Published: 7 April 2015
Revised: 9 November 2015

Safety Information

Early Warning System - Monitoring Communication

Medsafe emphasises that patients should NOT stop using any medicine or medical device subject to a monitoring communication. If you have any concerns with a medicine or medical device you are using, please contact your health professional. A monitoring communication does not mean that the medicine or medical device causes an adverse event.

M² logo Guaifenesin (guaiphenesin) and possible risk of tinnitus added to the medicines monitoring scheme

7 April 2015

The Centre for Adverse Reactions Monitoring (CARM) has recently received a report of tinnitus associated with the use of guaifenesin1 . The patient was reported to be taking guaifenesin 600 mg for an upper respiratory tract infection and experienced profound tinnitus followed by deafness in the right ear with facial and outer ear numbness.

In a second report, a patient who was using guaifenesin for a different indication experienced hearing loss in the right ear after the guaifenesin dose was increased to 600 mg twice daily.

There are no relevant literature reports of tinnitus, deafness or numbness with use of guaifenesin.

Products Affected

Guaifenesin is an expectorant used for the symptomatic relief of productive (chesty) coughs. Expectorants help to loosen phlegm and thin the mucus in the lungs.

Guaifenesin is available as a single-ingredient product or with other active ingredients for the treatment of cough and cold symptoms. It can be obtained over the counter from pharmacies or from other retail outlets such as supermarkets.

Products listed in the table below contain guaifenesin only.

Product name Sponsor
Codral Relief Mucus Cough, 20 mg/ml Johnson & Johnson (New Zealand) Limited
Maximum Strength Mucinex, 1200 mg Reckitt Benckiser (New Zealand) Limited
Mucinex, 600 mg Reckitt Benckiser (New Zealand) Limited
Robitussin Chesty Cough, 20 mg/ml Pfizer New Zealand Limited
Vicks Cough Syrup Honey Flavour Chesty Cough, 13.33 mg/ml Procter & Gamble Distributing New Zealand Limited
Vicks Formula 44 for Chesty Coughs, 1.333%w/v Procter & Gamble Distributing New Zealand Limited

Additional Information

Tinnitus can be described as ringing in the ears. Tinnitus can result from various causes such as exposure to loud sounds, ear wax build-up, certain medical conditions and some medicines. Sinus infections or a cold are also possible causes of tinnitus.

There is one data sheet for a guaifenesin-only containing product published on the Medsafe website — Mucinex.

Tinnitus is not listed as an adverse event in the Mucinex data sheet or in the product packaging. Adverse effects that are listed in the data sheet include gastrointestinal discomfort, nausea and vomiting, particularly in high doses. The development of kidney stones is listed to occur extremely rarely and reported to occur from taking large doses of guaifenesin for long periods of time.

The overall benefit-risk balance of guaifenesin remains positive.

Advice on how to use guaifenesin and other possible side effects can be found in the product packaging and data sheet.

Search for data sheet information

Regulator Actions

Medsafe is placing this safety concern on the medicines monitoring (M² logo) scheme to obtain further information on this possible adverse reaction. Please report any adverse events with guaifenesin, in particular tinnitus and other ear disorders.


Consumers and healthcare professionals are encouraged to send reports of suspected adverse reactions to the Centre for Adverse Reactions Monitoring (CARM).

Medsafe cannot give advice about an individual’s medical condition. If you have any concerns about a medicine you are taking Medsafe encourages you to talk to your healthcare professional.

How to report an adverse reaction


  1. Guaifenesin is the International Nonproprietary Name (INN); it is also known as guaiphenesin which is the British Approved Name (BAN).

Update to Original Communication

9 November 2015

This safety concern has been investigated through M2 Logo. No further cases were received. It was concluded that no link between guaifenesin and tinnitus was demonstrated. The balance of benefits and risks of harm for guaifenesin remains positive and no further action is required at this time.

Medsafe will re-investigate this concern should more information become available.

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