tindamax and Cerebyx Interactions

Interactions between tindamax(tinidazole) and Cerebyx (fosphenytoin)

fosphenytoin and tinidazole (Moderate Drug-Drug)

MONITOR: Coadministration with a nitroimidazole may increase the serum concentrations of phenytoin. The interaction has been reported with metronidazole, and the proposed mechanism is inhibition of phenytoin metabolism via CYP450 2C9. In one study, metronidazole (250 mg orally three times a day for 4 days) increased the half life of phenytoin (300 mg single intravenous dose) in healthy volunteers by 44% and reduced its clearance by 15% compared to control values. However, another study found no effect of metronidazole (400 mg orally twice a day) on the pharmacokinetics of orally administered phenytoin (300 mg single dose). No data are available for tinidazole.

MANAGEMENT: Pharmacologic response and serum phenytoin levels should be monitored more closely whenever metronidazole is added to or withdrawn from therapy, and the phenytoin (or fosphenytoin) dosage adjusted as necessary. Patients should be advised to notify their physician if they experience potential symptoms of phenytoin toxicity such as nausea, vomiting, nystagmus, slurred speech, lethargy, tremor, ataxia, hyperreflexia, and dysarthria. Given its structural similarities to metronidazole, the same precaution may be applicable during therapy with tinidazole, although clinical data are lacking.