Chlorpromazine
Also known as: Thorazine, aminazine
* **Handling:** Avoid getting the liquid solution on your hands or clothing, as it can cause contact dermatitis (skin irritation). Wash hands after administration. * **Urine Color:** This medication may discolor your pet's urine to a pink or red-brown color. This is a normal side effect and is not a cause for concern. * **Observation:** Keep your pet in a safe, quiet environment while sedated. Watch for excessive lethargy, unusual muscle tremors, or stiffness, and contact your veterinarian if these occur.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- General use
- General use
- General use
- As an antiemetic
- As an antiemetic
- As a preanesthetic
- Premedication for cattle undergoing standing procedures
- Premedication
- Premedication
- Restraint
- Prior to barbiturate anesthesia
- As an antiemetic
- As an antiemetic
- As an antiemetic
How it is given
Possible side effects
- Hypotension
- CNS stimulation (paradoxical)
- Bradycardia or tachycardia
- Extrapyramidal signs in cats (tremors, shivering, rigidity, loss of righting reflexes)
- Lethargy
- Diarrhea
- Loss of anal sphincter tone
- Ataxia, excitation, and panic reactions in horses
- Hypothermia or hyperthermia
Cautions & contraindications
- Horses (generally not recommended due to severe ataxia and panic reactions)
- Rabbits (IM injection causes severe muscle discomfort and swelling)
- Hypovolemia or shock
- Tetanus or strychnine intoxication (due to extrapyramidal effects)
- > **Important:** Intravenous injections must be diluted with saline to concentrations of no more than 1 mg/mL and administered slowly. Do not inject into arteries. * **MDR1 Mutation:** Dogs with MDR1 mutations (Collies, Australian Shepherds, etc.) may develop pronounced and prolonged sedation. Reduce initial doses by 25% in suspect patients. * **Aggressive Dogs:** Use cautiously as a restraining agent; it may make the animal more prone to startle and react to noises or sensory inputs. * **Debilitated Patients:** Use cautiously and in smaller doses in animals with hepatic dysfunction, cardiac disease, or general debilitation. * **Anesthesia:** Animals may require lower dosages of general anesthetics following phenothiazines.
Drug interactions
- Acetaminophen: Possible increased risk for hypothermia
- Antacids: May cause reduced GI absorption of oral phenothiazines
- Antidiarrheal mixtures (e.g., kaolin/pectin, bismuth subsalicylate): May cause reduced GI absorption of oral phenothiazines
- CNS Depressant Agents (barbiturates, narcotics, anesthetics): May cause additive CNS depression
- Dipyrone: May cause serious hypothermia
- Epinephrine: Phenothiazines block alpha-adrenergic receptors; concomitant epinephrine can lead to unopposed beta-activity causing vasodilation and increased cardiac rate (epinephrine reversal)
- Opiates: May enhance hypotensive effects; chlorpromazine dosages may need reduction
- Organophosphate Agents: Effects may be potentiated; do not give phenothiazines within one month of worming with these agents
- Paraquat: Toxicity may be increased by chlorpromazine
- Phenytoin: Metabolism may be decreased if given concurrently
- Physostigmine: Toxicity may be enhanced by chlorpromazine
Frequently asked questions
What is Chlorpromazine used for in pets?
* **Handling:** Avoid getting the liquid solution on your hands or clothing, as it can cause contact dermatitis (skin irritation). Wash hands after administration. * **Urine Color:** This medication may discolor your pet's urine to a pink or red-brown color. This is a normal side effect and is not a cause for concern. * **Observation:** Keep your pet in a safe, quiet environment while sedated. Watch for excessive lethargy, unusual muscle tremors, or stiffness, and contact your veterinarian if these occur.
Is Chlorpromazine safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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