Risperidone is an anti-psychotic medication used to treat schizophrenia, and to alleviate some of the symptoms in autism and bipolar disorder. It decreases the effects of certain neurotransmitters such as serotonin and dopamine, which are substances used by neurons to communicate. Due to these effects on the brain, as well as how the drug is broken down and excreted through the liver and kidneys, risperidone interactions can occur in connection with other medications.
Potential risperidone interactions often occur with drugs affecting the central nervous system (CNS), although interactions are possible with other substances, as well. Alcohol and other CNS depressants can increase the sedation that risperidone causes, and may have a significant impact on how this medication influences mood. For this reason, alcohol, depressants, and any recreational drugs should typically be avoided when taking this medication. Caution should be used when taking some medications for colds or coughs, as these can cause sedation or mood changes.
Another source of possible risperidone interactions is antidepressants. In particular, the mood stabilizer sibutramine should not be taken with this drug, because stroke, catatonia, and psychosis can occur. Other antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), tricyclics, and monoamine oxidase inhibitors (MAOIs) can affect how risperidone works, even if these drugs were taken weeks before. A doctor should be consulted before taking risperidone within five weeks of taking any antidepressant.
Drugs affecting blood pressure or heart rhythm require caution when being taken with this medication. Risperidone interactions can occur that involve drops in blood pressure, particularly with beta blockers like propranolol. Certain antibiotics may also interact with this drug and result in changes to the rhythm of the heart.
Antacids like cimetidine and ranitidine can decrease the metabolism, or breaking down of risperidone. The anti-psychotic medication clozapine can slow the rate at which this drug leaves the body through the kidneys. In both cases, the resulting risperidone interactions can lead to this medication affecting the body for longer than it normally does.
Additionally, some herbs and supplements can interact with risperidone. The herbal remedy kava kava may increase the chances of some side effects occurring, especially sedation. Melatonin, a compound found in the brain that also is found as a supplement, may influence the prevalence of some side effects of risperidone. Anti-psychotics may alter the levels of B vitamins in the body, so a doctor should be consulted before vitamin supplements are taken.