Other Brand Names

Nufapreg, Berlifed, Halfilyn, Promex, Halmezin, Mucozine, Metagan Expectorant, Zenirex.

How It Works

Promethazine is an antihistamine that works by blocking the action of histamine, a substance produced by the body during allergic reactions. Additionally, promethazine inhibits acetylcholine, which results in effects such as anti-nausea, sedation, and pain relief. These combined actions help alleviate various symptoms, including those related to allergies and nausea.

Indications

Promethazine is used to treat and prevent nausea and vomiting associated with specific conditions, such as during or after surgery and in cases of motion sickness. It also serves to manage allergy symptoms like rashes, itching, and runny nose. Additionally, promethazine can be used to induce sleepiness or relaxation before and after surgery, and it may also enhance the effects of certain opioid pain relievers (e.g., meperidine).

Contraindications

• Patients in a coma or those with impaired respiratory function

• Individuals at risk for respiratory failure, such as those with chronic obstructive pulmonary disease (COPD)

• People with lower respiratory tract disorders, such as asthma, bronchiectasis, or bronchitis

• Patients with central nervous system disorders

• Children under 2 years of age or those with symptoms of Reye's syndrome or liver disease

• Individuals who have recently taken antidepressants (MAOIs) in the past two weeks

Side Effects

Possible side effects of promethazine include:

• Digestive issues

• Ringing in the ears (tinnitus)

• Muscle weakness

• Allergic reactions

• Drowsiness

• Slowed heart rate, which may be accompanied by palpitations or irregular heartbeat

• Difficulty urinating

• Sensitivity to light

• Dry mouth

• Dry or red skin, especially when administered by injection

If any of these side effects persist or worsen, contact your doctor immediately.

Types

• Syrup (50/60/100 ml)

• Tablets

• 5 g cream

• Suppositories

• Injections

Dosage

Allergic conditions 

• Adults: For oral medications, 25 mg at night, with the option to increase to 50 mg if necessary, or 10-20 mg taken 2-3 times daily. For suppository, 26 mg at bedtime, or 12.5 mg after meals and at night, if needed.

• Children: Children under 2 years of age should not use this medication. For children aged 2-5 years, the dosage is 5-15 mg/day, 1-2 times a day. For children aged 5-10 years, the dosage is 10-25 mg/day, 1-2 times a day. For children over 10 years, the dosage is the same as the adult dose.

Nausea and Vomiting 

• Adults: For oral medications and suppository, 12.5-25 mg every 4-6 hours, or as needed. The maximum dose of oral medication is 100 mg. 

• Children 5-10 years: 12.5-37.5 mg daily.

• Children over 10 years: Same as the adult dosage but adjusted as needed. 

Motion Sickness

• Adults: For oral medicationss, 20-25 mg the evening before travel. The dose can be repeated after 6-8 hours if needed. For suppository, 25 mg, used 30-60 minutes before the trip. The dose can be repeated in 8-12 hours if needed.

• Children: 5 mg for children aged 2-5 years, 10 mg for children aged 5-10 years, and adult dose for children over 10 years, with doses taken the evening before travel. The dose may be repeated after 6-8 hours as necessary.

Insomnia 

• Adults: 20-50 mg once daily at night.

• Children: 15-20 mg for children aged 2-5 years, 20-25 mg for children aged 5-10 years, and adult dose for children over 10 years, all taken once daily at night.

Safety

• Promethazine may cause dizziness, drowsiness, or blurred vision. Avoid driving, operating machinery, or engaging in activities that require alertness until you feel safe to do so.
• During pregnancy, this medication should only be used during pregnancy if clearly needed. Discuss the risks and benefits with your doctor before use.
• It is not known whether promethazine passes into breast milk. As it may affect a nursing infant, consult your doctor before using this medication while breastfeeding.

Drug Interactions

• May enhance the effects of anticholinergic drugs like atropine.
• Promethazine may amplify the sedative effects of central nervous system depressants such as barbiturates, narcotic pain relievers (e.g., morphine), and tranquilizers.
• Combining promethazine with MAO inhibitors (antidepressants) can lead to potentially fatal side effects.

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