Dangerous Drug: Promethazine Hydrochloride(proe meth’ a zeen)
Histanal (CAN), Phenadoz, Phenergan, PMS-Promethazine (CAN), Promethegan
PREGNANCY CATEGORY C
Drug Classes
Antiemetic
Antihistamine
Anti–motion-sickness drug
Dopaminergic blocker
Phenothiazine
Sedative-hypnotic
Therapeutic Actions
Selectively blocks histamine-1 receptors, diminishing the effects of histamine on cells of the upper respiratory tract and eyes and decreasing the sneezing, mucus production, itching, and tearing that accompany allergic reactions in sensitized people exposed to antigens; blocks cholinergic receptors in the vomiting center that are believed to mediate the nausea and vomiting caused by gastric irritation, by input from the vestibular apparatus (motion sickness, nausea associated with vestibular neuritis), and by input from the chemoreceptor trigger zone (drug- and radiation-induced emesis); depresses the RAS, including the parts of the brain involved with wakefulness.
Indications
Symptomatic relief of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis; mild, uncomplicated urticaria and angioedema; amelioration of allergic reactions to blood or plasma; dermatographism, adjunctive therapy (with epinephrine and other measures) in anaphylactic reactions
Treatment and prevention of motion sickness; prevention and control of nausea and vomiting associated with anesthesia and surgery
Preoperative, postoperative, or obstetric sedation
Adjunct to analgesics to control postoperative pain
Adjunctive IV therapy with reduced amounts of meperidine or other opioid analgesics in special surgical situations, such as repeated bronchoscopy, ophthalmic surgery, or in poor-risk patients
Unlabeled uses: Treatment of nausea and vomiting in pregnancy, opioid-induced nausea and vomiting
Contraindications and Cautions
Contraindicated with hypersensitivity to antihistamines or phenothiazines, coma or severe CNS depression, bone marrow depression, vomiting of unknown cause, concomitant therapy with MAOIs, lactation (lactation may be inhibited).
Use cautiously with lower respiratory tract disorders (may cause thickening of secretions and impair expectoration), glaucoma, prostatic hypertrophy, CV disease or hypertension, breast cancer, thyrotoxicosis, pregnancy (jaundice and extrapyramidal effects in infants; drug may inhibit platelet aggregation in neonate if taken by mother within 2 wk of delivery), children (antihistamine overdose may cause hallucinations, seizures, and death), a child with a history of sleep apnea, a family history of SIDS, or Reye syndrome (may mask the symptoms of Reye syndrome and contribute to its development), the elderly (more likely
to cause dizziness, sedation, syncope, toxic confusional states, hypotension, and extrapyramidal effects).
Available Forms
Tablets—12.5, 25, 50 mg; syrup—6.25 mg/5 mL; suppositories—12.5, 25, 50 mg; injection—25, 50 mg/mL
Dosages
Adults
Allergy: Average dose is 25 mg PO or by rectal suppository, preferably at bedtime. If needed, 12.5 mg PO before meals and at bedtime; 25 mg IM or IV for serious reactions. May repeat within 2 hr if needed.
Motion sickness: 25 mg PO bid. Initial dose should be scheduled 30–60 min before travel; repeat in 8–12 hr if needed. Thereafter, give 25 mg on arising and before evening meal.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
