Promethazine Hydrochloride (Tablet)
- Perennial and seasonal allergic rhinitis.
- Vasomotor rhinitis.
- Allergic conjunctivitis due to inhalant allergens and foods.
- Mild, uncomplicated allergic skin manifestations of urticaria and angioedema.
- Amelioration of allergic reactions to blood or plasma.
- Anaphylactic reactions, as adjunctive therapy to epinephrine and other standard measures, after the acute manifestations have been controlled.
- Preoperative, postoperative, or obstetric sedation.
- Prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery.
- Therapy adjunctive to meperidine or other analgesics for control of postoperative pain.
- Sedation in both children and adults, as well as relief of apprehension and production of light sleep from which the patient can be easily aroused.
- Active and prophylactic treatment of motion sickness.
- Antiemetic therapy in postoperative patients.
Promethazine is well absorbed from the gastrointestinal tract. Clinical effects are apparent within 20 minutes after oral administration and generally last four to six hours, although they may persist as long as 12 hours. Promethazine is metabolized by the liver to a variety of compounds; the sulfoxides of promethazine and N-demethylpromethazine are the predominant metabolites appearing in the urine.
Dosage & Administration
Motion Sickness: The average adult dose is 25 mg taken twice daily. The initial dose should be taken one-half to one hour before anticipated travel and be repeated 8 to 12 hours later, if necessary. On succeeding days of travel, it is recommended that 25 mg be given on arising and again before the evening meal. For children, promethazine hydrochloride tablets, syrup, or rectal suppositories, 12.5 to 25 mg twice daily, may be administered.
Nausea and Vomiting: Antiemetics should not be used in vomiting of unknown etiology in children and adolescents. The average effective dose of promethazine hydrochloride for the active therapy of nausea and vomiting in children or adults is 25 mg. When oral medication cannot be tolerated, the dose should be given parenterally or by rectal suppository. 12.5 to 25 mg doses may be repeated, as necessary, at 4 to 6 hour intervals.
For nausea and vomiting in children, the usual dose is 0.5 mg per pound of body weight, and the dose should be adjusted to the age and weight of the patient and the severity of the condition being treated. For prophylaxisof nausea and vomiting, as during surgery and the postoperative period, the average dose is 25 mg repeated at 4- to 6-hour intervals, as necessary.
Sedation: This product relieves apprehension and induces a quiet sleep from which the patient can be easily aroused. Administration of 12.5 to 25 mg promethazine hydrochloride by the oral route or by rectal suppository at bedtime will provide sedation in children. Adults usually require 25 to 50 mg for nighttime, presurgical, or obstetrical sedation.
Preoperative and Postoperative Use: Promethazine hydrochloride in 12.5- to 25-mg doses for children and 50-mg doses for adults the night before surgery relieves apprehension and produces a quiet sleep.
For preoperative medication, children require doses of 0.5 mg per pound of body weight in combination with an appropriately reduced dose of narcotic or barbiturate and the appropriate dose of an atropine-like drug. Usual adult dosage is 50 mg promethazine hydrochloride with an appropriately reduced dose of narcotic or barbiturate and the required amount of a belladonna alkaloid.
Postoperative sedation and adjunctive use with analgesics may be obtained by the administration of 12.5 to 25 mg in children and 25- to 50-mg doses in adults. Promethazine hydrochloride tablets are contraindicated for children under 2 years of age.
Epinephrine: Because of the potential for promethazine to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with promethazine hydrochloride tablets overdose.
Anticholinergics: Concomitant use of other agents with anticholinergic properties should be undertaken with caution.
Monoamine Oxidase Inhibitors (MAOI): Drug interactions, including an increased incidence of extrapyramidal effects, have been reported when some MAOI and phenothiazines are used concomitantly. This possibility should be considered with promethazine hydrochloride tablets
Cardiovascular: Increased or decreased blood pressure, tachycardia, bradycardia, faintness.
Dermatologic: Dermatitis, photosensitivity, urticaria.
Hematologic: Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis.
Gastrointestinal: Dry mouth, nausea, vomiting, jaundice.
Respiratory: Asthma, nasal stuffiness, respiratory depression and apnea
Paradoxical Reactions: Hyperexcitability and abnormal movements have been reported in patients following a single administration of promethazine hydrochloride. Consideration should be given to the discontinuation of promethazine hydrochloride and to the use of other drugs if these reactions occur. Respiratory depression, nightmares, delirium, and agitated behavior have also been reported in some of these patients.
Pregnancy & Lactation
Promethazine hydrochloride tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Nursing mothers: It is not known whether Promethazine hydrochloride is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Promethazine hydrochloride tablets, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Carcinogenesis, mutagenesis, impairment of fertility: Long-term animal studies have not been performed to assess the carcinogenic potential of promethazine, nor are there other animal or human data concerning carcinogenicity, mutagenicity or impairment of fertility with this drug. Promethazine was nonmutagenic in the Salmonella test system of Ames.
Use in Special Population
Geriatric use: Clinical studies of promethazine formulations did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. Sedating drugs may cause confusion and over-sedation in the elderly; elderly patients generally should be started on low doses of promethazine hydrochloride tablets and observed closely.