Antipsychotics are used not only to treat schizophrenia but also bipolar disorder, psychotic depression and other psychiatric disorders. Second-generation antipsychotics, also known as "atypical antipsychotics" are often more effective and cause fewer side effects than older antipsychotics. As noted by psychiatrists Manu Mathews and David J. Muzina, atypical antipsychotics reduce the incidence of disorganized thoughts, and increase the patient's ability to pay attention to what is going on in the outside world.
Weight Gain
Many studies have found weight gain with atypical antipsychotics. In a study of 400 early-psychosis patients taking atypical antipsychotics for one year by Jeffrey P. McAvoy, M.D. and colleagues, 51.1 percent of subjects taking olanzapine gained weight, compared with 41.4 percent of those taking risperidone and 40.3 percent of those taking quetiapine.
Risk for Diabetes
According to the American Diabetes Association, clozapine and olanzapine cause an elevated risk for diabetes. In their analysis of the metabolic effects of atypical antipsychotics, Gabriela Balf, M.D. and colleagues note clozapine and olanzapine frequently cause glucose abnormalities at therapeutic dosages, while quetiapine sometimes causes abnormalities.
Abnormal Cholesterol Levels
Hyperlipidemia--abnormally high cholesterol levels--are found most commonly with clozapine and olanzapine, according to Mathews and Muzina. Balf and colleagues noted frequent abnormal cholesterol levels with clozapine and olanzapine and some abnormalities with quetiapine and ziprasidone.
Menstrual Irregularities
In the study by McAvoy and colleagues, 10 women took olanzapine, 10 took quetiapine and 16 took risperidone. The rate of menstrual difficulties was 47.1 percent among the women taking risperidone; 31.3 percent among the women taking olanzapine; and 23.8 percent among the women taking quetiapine.
Sexual Dysfunction
According to pharmacologists Glen L. Stimmel and Mary A. Gutierrez in their article on sexual dysfunction and psychiatric drugs, risperidone can cause erectile dysfunction and decreased sexual desire. Stimmel and Gutierrez say a lower dosage may resolve the problem or it may be necessary to change to a different antipsychotic. Some men resolve the problem with sildenafil--Viagra. The researchers noted that in one study of 636 patients taking one antipsychotic for at least four weeks, sexual dysfunction was present in 43 percent of subjects taking risperidone, 35 percent taking olanzapine and 18 percent taking quetiapine.
Daytime Drowsiness and Increased Sleep
McAvoy and colleagues found the rate of daytime drowsiness was 57.5 percent for patients taking quetiapine, 53.4 percent for those taking olanzapine and 49.6 percent for those on risperidone. The researchers also found patients slept more hours than normal on all three antipsychotics.
Uncontrollable Movements
Extrapyramidal symptoms is a term psychiatrists use to describe the uncontrollable movements caused by psychiatric drugs . Mathews and Muzina note risperidone may cause significant extrapyramidal symptoms in dosages higher than 6 mg per day. They also note earlier studies indicated aripiprazole caused no extrapyramidal symptoms but newer data reveals this drug can cause akathisia---a disorder characterized by constant rocking, pacing or shifting weight from one foot to the other. Olanzapine also may cause akathisia.
Agranulocytosis
Clozapine was the first atypical antipsychotic introduced in the United States and was described by R. J. Baldessarini and F. Rankenburg in 1991. It was known then that clozapine causes a rare side effect known as agranulocytosis--a dangerously lowered white blood cell count. This side effect occurs in 1 percent of users, according to Mathews and Muzina. As a result, patients must have their blood counts frequently monitored.
References
- Agency for Healthcare Research and Quality: Off-Label Use of Atypical Antipsychotic Drugs. July 2007
- "CNS Spectrums"; Sexual Dysfunction and Psychotropic Medications; Glen L. Stimmel, PharmD, BCPP and Mary A. Gutierrex, PharmD, BCPP; 2006
- "Cleveland Clinic Journal of Medicine"; Atypical Antipsychotics: New Drugs, New Challenges; Manu Mathews, M.D. and David J. Munzina, M.D.; August 2007
- "Diabetes Care"; Consensus Development Conference on Antipsychotic Drugs and Obesity and Diabetes; American Diabetes Association, American Psychiatric Associaton and American Association of Clinical Endocrinologists; 2004
- "New England Journal of Medicine"; Clozapine: A Novel Antipsychotic Agent; R.J. Baldessarini and F.R. Rankenburg; 1991
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