*(Adverse Effect Reported)
Chemistry - A propylamino phenothiazine derivative, promazine is structurally identical to chlorpromazine, but lacks the chlorine atom at the 2 position of the phenothiazine nucleus. It occurs as a bitter tasting, practically odorless, white to slight yellow crystalline powder. Promazine is freely soluble in alcohol and 333 mg are soluble in 1 ml of water at 25°C. The commercial injection has a pH from 4-4.5 and is dissolved in a solution of sterile water for injection.
Storage/Stability/Compatibility - Protect from prolonged exposure to air, protect from light, and store from 15-30°C. Avoid freezing the injectable product.
Upon prolonged exposure to air, promazine will oxidize and change to a pink or blue color. Do not use the injectable product if color changes (a slight yellowish tint is OK), or a precipitate forms.
The following products have been reported to be compatible when mixed with promazine injection: All usual intravenous fluids (except Ionosol B with Dextrose 5% or isotonic sodium bicarbonate), atropine sulfate, chlorpromazine HCl, chloramphenicol sodium succinate, diphenhydramine, droperidol, fentanyl citrate, glycopyrrolate, heparin sodium, hydroxyzine HCl, lidocaine HCl, meperidine, metoclopramide, metaraminol bitartrate, morphine sulfate, pentazocine lactate, promethazine, scopolamine HBr, & tetracycline HCl.
The following products have been reported as being incompatible when mixed with promazine: Ionosol B with dextrose 5%, aminophylline, chlorothiazide sodium, dimenhydrinate, fibrinogen, fibrinolysin (human), methohexital sodium, nafcillin sodium, penicillin g potassium, pentobarbital sodium, phenobarbital sodium, sodium bicarbonate (is reportedly compatible when 100 mg/l of promazine mixed with 2.4 mEq/l of bicarb in D5W), thiopental sodium, and warfarin sodium. Compatibility is dependent upon factors such as pH, concentration, temperature and diluents used. It is suggested to consult specialized references for more specific information (e.g., Handbook on Injectable Drugs by Trissel; see bibliography).
Pharmacology - Promazine has pharmacologic actions similar to acepromazine; refer to that monograph for a more detailed discussion of phenothiazine actions in animals.
Uses/Indications - Used basically for the same purposes as acepromazine; refer to that monograph for more information. Promazine is approved for use in dogs, cats, and horses.
Pharmacokinetics - Promazine is absorbed when given orally to non-ruminants; the drug is also apparently absorbed to some extent in ruminants when oral granules are used as they have some efficacy. In the dog, the onset of action following an IV dose is usually within 5 minutes, and following an IM dose within 30 minutes. Onsets of action reportedly are slightly longer in large animal species after parenteral administration. In horses, the onset of action after the oral granules have been consumed average around 45 minutes. The duration of action of promazine has been described as being dose-dependent, but generally ranges between 4-6 hours.
Promazine is metabolized in the liver primarily to glucuronide conjugates and these are excreted by the kidneys. In the horse, promazine metabolites are not detectable in the urine 72 hours after the last dose.
Contraindications/Precautions - Refer to the monograph for acepromazine for more information. Additionally, there are reports of horses being unusually sensitive to noise and reacting violently to sudden stimulation.
Adverse Effects/Warnings - Refer to the monograph for acepromazine for more information.
Refer to the monograph for acepromazine for more
Refer to the monograph for acepromazine for more
a)1.1 mg/kg IV as a tranquilizer (Lumb and Jones 1984)
b) 0.4 - 1.0 mg/kg IV (Robinson 1987)
c) 0.99 - 1.98 mg/kg PO (equivalent to 1.63 - 3.26 grams/100 lbs of body weight) One level capful of promazine granules (Fort Dodge) will treat 300 lbs of horse at a dosage of approximately 1.45 mg/kg. Onset of action generally starts in 45 minutes and lasts for 4-6 hours. (Package Insert - Promazine Granules, Fort Dodge)
a) A 200 kg bull calf became excited and repeatedly charged after the intramuscular administration of 70 mg promazine. An hour later, the calf was intubated and halothane anesthesia initiated. The calf stopped breathing and died within 2-3 minutes. No lesions were found at necropsy (Fowler,1981).
1981. Problems with immobilizing and anesthetizing elephants.
Proceedings of the American Association of Zoo Veterinarians 87-91
1) Cardiac rate/rhythm/blood pressure if indicated and possible to measure
2) Degree of tranquilization
3) Body temperature (especially if ambient temperature is very hot or cold)
Client Information - May discolor the urine to a pink or red-brown color; this is not abnormal.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times -
Promazine HCl Granules (Veterinary); 10.25 oz containers containing 8 grams of promazine HCl; each gram of granules contains 27.5 mg. of promazine HCl; (Fort Dodge); (Rx) Approved for use in horses.
Promazine HCl for Injection 2 mg/ml in 10 ml vials; 5 mg/ml in 2 ml, 10 ml, &100 ml vials; Sparine® (Wyeth-Ayerst), generic; (Rx)
Promazine HCl tablets 25 mg, 50 mg, 100 mg; Sparine® (Wyeth-Ayerst); Prozine-50® (Hauck); generic, (Rx)
Promazine HCl Oral Syrup 2 mg/ml in 120 ml bottles; Sparine® (Wyeth); (Rx)
Disclaimer: the information on this page is used entirely at the