Some Side Effects
First-generation antipsychotic drugs
Increased heart rate and decreased blood pressure
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 Neuroleptic Malignant Syndrome Neuroleptic malignant syndrome is confusion or unresponsiveness, muscle rigidity, high body temperature, and other symptoms that occur when certain antipsychotic (neuroleptic) drugs or anti-vomiting... read more )
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
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 Metabolic Syndrome Metabolic syndrome is characterized by a large waist circumference (due to excess abdominal fat), high blood pressure, resistance to the effects of insulin (insulin resistance) or diabetes,... read more )
Newer antipsychotic drugs are less likely to cause tremor, muscle stiffness, involuntary movements (including tardive dyskinesia), and neuroleptic malignant syndrome Neuroleptic Malignant Syndrome Neuroleptic malignant syndrome is confusion or unresponsiveness, muscle rigidity, high body temperature, and other symptoms that occur when certain antipsychotic (neuroleptic) drugs or anti-vomiting... read more , but other side 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 antipsychotic 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.