[New insights into the role of pholcodine in the treatment of cough in 2013?]

Toxicological detection of pholcodine in blood, urine and hair in three cases of fatal intoxication

Pholcodine is an opioid antitussive reputed for its low toxicity and absence of addictive effect. We report three cases of pholcodine intoxication with fatal outcome. Large concentrations of pholcodine were quantified by gas chromatography coupled to mass spectrometry (GC/MS) in peripheral postmortem blood (respectively 2890 ng/mL, 979 ng/mL and 12,280 ng/mL). Segmental hair analyses by GC/MS and detected pholcodine in three 1.5-2 cm segments (38-161 ng/mg, 8.54-41.6 ng/mg, and 0.26-2.66 ng/mg, respectively). These findings underline that pholcodine can be involved in fatal poisoning and raise the question of misuse or abuse and of taking account of this drug in opioid overdose prevention policies.

Codeine versus placebo for chronic cough in children

BACKGROUND

Cough in children is a commonly experienced symptom that is associated with increased health service utilisation and burden to parents. The presence of chronic (equal to or more than four weeks) cough in children may indicate a serious underlying condition such as inhaled foreign body or bronchiectasis. Codeine (and derivative)-based medications are sometimes used to treat cough due to their antitussive properties. However, there are inherent risks associated with the use of these medications such as respiratory drive suppression, anaesthetic-induced anaphylaxis, and addiction. Metabolic response and dosage variability place children at increased risk of experiencing such side effects. A systematic review evaluating the quality of the available literature would be useful to inform management practices.

OBJECTIVES

To evaluate the safety and efficacy of codeine (and derivatives) in the treatment of chronic cough in children.

SEARCH METHODS

We searched the Cochrane Airways Group Register of Trials, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1946 to 8 June 2016), EMBASE (1974 to 8 June 2016), the online trials registries of the World Health Organization and ClinicalTrials.gov, and the bibliographic references of publications. We imposed no language restrictions.

SELECTION CRITERIA

We considered studies eligible for analysis when: the participant population included children aged less than 18 years with chronic cough (duration equal to or more than four weeks at the time of intervention); and the study design evaluated codeine or codeine-based derivatives against placebo through a randomised controlled trial.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results to determine eligibility against a standardised criteria, and we had a pre-planned method for analysis.

MAIN RESULTS

We identified a total of 556 records, of which 486 records were excluded on the basis of title and abstract. We retrieved the remaining 70 references in full to determine eligibility. No studies fulfilled the inclusion criteria of this review, and thus we found no evidence to support or oppose the use of codeine or derivatives as antitussive agents for chronic cough in children.While chronic cough is not the same as acute cough, systematic reviews on the use of codeine efficacy for acute cough in children conclude an overall lack of evidence to support or oppose the use of over-the-counter cough and cold medications containing codeine (or derivatives) for treatment of acute cough in children. The lack of sufficient evidence to support the use of these medications has been consistently reaffirmed by medical experts in international chronic cough guidelines and by governing medical and pharmaceutical authorities in the USA, Europe, Canada, New Zealand, and Australia. Due to the lack of sufficient evidence to support efficacy, and the known risks associated with use - in particular the increased risks for children - these medications are now not recommended for children less than 12 years of age and children between 12 to 18 years with respiratory conditions.

AUTHORS' CONCLUSIONS

This review has highlighted the absence of any randomised controlled trials evaluating codeine-based medications in the treatment of childhood chronic cough. Given the potential adverse events of respiratory suppression and opioid toxicity, national therapeutic regulatory authorities recommend the contraindication of access to codeine in children less than 12 years of age. We suggest that clinical practice adhere to clinical practice guidelines and thus refrain from using codeine or its derivatives to treat cough in children. Aetiological-based management practices continue to be advocated for children with chronic cough.

Chronic dry cough: Diagnostic and management approaches

Cough is the most common symptom for which medical treatment is sought in the outpatient setting. Chronic dry cough poses a great diagnostic and management challenge due to myriad etiologies. Chronic cough has been commonly considered to be caused by gastroesophageal reflux, post-nasal drip or asthma. However, recent evidences suggest that many patients with these conditions do not have cough, and in those with cough, the response to specific treatments is unpredictable at best. This raises questions about the concept of a triad of treatable causes for chronic cough. This article discusses the mechanism and etiology of cough, along with recent advances in the field of cough, highlighting some of the diagnostic and management challenges.