Guaifenesin: Uses, Dosage, Side Effects and More

Generic Medicine Info Patient Medicine Information

This information is not country-specific. Please refer to the Hong Kong prescribing information.

Generic Medicine Info

Indications and Dosage

Oral
Cough

Adult: As conventional preparation: 100-200 mg 2-4 hourly if needed. Max: 800 mg daily. Alternatively, 200-400 mg 4 hourly if needed. Max: 2,400 mg daily. As extended-release preparation: 600-1,200 mg 12 hourly if needed. Max: 2,400 mg daily. Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).
Child: As conventional preparation: 6-<12 years 50-200 mg 4 hourly. Max: 6 doses/24 hours. ≥12 years Same as adult dose. As extended-release preparation: ≥12 years Same as adult dose. Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).

What are the brands available for Guaifenesin in Hong Kong?

Robitussin EX

Other Known Brands

Breacol
Excaugh
Glylate
Gufensin
Mucinex
Uni-Colex

Administration

Guaifenesin May be taken with or without food.

Special Precautions

Patient with chronic cough, cough accompanied by excessive phlegm, asthma, or acute asthma attack. Children. Pregnancy.

Adverse Reactions

Endocrine disorders: Hypouricaemia.
Gastrointestinal disorders: Stomach pain, nausea, vomiting.
Nervous system disorders: Headache, drowsiness, dizziness.
Renal and urinary disorders: Nephrolithiasis (large amount).
Skin and subcutaneous tissue disorders: Rash.

Overdosage

Symptoms: Nausea, vomiting, gastrointestinal discomfort, drowsiness, urinary calculi. Management: Symptomatic and supportive treatment.

Drug Interactions

May increase the rate of absorption of paracetamol. Increased risk of adverse effects with cough suppressants; not recommended to be concomitantly administered.

Lab Interference

May interfere with the determination of 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA); discontinue treatment 48 hours before collection of urine samples.

Action

Description:
Mechanism of Action: Guaifenesin increases the effective hydration of the respiratory gland, maintains the sol layer needed for ciliary clearance, and decreases the viscosity of the respiratory mucus, thus facilitating its removal by natural clearance processes.
Pharmacokinetics:
Absorption: Well absorbed from the gastrointestinal tract.
Distribution: Enters breast milk (small amounts).
Excretion: Via urine.

Chemical Structure

Storage

Store below 25°C. Do not refrigerate. Protect from light.

MIMS Class

Cough & Cold Preparations

ATC Classification

R05CA03 - guaifenesin ; Belongs to the class of expectorants. Used in the treatment of wet cough.

References

Asda Chesty & Mucus Cough Relief 100 mg/5 mL; Bell’s Healthcare Mucus Cough Guaifenesin 100 mg/5 mL; Belle’s Healthcare Chesty and Mucus Cough 100 mg/5 mL; Numark Mucus Cough Guaifenesin 100 mg/5 mL; Sainsbury’s Adult Chesty Cough Syrup Guaifenesin 100 mg/5 mL; Superdrug Chesty Cough Guaifenesin 100 mg/5 mL; Superdrug Mucus Cough Guaifenesin 100 mg/5 mL; Tesco Health Chesty Cough Relief 100 mg/5 mL; Lloyds Pharmacy Cough Expectorant 100 mg/5 mL; Co-op Mucus Cough; Well Pharmaceuticals Mucus Cough 100 mg/5 mL; Morrisons Chesty Cough 100 mg/5 mL; Careway Cough Expectorant 100 mg/5 mL Oral Solution (Bell, Sons & Co [Druggists] Ltd). MHRA. https://products.mhra.gov.uk. Accessed 25/04/2025.

Buckingham R (ed). Guaifenesin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/01/2023.

Citrex Cough Syrup 100 mg/5 mL (Idaman Pharma Manufacturing Sdn Bhd). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 25/04/2025.

Guaifenesin 200 mg Tablet (Healthlife of USA LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 09/01/2023.

Guaifenesin 400 mg Caplets (Gendose Pharmaceuticals LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 25/04/2025.

Guaifenesin 600 mg, 1,200 mg Tablet, Extended Release (Dr. Reddy’s Laboratories Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 25/04/2025.

Guaifenesin. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 25/04/2025.

Reckitt Benckiser (New Zealand) Limited. Mucinex and Maximum Strength Mucinex data sheet 23 January 2019. Medsafe. http://www.medsafe.govt.nz. Accessed 09/01/2023.

Robitussin (GlaxoSmithKline Consumer Healthcare Philippines Inc.). MIMS Philippines. http://www.mims.com/philippines. Accessed 09/01/2023.

Disclaimer: This information is independently developed by MIMS based on Guaifenesin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2025 MIMS. All rights reserved. Powered by MIMS.com