Prozine

Indications

Promethazine Hydrochloride is used for allergic conditions such as hay fever, allergic skin rashes, hives and itching; to prevent and treat nausea and vomiting, including motion sickness; for short-term help with sleep; and for sedation before or after surgery.

How It Works

Promethazine is a sedating antihistamine. It blocks histamine, the chemical that causes allergy symptoms, and also acts on the brain's vomiting and sleep centres, which reduces nausea and causes drowsiness.

Dosage and Administration

• Allergy, adults: commonly 10 to 20 mg two or three times a day, or 25 mg at bedtime.
• Motion sickness, adults: 25 mg the night before travel or 1 to 2 hours before setting off, repeated if needed as advised.
• Short-term sleep problems, adults: 25 mg at bedtime, for a few nights only.
• Children aged 2 years and over: as prescribed. Do not give to children under 2 years.
• Injections are given by a doctor or nurse.

Interactions

• Alcohol, sleeping pills, opioid painkillers, anxiety medicines and other sedating antihistamines increase drowsiness and can slow breathing.
• Do not use with, or within 14 days of stopping, MAO inhibitor antidepressants.
• Medicines with anticholinergic effects (for example Amitriptyline, Hyoscine) increase dry mouth, constipation and urinary problems.
• It may hide early signs of ear damage caused by some antibiotics, and can affect some allergy skin tests and pregnancy tests.

Contraindications

Children under 2 years (risk of dangerously slowed breathing), people in a coma or heavily sedated, allergy to promethazine or similar phenothiazine medicines, and use with MAO inhibitors.

Side Effects

Common: drowsiness (sometimes into the next day), dizziness, dry mouth, blurred vision, headache, constipation and difficulty passing urine. Children and older people may become restless or confused instead of sleepy.

Get urgent medical help for slow or difficult breathing, a fit (seizure), high fever with stiff muscles, uncontrollable movements, yellowing of the skin or eyes, swelling of the face or throat, or, after an injection, severe pain, swelling or colour change around the injection site or in the hand or arm.

Pregnancy and Lactation

Use in pregnancy only if a doctor advises it; it is usually avoided close to delivery because it can affect the newborn. It may pass into breast milk and make the baby drowsy, so ask the doctor before using while breastfeeding.

Precautions and Warnings

• Do not drive or operate machinery if drowsy; avoid alcohol.
• Use with care in older people and in people with epilepsy, asthma or other breathing problems, glaucoma, enlarged prostate or difficulty passing urine, liver disease or heart disease.
• It can make the skin more sensitive to sunlight.
• Not for long-term use as a sleeping pill.

Overdose

Overdose can cause deep sleep, confusion, agitation, hallucinations, fits, fast heartbeat and breathing problems, and is especially dangerous in children. Seek emergency help immediately.

Therapeutic Class

Sedating antihistamine (phenothiazine type); antiemetic.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.