Formulary
Promethazine hydrochloride: Indications, Dosing, Side Effects and Interactions
Promethazine hydrochloride clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 4 min read
Promethazine hydrochloride: Indications, Dosing, Side Effects and Interactions
Promethazine hydrochloride clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Symptomatic relief of allergy such as hay fever and urticaria,Insomnia associated with urticaria and pruritus**
- **Child** (By Mouth): 10-17 years 10-20 mg 2-3 times a day, alternatively 25 mg once daily, dose to be taken at night, increased if necessary to 25 mg twice daily.
- **Adult** (By Mouth): 10-20 mg 2-3 times a day.
- **Adult** (By Deep Intramuscular Injection): 25-50 mg (max. per dose 100 mg).
**Emergency treatment of anaphylactic reactions**
- **Adult** (By Slow Intravenous Injection): 25-50 mg, to be administered as a solution containing 2.5 mg/mL in water for injections; maximum 100 mg per course.
**Sedation (short-term use)**
- **Child** (By Mouth): 10-17 years 25-50 mg.
- **Adult** (By Mouth): 25-50 mg.
- **Adult** (By Deep Intramuscular Injection): 25-50 mg.
**Nausea,Vomiting,Vertigo,Labyrinthine disorders,Motion sickness**
- **Child** (By Mouth): 10-17 years 20-25 mg, to be taken at bedtime on night before travel, repeat following morning if necessary.
- **Adult** (By Mouth): 20-25 mg, to be taken at bedtime on night before travel, repeat following morning if necessary.
**Symptomatic relief of allergy such as hay fever and urticaria, Insomnia associated with urticaria and pruritus for promethazine hydrochloride**
- **Child 2-4 years** (By mouth): 5 mg twice daily, alternatively 5-15 mg once daily, dose to be taken at night.
- **Child 5-9 years** (By mouth): 5-10 mg twice daily, alternatively 10-25 mg once daily, dose to be taken at night.
- **Child 10-17 years** (By mouth): 10-20 mg 2-3 times a day, alternatively 25 mg once daily, dose to be taken at night, increased if necessary to 25 mg twice daily.
**Sedation (short-term use) for promethazine hydrochloride**
- **Child 2-4 years** (By mouth): 15-20 mg.
- **Child 5-9 years** (By mouth): 20-25 mg.
- **Child 10-17 years** (By mouth): 25-50 mg.
**Sedation in intensive care for promethazine hydrochloride**
- **Child 1 month-11 years** (By mouth, or by slow intravenous injection, or by deep intramuscular injection): 0.5-1 mg/kg 4 times a day (max. per dose 25 mg), adjusted according to response.
- **Child 12-17 years** (By mouth, or by slow intravenous injection, or by deep intramuscular injection): 25-50 mg 4 times a day, adjusted according to response.
**Nausea, Vomiting, Vertigo, Labyrinthine disorders, Motion sickness for promethazine hydrochloride**
- **Child 2-4 years** (By mouth): 5 mg, to be taken at bedtime on night before travel, repeat following morning if necessary.
- **Child 5-9 years** (By mouth): 10 mg, to be taken at bedtime on night before travel, repeat following morning if necessary.
- **Child 10-17 years** (By mouth): 20-25 mg, to be taken at bedtime on night before travel, repeat following morning if necessary.
Cautions
General cautions: Epilepsy; prostatic hypertrophy (in adults); pyloroduodenal obstruction; severe coronary artery disease; susceptibility to angle-closure glaucoma; susceptibility to QT interval prolongation; urinary retention Specific cautions: With intravenous use Avoid extravasation with intravenous injection
Contraindications
Should not be given to children under 2 years, except on specialist advice, due to the potential for fatal respiratory depression (in children)
Side effects
General side-effects: Frequency not known Arrhythmias; blood disorder; confusion; dizziness; drowsiness; dry mouth; headache; hypotension; jaundice; movement disorders; palpitations; photosensitivity reaction; QT interval prolongation; urinary retention; vision blurred Specific side-effects: Frequency not known With oral use Agranulocytosis; angle closure glaucoma; anticholinergic syndrome; anxiety; insomnia; leucopenia; nasal congestion; nausea; rash; seizure; thrombocytopenia; tinnitus; tremor; vomiting With parenteral use Appetite decreased; epigastric discomfort; fatigue; haemolytic anaemia; hypersensitivity; muscle spasms; nightmare; restlessness; skin reactions Side-effects, further information Elderly patients are more susceptible to anticholinergic side-effects.
Interactions
**Severe interactions:**
- Monoamine-oxidase inhibitors (MAOIs) Severe reactions, including serotonin syndrome (see below), may occur when this product is taken concomitantly, or within two weeks of taking, an MAOI.
- Warfarin and other coumarins The anticoagulant effect of warfarin and other coumarins may be enhanced by prolonged regular daily use of paracetamol with increased risk of bleeding; occasional doses...
**Other interactions (13):**
- Medical advice should be sought before taking paracetamol-promethazine-dextromethorphan in combination with these drugs: Alcohol Concomitant use of alcohol with dextromethorphan and promethazine may...
- The hepatotoxicity of paracetamol may be potentiated by excessive intake of alcohol.
- Co-administration with medicines containing e.g.
- Anticholinergic drugs such as atropine, MAOIs and tricyclic antidepressants As promethazine has some anticholinergic activity, the effects of some anticholinergic drugs may be potentiated.
- Cholestyramine The speed of absorption of paracetamol may be reduced by cholestyramine.
- CNS depressant drugs such as antipsychotics, hypnotics or anxiolytics Promethazine and dextromethorphan may potentiate the additive CNS depressant effects of other CNS depressant drugs or alcohol,...
Pregnancy
Most manufacturers of antihistamines advise avoiding their use during pregnancy; however, there is no evidence of teratogenicity. Use in the latter part of the third trimester may cause adverse effects in neonates such as irritability, paradoxical excitability, and tremor.
Breast feeding
Most antihistamines are present in breast milk in varying amounts; although not known to be harmful, most manufacturers advise avoiding their use in mothers who are breast-feeding.
Hepatic impairment
Manufacturer advises caution.
Renal impairment
Use with caution. M
Medicinal forms
Solution,Tablet,Solution,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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