Codeine / guaifenesin Side Effects

Some side effects of codeine / guaifenesin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to codeine / guaifenesin: oral capsule, oral liquid, oral syrup, oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking codeine / guaifenesin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop taking this medication and call your doctor at once if you have any of these serious side effects:

• severe dizziness or drowsiness;

• confusion, hallucinations, unusual thoughts or behavior;

• urinating less than usual or not at all; or

• slow heart rate, weak pulse, fainting, weak or shallow breathing.

Less serious side effects include:

• dizziness, drowsiness, headache;

• warmth, redness, or tingling under your skin;

• nausea, vomiting, upset stomach;

• constipation; or

• skin rash or itching.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to codeine / guaifenesin: oral capsule, oral liquid, oral syrup, oral tablet

General

Guaifenesin is generally well tolerated.

Nervous system

Nervous system side effects of codeine have included mental and respiratory depression, stupor, delirium, somnolence, and dysphoria. An increased risk of falls and hip fractures has been associated with codeine therapy, particularly in the elderly. Nervous system side effects of guaifenesin have included dizziness and headache.

Opioids may result in psychotic symptoms in some patients.

One retrospective study of elderly patients who sustained a hip fracture suggested that the relative risk of hip fracture was 1.6 in patients using codeine compared to age-matched non-users.

Other

Other side effects of codeine have included withdrawal symptoms after either abrupt cessation or fast tapering of narcotic analgesics, including codeine, and have included agitation, restlessness, anxiety, insomnia, tremor, abdominal cramps, blurred vision, vomiting and sweating.

Cardiovascular

Cardiovascular adverse effects of codeine have included hypotension and dizziness.

Hypotension is rare and has been reported most frequently with high doses of codeine.

Gastrointestinal

Gastrointestinal side effects of codeine have included nausea, vomiting, and constipation. Severe constipation and ileus resulting in colonic perforation have been also reported. Four cases of acute pancreatitis have been reported. Gastrointestinal side effects of guaifenesin have included upset stomach and vomiting with higher than recommended doses. Doses recommended for expectoration are rarely associated with gastrointestinal upset.

Genitourinary

Genitourinary side effects of codeine have included urinary retention.

Dermatologic

Dermatologic side effects of codeine have included rash. Codeine-induced rash may be related to direct stimulation of histamine release. There are also case reports of severe scarlatiniform eruptions. Dermatologic side effects of guaifenesin have also included rash.

Renal

Renal side effects of codeine have included acute renal failure (which may respond to naloxone therapy).

Immunologic

Immunologic side effects of codeine have included one study of a patient with exercise-induced anaphylaxis and three control subjects. This study found a correlation between codeine wheal size and recent exercise.

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