Name: Haloperidol (Haldol)
Class: Psychopharmacological Agents (Antipsychotic) (Butyrophenone Derivative)
Mechanism: Blocks DA (esp. in limbic areas), muscarinic, a-adrenergic, H1 histaminic, & 5-HT2 receptors.
Absorption: Dist.: Metabolism.: Excretion, t½:
Toxicity/S.E.s: High incidence of extrapyramidal toxicity. Early onset extrapyramidal disorders—pseudo-Parkinsonism, akathisia, acute dystonias (dosage reduction or anticholinergics help). Late onset extrapyram. disorder—tardive dyskinesia (can be irreversible). Hyperprolactinemia, amenorrhea, infertility. Antimuscarinic effects. Orthostatic hypotension, impotence (a). Sedation (H1). Weight gain. Allergic agranulocytosis (esp. w/clozapine (1-2%)). Neuroleptic malignant synd.—hyperpyrexia, catatonia, excessive muscle rigidity, altered mental status, ANS instability; incidence 1%, mortality 15%. For NMS stop Rx, admin. dantrolene (muscle relaxant) & dopamine agonists (e.g., bromocriptine). Drug interactions—may potentiate actions of other CNS depressants.
Utility: Treat schizophrenia, Tourette’s syndrome, manic episodes, intractable hiccough, emesis. Preanesthetic.
Features: Drug holidays important to reduce tendency for tardive dyskinesia and test for continued need. Big problem w/non-compliance. Limit doses to min. side effects.