Common Antimicrobials in the Treatment of Urinary Tract Infection
| Drug | Absorption (bioavailability following oral admin) | Amount excreted unchanged in urine | Dosing in renal impairment |
|---|---|---|---|
| Amoxicillin | 89% | 60% | Oral – high dose amoxicillin reduce dose if eGFR <10 mL/min IV – high dose amoxicillin reduce dose if eGFR <30 mL/min (risk of crystalluria with high doses) |
| Co-amoxiclav | 75% | 60% amoxicillin 40% clavulanic acid | Oral – no dose adjustment required IV – reduce dose if eGFRl <30 mL/min |
| Cefalexin | >90% | >90% | Reduce dose if eGFR <50 mL/min |
| Ciprofloxacin | 70–80% | 40–70% | Oral – reduce dose if eGFR <20 mL/min IV – reduce dose if eGFR <20 mL/min |
| Trimethoprim | >90% | 40–60% | Reduce dose if eGFR <30 mL/min |
| Nitrofurantoin | 94% (lower if administered without food) | 30–40% | Contraindicated if eGFR <45 mL/min |
| Fosfomycin | 40% | >70% | Avoid if eGFR <10 mL/min |
| Gentamicin | N/A | 95% | Reduce dose if eGFR <20 mL/min |
| Amikacin | N/A | 95% | Reduce dose if eGFR <20 mL/min |