Is promethazine (Phenergan) DM safe for a 9-year-old to treat cough and what is the recommended dose?

Promethazine DM Safety and Dosing for a 9-Year-Old Child

Promethazine DM is not recommended for treating cough in a 9-year-old child due to safety concerns and lack of proven efficacy in pediatric populations. 1, 2

Safety Concerns

• Promethazine carries a black box warning stating it should not be used in children under 2 years of age due to the risk of fatal respiratory depression 2
• Even in children over 2 years, caution is strongly advised, and the lowest effective dose should be used if prescribed 2
• The FDA and pediatric advisory committees have recommended against using cough and cold medications (including those containing promethazine) for children under 6 years of age due to potential toxicity and limited evidence of effectiveness 1
• Significant adverse events associated with promethazine in children include:
  • Sedation and CNS depression 2, 3
  • Respiratory depression 2
  • Agitation and hallucinations 3
  • Seizures and dystonic reactions 3
  • Potentially life-threatening events 3

Efficacy Evidence

• According to the American College of Chest Physicians (ACCP) guidelines, cough suppressants and over-the-counter cough medicines should not be used in children as they may cause significant morbidity and mortality 1
• Controlled trials have shown that antihistamine-decongestant combination products (like promethazine DM) are not effective for symptoms of upper respiratory tract infections in young children 1
• The ACCP explicitly states: "In children with cough, cough suppressants and other over-the-counter cough medicines should not be used as patients, especially young children, may experience significant morbidity and mortality." 1

Alternative Approaches

• For children with cough, the ACCP recommends:
  • Identifying and addressing specific causes of cough when possible 1
  • Avoiding exposure to exacerbating factors such as tobacco smoke 1
  • Addressing parental concerns and expectations regarding cough management 1
  • For children with risk factors for asthma, a short trial of inhaled corticosteroids may be considered under medical supervision 1

FDA Labeling Information

• While the FDA label for promethazine includes dosing for children over 2 years (0.5 mg per pound of body weight), it comes with significant warnings 2
• The label explicitly states that promethazine should be used with extreme caution in pediatric patients 2 years and older 2
• Concomitant use with other respiratory depressants should be avoided 2

Conclusion

Based on current guidelines and safety data, promethazine DM should not be used to treat cough in a 9-year-old child. The potential risks outweigh any benefits, especially given the lack of proven efficacy in pediatric populations 1, 2. Parents should consult with a healthcare provider for appropriate management strategies for childhood cough.