Indications
Guaifenesin (also spelled Guaiphenesin) is an expectorant. It is used to loosen thick mucus (phlegm) in the chest so it is easier to cough up, for example in chesty coughs with colds, flu and acute bronchitis. It is found in many cough syrups and tablets, often combined with other medicines.
How It Works
Guaifenesin increases the amount of fluid in the airways and makes mucus thinner and less sticky, so coughing clears it more easily. It does not stop the cough itself.
Dosage and Administration
- Adults and children 12 years and over: usually 200 to 400 mg every 4 hours as needed, no more than 2,400 mg in 24 hours.
- Long-acting tablets: usually 600 to 1,200 mg every 12 hours, no more than 2,400 mg in 24 hours. Swallow whole; do not crush or chew.
- Children under 12 years: only as advised by a doctor or as stated on a children’s product. Cough and cold medicines should not be given to children under 6 years unless a doctor advises.
Drink plenty of water while taking it. For combination products, follow the dose on the pack, as the other ingredients may limit the dose.
Interactions
- It has few interactions on its own, but combination products may contain decongestants, antihistamines or cough suppressants that do interact with other medicines; check the label and ask a pharmacist.
- Avoid taking two products that both contain Guaifenesin.
- It can affect some urine laboratory tests; tell the laboratory if you are taking it.
Contraindications
- Allergy to Guaifenesin or any ingredient of the product
- Children under 6 years, unless a doctor advises
Side Effects
It is usually well tolerated. Some people get nausea, vomiting, stomach upset, dizziness, headache or a rash. Very high doses taken for a long time have been linked to kidney stones.
Get urgent medical help if there is swelling of the face or throat, difficulty breathing or a widespread rash. See a doctor if there is coughing up blood, breathlessness or chest pain, high fever, or a cough that lasts more than 7 days or keeps coming back.
Pregnancy and Lactation
There is limited information on safety in pregnancy, so avoid it, especially in the first 3 months, unless a doctor advises. During breastfeeding, use only if a doctor or pharmacist advises.
Precautions and Warnings
- Not for long-term coughs caused by smoking, asthma or COPD, or coughs with a lot of mucus, unless a doctor advises.
- Some syrups contain sugar or alcohol; people with diabetes or liver problems should check the label.
- Tell the doctor if you have porphyria or kidney problems.
Overdose
Too much can cause nausea, vomiting and drowsiness. With combination products, the other ingredients may be more dangerous in overdose. Seek medical help and take the pack with you.
Therapeutic Class
Expectorant (cough medicine).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Keep syrup bottles tightly closed.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.