Codeine may be no cure for cough

Scientists at the University of Manchester’s North West Lung Centre have found that codeine – a standard ingredient in cough remedies – could be no more effective than an inactive placebo compound at treating cough.

Researchers at the Centre, which is based at Wythenshawe Hospital, studied a sample of patients with chronic lung disease. After coughing was induced with citric acid they were given either codeine or a placebo, and sent home wearing a lapel microphone to record their coughing during the day and night.

Lead researcher Dr. Jacyln Smith said: “Codeine has long been considered the standard anti-cough agent against which others are measured, but until now little has been known about its impact in patients with chronic lung diseases.

“After the placebo treatment the patients’ coughing fell from an average of 8.27 seconds per hour to 7.22 seconds, and after codeine to 6.41 seconds.

“Although there was a significant reduction after codeine, from a statistical standpoint there was really no difference between codeine and placebo – despite the fact that the dose of codeine used far exceeds that in over-the-counter cough remedies.”

The findings were reported in Journal of Allergy and Clinical Immunology, and seem to confirm some medics’ view that reductions in coughing after codeine are attributable to a placebo effect.

Dr Smith concluded: “The effective treatment of chronic dry cough is an important unmet need in patients with chronic respiratory diseases, post-viral coughing and persistent coughing of unknown cause. Studies of cough in other clinical situations are urgently needed if codeine is to be continued to be used as a remedy.”