Carbamazepine

Antidepressant and Antimanic Medications: Carbamazepine

Carbamazepine is an anticonvulsant drug structurally related to the TCAs. As with the TCAs, its absorption and metabolism are variable. Carbamazepine is rapidly absorbed, with peak plasma levels occurring within 4-6 hours. Eighty percent of plasma carbamazepine is protein-bound, and its half-life ranges from 13 to 17 hours. Carbamazepine is metabolized by the hepatic CYP2D6 system. It induces the CYP enzymes, causing an increase in the rate of its own metabolism over time as well as that of other drugs metabolized by the CYP system. This often results in having to raise the total dose within 2-4 months of treatment initiation.

Concomitant administration of carbamazepine with oral contraceptives, warfarin, theophylline, doxycycline, haloperidol, TCAs, or valproic acid leads to decreased plasma levels of these other drugs. Concomitant administration of drugs that inhibit the CYP system will increase plasma levels of carbamazepine. These drugs include fluoxetine, cimetidine, erythromycin, isoniazid, and calcium channel blockers and propoxyphene. Concomitant administration of phenobarbital, phenytoin, and primidone causes a decrease in carbamazepine levels through induction of the CYP enzymes.

Antidepressant and Antimanic Medications Introduction Diagnostic Indications and Contraindications

• Indications for Use of Antidepressant and Antimanic Medications
• Contraindications to Use of Antidepressant and Antimanic Medications
• General Treatment Guidelines Antidepressant Medications: Pharmacological Properties and Evidence for Acute-Phase Efficacy