Promethazine HCL
Class: Sedating antihistamine with antimuscarinic, significant sedative and some serotonin-antagonistic properties
Manufacturer: Dawa Limited, Plot No. 7879/8, Baba Dogo Road, Ruaraka
Dosage Form: Tablet, Syrup, Injection
Similar Brands:
Uses:
Promethazine hydrochloride is used for their antiemetic action in the prevention and treatment of nausea and vomiting in conditions such as motion sickness, drug-induced vomiting, and post-operative vomiting. It is also used for the symptomatic treatment of nausea and vertigo caused by Ménière’s disease and other vestibular disorders.
Promethazine hydrochloride is also employed pre and postoperatively in surgery and obstetrics for its sedative effects and for the relief of apprehension where it is often given with pethidine hydrochloride.
Promethazine hydrochloride may be used for night time sedation.
Dosage:
The following doses of promethazine have been given by mouth;
Adults
Allergic conditions: 25mg at night increased to 25mg twice daily if necessary or alternative 10 to 20mg two to three times daily.
Short term management of insomnia: 20mg to 50mg at night.
Prevention of motion sickness: 20mg to 25mg the night before travelling following by a similar dose the following morning if necessary.
Nausea and vomiting arising from causes such as labyrinthitis: 25mg at night which may be increased to 50mg or 75mg at night or to 25mg two to three times daily if necessary to a maximum of 100mg daily.
For severe vomiting in pregnancy, a dose of 25mg at night, increased to a maximum of 100mg is recommended.
Children
Allergic conditions: 2 to 5 years, 5 to 15mg daily in one or two divided doses; 5 to 10 years, 10mg to 25mg daily in one or two divided doses.
Night sedation or premedication: 2 to 5 years, 15mg to 20mg; 5 to 10 years, 20 to 25mg.
Prevention of motion sickness: 2 to 5 years, 5mg; 5 to 10 years, 10mg given the night before the journey and repeated on the following morning if necessary.
Injection
Promethazine is given parenterally by deep intramuscular injection as a solution of 25 or 50mg/mL.
It may be given by slow intravenous injection or injected into the tubing of a freely running infusion in concentrations of not more than 25mg/mL, although it is usually diluted to 2.5mg/mL
The rate of infusion should not exceed 25mg/minute. The usual parenteral dose for all indications apart from nausea and vomiting is 25 to 50mg; a dose of 100mg should not be exceeded.
Doses of 12.5mg to 25mg, repeated at intervals of not less than 4 hour, may be given for the treatment of nausea and vomiting, although not more than 100mg is usually given in 24 hours.
Children aged 5 to 10 years may be given 6.25 to 12.5mg of promethazine hydrochloride by deep intramuscular injection.
Side Effects:
The most common side effects is CNS depression, with effects varying from slight drowsiness to deep sleep, and including lassitude, dizziness and incardination.
Others include headache, psychomotor impairment, and antimuscarinic effects, such as dry mouth, thickened respiratory tract secretions, blurred vision, urinary difficult or retention, constipation and increased gastric reflux.
Occasional one includes nausea, vomiting, diarrhea, or epigastric pain, palpitations and arrhythmias.
Promethazine may sometimes cause rashes and hypersensitivity reactions (including bronchospasm, angioedema, and anaphylaxis) and cross-sensitivity to related drugs may occur.
Photosensitivity can be a problem to promethazine.
Blood disorders, including agranulocytosis, leucopenia, haemolytic anaemia, and thrombocytopenia, although rare, have been reported.
Jaundice has also been observed.
Other adverse effects that have been reported with promethazine include convulsions, sweating, myalgia, paraesthasias, extrapyramidal effects, tremor, sleep disturbances, depression, confusion, tinnitus, and hypotension and hair loss
Warnings & Precautions:
Drowsiness is a prevalent with promethazine and those affected should not drive or operate machinery; alcohol should be avoided.
Because of its antimuscarinic actions, promethazine should be used with care in conditions such as angle-closure glaucoma, urinary retention, prostatic hyperplasia or pyloroduodenal obstruction.
Occasional reports of convulsions in patients taking antihistamines suggest a need for caution in patients with epilepsy.
Caution is needed in hepatic impairment and renal impairment since many antihistamines are excreted in urine in the form of active metabolites.
Promethazine should not be given to neonates and young children owing to their increased susceptibility to antimuscarinic effects.
Pregnancy & Lactation:
For severe vomiting in pregnancy, a dose of 25mg at night, increased to a maximum of 100mg is recommended.
Drug Interactions:
Promethazine may enhance the sedative effects of antidepressants including alcohol, barbiturates, hypnotics, opiod analgesics, anxiolytic sedatives, and antipsychoyics. Promethazine has an additive antimuscarinic action of other antimuscarinic drugs, such as atropineand some depressants (both tricyclic an MAOIs). It has been suggested that some sedating antihistamines could mask the warning signs of damage caused by ototoxic drugs such as aminoglycosides antibiotics.
Antihistamines may suppress the cutaneous histamine response to allergen extracts and should be stopped several days before skin testing.
Contraindications:
Depressants (both tricyclic and MAOIs)
Price: Ksh 500
Notes:
Ref: DP/LL/04/10
Ksh 500/- is the retail price for a pack of 100 tablets.