Robitussin (Guaifenesin)


Robitussin (guaifenesin) is an expectorant. It helps reduce congestion in your chest and throat, making it easier for you to cough out through your mouth. Here’s everything you need to know, including how it works, as well as uses, contraindications, side effects, interactions, storage and precautions.

Action And Clinical Pharmacology

Guaifenesin enhances the output of lower respiratory tract fluid. The enhanced flow of less viscid secretions promotes ciliary action, and facilitates the removal of inspissated mucus. As a result, dry, unproductive coughs become more productive and less frequent.

Dextromethorphan is a synthetic, non-narcotic, centrally-acting cough suppressant. The antitussive effectiveness of dextromethorphan has been demonstrated in both animal and human clinical studies, and the incidence of toxic effects has been remarkably low.

Pseudoephedrine produces vasoconstriction resulting in a nasal decongestant effect.

Indications And Clinical Uses

It is used for the treatment of dry cough with a characteristic viscous and poorly separated sputum, which occurs in infections of the upper and lower respiratory tract.

In particular, Robitussin is used in the treatment of:

  • pharyngitis, laryngitis, tracheitis;
  • bronchitis, pneumonia, cystic fibrosis;
  • bronchospasm, tuberculosis;
  • pneumoconiosis.

The drug is also used for the rehabilitation of the bronchial tree in the pre-and postoperative periods.

You shouldn’t use this drug for coughs related to: smoking, asthma, emphysema, chronic bronchitis. Consult your health care professional about other treatments for these types of coughs.


Do not use this drug if you have hypersensitivity to dextromethorphan, as well as if you suffer from bronchitis. The drug is not used as part of a complex treatment together with mucolytic drugs. It is not intended to treat patients suffering from bronchial asthma, as its use can cause deterioration of sputum separation and increase the resistance of the respiratory tract.

Relative contraindications are liver dysfunction, wet cough, and the first trimester of pregnancy.


Before prescribing medication to suppress or modify cough, it is important to ascertain that the underlying cause of the cough is identified, that modification of the cough does not increase the risk of clinical or physiologic complications, and that appropriate therapy for the primary disease is provided.

Before you begin using this product, be sure to inform your heath care provider about any medical conditions or allergies you may have, any drugs you are taking, whether you are pregnant or breast-feeding, etc.

If cough worsens, lasts for more than 1 week or is accompanied by high fever, or in patients with hypertension, consult a physician. Do not exceed recommended dosage. Keep safely out of reach of children.

This medicine may worsen your thinking or reactions. Be especially careful if you drive a car or do anything that requires you to be highly concentrated.

Adverse Reactions

The following may possibly occur:

  • nausea;
  • gastrointestinal upset;
  • drowsiness;
  • vomiting;
  • dry mouth;
  • nervousness;
  • insomnia;
  • confusion;
  • dizziness;
  • stomach ache;
  • CNS stimulation;
  • muscular weakness;
  • palpitation;
  • difficulty in micturition.

This is not a complete list of side effects. Contact your health care provider for medical advice about side effects. You may also report side effects to U.S. Food and Drug Administration (FDA) at 1-800-FDA-1088.

Forms and dosage

Robitussin comes both as an oral liquid and oral tablets. In addition, the medicine is available as liquid-filled capsules. It can be used by adults and children over 12 years old.

The recommended dose is 600-1200 every 12 hours. The maximum recommended dose is 2.4 g per day. You should consult a doctor if your symptoms last for more than 7 days.

The dosage of the drug is selected by a doctor based on the severity of the disease and the dosage form used.

There are also several products available for children aged 4 and older:

  • Robitussin 12 Hour Cough Relief (dextromethorphan)
  • Children’s Robitussin Cough & Chest Congestion DM (dextromethorphan and guaifenesin)
  • Children’s Mucinex Chest Congestion (guaifenesin)
  • Children’s Robitussin 12 Hour Cough Relief (dextromethorphan)

How should I take Robitussin?

Use the product exactly as directed in the instructions, or as recommended by your health care professional. Do not use exceed/reduce the dosage of the medicine on your own, and do not use it for longer than recommended.

The medicine is not used in children younger than 4 years old. Always consult a health care professional before giving this medicine to a child. 

It’s recommended that you drink more fluids during the treatment course. This will help loosen the congestion.

You can take the medicine regardless of food. Take it with food if it irritates your stomach.

Measure the liquid form of guaifenesin with a special spoon or cup attached to the bottle, not a usual table spoon.

Do not crush, break or chew a tablet/capsule. Swallow it whole. Crushing, breaking or chewing a tablet/capsule may cause too much of the medicine to be released at once.

Can Robitussin interact with other drugs?

This cough medicine can interact with other drugs, vitamins, or herbal supplements. These include drugs from the MAOI class used to treat depression, Parkinson’s disease, and other psychiatric conditions. MAOIs include:

  • rasagiline;
  • selegiline;
  • isocarboxazid;
  • phenelzine;
  • tranylcypromine.

To avoid interactions, inform your health care professional or pharmacist about all the drugs, vitamins, or herbal supplements you’re currently taking or going to take.

What happens if I overdose?

There are no medically documented cases of Guaifenesin overdose.

Taking too much guaifenesin can cause:

  • giddiness;
  • confusion;
  • slow breathing;
  • fast heart rate;
  • nervousness;
  • nausea;
  • unsteadiness;
  • dizziness;
  • vomiting;
  • agitation;
  • restlessness;
  • vision changes;
  • shortness of breath;
  • seizures;
  • hallucinations;
  • coma.

If you have taken too much of this product, seek emergency care or call the Poison Help line at 1-800-222-1222.

What happens if I miss a dose?

Since this medicine is taken when needed, you may not be on a dosing schedule. If you are taking the medicine on a regular basis, take the missed dose as soon as you realize your mistake. Skip the missed dose if it is almost time to take your next scheduled dose. Do not take more medicine than needed.

Pregnancy and breastfeeding

Guaifenesin should be used with caution during pregnancy and breastfeeding – only in cases where the expected therapeutic effect for the mother exceeds the potential risk to the fetus or infant. It is not known whether the product will harm an unborn baby. It is not known if the product is secreted into breast milk.


Store at room temperature away from moisture, heat, and direct sunlight.

Syrup, tablets and capsules should be stored below 30 C (86 F). Do not refrigerate the liquid.


IMPORTANT: This is a summary and does NOT have all possible information about this medicine. This information does not assure that this medicine is safe or appropriate for you. This information cannot be used as a substitute for medical advice. Consult your health care provider if you have any health condition. Always ask your health care provider for complete information about this medicine and your individual health needs.

Posted by

Connected Diseases :

Common Cold

General Illness Information Medical Term: Upper Respiratory Infection, URI Common name: Common Cold Description: A contagious viral infection of the upper-respiratory passages Causes: Any of at…