butyrophenone

Butyrophenones are a class of antipsychotic drugs that share a butyrophenone chemical core. They act chiefly as antagonists of dopamine D2 receptors in the brain, producing potent antipsychotic effects. As a group they are considered typical (first-generation) antipsychotics and are generally more likely to cause extrapyramidal symptoms than many later agents. Some butyrophenones also have antiemetic properties and have been used to treat severe nausea and vomiting or agitation.

Notable members include haloperidol, the prototypical butyrophenone; droperidol, used as an antiemetic and preoperative sedative; and spiroperidol, an older agent formerly employed for schizophrenia. These drugs can be given orally or by injection (intramuscular or intravenous), with varying onset times suitable for acute as well as maintenance therapy in some cases. They are frequently used in inpatient psychiatry for acute agitation and in emergency settings to control severe psychosis.

Pharmacokinetically, butyrophenones are lipophilic and extensively metabolized by the liver, often yielding active metabolites and long durations of action for agents such as haloperidol. They are primarily excreted in the urine and feces. Dosing and choice of agent depend on the clinical situation and risk of adverse effects.

Common adverse effects include extrapyramidal symptoms such as dystonia, akathisia, and Parkinsonism, as well as tardive dyskinesia with long-term use. Cardiac risks include QT interval prolongation, particularly with certain agents and routes of administration (for example, droperidol). People with cardiovascular disease, the elderly, or those taking other QT-prolonging drugs require careful monitoring. Neuroleptic malignant syndrome is a rare but life-threatening potential complication.