Carbamazepine and Nefazodone interaction

Concomitant use of nefazodone.

This may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect.

Concomitant use of nefazodone ( 4 )

Nefazodone (CYP3A4 Substrate) The use of EQUETRO is contraindicated with the use of nefazodone because the concomitant use may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect of nefazodone.

Known hypersensitivity to tricyclic antidepressants ( 4 )

CONTRAINDICATIONS Coadministration of terfenadine, astemizole, cisapride, pimozide, or carbamazepine with nefazodone hydrochloride is contraindicated (see WARNINGS and PRECAUTIONS ).

Interaction with Carbamazepine The coadministration of carbamazepine 200 mg BID with nefazodone 200 mg BID, at steady state for both drugs, resulted in almost 95% reductions in AUCs for nefazodone and hydroxynefazodone, likely resulting in insufficient plasma nefazodone and hydroxynefazodone concentrations for achieving an antidepressant effect for nefazodone.

Consequently, it is recommended that nefazodone not be used in combination with carbamazepine (see CONTRAINDICATIONS and PRECAUTIONS ).

With coadministration of the two drugs there were significant increases in the steady-state C max and AUC of carbamazepine (23% and 23%, respectively), while the steady-state C max and the AUC of the carbamazepine metabolite, 10,11 epoxycarbamazepine, decreased by 21% and 20%, respectively.

Carbamazepine – The coadministration of nefazodone (200 mg BID) for 5 days to 12 healthy subjects on carbamazepine who had achieved steady state (200 mg BID) was found to be well tolerated.