Acepromazine Maleate
A phenothiazine tranquilizer used for restraint, sedation and preanesthetic medication. It provides no analgesia; painful procedures require an analgesic component.
Response varies with temperament, physiological status and concurrent medication. Clinical preanesthetic doses are commonly much lower than older injectable label doses.
Group
Phenothiazine tranquilizer and sedative
Mechanism of Action
Central dopamine-receptor blockade produces tranquilization and contributes to antiemetic activity. Peripheral alpha-1 adrenergic blockade causes vasodilation and can lower blood pressure.
It reduces requirements for concurrent anesthetics. Increased digital blood flow in horses underlies its use as an adjunct in laminitis.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Sedation | 0.025–0.1 mg/kg | IM, SC | Once | Maximum 3 mg/dose; Individualize to response; ABCB1-deficient dogs require a lower dose. |
| Sedation | 0.025–0.1 mg/kg | IV | Once | Maximum 3 mg/dose; Individualize to response; ABCB1-deficient dogs require a lower dose. Administer slowly when using intravenous access. |
| Sedation | 0.5–2.2 mg/kg | PO | Every 6–8 h | Oral response is variable; this regimen is distinct from injectable premedication. |
| Anesthetic adjunct | 0.01–0.05 mg/kg | IV | Once | Maximum 3 mg/dose; Use with other anesthetic agents and reduce their requirements. Inject slowly. |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Sedation | 0.025–0.1 mg/kg | IM, SC | Once | |
| Sedation | 0.025–0.1 mg/kg | IV | Once | Inject slowly. |
| Sedation | 1.1–2.2 mg/kg | PO | Every 6–8 h | Oral response is variable; this regimen is distinct from injectable premedication. |
| Anesthetic adjunct | 0.01–0.05 mg/kg | IV | Once | Use with other anesthetic agents and reduce their requirements. Inject slowly. |
Horse
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Sedation | 0.04–0.1 mg/kg | IM | Every 36–48 h | If repeat treatment is necessary, the longer interval is preferred; frequent repeat administration increases adverse-effect concerns. Consider penile-prolapse risk in males. |
| Perioperative sedation | 0.01–0.05 mg/kg | IM, SC | Once | Consider penile-prolapse risk in males. |
| Perioperative sedation | 0.01–0.05 mg/kg | IV | Once | Consider penile-prolapse risk in males. Inject slowly and avoid intracarotid administration. |
| Laminitis adjunct | 0.04 mg/kg | IV | Vasodilator adjunct without analgesic activity. Inject slowly and monitor blood pressure. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Tranquilization | 0.13–0.26 mg/kg | PO | Monitor blood pressure; meat and milk withdrawal must be established for the actual use. | |
| Tranquilization | 0.03–0.1 mg/kg | IM | Monitor blood pressure; meat and milk withdrawal must be established for the actual use. | |
| Tranquilization | 0.01–0.02 mg/kg | IV | Monitor blood pressure; meat and milk withdrawal must be established for the actual use. |
Pig
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Tranquilization | 0.03–0.2 mg/kg | IV, IM, SC | Once | Adult pigs only; meat withdrawal must be established for the actual use. |
Indications
- Chemical restraint for examination, imaging and minor procedures.
- Preanesthetic medication and adjunctive sedation.
- Antiemetic effects in small animals.
- Adjunctive management of equine laminitis through peripheral vasodilation.
Contraindications
- Avoid in animals with previous phenothiazine-associated dystonia or extrapyramidal reactions.
- Do not use with organophosphate antiparasiticides, for organophosphate-poisoning tremors, or with procaine hydrochloride.
- Hypovolemia, shock, pre-existing hypotension and cardiovascular disease increase the risk of severe hypotension.
- ABCB1-deficient dogs may develop exaggerated or prolonged sedation; reduce the dose or select another agent.
- Brachycephalic dogs may develop marked vagal effects; hepatic dysfunction and debilitation warrant dose reduction.
- Male horses, including geldings, risk prolonged penile protrusion or permanent paraphimosis.
- A history of seizures warrants individualized assessment, but clinical evidence does not establish a consistent increase in seizures.
- Some preparations exclude food-producing animals; no universal meat or milk withdrawal interval can be assigned.
Interactions
- Opioids, sedatives and general anesthetics produce additive depression and reduce anesthetic requirements.
- Other vasodilators and hypotensive drugs can intensify hypotension.
- Organophosphates and procaine hydrochloride have clinically important potentiating interactions.
- Epinephrine can worsen phenothiazine-induced hypotension; alternative pressors may be required.
Adverse effects
- Sedation, ataxia and prolonged recovery.
- Hypotension, especially after rapid intravenous administration.
- Paradoxical excitation, disinhibition or aggression.
- Excessive vagal tone, particularly in brachycephalic dogs.
- Rare dystonia, twitching or other extrapyramidal effects.
- Penile prolapse and potentially irreversible paraphimosis in horses.
Toxicity
Excess exposure can cause sustained depression, hypotension or cardiovascular collapse. Provide cardiovascular and respiratory support and monitor blood pressure. Avoid epinephrine for drug-induced hypotension. There is no specific reversal agent.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| PromAce Injectable 10 mg/mL Strength is expressed as acepromazine maleate. Not for horses intended for human consumption. | Injection | 10 mg / mL | IV, IM, SC |
| ZyVet Acepromazine Maleate Tablets 10 mg Zydus Animal Health and Investments Limited Labeled for dogs; not for animals intended for human consumption. | Tablet | 10 mg / tablet | PO |
| ZyVet Acepromazine Maleate Tablets 25 mg Zydus Animal Health and Investments Limited Labeled for dogs; not for animals intended for human consumption. | Tablet | 25 mg / tablet | PO |
