Pharmacology Mnemonics - Flash Cards

Name: Nitrofurantoin (Furadantin)

Class: UTI Agent

Mech.: Unclear. Baceria activate nitrofurantoin more rapidly than do mammalian cells. Bacteriostatic in low conc., cidal in high conc.

Absorption: Rapidly and completely absorbed after oral admin.

Distribution: Antibact. conc. not achieved in plasma. Active in urine.

Metab.:

Excretion, t½:

Toxicity/S.E.s: GI effects, pulm. toxicity (acute pneumoinitis, subacute interstitial pulonary fibrosis), hypersensitivity rxns. chronic hepatitis, neuro efffects. Turns urine brown. Not for preg. women or infants (hemolytic anemia). Not to be mixed w/probenecid.

Utility: Uncomplicated lower UTIs caused by E. coli, Enteroccus, prevention of recurrence of UTIs.

Special Features: Effect enhanced by urine pH£5.5.

Name: Methenamine

Class: UTI Agent

Mech.: Decomposes at pH £5.5 to NH4+ and formaldehyde (bactericidal).

Absorption: Oral very good, but ¯ pH of stomach decomposes lots of the drug. Enteric-coated tablet solves most of problem.

Distribution: Activated 1° in urine.

Metab.: NH4+ production requires fxning liver for excretion. Kidneys only important if methenamine mandelate or hippurate is used.

Excretion, t½: Excreted in urine. NH4+ reduced requires liver for excretion.

Toxicity/S.E.s: GI distress. Long term = rash, hematuria, albuminuria, painful/frequent micturition.

Utility: Chronic suppression of UTIs.

Special Features: No resistance formation. Orgs which raise urine pH inhibit formaldehyde formation ® ¯ sensitivity.