Promethazine (Phenergan®)
Antihistamine
Phenothiazine
Antiemetic
Long acting derivative of phenothiazine with marked antihistaminic activity and prominent sedative, amnesic, antiemetic, and anti-motion sickness actions. Unlike other phenothiazine derivaties, it is relatively free of extrapyramidal side effects; however, in high doses it carries same potential for toxicity. In common with other antihistamines, exerts antiserotonin, anticholinergic, and local anesthetic action. Anti-emetic action thought to be due to the depression of the CTZ in medulla.
< 1 min IV
4-6 hours
Nausea and vomiting due to stimulation of CTZ (not from GI bleed, CHI, etc)
To potentiate the effects of analgesics
Motion sickness
Pre-and postoperative, obstetric (during labor) sedation
Hypersensitivity
Comatose states
Patients who are CNS depressed (alcohol, barbiturates, narcotics)
When signs of Reye's syndrome are present.
Hypotension
Sedation, dizziness
May impair mental and physical ability
Allergic reactions
Dysrhythmias
Nausea and vomiting
Hyperexcitabilty
Use in children may cause hallucinations, convulsions and sudden death
EPS are possible but much less likely than with other phenothiazines.
Concomitant use of CNS depressants may have an additive sedative effect
Increased incidence of extrapyramidal effects when given with some MAO inhibitors
25, 50 ml/ml in 1 ml ampules and Tubes syringes
IV/IM: 12.5 – 25 mg
IV/IM: 0.5 – 1 mg/kg
Pregnancy Safety: Category C (generally considered safe for use during labor)
Use caution in patients with asthma, peptic ulcer and bone marrow depression
Antiemetics should not be used in children with vomiting of unknown etiology.
Care must be taken to avoid accidental intro-arterial injection
IM injections are the preferred route of administration