Guaifenesin-Codeine 100mg-10mg/5mL Dosing
For adults and children ≥12 years, the recommended dose is 10 mL (2 teaspoonfuls) every 4 hours, not to exceed 6 doses in 24 hours, which provides 200mg guaifenesin and 20mg codeine per dose. 1
Critical Safety Warning: Codeine Contraindication
Codeine is contraindicated in all children <12 years of age and should not be prescribed for this population. 2 The FDA issued a boxed warning following identification of 21 pediatric deaths (out of 24 total codeine-related fatalities) in children <12 years old from respiratory depression, with 8 of these deaths occurring after tonsillectomy despite appropriate dosing. 2 Children with genetic polymorphisms causing ultra-rapid metabolism of codeine to morphine, particularly those with obstructive sleep apnea, face substantially elevated risk of fatal respiratory depression. 2
Adult and Adolescent Dosing (≥12 Years)
Standard Dosing
- Dose: 10 mL (2 teaspoonfuls) every 4 hours 1
- Maximum frequency: 6 doses per 24 hours 1
- Per dose content: 200mg guaifenesin + 20mg codeine 1
- Daily maximum: 1200mg guaifenesin + 120mg codeine
Administration Considerations
- Guaifenesin can be taken without regard to meals, though administration with food may improve gastrointestinal tolerability 2
- The 4-hour dosing interval is necessary due to guaifenesin's short half-life 3
Pediatric Considerations (6 to <12 Years)
While the FDA label for codeine-containing products lists dosing for children 6 to <12 years (5 mL every 4 hours), this directly contradicts the FDA's 2017 contraindication against codeine use in children <12 years. 1, 2 The contraindication takes precedence over older labeling. Alternative non-codeine containing cough preparations should be used in this age group.
Guaifenesin Component Dosing Reference
When considering guaifenesin alone (without codeine):
- Adults and children ≥12 years: 200-400mg (10-20 mL of 100mg/5mL formulation) every 4 hours 4
- Children 6 to <12 years: 100-200mg (5-10 mL) every 4 hours 4
- Children 2 to <6 years: 50-100mg (2.5-5 mL) every 4 hours 4
Clinical Pearls and Pitfalls
Common pitfall: Prescribing codeine-containing products to adolescents 12-18 years who are obese or have conditions like obstructive sleep apnea. 2 While not absolutely contraindicated in this age group, the FDA and American Academy of Pediatrics recommend against use due to increased risk of respiratory complications. 2
Screening limitation: Testing for CYP2D6 genetic polymorphisms to identify ultra-rapid metabolizers is unreliable, as some patients with normal metabolism may be induced to become ultra-rapid metabolizers. 2
Alternative approach: For cough management in any pediatric patient, safer non-codeine alternatives should be prioritized given the availability of effective options without the risk profile of opioids. 2