Nighttime Codeine Cough Suppressant Dosing
For a single nighttime dose of codeine as a cough suppressant, use 30-60 mg at bedtime, typically formulated in combination with guaifenesin (expectorant) or phenyltoloxamine (antihistamine) in syrup preparations. 1
Recommended Dosing
- Single bedtime dose: 30-60 mg codeine 1
- Standard dosing table indicates codeine can be given 30-60 mg every 4-6 hours as needed (qid), but for nighttime-only use, a single dose at bedtime is appropriate 1
- FDA-approved formulations typically contain 10 mg codeine per 5 mL (teaspoon), meaning 15-30 mL (3-6 teaspoons) would provide the 30-60 mg range 2
Common Combination Formulations
Codeine is typically combined with:
Primary Combinations:
- Guaifenesin (expectorant): Most common formulation contains codeine 10 mg + guaifenesin 100 mg per 5 mL 2
- Phenyltoloxamine (antihistamine): Studies used codeine 30 mg twice daily with phenyltoloxamine 10 mg, showing positive results 1
- Chlorpheniramine (antihistamine): First-generation antihistamines are often combined with codeine; sedation is valuable for disturbing nighttime cough 1, 3
Rationale for Combinations:
- The antihistamine component provides additional sedation beneficial for sleep disturbance from cough 1
- Guaifenesin acts as an expectorant, though its primary role is in productive cough 2
- For dry, nonproductive nighttime cough specifically, the codeine-antihistamine combination is preferred over codeine-guaifenesin 3
Important Clinical Caveats
Efficacy Concerns:
- Codeine has significant limitations: Despite being widely used as the "gold standard" antitussive, evidence for its efficacy in acute upper respiratory tract infections is weak 1
- Multiple studies show codeine is no more effective than placebo for cough associated with common cold 4, 5
- Codeine is "less preferred" compared to other opioids (pholcodine, hydrocodone, morphine) due to its greater side effect profile 1
Safety Considerations:
- Schedule III controlled substance when combined with other agents; Schedule II when used alone 1
- Codeine is a prodrug requiring CYP2D6 metabolism to morphine for effect; genetic variability affects response 6
- Avoid in children under 12 years due to safety concerns 7
- Maximum daily dose should not exceed 360 mg total 1
- Risk of dependence with prolonged use; limit to short-term symptomatic relief only 6
Alternative Consideration:
If codeine is unavailable or contraindicated, dextromethorphan 30-60 mg at bedtime is a non-opioid alternative with similar (albeit modest) efficacy and better safety profile 1