Haloperidol is an antipsychotic medication used to treat schizophrenia, mania and other forms of psychosis. It acts by blocking the effects of dopamine, a chemical in the brain that affects thinking, behavior and feelings. Several possible side effects are associated with the use of this neuroleptic drug.

Some of these include:

• Cardiovascular effects such as prolonged QT interval and Torsades de pointes.
• Effects on the skin and hair include seborrheic dermatitis, acne, alopecia, urticaria, hyperhidrosis and contact sensitivity.
• Effects on the reproductive system include male breast enlargement (gynecomastia), amenorrhea, erectile dysfunction, failed ejaculation and irregular menstruation.
• Gastrointestinal side effects include abdominal pain, dry mouth, constipation, inability to swallow (dysphagia), nausea, swollen tongue and paralytic ileus (slowed peristalsis in the gut).
• In rare cases, jaundice and hepatitis occur as adverse effects.
• Musculoskeletal and connective tissue effects include back pain, muscle rigidity, stiff joints, weak muscles and pain in the extremities.
• Anticholinergic side effects include dry mouth, constipation and blurred vision.
• Respiratory system effects include dry throat, respiratory distress, nasal congestion, upper respiratory tract congestion, wheezing and laryngospasm.
• Effects on the nervous system include parkinsonism, dysarthria, dyskinesia, dystonia, convulsion, drooling, sedation, lethargy, tremor and tics.
• Adverse psychiatric effects include anxiety, insomnia, delirium, depression, panic attack, restlessness, nervousness and agitation.