Codeine-Containing Cough Medicines
Codeine is available as a prescription cough suppressant, most commonly formulated as codeine phosphate 10 mg combined with guaifenesin 100 mg per 5 mL (teaspoonful), marketed as an antitussive-expectorant combination. 1
Clinical Context and Appropriate Use
Codeine should be reserved specifically for chronic bronchitis, not for upper respiratory infections (URI) or common colds. 2 The American College of Chest Physicians guidelines explicitly state that codeine is effective only in chronic bronchitis/COPD, where it suppresses cough counts by 40-60%, but has limited to no efficacy in URI-related cough. 2
Key Limitations of Codeine
- Codeine is NOT recommended for acute cough from upper respiratory infections despite being commonly prescribed for this indication. 2
- Multiple studies demonstrate codeine performs no better than placebo for URI-related cough. 2
- The evidence supporting codeine even in chronic bronchitis comes from small patient populations. 2
Superior Alternatives to Codeine
When an opioid antitussive is indicated, hydrocodone or pholcodine are preferred over codeine due to codeine's greater side effect burden. 3 Additionally:
- Dextromethorphan has been shown to be more effective than codeine for cough control, including in lung cancer patients, making it a superior non-opioid alternative. 3, 4
- For patients requiring opioid-level cough suppression, the treatment hierarchy progresses from codeine 30-60 mg four times daily → hydrocodone 5 mg twice daily → morphine 5-10 mg slow-release twice daily. 4
Formulation Details
The FDA-approved codeine cough preparation contains: 1
- Codeine Phosphate USP 10 mg per 5 mL (antitussive component)
- Guaifenesin USP 100 mg per 5 mL (expectorant component)
This combination addresses both cough suppression (via central opioid action) and mucus clearance (via expectorant action). 1, 5
Important Clinical Caveats
- Codeine is a prodrug requiring CYP2D6 metabolism to morphine for its therapeutic effect, meaning genetic variability significantly affects efficacy and side effects. 6
- Codeine carries typical opioid side effects including drowsiness, nausea, constipation, and potential for dependence. 4
- Use should be limited to only when and as long as clinically necessary, particularly in children. 6
- The evidence quality for codeine as an antitussive remains surprisingly low despite its widespread historical use. 3
When Codeine May Be Appropriate
Codeine-containing preparations may be considered in: 7, 5
- Chronic bronchitis with dry, nonproductive cough 2
- Advanced cancer patients where its multifaceted effects (analgesic, sedative, antitussive) provide benefit 7, 6
- Situations where nighttime cough disrupts sleep, as the sedative properties can be valuable 5
The key principle: Always identify and treat the underlying cause of cough rather than reflexively suppressing symptoms with codeine. 3, 4