FDA approves new drug for schizophrenia

January 22, 2007

The Food & Drug Administration recently approved paliperidone (Invega, Janssen, L.P.), an atypical antipsychotic, for the treatment of schizophrenia, a disease that affects more than two million Americans. It is the first new treatment for schizophrenia to be approved since 2003.

The drug is a once-daily extended-release (ER) system designed to deliver paliperidone, the active metabolite of risperidone, through the OROS osmotic drug technology. The delivery system consists of an osmotically active trilayer core surrounded by a subcoat and semipermeable membrane that controls the rate at which water enters the tablet core, which in turn determines the rate of drug delivery. "The ER system allows for less peak-to-trough variability, and, from a clinical aspect, less variable levels mean more stable patients," stated Kristin Murphy, Pharm.D., CCP, a consultant pharmacist at a developmental center in New Jersey.

"Paliperidone could be a second- or third-line agent for most patients; however, it does have potential advantages for some patients such as those with liver disease or hepatitis C," stated Ryan Carnahan, Pharm.D., M.S., BCPP, assistant professor, University of Oklahoma College of Pharmacy, and director of PACT Research at the university's College of Medicine. "Paliperidone may also be especially good for slow metabolizers due to the lack of clinically significant CYP450 inhibition or induction." Paliperidone is not expected to cause clinically important pharmacokinetic interactions with drugs metabolized by cytochrome P450 (CYP450), and there is no dose adjustment needed in patients with mild to moderate hepatic impairment.

The recommended dose of paliperidone is 6 mg once daily, administered in the morning without regard to food. That's "especially important for psychotropics because compliance is a major issue in psychiatric patients," said Murphy. "In trials, paliperidone was taken without regard to meals. However, as pharmacists, we must keep in mind that exposure to paliperidone increases with food. So, it is important to remind patients to be consistent in the administration."

The manufacturer recommends a dose adjustment for patients with mild to moderate renal impairment. The maximum recommended dose for patients with a creatinine clearance (CrCl) ≥50 to <80 ml/min is 6 mg once daily, and patients with a CrCl 10 to <50 ml/min, the maximum recommended dose is 3 mg once daily.

Paliperidone will be available this month in unit-dose packs of 100 and bottles of 30 or 350 extended-release tablets.

TIPS TO REMEMBER Invega

THE AUTHOR is a writer based in New Jersey.