Chapter 92: Sulfonamides and Trimethoprim Flashcards
Sulfonamides MOA
broad spectrum antibiotics
suppress bacterial growth-inhibiting of folic acid synthesis
disrupts productions of DNA/RNA
Mammalian cells do not manufacture their own folate
Sulfonamides Uses
primary UTI
other uses: nocardiosis, chlamydia trachomatis, conjugation therapy for toxoplasmosis/malaria, ulcerative colitis
Adverse Effects of Sulfonamides
Hypersensitivity reactions
Stevens-Johnsons
Photosensitivity
GI upset
Hematologic effects
Kernicterus
Renal damage - Crystalluria
Phlebitits - dilute IV - PO (full glass of water)
Drug Interactions of Sulfonamides
intensifies warfarin, phenytoin, and oral hypoglycemics
Preparations of Sulfonamides
systemic: based on duration of action
Short acting:for UTIs (sulfisoxazole)
Long acting:UTI (sulfamethoxazole)
Topical: high incidence of hypersensitivity (not used routinely)
MOA of Trimethoprim
inhibits dihydrofolate –> suppresses bacterial synthesis of DNA, RNA, proteins
highly lipid soluble
Use of Trimethoprim
initial therapy of acute, uncomplicated UTIs
Adverse Effects of Trimethoprim
Hyperkalemia (careful with ACEI, ARBs, Spiralactone)
Gastrointestinal (N/V)
Itching, rash
Hematologic effects (in patients with folic acid deficiency)
Not used in pregnancy/lactation (fetal malformations and can interfere with folic acid utilization in infants)
Trimethoprim/sulfaethoxazole (Bactrim and Septra) MOA
inhibits consecutive steps in tetrahydrofolic acid synthesis
combined product inhibits sequential steps in bacterial folic acid synthesis (much more powerful than either TMP or SMZ alone)
Resistance and Broad Spectrum of TMP-SMZ (Bactrim and Septra)
Resistance: less when used together
Broad spectrum: gram positive and negative
TMP-SMZ (Bactrim and Septra) uses
UTI
Pneumocytosis
pneumonia
shigellosis
OM
bronchitis
pertussis
prophylaxsis in immunosuppressed/immunocompromised
