MajorAntiepileptics. Carboxamide derivatives×Tetracyclines
Updated · Methodology
Mechanism
Carbamazepine induces CYP3A4 and accelerates hepatic doxycycline metabolism. Doxycycline half-life shortens from 16 to 7 hours; plasma levels fall.
Symptoms
The patient feels nothing. Risk of subtherapeutic antimicrobial concentrations and treatment failure rises – particularly with pathogens at the susceptibility breakpoint.
Management
Increase doxycycline to 200 mg twice daily during the course (instead of standard 100 mg twice daily). Alternative antibiotics without induction-driven loss: a cephalosporin, amoxicillin, azithromycin. Alternative anticonvulsants without induction: levetiracetam, lamotrigine.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Doxycycline hyclate tablet (Alembic Pharmaceuticals Inc.) – Prescribing Information (2008)– ; DailyMed setid cff08863-7156-49d0-abbd-8f9274302886
- AEMPS: Ficha técnica: Carbamazepina (nº registro 62621), sección 4.5 (2025)– AEMPS, CIMA, nº registro 62621, sección 4.5
- AEMPS: Ficha técnica: Doxiciclina (nº registro 47077), sección 4.5 (2025)– AEMPS, CIMA, nº registro 47077, revisión 12/2025, sección 4.5