates CSF, as it is lipid soluble.
What drug inhibits Squalene epoxidase?
Terbinafine, preventing conversion of squalene to squalene epoxide.
Number one drug for treatment of tinea infections.
What lab abnormality will we see in a sub-set of pts taking TMP-SMX?
Leukopenia.
What are the NRTIs?
Zidovudine (AZT): SE: hematotoxicity, peripheral neuropathy.
Didanosine: SE: Pancreatitis, peripheral neuropathy
Lamivudine: used in Hepatitis B. No SE
What is the monophosphate nucleotide anolog (NtrTI)?
Tenofovir.
What are the fusion inhibitor drugs used for HIV?
Enfuvirtide: binds to gp41 and inhibits the fusion HIV-1 to CD-4+ cells.
Maraviroc: blocks the binding of the gp-120 HIV protein to CCR5 on macrophage surface to prevent viral entry.
What is the MOA of Zanamivir and Oseltamivir?
Inhibit neuraminidases of influenza A and B (enzymes that prevent clumping of virions, so that more particles are available for infecting host cells).
What is the DOC for treating Amebiasis , Giardiasis, and Trichomoniaisis?
Metronidazole
What is the prophylaxis for Plasmodial infections (malaria)?
Chloroquine.
P. Vivax and P. Ovale need to be treated with two drugs? Why?
Chloroquine gives us a clinical cure, gets rid of the fever, but once the drug is discontinued the liver form of plasmodium infects us against, hence these pts need to be treated with Primaquine as well.
SE of antimalarials in G6PD deficiency pts.?
Hemolysis. Caused byPimaquine and Quinine / Quinidine (Cinchonism).
A non-antilmalarial drug that can also cause this is sulfonamides
What is the MOA of Oseltamivir / Zanamivir?
Inhibit influenza nuraminidase, decreases release of progeny virus.
Thymidine kinase is a viral enzyme that adds phosphate groups to guanosine anologs, thereby activating the metabollite form of the drug. Which drug is this? what does it inhibit?
Acyclovir, famciclovir, and valacyclovir. Triphosphate formed by cellular enzymes, preferentially inhibits viral DNA pol by chain termination. For HSV / VZV
Ganciclovir has similar MOA but targets CMV
What’s the MOA of NRTIs and what can we give HIV pts to counteract toxicity?
It competitive inhibits nucleotide binding to reverse transcriptase and terminates DNA chain. It causes BM supression which can be reversed with granulocyte colony-stimulating factor (G-CSF) and Erythropoietin)
All need to be phosphorylated to be active
