Merck Manual

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Antipsychotic Drugs

Antipsychotic Drugs

Drug

Some Side Effects

Comments

First-generation antipsychotic drugs

Chlorpromazine

Fluphenazine*

Haloperidol*

Loxapine

Molindone

Perphenazine

Pimozide

Thioridazine

Thiothixene

Trifluoperazine

Dry mouth

Blurred vision

Seizures

Increased heart rate and decreased blood pressure

Constipation

Sudden but often reversible tremor and muscle stiffness that may progress to rigidity

Involuntary movements of the face and arms (tardive dyskinesia)

Muscle rigidity, fever, high blood pressure, and changes in mental function (neuroleptic malignant syndrome)

Side effects are much more likely in older people and in people with impaired balance or serious medical disorders.

Long-acting injectable forms of haloperidol and fluphenazine are available.

Eye examination and electrocardiography (ECG) are recommended while people are taking thioridazine.

Second-generation antipsychotic drugs

Aripiprazole*

Asenapine

Brexpiprazole

Cariprazine

Clozapine

Iloperidone

Lumateperone

Lurasidone

Olanzapine*

Paliperidone

Quetiapine

Risperidone*

Ziprasidone

Drowsiness and weight gain (most common), which can be substantial

Some of these drugs increase risk of accumulation of fat in the abdomen, abnormal cholesterol levels in the blood, high blood pressure, and resistance to the effects of insulin (metabolic syndrome)

Newer antipsychotic drugs are less likely to cause tremor, muscle stiffness, involuntary movements (including tardive dyskinesia), and neuroleptic malignant syndrome, but these effects may occur.

A long-acting injectable form is available for aripiprazole, olanzapine, and risperidone.

Clozapine is used much less often because it can cause bone marrow suppression, a reduced white blood cell count, and seizures. However, it is often effective in people who are not responsive to other drugs.

Clozapine and olanzapine are most likely to cause weight gain, and aripiprazole is the least likely.

Ziprasidone does not cause weight gain but may lead to abnormalities on an electrocardiogram.

Aripiprazole, brexpiprazole, cariprazine, and ziprasidone are less likely to cause metabolic syndrome.

Lumateperone has a lower risk of motor and metabolic side effects, but it is contraindicated in older people with dementia-related psychosis.

* Available as a long-acting intramuscular (IM) injection for people who have difficulty taking oral drugs.