ANTIMICROBIALS Flashcards
The AE of which drug can be largely prevented by administration of histamines and a slow infusion rate?
Vancomycin (red man syndrome)
Which tetracycline is rarely used as an antibiotic but instead to act as a diuretic in SIADH?
Demeclocycline
What is the mechanism of resistance to tetracyclines?
Decreased uptake by cells or increased efflux by PLASMID ENCODED GENES
What autoantibodies may be found in the serum of a person on isoniazid?
Antihistone; it causes a lupus like syndrome
Which enzyme activates isoniazid to the active form?
Mycobacterial Catalase Peroxidase (KatG)
Which antifungal binds ergosterol but is only available topically? Which is used systemically?
Nystatin; Ergosterol
What is the mechanism of resistance to acyclovir?
mutation of viral thymidine kinase
The uptake of which type of antibiotics is inhibited by divalent cations?
Tetracyclines
Which drugs inhibit 50 S and prevent translocation?
Macrolides
Which type of antibiotics is aztreonam synergistic with?
aminoglycosides
What is nifurtimox used to Tx?
Trypanosoma cruzi
Which aminopenicillin has the greatest oral bioavailability?
amOxicillin (greater Oral) than ampicillin
Which carbapenem does not require coadministration of cilastatin? What does this mean?
Meropenem, it is not degraded in kidneys by dehydropeptidase I
MOA of oseltamivir
neuraminidase inhibitor that decreases release of influenza A and B viral progeny
What 2 types of HSV infections can you use acyclovir for? What is the benefit of valacyclovir?
mucocutaneous (i.e. genitals and cold sores) and encephalitis; better oral bioavailability
What do you use to treat NADPH oxidase deficiency?
IFN gamma
MOA of trimethoprim
Inhibits dihydrofolate reductase
How do you prevent postsurgical infection due to S. aureus?
Cefazolin
What can be treated with IFN alpha? (3)
HBV, HCV, and Kaposi
What cephalosporin is used prior to surgery to prevent S. aureus skin infections?
cefazolin
Why do you avoid chloramphenicol in pregnancy?
Gray Baby syndrome, baby has low levels of UDP glucuronyl transferase
MOA of foscarnet
Pyrophosphate analog that inhibits CMV viral DNA polymerase
Which drugs inhibit fungal cell wall synthesis by inhibiting B-glucan?
Caspofungin and Anidulfungin
What is the mechanism of resistance to ganciclovir?
mutated CMV DNA polymerase or viral kinase
In which circumstance could you use foscarnet in a ganciclovir resistant strain of CMV?
If the resistance is from lack of viral kinase. Foscarnet does not require viral kinase, however, if the resistance is from viral DNA pol then neither will work
What highly virulent bug is covered by ceftaroline?
MRSA
This antibiotic blocks peptidyltransferase at the 50S subunit
Chloramphenicol
What is pyrimethamine used to treat?
Toxoplasmosis
What is sodium stibogluconate used to Tx?
Leishmaniasis
What is the mechanism of resistance to penicillins?
Beta Lactamase
Why do you avoid fluoroquinolones in pregnancy?
Cartilage damage
Why do you avoid ribavirin in pregnancy?
Teratogenic
Which TB drug may cause optic neuropathy?
Ethambutol
MOA of zanamavir
neuraminidase inhibitor that decreases release of influenza A and B viral progeny
Which drugs are given as prophylaxis for A) Mycobacterium tuberculosis B) MAC and C) M. leprae?
A) Isoniazid B) Azithromycin (when CD4
What is Terbinafine? Terbutaline?
Terbinafine is an antifungal that inhibits squalene epoxidase and is used to Tx dermatophytes; Terbutaline is a B2 agonist used to relax the uterus
Which generation of cephalosporins covers gram positive bacteria and Proteus, E. coli, Klebsiella, Haemophilus, Enterobacter, and Neisseria?
Second Generation (HEN PEcK)
What inhibits the uptake of tetracyclines?
Divalent cations: milk, antacids, or iron
What is triple therapy for H pylori?
Metronidazole, Clarithromycin and PPI’s
Which 2 antifungals affect cell wall synthesis?
Caspofungin and Anidulfungin
Which antiviral inhibits IMP dehydrogenase?
Ribavirin
How can you reverse the bone marrow suppression caused by NRTI’s?
G-CSF and EPO
What kind of drugs are nevirapine, delavirdine, and efavirenz?
NNRTI’s
How do you prophylax against gonorrhea?
Ceftriaxone
What 7 bugs are covered by aminopenicillins that are not by penicillins?
Haemophilus influenzae b, E. coli, Listeria, Proteus, Salmonella, Shigella, and Enterococci (HELPSS kill enterococci)
How do you treat tuberculous leprosy?
Dapsone and Rifampin
What are 3 AE of ampicillin?
Hypersensitivity, Ampicillin rash if underlying mono, and pseudomembranous colitis
How do you prophylax against meningitis?
Ciprofloxacin = adults; Rifampin = kids
What is the MOA of raltegravir?
inhibits HIV integrase
What makes nafcillin, oxacillin, and dicloxacillin resistant to beta lactamases?
They have a bulky R group which sterically hinders them
MOA of metronidazole?
disulfiram like reaction, headache, and metallic taste
This TB drug blocks arabinosyltransferase and decreases carbohydrate polymerization of the cell wall
Ethambutol
Major AE of rifampin
orange body fluids and hepatoxicity (induce CYP450)
Which drug is used against cryptococcus and is converted to 5-FU by cytosine deaminase?
Flucytosine
What are the AE of penicillins (2)?
Hypersensitivity reactions and Hemolytic anemia
Aminoglycosides and tetracyclines both act on _____ S
30 S
What drug is used to treat Giardia in A) Non pregnant and B) Pregnant
A) metronidazole B) Paramomycin
Which antibiotic inhibits dihydrofolate reductase? Which drug also does this as an antineoplastic?
Trimethoprim; Methotrexate
Which antifungals inhibit nucleic acid synthesis?
5-Flucytosine
This tetracycline is excreted fecally rather than renally
Doxycycline
What is the antiviral that inhibits IMP dehydrogenase indicated for (2)?
This is ribavirin (Chronic Hepatitis C and RSV)
What molecule is truly a “quinolone”?
nalidixic acid –all others are FLUOROquinolones
Which 30S inhibitors are bacteriostatic and bactericidal?
Bactericidal = aminoglycoside; Bacteriostatic = tetracyclines
Which electrolytes need to be supplemented when on amphotericin B?
K and Mg
What is the difference between acyclovir and ganciclovir?
Not much really, both are guanosine analogs that are monophosphorylated by a viral kinase HOWEVER, ganciclovir is more effective against CMV and acyclovir is more effective against HSV
Name the 3 NNRTI’s
Nevirapine, Efavirenz, and Delavirdine
Which cephalosporin covers MRSA?
Ceftaroline
What other disorders can hydroxychloroquine be used for aside from malaria?
Rheumatologic disorders
What is special about tenofovir when compared to other NRTI’s?
Does not have to be activated
What may relieve the bone marrow issues of trimethoprim?
Leucovorin = same as rescue for methotrexate (folinic acid)
MOA of nystatin
Binds ergosterol to form membrane pores in fungi; unlike amphotericin B, only available topically because too toxic
How do you prophylax against syphilis?
Benzathine penicillin G
What determines the half life of isoniazid?
whether the person is a fast or slow acetylator
Which generation of cephalosporins covers gram positive bacteria and Proteus, E. coli, and Klebsiella?
First Generation (PEcK)
What is the MOA of aztreonam?
Monobactam that prevents peptidoglycan crosslinking by binding to PBP3
What must you co-administer with cidofovir?
It is nephrotoxic so it should be given probenicid and IV saline to decrease toxicity
What bugs are covered by first generation cephalosporins?
Gram positives and Proteus, E. coli, and Klebsiella (PeCK)
Which 3rd generation cephalosporin is used against Pseudomonas?
Ceftazidime
How do you prophylax against strep pharyngitis in a kid with Hx of rheumatic fever?
oral penicillin
What is the MOA of griseofulvin?
Interferes with fungal microtubules and disrupts mitosis
How do you prophylax against gonococcal and chlamydial conjunctivitis in a newborn?
Erythromycin ointment
What are the 2 most serious side effects of amphotericin
Nephrotoxicity and Arryhthmias (and the arrhythmias are ultimately due to the nephrotoxicity)
What is the mechanism of resistance to macrolides
methylation of the 23S rRNA binding site
Which type of bugs can vancomycin be used against?
GRAM POSITIVE ONLY
This TB drug blocks the synthesis of mycolic acid
Isoniazid
This TB drug blocks DNA dependent RNA polymerase
Rifampin
What drug inhibits HIV integrase
Raltegravir
Which antifungal drug interferes with microtubule function and may be carcinogenic?
Griseofulvin
MOA of ergosterol
Binds ergosterol to form membrane pores in fungi
Describe the full MOA of acyclovir
Gets into cells and is monophosporylated by viral thymidine kinase to the active form. This then functions as a guanosine analog and causes CHAIN TERMINATION (no 3’ OH)
Which type of beta-lactam have seizures as an AE?
Carbapenems
What bugs are covered by second generation cephalosporins?
Gram positives, Haemophilus, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella (HEN PEcK)