Risperdal Side Effects: What to Expect and How to Stay Safe

Risperdal (risperidone) helps many people with schizophrenia, bipolar disorder, and irritability linked to autism. But it also causes side effects that range from mild and temporary to serious and long-lasting. Knowing what to watch for and when to act makes a big difference for safety and comfort.

Common and mild side effects

Some effects show up right away and often get better after a few days or weeks. Expect possible drowsiness, dizziness (especially when standing up), dry mouth, constipation, and increased appetite. Weight gain is common—track your weight and eating habits early so small changes don’t become a big problem. You might also notice blurred vision, mild tremor, or sexual side effects like lower libido or erectile difficulties. If you feel restless or can’t sit still (akathisia), tell your prescriber—adjusting the dose or adding a short-term medicine can help.

For many people these issues are manageable with simple fixes: take the dose at night if it makes you sleepy, increase fiber and water for constipation, and add light daily exercise to control weight. Still, don’t shrug off new symptoms—document them and bring the list to follow-up visits.

Serious risks and what to do

Some side effects need urgent attention. Risperidone can raise blood sugar and lipids, so regular checks for fasting glucose, A1c, and cholesterol are recommended—especially if you have diabetes or metabolic risk factors. High prolactin levels are another concern; they can cause breast swelling, unexpected milk production, missed periods, or sexual changes. If you notice these, talk to your doctor—blood tests can confirm the issue.

Tardive dyskinesia (involuntary facial or body movements) may appear after long-term use and can be permanent if ignored. Report any new facial grimacing, tongue movements, or limb jerks immediately. Neuroleptic malignant syndrome (NMS) is rare but serious—look for sudden high fever, severe muscle stiffness, confusion, and fast heartbeat; go to the ER if that happens. Older adults with dementia-related psychosis have a higher risk of stroke and death while on antipsychotics; this drug is generally avoided in that setting.

Risperidone interacts with other drugs. Avoid combining it with heavy alcohol use, strong sedatives, or medicines that affect the heart rhythm (QT prolongation). Some antidepressants and antifungals change risperidone levels—check with your pharmacist or doctor before adding anything.

Don’t stop Risperdal abruptly; withdrawal or return of symptoms can occur. If you need to stop, your provider should taper the dose. Practical steps: keep a symptom diary, schedule regular blood work (weight, glucose, lipids, prolactin), and ask for movement checks at visits. If you’re pregnant, breastfeeding, or have Parkinson’s disease, discuss risks and alternatives with your prescriber.

Questions or worried about a change? Call your prescriber. Quick reporting and simple monitoring often prevent small side effects from becoming big problems.