Repeated exam questions — memorize these ⭐
Sulfasalazine is poorly absorbed from the GIT.
Crystalluria and kernicterus are associated with sulfonamides.
Sulfonamides can cause kernicterus by displacing bilirubin from albumin.
Trimethoprim inhibits DHFR, NOT DHPS.
Sulfonamides inhibit DHPS, NOT DHFR.
Sulfonamides are structural analogues of PABA, NOT dihydrofolate.
Sulfasalazine is used for ulcerative colitis.
Sulfacetamide is used in ophthalmic bacterial infections.
Silver sulfadiazine is used topically for burn wounds.
Sulfadoxine + pyrimethamine is used for malaria.
Sulfadiazine + pyrimethamine is used for toxoplasmosis.
Co-trimoxazole = TMP + SMX in a 1 : 5 ratio.
Co-trimoxazole produces sequential folate-pathway blockade and is bactericidal.
Sulfonamides can cause hemolytic anemia in G6PD deficiency.
Hydration helps prevent crystalluria; folic acid is not the preventive measure.
Sulfonamides are contraindicated near term and in newborns because of kernicterus risk.
Sulfadoxine is long-acting, with a half-life of 7–9 days.
Sulfonamides potentiate warfarin and increase bleeding risk.
Co-trimoxazole is used for PCP, UTIs and shigellosis.
Sulfonamides alone are generally bacteriostatic; co-trimoxazole is bactericidal through synergy.
Sulfasalazine is poorly absorbed from the GIT.
Crystalluria and kernicterus are associated with sulfonamides.
Sulfonamides can cause kernicterus by displacing bilirubin from albumin.
Trimethoprim inhibits DHFR, NOT DHPS.
Sulfonamides inhibit DHPS, NOT DHFR.
Sulfonamides are structural analogues of PABA, NOT dihydrofolate.
Sulfasalazine is used for ulcerative colitis.
Sulfacetamide is used in ophthalmic bacterial infections.
Silver sulfadiazine is used topically for burn wounds.
Sulfadoxine + pyrimethamine is used for malaria.
Sulfadiazine + pyrimethamine is used for toxoplasmosis.
Co-trimoxazole = TMP + SMX in a 1 : 5 ratio.
Co-trimoxazole produces sequential folate-pathway blockade and is bactericidal.
Sulfonamides can cause hemolytic anemia in G6PD deficiency.
Hydration helps prevent crystalluria; folic acid is not the preventive measure.
Sulfonamides are contraindicated near term and in newborns because of kernicterus risk.
Sulfadoxine is long-acting, with a half-life of 7–9 days.
Sulfonamides potentiate warfarin and increase bleeding risk.
Co-trimoxazole is used for PCP, UTIs and shigellosis.
Sulfonamides alone are generally bacteriostatic; co-trimoxazole is bactericidal through synergy.
❤8
Broad spectrum quick review
Macrolides → 50S; Tetracyclines → 30S.
Clindamycin → pseudomembranous colitis due to C. difficile.
Erythromycin → motilin agonist, GI upset, CYP450 inhibition, highest QT-prolongation tendency.
Erythromycin estolate → cholestatic jaundice.
Clarithromycin → active 14-hydroxy metabolite; H. pylori.
Azithromycin → half-life 3 days, once daily, no CYP450 inhibition.
Telithromycin → may worsen myasthenia gravis.
Fusidate → Staphylococci, including MRSA; good bone penetration..
Doxycycline → DOC for Lyme disease and anthrax prophylaxis.
Demeclocycline → nephrogenic diabetes insipidus; used in SIADH.
Minocycline → vertigo and ataxia.
Expired Tetracycline → Fanconi syndrome.
Tetracyclines → tooth discoloration and suppression of bone growth in developing children/fetus.
Chloramphenicol → 50S peptidyl transferase inhibition.
Chloramphenicol → dose-related bone-marrow suppression + idiosyncratic marrow toxicity.
Chloramphenicol in neonates → gray baby syndrome.
Chloramphenicol resistance → plasmid-encoded acetyltransferase.
Macrolides → 50S; Tetracyclines → 30S.
Clindamycin → pseudomembranous colitis due to C. difficile.
Erythromycin → motilin agonist, GI upset, CYP450 inhibition, highest QT-prolongation tendency.
Erythromycin estolate → cholestatic jaundice.
Clarithromycin → active 14-hydroxy metabolite; H. pylori.
Azithromycin → half-life 3 days, once daily, no CYP450 inhibition.
Telithromycin → may worsen myasthenia gravis.
Fusidate → Staphylococci, including MRSA; good bone penetration..
Doxycycline → DOC for Lyme disease and anthrax prophylaxis.
Demeclocycline → nephrogenic diabetes insipidus; used in SIADH.
Minocycline → vertigo and ataxia.
Expired Tetracycline → Fanconi syndrome.
Tetracyclines → tooth discoloration and suppression of bone growth in developing children/fetus.
Chloramphenicol → 50S peptidyl transferase inhibition.
Chloramphenicol → dose-related bone-marrow suppression + idiosyncratic marrow toxicity.
Chloramphenicol in neonates → gray baby syndrome.
Chloramphenicol resistance → plasmid-encoded acetyltransferase.
❤11