MEDICATION GUIDES · GUIDE 04
Antipsychotics
First-generation medicines such as haloperidol and newer second-generation medicines such as risperidone, olanzapine, quetiapine, aripiprazole, and ziprasidone.
These guides describe patterns across a drug class, not a prediction for one person. Benefits, side effects, interactions, and tapering needs vary by medication, dose, health history, and other treatments. Never start, stop, or change a psychiatric medication without the prescribing clinician.
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How they work—and what they treat
Antipsychotics reduce symptoms such as hallucinations and delusions largely by changing dopamine signaling. Second-generation medicines also affect serotonin. That broad model is well supported, while the complete path from receptor effects to a person’s improvement is still being studied.
They are central treatments for schizophrenia and schizoaffective disorder. Second-generation medicines are also used in acute mania, bipolar disorder, and treatment-resistant depression. Clozapine is reserved for schizophrenia that has not responded to other antipsychotics and is also approved to reduce repeated suicidal behavior in schizophrenia or schizoaffective disorder.
Newer does not automatically mean better: first- and second-generation medicines tend to have different side-effect tradeoffs.
SOURCE · NAMI MEDICATION OVERVIEW SOURCE · NAMI CLOZAPINE GUIDE
What to expect—and when
Sleepiness, dizziness, dry mouth, constipation, blurred vision, nausea, headache, restlessness, sexual effects, and lightheadedness when standing can occur. Weight gain and appetite increase are especially common with some second-generation medicines. Many early effects ease; persistent or difficult effects should be reported rather than handled by stopping alone.
Calming, sleep, or agitation may improve within days. Hallucinations and delusions often begin improving in about 1–2 weeks, while fuller benefit can take 2–3 months. Those ranges come largely from clozapine patient guidance and are useful orientation—not a promise for every antipsychotic or person.
SOURCE · MIND SIDE-EFFECTS GUIDE SOURCE · NAMI CLOZAPINE GUIDE
Monitoring and urgent warning signs
Monitoring usually includes weight and waist, blood pressure, fasting blood sugar or HbA1c, and cholesterol before treatment and regularly afterward. Clinicians also check for abnormal involuntary movements; NAMI patient materials advise screening about every three months during long-term treatment. An EKG may be needed for heart history or a medicine that can affect rhythm.
- Neuroleptic malignant syndrome: high fever or heavy sweating with severe muscle stiffness, confusion, fast heartbeat, rapid breathing, or blood-pressure changes is an emergency.
- Tardive dyskinesia: new repetitive movements—lip-smacking, tongue movements, chewing, or jerky limb movements—need prompt review. Risk rises with longer exposure and is generally higher with first-generation drugs.
- Other movement problems: severe inner restlessness, painful muscle spasms, neck twisting, eyes rolling upward, or marked stiffness need prompt medical advice.
- Clozapine: fever, sore throat, mouth ulcers, chills, or flu-like symptoms can signal dangerously low white blood cells; severe constipation can also become life-threatening. Contact the treatment team right away.
- Heart or metabolic signs: fainting, palpitations, or a very fast or irregular heartbeat need urgent assessment. Rapid weight gain, constant thirst, or frequent urination should also be reported.
SOURCE · NIMH CATIE UPDATE SOURCE · NAMI TARDIVE DYSKINESIA SOURCE · MIND
How individual antipsychotics differ
Long-acting injections: these are the same medicines in slow-release form, usually given by a nurse every two weeks to three months depending on the drug. They can help when daily pills are hard to remember or swallow and can keep medication levels steadier. Not every antipsychotic has an injectable form.
Clozapine update, interactions, pregnancy, and stopping
Clozapine blood tests still matter: its label calls for regular white-blood-cell or neutrophil monitoring. Older materials may describe the U.S. REMS paperwork program as current, but the FDA ended that formal program on February 24, 2025. Follow the prescriber and current label rather than outdated enrollment instructions.
Interactions: cigarette smoke can lower clozapine blood levels by up to 50% and also affects olanzapine; nicotine replacement does not have the same effect. Tell the prescriber before starting or stopping smoking. Alcohol and sedatives can worsen drowsiness. Some antibiotics, antidepressants, seizure drugs, blood-pressure drugs, and heart-rhythm drugs can change antipsychotic levels or risks, so share the complete medicine and supplement list.
Pregnancy and breastfeeding: untreated psychosis and sudden relapse also carry risks. Third-trimester exposure can cause temporary movement, feeding, breathing, muscle-tone, or withdrawal symptoms in a newborn, and antipsychotics can pass into breast milk. Discuss treatment early with psychiatric and obstetric clinicians; do not stop suddenly because of pregnancy.
Stopping: taper with the prescriber, generally over at least four weeks. Sudden stopping can bring nausea, sleep problems, restlessness, relapse, or rebound symptoms. If more than about two days of clozapine are missed, the prescriber may need to restart at a lower dose.
SOURCE · ASCP CLOZAPINE REMS UPDATE SOURCE · NAMI CLOZAPINE GUIDE SOURCE · MIND TAPER GUIDANCE
