Novartis Consumer Health
Action And Clinical Pharmacology: Promethazine is an antihistamine with sedative, antiemetic and antispasmodic properties. In addition, it exerts local anesthetic effects and potentiates analgesics, anesthetics and other CNS depressants.
Indications And Clinical Uses: Allergic reactions: hay fever, urticaria, vasomotor rhinitis, skin allergies, poison ivy, insect bites; for the relief of pruritus due to various dermatologic conditions. Nausea and vomiting of various etiologies: motion sickness, radiation sickness, surgery, anesthesia and gastroenteritis, centrally acting emetics, metabolic or endocrine disorders.
It is also employed as a sedative, hypnotic and tranquilizer in insomnia, nervousness, anxiety, tension; as a local anesthetic for the relief of pruritus and mild burns; as a pre- and postoperative medication in obstetrical analgesia and as a potentiator of anesthetics.
Contra-Indications: Hypersensitivity to phenothiazines, in patients with glaucoma or those in a coma due to CNS depressants.
Promethazine is not recommended for infants below 2 years of age.
Precautions: Promethazine can potentiate CNS depressants such as barbiturates, narcotics, analgesics, and general anesthetics; therefore, dosages of these agents should be reduced when administered concomitantly with promethazine.
Because of its antiemetic properties, promethazine can mask symptoms of intestinal obstruction or intracranial pressure; thus it is necessary to establish the etiology of nausea and vomiting before using high doses of the drug.
Occupational Hazards: Patients should be warned that promethazine may cause drowsiness or dizziness; in such cases, abstain from driving an automobile or operating machinery until this effect has worn off.
Children: Use is not recommended in infants up to 2 years of age because of the possible absence or deficiency of detoxifying enzymes and inefficient renal function usually noted in this age group, and also because of its possible effect on sleep pattern.
Adverse Reactions: Promethazine is a phenothiazine derivative. Although the likelihood of those side effects associated with antipsychotic phenothiazines occurring with promethazine seem to be minimal, the possibility exists, especially at higher doses or with prolonged administration.
Adverse reactions with promethazine are those usually seen during antihistamine therapy; they are generally mild and rarely necessitate discontinuation of treatment.
Most frequent side effects are drowsiness and certain anticholinergic effects: dryness of the mouth and more rarely, blurring of vision, dizziness and asthenia.
More rarely, the following effects on the cardiovascular system may be seen, at the beginning of promethazine parenteral therapy mainly: hypotension and tachycardia; occasionally it will be accompanied by nausea and vomiting.
The following have been reported with a rare incidence: paradoxical reactions characterized by hyperexcitability and/or nightmares, especially in children; allergic reactions, including contact dermatitis; photosensitivity; leukopenia.
Symptoms And Treatment Of Overdose: Symptoms: Sedation, respiratory depression, possible convulsions, coma.
Treatment: No specific antidote. After gastric lavage, treatment is symptomatic. If a pressor agent is necessary, norepinephrine may be used, not epinephrine as it may further depress blood pressure. Centrally acting emetics are ineffective because of the strong antiemetic action of promethazine.
It must be borne in mind that overdosage has been reported after use of the cream over extensive skin areas.
Dosage And Administration: Oral (dosage expressed in terms of promethazine HCl): Adults: Antihistaminic (H1 receptor): 25 mg at bedtime as needed.
Antiemetic: 25 mg initially, then 25 mg every 4 to 6 hours as needed.
Sedative-hypnotic: 25 to 50 mg as needed.
Do not exceed 100 mg daily.
Geriatric patients may be more sensitive to the effects of the usual adult dose.
Children (over 2 years of age): Antihistaminic (H1 receptor): 0.125 mg/kg of body weight every 4 to 6 hours or 0.5 mg/kg of body weight at bedtime as needed; or 5 to 10 mg 3 times a day or 25 mg at bedtime as needed.
Antiemetic: 0.25 to 0.5 mg/kg of body weight every 4 to 6 hours as needed; or 25 mg every 4 to 6 hours as needed.
Sedative-hypnotic: 0.5 to 1 mg/kg of body weight as needed or 25 mg as needed.
Not recommended for use in infants before 2 years of age.
Topical: Apply 2 or 3 times a day to affected area. Avoid application to extensive skin areas. Do not exceed 10% of body surface.
Availability And Storage: Cream: Each tube contains: promethazine base 2% in a scented, nongreasy water miscible base. Nonmedicinal ingredients: Fragrance, glyceryl monostearate, lanolin, methylparaben, propylparaben, stearyl alcohol, stearic acid, triethanolamine and water. Tubes of 30 g.
Tablets: Each tablet contains: promethazine HCl 25 mg (brown, coated) or 50 mg (blue, coated). Nonmedicinal ingredients: burnt umber, dibasic calcium phosphate, magnesium stearate, microcrystalline cellulose, polacrillin potassium and sodium oleate. Tartrazine-free. Bottles of 100.
PHENERGAN® Preparations Novartis Consumer Health Promethazine HCl Antihistamine