Medicines & Supplements A to Z > Dextromethorphan


Last updated on June 26, 2019.

Overview   |   Dosage   |   Side Effects   |   Where To Buy  

GENERIC NAME: Dextromethorphan


COMMON BRANDS IN HONG KONG: Robitussin DM (Dextromethorphan and guaifenesin), Dexcophan, Tussidex Forte

What is Dextromethorphan for?

Dextromethorphan belongs to a group of medications called antitussives. It is a cough suppressant used to provide symptomatic relief of dry coughs caused by the common cold (no phlegm) and bronchial irritation. It reduces your feeling of need to cough by decreasing activity in certain parts of the brain that cause coughing.

How to use it?

Dextromethorphan is commonly abbreviated as DM on cough and cold products. It is available in single ingredient products, but is also available in many combination cough and cold products. Dextromethorphan is taken by mouth and can be used in adults and children older than 4 years old. For the conventional preparation, you should take 12-40 mg every 4 hours or 30 mg every 6-8 hour and the maximum dose is 120 mg daily. For the extended-release preparation, you should take 60 mg every 12 hours and the maximum dose is 120 mg daily. For lozenges, you should suck no more than 12 lozenges daily.

What are the side effects of Dextromethorphan?

Common side effects of Dextromethorphan include dizziness, drowsiness, and fatigue. Avoid driving or operating machinery until you know how you respond to Dextromethorphan.

Where to buy Dextromethorphan in Hong Kong?

In Hong Kong, Dextromethorphan is an over-the-counter medicine and can be purchased without a prescription in a pharmacy by speaking with the pharmacist. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

For detailed information about the use of Dextromethorphan in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.