8.7 Flashcards
Where does Trimethoprim work?
Inhibits Dihydrofolate reductase.
inhibits purine, pyrimidine, & amino acid synthesis
What are the clinical applications of Trimethoprim?
- UTI’s
- Bacterial prostatitis
- Bacterial vaginitis
What are the adverse effects of Trimethoprim?
- Antifolate effects (contraindicated in pregnancy)
* Skin rash, pruritus
What is the drug of choice for PCP
Cotrimoxazole
What are the clinical applications of Cotrimoxazole?
• Uncomplicated UTI’s (drug of choice) • PCP (drug of choice) • Nocardiosis (drug of choice) • Toxoplasmosis (alternative drug) • Respiratory, ear, sinus infections (H.influenzae, M.catarrhalis)
What are the adverse effects of Cotrimoxazole?
- Dermatologic (common)
- GI
- Hematologic (hemolytic anemia)
- AIDS patients = higher incidence
- Contraindicated in pregnancy (esp. 1st trimester)
What does Metronidazole mainly affect?
Activity against anaerobic bacteria (including bacteroides & Clostridium)
(below diaphram)
What is needed for Metronidazole to be effective?
Aerobic conditions bc undergoes reductive bioactivation of nitro group by ferrodoxin.
What are the clinical applications of Metronidazole?
- C.difficile infections (drug of choice)
- Anaerobic or mixed intra-abdominal infections
- Vaginitis (trichomonas & bacterial vaginosis, G.vaginalis)
- Brain abscesses
- H.pylori eradication (in combination)
What are the adverse effects of Metronidazole?
- GI irritation, stomatitis, peripheral neuropathy (prolonged use)
- Headache, dark coloration of urine
- Leukopenia, dizziness, ataxia (rarer)
- Opportunistic fungal infections
- Disulfiram-like effect (avoid alcohol)
- Use generally not advised in 1st trimester
Which drug is a urinary antiseptic?
Nitrofurantoin
What are the adverse effects of Nirofurantoin?
- Anorexia, nausea & vomiting.
* Neuropathies, hemolytic anemia (G6PD deficient patients)
What are the contraindications of Nitrofurantoin?
- Significant renal insufficiency
- Pregnancy at term (38-42 weeks)
- Infants <1 month (risk of hemolytic anemia)
