University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• Does the use of cough suppressants (e.g. dextromethorphan) work in decreasing night-time coughing in children?

Clinical Bottom Lines

1. Dextromethorphan and codeine were not better than placebo in reducing night-time coughing in children.¹
2. There was a correlation between the improvement in night-time cough with the severity of symptoms at initiation of therapy (the more severe the coughing, the more improvement seen over the 3 study days).

Summary of Key Evidence

1. This was a double randomized prospective study of 49 children age 18 months to 12 years of age using codeine, dextromethorphan, and a placebo over three nights.¹  Parents  filled out an intake questionnaire prior to admission into the study and then every morning for 3 days.  The parents subjectively rated the amount of coughing, loss of sleep secondary to coughing, and post-tussive emesis.
2. Inclusion criteria - winter months from 1988-1991 in private pediatricians offices with c/o night-time cough.  To be eligible, patients need be 18 mo to 12 yrs of age, having a significant cough of <14 days.  A patient must have had parental rating of cough as "often-one prolonged coughing episode or about 10-20 coughs during the night or both or "very often-more than one prolonged coughing episode during the night or more than 20 coughs at night."
3. Exclusion criteria- they had an underlying lung disease (asthma, CF, BPD), the cause of their cough was reactive airway disease, or if other medications such as antibiotics or bronchodilators were needed during this illness.
4. Outcome- parental responses were transformed into a scale: cough score (0= none and 4= very often), loss of sleep score, and post-tussive emesis score.  Results of scores were compared by using Mann-Whitney tests.  Overall reduction in cough score was evaluated with generalized estimation equation techniques.  For all analyses, differences were considered significant when the p value was <0.05.
5. Results- 49 patients (4.7 mean-age) enrolled with 13 receiving placebo, 19 dextromethorphan (DM), and 17 codeine.  Cough and Composite scores improved in each group on each day of the study with no significant difference between placebo, DM, or codeine groupings.  Neither codeine nor DM was significantly better than placebo (p=0.70 and p=0.41 respectively).  Reduction in cough was related to severity of cough at initiation of therapy (p=0.007).

Additional Comments

• Study size is small; it seems that through a three winter period more than 49 children could have been enrolled.
• Were the doses of the cough suppressants appropriate for weight? They were dosed according to age alone. The codeine dose may have been too small to see an effect.
• All that coughs in the middle of the night may not just be a common cold.
• It would be helpful to see the actual questionnaire to evaluate the subjective versus objective components.
• A sizable number of patients (n=8, 14%) were lost to follow-up.

Citation

1. Taylor J, Novack A, Almquist J, and Rogers J.  Efficacy of cough suppressants in children. J Pediatrics 1993; 122:799-802.
2. Smith MBH, Fledman W.  Over-the-counter cold medications.  A critical review of clinical trials between 1950 and 1991.  JAMA 1993; 269:2258-2263.

CAT Author: Jim Barry, MD

CAT Appraisers: John Frohna, MD

Date appraised: March 29, 1999