- What Is Drug Used For?
- Pharmacology / Actions
- Before you take Drug
- Contraindications / Precautions / Warnings
- Adverse Effects
- Reproductive / Nursing Safety
- Overdosage / Acute Toxicity
- Drug Interactions
- Laboratory Considerations
- How to use Drug
TRIMEPRAZINE TARTRATE WITH PREDNISOLONE (Temaril-P)
PHENOTHIAZINE ANTIHISTAMINE & CORTICOSTEROID
Highlights of Prescribing Information
- Combination phenothiazine antihistamine & corticosteroid used for pruritus & potentially as an antitussive
- Relatively Contraindicated: Systemic fungal infections, hypovolemia, or shock & in patients with tetanus or strychnine intoxication. Caution: Hepatic dysfunction, cardiac disease, active bacterial or viral infections, peptic ulcer, acute psychoses, corneal ulcer, Cushingoid syndrome, diabetes, osteoporosis, chronic psychotic reactions, predisposition to thrombophlebitis, hypertension, CHF, renal insufficiency, general debilitation, very young animals
- Goal is to use as much as is required & as little as possible for as short an amount of time as possible
- Primary adverse effects: Sedation, may cause significant hypotension, cardiac rate abnormalities, hypo- or hyperthermia, “Cushingoid” effects with sustained use
- Many potential drug & lab interactions
What Is Drug Used For?
Trimeprazine with prednisolone is used for the treatment of pruritic conditions, especially if induced by allergic conditions. Many dermatologists believe that when prednisolone is combined with trimeprazine (Temaril-P), less prednisolone is required to control pruritus. The manufacturer suggests the drug is for use in dogs either for pruritic conditions or as an antitussive.
Pharmacology / Actions
Trimeprazine has antihistaminic, sedative, antitussive, and antipruritic qualities. The veterinary-approved product also has prednisolone in its formulation that provides additional antiinflammatory effects.
The pharmacokinetics of trimeprazine have apparently not been studied.
Before you take Drug
Contraindications / Precautions / Warnings
The contraindications and precautions of this product follow those of the other phenothiazines and antihistaminic agents. For more information, it is suggested to review the acepromazine and chlorpheniramine monographs.
For trimeprazine, possible adverse reactions include: sedation, depression, hypotension and extrapyramidal reactions (rigidity, tremors, weakness, restlessness, etc.).
Additional adverse effects, if using the product containing steroids include: elevated liver enzymes, weight loss, polyuria/polydipsia, vomiting, and diarrhea. If used chronically, therapy must be withdrawn gradually and Cushing’s syndrome may develop.
The manufacturer of the veterinary combination product (Temaril-P) includes the following adverse effects in its package insert: sodium retention and potassium loss, negative nitrogen balance, suppressed adrenocortical function, delayed wound healing, osteoporosis, possible increased susceptibility to and/or exacerbation of bacterial infections, sedation, protruding nictitating membrane, blood dyscrasias. In addition, intensification and prolongation of the action of sedatives, analgesics or anesthetics can be noted and potentiation of organophosphate toxicity and of procaine HCL activity.
Reproductive / Nursing Safety
The manufacturer of the veterinary combination product (Temaril-P) warns that corticosteroids can induce the first stages of parturition if administered during the last trimester of pregnancy.
Overdosage / Acute Toxicity
Acute overdosage should be handled as per the acepromazine monograph found at the beginning of the book.
The following drug interactions have either been reported or are theoretical in humans or animals receiving promethazine (a related phenothiazine antihistamine) or prednisolone and may be of significance in veterinary patients:
■ ACE INHIBITORS: Phenothiazines may increase effects
■ AMPHOTERICIN B: When administered concomitantly with gluco-corticoids may cause hypokalemia
■ ANTACIDS: May cause reduced GI absorption of oral phenothiazines
■ ANTIDIARRHEAL MIXTURES (e.g., Kaolin/pectin, bismuth subsalicylate mixtures): May cause reduced GI absorption of oral phenothiazines
■ ANTICHOLINESTERASE AGENTS (e.g., pyridostigmine, neostigmine, etc.): In patients with myasthenia gravis, concomitant glucocorticoid with these agents may lead to profound muscle weakness. If possible, discontinue anticholinesterase medication at least 24 hours prior to corticosteroid administration.
■ ASPIRIN (salicylates): Glucocorticoids may reduce salicylate blood levels
■ CISAPRIDE: Increased risk for cardiac arrhythmias when used with phenothiazines
■ CNS DEPRESSANT AGENTS (barbiturates, narcotics, anesthetics, etc.): May cause additive CNS depression if used with phenothiazines
■ CYCLOPHOSPHAMIDE: Glucocorticoids may also inhibit the hepatic metabolism of cyclophosphamide; dosage adjustments may be required.
■ CYCLOSPORINE: Concomitant administration of may increase the blood levels of each, by mutually inhibiting the hepatic metabolism of each other; clinical significance of this interaction is not clear
■ DIGOXIN: Secondary to hypokalemia, increased risk for arrhythmias
■ DIURETICS, POTASSIUM-DEPLETING (furosemide, thiazides): When administered concomitantly with glucocorticoids may cause hypokalemia
■ EPHEDRINE: May increase metabolism
■ ESTROGENS: The effects of hydrocortisone, and possibly other glucocorticoids, maybe potentiated by concomitant administration with estrogens
■ INSULIN: Requirements may increase in patients receiving glucocorticoids
■ KETOCONAZOLE: May decrease metabolism
■ MITOTANE: May alter the metabolism of steroids; higher than usual doses of steroids may be necessary to treat mitotane-induced adrenal insufficiency
■ NSAIDS: Administration of other ulcerogenic drugs with glucocorticoids may increase risk
■ PAROXETINE: May increase phenothiazine plasma levels
■ PHENOBARBITAL: May increase the metabolism of glucocorticoids
■ PHENYTOIN: May increase the metabolism of glucocorticoids
■ RIFAMPIN: May increase the metabolism of glucocorticoids
■ VACCINES: Patients receiving corticosteroids at immunosuppressive dosages should generally not receive live attenuated-virus vaccines as virus replication may be augmented; a diminished immune response may occur after vaccine, toxoid, or bacterin administration in patients receiving glucocorticoids
■ Glucocorticoids may increase serum cholesterol and urine glucose levels.
■ Glucocorticoids may decrease serum potassium.
■ Glucocorticoids can suppress the release of thyroid stimulating hormone (TSH) and reduce T3 & T4 values. Thyroid gland atrophy has been reported after chronic glucocorticoid administration. Uptake of I131 by the thyroid may be decreased by glucocorticoids.
■ Reactions to skin tests may be suppressed by glucocorticoids or trimeprazine.
■ False-negative results of the nitroblue tetrazolium test for systemic bacterial infections may be induced by glucocorticoids.
How to use Drug
Drug dosage for dogs:
a) For antipruritic and antitussive therapy: Weight up to 10 lb = 1/2 tab PO twice daily; 11 – 20 lb = 1 tablet twice daily; 21-40 lb = 2 tablets twice daily; over 40 lb = 3 tablets twice daily. After 4 days reduce dose to 1/2 of initial dose or to an amount just sufficient to maintain remission of symptoms; adjust as necessary. (Package Insert; Temaril-P — Pfizer)
b) For treatment of pruritus: 1 tablet per 10 kg of body weight once daily for 3 – 5 days, then every other day. Giving with an EFA (essential fatty acid) may reduce the dose and frequency, if not the need for, glucocorticoids. ()
c) For atopic dermatitis: 1 tablet of Temaril-P per 5 kg body weight q12h for one week, then once daily for one week, then q48h (every other day). ()
■ Degree of sedation, and anticholinergic effects
■ Adverse effects associated with corticosteroids
■ Follow veterinarians dosage recommendations carefully
■ Dog’s appetite and water consumption may increase
■ If side effects are worrisome, contact veterinarian
Chemistry / Synonyms
A phenothiazine antihistamine related to promethazine, trimeprazine tartrate occurs as an odorless, white, to off-white crystalline powder with a melting range of 160- 164°C. Approximately 0.5 gm is soluble in 1 mL water, and 0.05 gm is soluble in 1 mL of alcohol. Trimeprazine Tartrate may also be known as: trimeprazine tartrate, alimemazine tartrate, Chemists Own Peetalix, Nedeltran, Panectyl, Repeltin, Temaril, Theralen, Theralene, Theralene, Vallergan, or Variargil.
Storage / Stability
Store trimeprazine products at room temperature (15-30°C); protect tablets from light.
Dosage Forms / Regulatory Status
No single agent trimeprazine products are approved for veterinary medicine.
Trimeprazine Tartrate 5 mg; Prednisolone 2 mg Tablets; Temaril-P Tablets (Pfizer); (Rx). Approved for use in dogs. Trade name in Canada is Vanectyl-P.
The ARCI (Racing Commissioners International) has designated this drug as a class 4 substance. See the appendix for more information.
Human-Labeled Products: None
Selections from the book: “Plumb’s Veterinary Drug Handbook. Sixth Edition”. 2008