What are the side effects of haloperidol and olanzapine?

Haloperidol

The most common side effects associated with Haldol are:

  • extrapyramidal effects (sudden, often jerky, involuntary motions of the head, neck, arms, body, or eyes, muscle stiffness, akathisia, Parkinsonism),
  • dizziness,
  • hyperactivity,
  • tiredness, and
  • nausea.

Other important side effects are:

Haldol may cause a condition called “orthostatic hypotension” during the early phase of treatment (first week or two). Orthostatic hypotension causes patients to become dizzy upon arising from a lying or sitting position because of a drop in blood pressure.

Haldol also may cause abnormal heart beats, sudden death, seizures, decreases in red and white blood cells, and withdrawal symptoms.

Elderly patients with dementia-related psychosis and treated with antipsychotic drugs such as Haldol are at an increased risk of early death.

Olanzapine

WARNING

  • Elderly patients with dementia related psychosis treated with antipsychotics are at an increased risk of death.
  • When using olanzapine and fluoxetine in combination, also refer to the boxed warning section of the package insert for Symbyax.

Common side effects

Common side effects seen with olanzapine are:

Several disorders of movement also may occur with olanzapine, for example, extrapyramidal effects (sudden, often jerky, involuntary motions of the head, neck, arms, body, or eyes). Tardive dyskinesia (involuntary movements of the mouth, tongue, jaw, or eyelids) also may occur in 1 in 100 patients receiving olanzapine. Some cases can be irreversible. The likelihood of developing tardive dyskinesia increases with prolonged treatment.

There may be an increased risk of elevated blood sugar levels and diabetes with olanzapine as well as the other antipsychotic medications in its class. Patients should be tested during treatment for elevated blood sugar. Additionally, persons with risk factors for diabetes, including obesity or a family history of diabetes, should have their fasting levels of blood sugar tested before starting treatment and periodically throughout treatment to detect the onset of diabetes. Any patient developing symptoms that suggest diabetes during treatment should be tested for diabetes.

Patients may develop severe sedation, coma, and or delirium after an injection of extended release olanzapine. Patients must be examined for 3 hours after receiving an injection.

Olanzapine may increase prolactin levels. Increased prolactin levels may manifest as abnormal menstruation, sexual dysfunction, and breast enlargement.