May alter cardiac conduction (life-threatening arrhythmias occurred with therapeutic doses of phenothiazines). Phenothiazines may cause anticholinergic effects (should be used with caution in decreased gastrointestinal motility, urinary retention, benign prostatic hypertrophy, xerostomia, or visual problems). May cause extrapyramidal symptoms, including pseudoparkinsonism, acute dystonic reactions, akathisia, and tardive dyskinesia. Use may be associated with neuroleptic malignant syndrome. May cause orthostatic hypotension (use with caution in cerebrovascular disease, cardiovascular disease, hypovolemia, or concurrent medication use which may predispose to hypotension/bradycardia). May be sedating. Impaired core body temperature regulation may occur. Use with caution in bone marrow suppression (leukopenia and agranulocytosis reported), severe cardiovascular disease, narrow-angle glaucoma (may be exacerbated by cholinergic blockade), severe hepatic impairment, myasthenia gravis (may be exacerbated by cholinergic blockade), and Parkinson’s disease (may have increased risk of tardive dyskinesia). Use with caution in severe renal impairment, in severe respiratory disease (asthma, COPD, sleep apnea)(may lead to potentially fatal respiratory depression), and in risk of seizures, including patients with history of seizures, head trauma, brain damage, alcoholism, or concurrent therapy with medications which may lower seizure threshold. May mask toxicity of other drugs or conditions (e.g. intestinal obstruction, Reye’s syndrome, brain tumor) due to antiemetic effects. Effects may be potentiated when used with other sedative drugs or ethanol. Respiratory fatalities reported in children <2 years of age (other drugs with respiratory-depressant effects should be avoided). Injection may contain sodium metabisulfite (may cause allergic reaction). Not for SubQ or intra-arterial administration. I.M. route of parenteral administration preferred. I.V. use associated with severe tissue damage.