Patient Information Leaflet: Promethazine Hydrochloride
Introduction Promethazine Hydrochloride is an antihistamine commonly used to treat allergies, nausea, vomiting, and motion sickness. It also has sedative properties and is sometimes used for short-term sleep aid. This medication is available in oral and injectable forms and should be used with caution, especially in young children and elderly patients.
Indications and Dosage Promethazine Hydrochloride is prescribed for various conditions, including:
- Allergies (e.g., hay fever, urticaria)
- Insomnia (especially when associated with pruritus)
- Short-term sedation
- Nausea and vomiting from various causes, including motion sickness
Dosage:
By Mouth:
- Children (2–4 years): 5 mg twice daily or 5–15 mg once daily at night
- Children (5–9 years): 5–10 mg twice daily or 10–25 mg once daily at night
- Children (10–17 years): 10–20 mg two to three times daily or 25 mg once at night (may increase to 25 mg twice daily if necessary)
- Adults: 10–20 mg two to three times daily
By Deep Intramuscular Injection:
- Adults: 25–50 mg per dose (maximum 100 mg per dose)
Emergency Treatment (Anaphylactic Reactions):
- By Slow Intravenous Injection: 25–50 mg (maximum of 100 mg per course)
For Motion Sickness:
- Children (2–4 years): 5 mg at bedtime before travel; repeat in the morning if needed
- Children (5–9 years): 10 mg at bedtime before travel; repeat in the morning if needed
- Children (10–17 years): 20–25 mg at bedtime before travel; repeat in the morning if needed
- Adults: 20–25 mg at bedtime before travel; repeat in the morning if needed
Unlicensed Use:
- Promethazine is not licensed for sedation in children under 2 years unless advised by a specialist.
Important Safety Information
- Caution: Over-the-counter cough and cold medications containing promethazine should not be given to children under 6 years without professional medical advice.
- Fatal Respiratory Depression: There is a significant risk of respiratory depression in children under 2 years, and specialist advice should be sought before administration.
Contraindications Promethazine should not be used in the following cases:
- Children under 2 years (unless advised by a specialist)
- Known hypersensitivity to promethazine or any of its components
Cautions Promethazine should be used cautiously in individuals with:
- Epilepsy
- Prostatic hypertrophy
- Pyloroduodenal obstruction
- Severe coronary artery disease
- Susceptibility to angle-closure glaucoma
- QT interval prolongation
- Urinary retention
When administering intravenously, avoid extravasation to prevent tissue damage.
Drug Interactions Inform your healthcare provider about all other medications, including over-the-counter and herbal medicines, as promethazine can interact with other drugs.
Side Effects Promethazine may cause side effects, which range from common to rare:
Common Side Effects:
- Drowsiness
- Dry mouth
- Dizziness
- Confusion
- Blurred vision
- Urinary retention
Less Common Side Effects:
- Arrhythmias
- Blood disorders
- Seizures
- Angioedema
- Photosensitivity reactions
Elderly patients may be more susceptible to side effects such as confusion and drowsiness.
Use During Pregnancy and Breastfeeding
- Pregnancy: Consult a doctor before use. While no conclusive evidence of teratogenic effects exists, promethazine may cause adverse effects in newborns when used in the third trimester.
- Breastfeeding: Promethazine is present in breast milk. Consult a healthcare provider before using while breastfeeding.
Use in Patients with Hepatic and Renal Impairment
- Hepatic Impairment: Use with caution, as metabolism may be affected.
- Renal Impairment: Use cautiously to prevent drug accumulation and increased side effects.
Patient and Carer Advice
- Drowsiness Alert: Promethazine can cause drowsiness, affecting alertness and the ability to perform skilled tasks, such as driving.
- Avoid Alcohol: Alcohol can enhance sedative effects, leading to increased drowsiness.
- Regular Monitoring: Regular follow-ups with a healthcare provider may be needed to assess the medication’s effectiveness and side effects.
Professional Considerations
- Dental Practitioners: May prescribe promethazine for specific indications.
- Prescribing Caution: Promethazine is considered less suitable for prescribing solely as a sedative.
- Emergency Use: Promethazine Hydrochloride injection can be administered without a prescription in emergency situations to save lives.
Medicinal Forms Promethazine Hydrochloride is available in different formulations:
- Oral Tablets: 10 mg, 25 mg
- Oral Solution: 5 mg/5 mL
- Solution for Injection
Conclusion Promethazine Hydrochloride is a versatile antihistamine used for treating allergies, nausea, vomiting, and motion sickness. While it is effective for short-term sedation and emergency situations, its use requires caution, particularly in children, elderly individuals, and those with underlying health conditions. Always follow your doctor’s advice and report any concerning side effects immediately. For further guidance, consult a healthcare provider or pharmacist.
