Acepromazine

Preanesthetic sedation and tranquilization in horses, dogs, and cats; adjunct to general anesthesia; anxiety/behavior management; laminitis (improves digital blood flow); control of CNS stimulant toxicoses. Phenothiazine derivative tranquilizer and sedative. Mechanism: central dopamine (D2) receptor antagonist; also blocks alpha-1 adrenergic, muscarinic, and histamine H1 receptors. Produces dose-dependent sedation, muscle relaxation, and antiemesis. Causes peripheral vasodilation via alpha-1 blockade. No analgesic properties. Not reversible. Hepatically metabolized; urine excreted. Key information DEA: Not scheduled. Store below 25°C; protect from light. Do NOT use in horses with hypovolemia/shock — fatal hypotension risk. Avoid in brachycephalic breeds (respiratory compromise). Do not use as sole agent for restraint in aggressive animals. Lowers seizure threshold. Causes irreversible penile prolapse in male horses (use with caution). No analgesic effect — combine with opioid if pain present.

Injectable: administer IM or IV (dilute for IV; give slowly). Oral tablets: Administer orally. May be given with food to improve compliance and reduce GI upset. Horses: IM injection into large muscle mass (neck or gluteals). Dose range varies widely by species — use lowest effective dose. Onset: 15–30 min (IM), 5–10 min (IV). Store at room temperature; protect from light. If a dose is missed This medication is administered by a veterinarian or veterinary staff in a clinical setting. Missed doses are managed by your veterinary team — contact your veterinarian to reschedule.

Cardiovascular: hypotension (alpha-1 blockade), bradycardia, peripheral vasodilation. CNS: prolonged sedation, paradoxical excitation (rare). Horses: persistent penile prolapse/paraphimosis (dose-dependent risk, especially in stallions). Thermoregulatory: impaired ability to regulate body temperature. Seizures: may lower seizure threshold in predisposed animals. Respiratory depression at high doses.

For animals Contraindicated in hypovolemic, hypotensive, or shock patients — fatal hypotension risk. Avoid in brachycephalic breeds (airway compromise), epileptic patients (lowers seizure threshold), debilitated or geriatric animals, and animals with hepatic disease. Do not use as the sole anesthetic agent. Stallions: significant risk of persistent penile prolapse/paraphimosis — use with caution and monitor closely; consider alternatives. Giant breed dogs: dose by lean body weight. Boxers: idiosyncratic hypotension reported. MDR1-mutant dogs: increased sensitivity. Use lowest effective dose. For people handling this medication Wear gloves when handling. Avoid skin and eye contact. May cause drowsiness if absorbed — do not drive or operate machinery after accidental skin contact. Wash hands thoroughly with soap and water after handling. Keep out of reach of children. If ingested, contact Poison Control.

Contact your veterinarian immediately. Overdose causes profound sedation, low blood pressure, and abnormal heart rhythm. Supportive care including IV fluids and vasopressors may be needed. There is no specific reversal agent.