The Pharmaceutical Journal
Vol 269 No 7224 p699
16 November 2002

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Dangerous cough advice on the radio

Potentially dangerous advice on treating coughs was given to the public by BBC Radio 4's You and yours programme on 7 November.

Reporting on a University of Bristol study published in the BMJ in February (PJ, 9 February, p166), which suggests that few cough medicines are effective, the programme may have led people to believe that it is acceptable to take up to four times the recommended dose of certain mixtures.

Listeners will have heard Professor Alyn Morice, professor of respiratory medicine at the University of Hull, tell people that the most effective cough suppressant was dextromethorphan. He said: "If you can get that dextromethorphan ingredient and take it at an adequate dose, that's about 40 to 60mg, you get a really significant suppression of the cough reflex. ... The manufacturers recommend 15mg, that sort of thing, whereas our work shows quite clearly that a larger dose, say 60mg, you know, a good slug of it, really does suppress your cough."

Anthony Cox, adverse drug reactions pharmacist at the West Midlands Centre for Adverse Drug Reaction Reporting said: "Pharmacists should be aware of this advice and be vigilant when supervising sales of dextromethorphan products. In trying to take a 60mg dose of dextromethorphan customers may take higher doses of other ingredients, such as pseudoephedrine, which are not without potential adverse effects. In some cases they may be exposed to an overdose of paracetamol. Comments like these reinforce the erroneous belief that over-the-counter medicines are innocuous. Given that more potent medicines are being considered for POM to P switches it is important that they are given the same respect as other medicines."

Professor Morice told The Journal on 13 November that he had in mind cough mixtures which contained only dextromethorphan, eg, Benylin Dry Coughs Non Drowsy and Robitussin Dry Cough. He had not intended to give the impression that taking more than the recommended dose of medicines generally was advisable. He fully supported the suggestion that pharmacists should be vigilant over sales of cough medicines.

Other active ingredients that are found in medicines with dextromethorphan include pseudoephedrine, triprolidine, paracetamol, promethazine, diphenhydramine, terpin hydrate and various volatile oils.

Sufficient Night Nurse to give a 60mg dose of dextromethorphan also contains 4g of paracetamol and 80mg of promethazine. Anyone who takes enough Benylin Cough and Congestion mixture to get 60mg of dextromethorphan will also take 200mg of pseudoephedrine and 130mg of diphenhydramine.

The Royal Pharmaceutical Society's public relations unit has been trying unsuccessfully to contact the producers of You and yours since the programme was broadcast.