PHENYTOIN AND RIMONABANT

The manufacturers predict that potent inducers of CYP3A4 such as phenytoin (and therefore possibly fosphenytoin) may lower the serum levels of rimonabant. This is based on the fact that potent inhibitors of CYP3A4 increase rimonabant levels (see under azoles).
Caution is recommended with concurrent use of phenytoin. Patients should be monitored to ensure rimonabant remains effective.