Antimicrobial Anticonvulsant Antimicrobial Effect Anticonvulsant Effect
Itraconazole Carbamazepine None ↓ level
Phenytoin ↓ level ↑ level
Fluconazole Phenytoin ↓ level ↑ level
Ketoconazole Phenytoin ↓ level ↑ level
Chloramphenicol Phenytoin None ↑ toxicity
Clindamycin Diazepam None ↑ effect
Doxycycline Phenobarbital ↓ absorption,
↓ serum terminal half-life
↑ level
Ciprofloxacin Phenytoin None ↑ or ↓
Isoniazid Carbamazepine None ↑ level
Phenytoin None ↑ level
Erythromycin Carbamazepine None ↑ level, toxicity
Phenytoin None ↑ level
Valproate None ↑ level
Clarithromycin Carbamazepine None ↑ level, toxicity
Phenytoin None ↑ level
Valproate None ↑ level
Mefloquine Valproate None ↓ level
Metronidazole Phenobarbital ↓ level  
Phenytoin ↓ level
Pentamidine Valproate ↑ risk of pancreatitis None
Nelfinavir Carbamazepine ↓ level ↑ level
Clonazepam ↓ level ↑ level
Phenobarbital ↓ level ↑ level
Phenytoin ↓ level ↑ level
Ritonavir Carbamazepine ↓ level ↑ level
Clonazepam ↓ level ↑ level
Phenobarbital ↓ level ↑ level
Phenytoin ↓ level ↑ level
Saquinavir Carbamazepine ↓ level ↑ level
Clonazepam ↓ level ↑ level
Phenobarbital ↓ level ↑ level
Phenytoin ↓ level ↑ level
Rifamycins Phenytoin None ↓ level
Sulfonamides Phenytoin None ↑ level
Sulfamethoxazole-
trimethoprim
Phenytoin None ↑ level
Zalcitabine (ddC) Valproate ↑ risk of pancreatitis None

= decreased; = increased

Data from P Hantson, F Leonard, JM Maloteaux, P Mahieu. How epileptogenic are the recent antibiotics? Acta Clin Belg 1999; 54: 80-87; DN Gilbert, RC Moellering, MA Sande. Guide to Antimicrobial Therapy. Hyde Park, VT: Antimicrobial Therepy, 2000; 129-133.

Authored By: 
P Hantson
F Leonard
JM Maloteaux
P Mahieu
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