Most side effects of antipsychotic medications are mild. Many common ones lessen or disappear after the first few weeks of treatment. These include drowsiness, rapid heartbeat, and dizziness when changing position.

Some people gain weight while taking medications and need to pay extra attention to diet and exercise to control their weight. Other side effects may include a decrease in sexual ability or interest, problems with menstrual periods, sunburn, or skin rashes. If a side effect occurs, the doctor should be told. He or she may prescribe a different medication, change the dosage or schedule, or prescribe an additional medication to control the side effects.

Just as people vary in their responses to antipsychotic medications, they also vary in how quickly they improve. Some symptoms may diminish in days; others take weeks or months. Many people see substantial improvement by the sixth week of treatment. If there is no improvement, the doctor may try a different type of medication. The doctor cannot tell beforehand which medication will work for a person. Sometimes a person must try several medications before finding one that works.

If a person is feeling better or even completely well, the medication should not be stopped without talking to the doctor. It may be necessary to stay on the medication to continue feeling well. If, after consultation with the doctor, the decision is made to discontinue the medication, it is important to continue to see the doctor while tapering off medication. Many people with bipolar disorder, for instance, require antipsychotic medication only for a limited time during a manic episode until mood-stabilizing medication takes effect. On the other hand, some people may need to take antipsychotic medication for an extended period of time. These people usually have chronic (long-term, continuous) schizophrenic disorders, or have a history of repeated schizophrenic episodes, and are likely to become ill again. Also, in some cases a person who has experienced one or two severe episodes may need medication indefinitely. In these cases, medication may be continued in as low a dosage as possible to maintain control of symptoms. This approach, called maintenance treatment, prevents relapse in many people and removes or reduces symptoms for others.

Multiple medications. Antipsychotic medications can produce unwanted effects when taken with other medications. Therefore, the doctor should be told about all medicines being taken, including over-the-counter medications and vitamin, mineral, and herbal supplements, and the extent of alcohol use. Some antipsychotic medications interfere with antihypertensive medications (taken for high blood pressure), anticonvulsants (taken for epilepsy), and medications used for Parkinson's disease. Other antipsychotics add to the effect of alcohol and other central nervous system depressants such as antihistamines, antidepressants, barbiturates, some sleeping and pain medications, and narcotics.

Other effects. Long-term treatment of schizophrenia with one of the older, or "conventional," antipsychotics may cause a person to develop tardive dyskinesia (TD). Tardive dyskinesia is a condition characterized by involuntary movements, most often around the mouth. It may range from mild to severe. In some people, it cannot be reversed, while others recover partially or completely. Tardive dyskinesia is sometimes seen in people with schizophrenia who have never been treated with an antipsychotic medication; this is called "spontaneous dyskinesia." However, it is most often seen after long-term treatment with older antipsychotic medications. The risk has been reduced with the newer "atypical" medications. There is a higher incidence in women, and the risk rises with age. The possible risks of long-term treatment with an antipsychotic medication must be weighed against the benefits in each case. The risk for TD is 5 percent per year with older medications; it is less with the newer medications.

This information has been provided with the kind permission of The National Institute of Mental Health (www.nimh.nih.gov).