Chlorpromazine

Phenothiazine tranquilizer/antiemetic for nausea and vomiting in dogs and cats; mild sedation; adjunct in anesthetic protocols. Phenothiazine antipsychotic/antiemetic. Mechanism: dopamine D2 receptor antagonist; also blocks alpha-1 adrenergic, H1 histamine, and muscarinic receptors. Produces sedation, antiemesis (via chemoreceptor trigger zone blockade), and mild analgesia. Lower potency phenothiazine with more sedation and cardiovascular effects than high-potency agents. Key information Phenothiazine antiemetic/tranquilizer. Do not use in horses with hypovolemia. Causes significant hypotension. IV use: dilute and administer slowly. Lower seizure threshold.

Injectable: Administer IV or IM as directed. Give IV slowly and diluted. IM: inject deep into large muscle mass. Onset: 15–30 min (IM), 5 min (IV). Store at room temperature; protect from light. Protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one.

Hypotension, sedation, tachycardia, anticholinergic effects (dry mouth, urinary retention, ileus). Extrapyramidal signs (tremors, rigidity). Penile prolapse (horses). Myelosuppression (prolonged use). Hypothermia/hyperthermia (thermoregulatory impairment). Lowers seizure threshold.

For animals Avoid in hypovolemic or hypotensive patients (alpha-1 blockade). Avoid in epileptic patients (lowers seizure threshold). Horses: risk of persistent penile prolapse. Use with caution in hepatic impairment. Use with caution in pregnant animals. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Phenothiazine — may cause contact dermatitis with skin contact. Avoid getting in eyes. May cause drowsiness if absorbed. Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact.

Contact your veterinarian. Phenothiazine overdose causes prolonged sedation, low blood pressure, and extrapyramidal effects. Supportive care required.