Medicines & Supplements A to Z > Guaifenesin


Last updated on 22/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Guaifenesin 


BRAND NAME(S) IN HONG KONG: Barlodin (Contains Guaifenesin, Dextromethorphan, Bromhexine), Breacol 避爾咳, Codaewon (Contains Guaifenesin, Chlorpheniramine, Dihydrocodeine and Methylephedrine), Gufensin, Mucinex 美清痰, Panadol Cold & Cough 必理痛傷風咳丸 (Contains Guaifenesin, Paracetamol and Phenylephrine), Robitussin EX 樂必治, Tussin DM 基柏 (Contains Guaifenesin and Dextromethorphan)

DRUG CLASS: Expectorant 

USED FOR: Cough with phlegm 

OTHER DRUGS IN THE SAME CLASS: Ammonium Chloride, Cocillana, Ipecacuanha

– 100mg, 200mg (tablets)
– 600mg, 1200mg (expended-release tablets)
– 100mg/5ml (syrups)

What is Guaifenesin for?

Guaifenesin belongs to a group of medications called expectorants like Cocillana. It works by thinning and liquefying your phlegm so that it can be coughed out more easily. Therefore, it is most commonly used for treating wet cough.

How to use it?

Guaifenesin is taken orally either in conventional tablets or syrup form.

The usual adult or child (≥ 12 years) dose is 200-400 mg every 4 hours. The dose of long-acting Guaifenesin (Mucinex) is 600-1200 mg every 12 hours. 

For children aged 6 to 11 years old, the usual dose is 100 mg 4 times daily (maximum dose of 400 mg).

What are the side effects of Guaifenesin?

Common side effects of Guaifenesin include dizziness, headache, nausea and vomiting.

Who should not take Guaifenesin?

People who are allergic to Guaifenesin or any component of the formulation.

Pharmacist Tips:

– Do not use over-the-counter cold and cough products in children under the age of 6.
– Shake suspension well before use.
– Take Guaifenesin with a large amount of fluid for the drug to work properly.
– Guaifenesin is often found in many combination products. Do not use more than one product containing the same active ingredients at the same time to avoid overdose.

Common dosing schedule:
You can take Guaifenesin with or without food.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Guaifenesin may interact with:
There is no significant drug interaction for Guaifenesin.

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Guaifenesin in Hong Kong?

In Hong Kong, Guaifenesin is an over-the-counter medicine which can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. 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

Need more information?

For detailed information about the use of Guaifenesin 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.