Mucolytics and Expectorants

Medication Information Leaflet

What are these medications for?

Mucolytics and expectorants are a group of medications that works by thinning and loosening mucus in the airways, helping to clear chest congestion, thus making breathing easier. Common examples of expectorants include Guaifenesin and Ammonium chloride. Common examples of mucolytics are Acetylcysteine, Ambroxol, Bromhexine and Carbocisteine.

How should I take these medications?

  • Take these medications as recommended by your healthcare professional. Consult your healthcare professional if you are not sure how to take these medications correctly.
  • Some of these medications should be taken after food e.g. Ambroxol. Others such as Acetylcysteine and Bromhexine may be taken with or without food.
  • For syrups, shake the bottle well before use.
  • For effervescent tablets and sachets, completely dissolve one tablet or the recommended amount of sachets in at least half a cup of water.
  • If your symptoms persist or worsen after one week of taking these medications, please talk to your healthcare professional.

What should I do if I forget to take these medications?

Mucolytics and expectorants may be taken when required for a short period of time. This means that you do not have to take them if you do not have any symptoms. If you miss a dose, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue normally. Do not take two doses or extra medication to make up for the missed dose.

What precautions should I take when taking these medications?

Inform your healthcare professional if:

  • You are allergic to mucolytics and expectorants, or any other ingredients used in these medications.
  • You are taking any other medications, including supplements, traditional medications and herbal remedies.
  • You have existing conditions such as gastric ulcers, liver or kidney problems and lung conditions such as Chronic Obstructive Lung Disease (COPD) or severe uncontrolled asthma.
  • You are pregnant, planning to become pregnant or breastfeeding.

What are some common side effects of these medications?

  • Some expectorant products may cause drowsiness or dizziness.
    • Avoid driving, operating machinery or other activities which require concentration if affected.
  • Common side effects may include nausea, vomiting and abdominal pain.
    • These side effects are usually mild and will pass quickly.

What are some rare but serious side effects that I need to see a doctor immediately?

The symptoms of a drug allergy include one or more of the following:

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

Signs that your condition may require further medical attention include:

  • Cough with thick yellow or green phlegm or mucus, or blood
  • Fever of more than 38.6°C
  • Unintended weight loss
  • Drenching night sweats
  • Cough lasting for longer than 3-4 weeks
  • Development of new symptoms during self-treatment

If you experience any of these symptoms, you should stop these medications and see your doctor immediately.

What food or medication should I avoid when I take these medications?

Let your healthcare professional know if you are taking, or planning to take any other herbal products, supplements or medications. 

How should I store these medications?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

For syrups, discard the bottle 6 months after opening or if expired, whichever is sooner.

How do I throw these medications away safely?

Pack these medications into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.


This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

The information above is solely for informational purposes only and is not intended as a substitute for the advice provided by your physician, pharmacist or other healthcare professional. You should not use the information for diagnosing or treating a health problem or disease, or prescribing any medicine or other treatment. Always speak with your physician, pharmacist or other healthcare professional before taking any medicine or supplement, or adopting any treatment for a health problem. Under no circumstances will the National Medication Information workgroup be liable to any person for damages of any nature arising in any way from the use of such information.

Last updated on November 2023


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