by Dr. Manura Nanayakkara

Created on: November 01, 2010

Haloperidol is a typical and older antipsychotic medication prescribed for schizophrenia, psychotic disorders, Tourette syndrome and bipolar mania. Haloperidol is available as tablets, rapid acting intramuscular injections and longer acting intramuscular depot preparations.

How Haloperidol works?

Schizophrenia and other psychotic disorders are caused by an imbalance in dopamine neurotransmission in the brain. Haloperidol corrects that dopamine imbalance and treats psychosis. But it takes around two to three weeks. So patients won’t see an immediate benefit. But side effects occur immediately and wane after two to three weeks.

Rapid acting intramuscular preparation is given to calm down disturbed psychiatric patients. Longer acting preparation (depot) is given for the non-compliant patients.

What the doctor should know before writing a prescription?

 Patient’s complete medical history including allergies and over the counter medications currently taking are important to the prescribing doctor. In addition the doctor should know whether the patient is having following problems.

* Kidney diseases

* Liver problems

* Cardiac diseases

* Parkinson’s disease

* Epilepsy

* Myasthenia Gravis

* Enlargement of the prostate gland

* Susceptibility to angle closure glaucoma

 Doctor should also know whether the patient is pregnant, planning to get pregnant or breast feeding.

What are the dangerous side effects?

Neuroleptic Malignant Syndrome is a potentially life threatening complication of Haloperidol. If the patient rapidly becomes unconscious with fever, muscle rigidity, low/high blood pressure, sweating, and urinary incontinence then he/she must be sent to an emergency medical unit.

Some patients can get allergic reactions including anaphylactic reaction. It is characterized by widespread hives, shortness of breath and chest tightness. It is more common in intramuscular preparations.  If it is present, urgent medical advice must be sought.

 What are the common side effects?

 Drowsiness is the most common side effect patients complain, especially at start of the treatment. This can affect skilled tasks such as operating machinery and driving. So it is advisable not to do such tasks until the patient knows how it affects his /her body. In addition, drowsiness is enhanced by taking alcohol.

Abnormal involuntary movements may occur in all age groups and at any dose. But they occur more frequently in children and young adults, following intramuscular administration, and with higher doses. Abnormal movements include movements in neck, limbs, and rhythmic protrusion of the tongue.

Other common side effects are dry mouth, constipation, confusion in elderly, difficulty in urination, and blurred vision. In addition, some women may notice changes in their menstrual cycle.

What are uncommon side effects?

 Headache, seizures, gastro intestinal disturbances, cardiac rhythm abnormalities, and reduced blood pressure are other uncommon side effects. In addition patient can feel dizzy after taking this drug due to reduced blood pressure, especially early in the regimen.

Summary

Haloperidol is a typical antipsychotic medication prescribed for schizophrenia. It has many nasty side effects. Before taking this drug, it is advisable to discuss it with your doctor.

Sources

British National Formulary

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