Monthly Shot Treats Schizophrenia
Injectable Drug Could Make Treatment Plan Easier to Follow
May 6, 2008 (Washington) -- A new, once-a-month shot shows promise for the treatment of schizophrenia.
The new drug is called paliperidone palmitate. It's an injectable form of the second-generation, or "atypical," antipsychotic medication Invega.
A study pitting injectable paliperidone palmitate against placebo was halted early because of its clear benefit in preventing relapses, says David Hough, MD.
Hough is a psychiatrist who led the study while at Johnson & Johnson, which makes paliperidone palmitate and funded the work.
The study involved more than 300 people with schizophrenia whose condition stabilized when they were given injectable paliperidone palmitate for six months. Then, half were randomly assigned to continue the drug and the other half to a placebo.
Over the next year, 40% of those taking placebo relapsed, Hough tells WebMD. In contrast, only 10% to 15% of those given injectable paliperidone palmitate relapsed.
The most common side effects were weight gain and stomach flu.
The findings were presented at the annual meeting of the American Psychiatric Association.
Schizophrenia afflicts about 2.4 million American adults in a given year. Typically beginning in young adulthood, patients suffer hallucinations, delusions, and disordered thinking. There is no cure.
The first generation of antipsychotics, such as Thorazine and Haldol, proved quite effective in reducing the intensity of symptoms. But the drugs had side effects resembling Parkinson's disease: tremor, rigid muscles, and abnormal or restless movements.
More than a decade ago, the second generation of atypical antipsychotic drugs was introduced. They're much less likely to cause Parkinson's-like side effects, although they do carry an increased risk of extreme weight gain and type 2 diabetes.
Most of the second-generation antipsychotics -- such as Clozaril, Risperdal, Zyprexa, Seroquel, Geodon, and Abilify -- come only in pill form.
The only second-generation injectable drug for schizophrenia, Risperdal Consta, has to be given every two weeks.
Compliance an Issue
Because it only requires going to the doctor once a month, injectable paliperidone palmitate may make it more likely a person will comply with his or her treatment plan, doctors say.
"Using an injectable agent ensures the drug gets into the blood. You're not relying on the patient to remember to take a pill every day," Hough says.