What is the impact of probenecid on tigecycline's dosage?

Probenecid and tigecycline don’t usually “talk” to each other in a way that would require you to change the tigecycline dose.

Why?

| What probenecid does | Tigecycline’s main elimination route | Result |
|----------------------|-------------------------------------|--------|
| Inhibits renal tubular secretion (OAT1/3) and some cytochrome‑P450 enzymes | Tigecycline is largely eliminated by the gut (fecal excretion), with only a small fraction cleared by the kidneys | The inhibition of renal secretion doesn’t markedly alter tigecycline’s overall clearance. |
| Reduces the renal clearance of drugs that are true OAT substrates (e.g., penicillins, cephalosporins) | Tigecycline is not a significant OAT substrate | No appreciable change in plasma levels. |
| Has minimal effect on the CYP3A4‑mediated metabolism that contributes to tigecycline clearance | Tigecycline is metabolized primarily by phase‑II conjugation and not heavily by CYP3A4 | No CYP‑mediated interaction. |

Clinical take‑away

- No dose adjustment of tigecycline is needed when probenecid is given.
- Routine monitoring of efficacy and safety should still be performed, but you can generally keep the standard tigecycline regimen (e.g., 100 mg IV loading dose, 50 mg IV q12 h).
- If you’re using probenecid for gout or other indications, simply continue both drugs at their usual doses.

Bottom line: The impact of probenecid on tigecycline dosage is negligible, so keep the tigecycline dose unchanged.