Peridol

Indications

Haloperidol is an antipsychotic medicine. It is used to treat schizophrenia and other psychotic illnesses (where a person loses touch with reality, for example hearing voices or holding false beliefs), severe agitation, acute mania in bipolar disorder, delirium in hospital, Tourette's syndrome and severe tics, and sometimes persistent nausea and vomiting, for example in palliative care. It is available as tablets, oral drops and injections.

How It Works

Haloperidol blocks dopamine D2 receptors in the brain. Too much dopamine activity in certain brain pathways is linked to hallucinations, delusions and severe agitation. By reducing this signalling, Haloperidol calms the mind and reduces psychotic symptoms. Blocking dopamine in the vomiting centre also explains its anti-sickness effect.

Dosage and Administration

The dose depends on the condition, age and response, and is set and adjusted by the doctor. Take tablets or drops exactly as prescribed, at the same times each day, with or without food. Older people usually need lower doses. Injections are given by a doctor or nurse; long-acting (depot) injections are given into a muscle every few weeks. Do not stop suddenly without medical advice.

Interactions

• Medicines that prolong the QT interval (a heart rhythm measure), such as Amiodarone, Sotalol, Erythromycin, Methadone, some antidepressants and other antipsychotics, increase the risk of dangerous heart rhythms.
• Alcohol, sleeping pills, opioid painkillers and sedating antihistamines add to drowsiness.
• Carbamazepine, Phenytoin and Rifampicin can lower Haloperidol levels; Fluoxetine, Paroxetine, Itraconazole and Ritonavir can raise them.
• It opposes Levodopa and other Parkinson's medicines.
• With Lithium, rare cases of confusion and nerve toxicity have been reported.

Contraindications

• Allergy to Haloperidol.
• Coma or severe depression of brain function, for example from alcohol or sedatives.
• Parkinson's disease or dementia with Lewy bodies.
• Known QT prolongation, recent heart attack, uncontrolled heart failure or certain heart rhythm disorders.
• Low potassium or magnesium that has not been corrected.

Side Effects

Common side effects include movement problems (stiffness, tremor, slow movement, restlessness called akathisia, and sudden muscle spasms of the neck, eyes or tongue), drowsiness, dizziness, dry mouth, constipation, blurred vision, weight gain and headache. Raised prolactin may cause breast swelling, milk discharge, period changes or sexual problems.

Less common but serious effects include tardive dyskinesia (lasting involuntary movements of the face or body), dangerous heart rhythms, blood clots, low white cell count, fits and neuroleptic malignant syndrome (high fever, rigid muscles, confusion).

Get urgent medical help if you have a high fever with stiff muscles and confusion, fainting or a fast or irregular heartbeat, a painful swollen leg or sudden breathlessness, a fit, a severe muscle spasm affecting breathing or swallowing, or signs of infection such as fever and sore throat.

Pregnancy and Lactation

Use in pregnancy only if the doctor decides the benefit outweighs the risk. Babies exposed in the last three months may have temporary movement problems, drowsiness, feeding or breathing difficulty after birth. Haloperidol passes into breast milk; the doctor will decide whether breastfeeding is suitable, and the baby should be watched for drowsiness or abnormal movements.

Precautions and Warnings

Older people with dementia have a higher risk of stroke and death with antipsychotics; Haloperidol is not approved for dementia-related behaviour. Tell your doctor about heart disease, epilepsy, liver disease, thyroid problems, depression, low blood pressure, or a history of blood clots. An ECG may be needed. It can cause drowsiness: do not drive or operate machinery until you know how it affects you, and avoid alcohol. Stay cool and drink fluids in hot weather.

Overdose

Overdose may cause severe stiffness and tremor, very low blood pressure, extreme drowsiness, coma and dangerous heart rhythms. Seek emergency help immediately; hospital treatment is supportive with heart monitoring.

Therapeutic Class

First-generation (typical) antipsychotic, butyrophenone.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Injections are stored as directed on the pack. Do not freeze.