Drugs of LUTI and STI Flashcards
What is the MOA of trimethoprim-sulfamethoxazole (Bactrim)?
The two compounds in this drugs inhibit sequential steps in folate synthesis, preventing the use of PABA.
Sulfamethoxazole - inhibits dihydropterate synthase
Trimethoprim - inhibits dihydrofolate reductase
Describe ADRs and CIs of bactrim.
ADR - rash, HA, depression, stevens-johnson syndrome, and photosensitivity
CI - can increase the effects/concentrations of warfarin, digoxin, and phenytoin
Describe the MOA, ADRs, and CIs for nitrofurantoin.
MOA - metabolic reduction forms reactive intermediates which damage DNA; bacteria reduce more rapidly
ADR - Macrocrystalline prep. better tolerated; course shouldn’t be longer than 14 days; repeated courses interrupted by rest periods
CI - pregnant women and impaired renal function
Describe the MOA, ADRs, and CIs for methenamine.
MOA - decomposes to formaldehyde in water; assisted by acidification (i.e. stomach and urinary bladder)
ADR - rash, hematuria, painful/frequent micturition, low systemic toxicity
CI - hepatoinsufficiency due to ammonia formation from gastric decomposition
Describe the MOA and ADRs of fosfomycin?
MOA - inhibits pyruvyl transferase and, therefore, cell wall synthesis, specifically the formation of reduced NAMs.
ADR - abdominal pain, headache, diarrhea, nausea
Describe fluoroquinolones with respect to prototypes, MOA, and ADRs.
Prototypes - ciprofloxacin and levofloxacin
MOA - inhibits DNA gyrase and topoisomerase IV
ADRs - Rash, CNS/GI disturbances, tendon rupture, and photosensitivity
Describe the MOA of beta-lactams. What are the adverse effects of penicillin-G? What is ampicillin the DOC for? What are the ADRs of ceftriaxone?
PBPs remove a D-ala from the D-ala-D-ala of peptidoglycans in the process of cross-linking. Beta-lactams covalently bind PBPs leading to cell autolysis.
Penicillin-G - allergic reactions, nephrotoxicity, and jarisch-herxheimer phenomenon
Ampicillin - DOC for susceptible enterococci
Ceftriaxone - cross-reactivity with penicillin, alcohol intolerance, diarrhea
Describe the MOA and ADR of azithromycin
MOA - reversibly binds 50s ribosomal subunit inhibiting transpeptidation of the new peptide from the Acceptor Site
ADR - GI disturbance, Arrythmias, QT prolongation, hepatotoxicity, and increases concentration of digoxin and warfarin
Describe MOA, ADR, and DDI with respect to metronidazole.
MOA - prodrug, which is metabolized to nitro radicals within bacteria which damage DNA
ADR - HA, dry mouth, metallic taste, GI disturbance, CNS disturbances, and disulfiram effect
DDI - induces metabolism of phenobarbital, prednisone, and rifampin; increase aPT in warfarin patients
Define uncompicated, compicated, reccurent, reinfection, and relapse UTIs.
Uncomplicated - Infection with the lack of structural or functional abnormalities. Most likely pre-menopausal women. Doesn’t occur in men, they are complicated by definition.
Compicated - occurs in the presence of a predisposing factor which has altered urinary tract flow
Recurrent - 2 w/i 6 months or 3 w/i a year in non-pregnant women
Reinfection - a different etiologic organism, MC cause of recurrent
Relapse - same etiologic organism
What are the main causes of uncomplicated UTI?
E. Coli and Staph. Saprophyticus
How do you Tx uncomplicated cystitis?
TMP/SMX (bactrim) > nitrofurantoin > fosfomycin > Fluoroquinolones
What are the benefits and CIs for short-course UTI Abx therapy?
Benefits - increased compliance, decreased ADRs/costs/resistance
CI - complicated cystitis, male UTI, and previous infection d/t resistant organism
What is the Tx of N. gonorrhea infection?
IM ceftriaxone
Note: Use azithromycin if penicillin-allergic
What is the Tx of chlamydia?
Azithromycin as a single dose and 7 days of doxycycline
