Scientists at a World Health Organisation drug-monitoring centre in Sweden, who studied almost 10,000 reports of adverse reactions in 17 countries, found there were risks associated with all five non-sedating antihistamines examined. Although the overall risks were low - less than one adverse reaction per 4 million daily doses - they were highest with terfenadine, loratadine and astemizole.
The researchers, Marie Lindquist and Professor Ralph Edwards, found 98 deaths linked with terfenadine, 13 with loratadine, eight with astemizole and two with cetrizine. All the drugs, including the fifth, acrivastine, were linked with adverse reactions involving the heart. They said the findings "reflect doctors' concerns with these products but do not provide a definite answer."
Last week, the UK Committee on Safety of Medicines (CSM) announced that it was recommending that terfenadine be made a prescription-only medicine after reports that it had been linked with 14 heart-related deaths in Britain. Pharmacists cleared their shelves of products containing the drug and were advised to recommend alternatives.
However, the Swedish researchers, writing in The Lancet, say "some of the alternatives to terfenadine may have similar problems." But the journal says the Committee on Safety of Medicines may not have gone far enough. Although astemizole is under close review in the United Kingdom because of its potential to cause heart problems, the other drugs are not. The CSM "needs to keep a close eye on all non-sedating antihistamines", it says.
Terfenadine, which has been available in Britain since 1982, should not be taken by people with heart or liver problems or who are taking antibiotics or antifungals, and it should also not be taken with grapefruit juice.
Eight million packets of the drug were sold last year. It is one of the most popular on the market and is contained in eleven brands of hay fever remedy. France, Greece and Luxembourg have recently taken the drug off the market and America is also considering a total ban.
Boots said loratadine, astemizole and cetirizine are also sold over the counter. Loratadine is contained in a Boots own brand, Hayfever Relief All Day Antihistamine, and the product Clarityn. Astemizole was sold under the brand names Pollon-eze and Hismanal. Cetirizine is sold as Zirtek. New advice, the chemists group added, had recently gone out to pharmacists to question patients about their medical history before selling them astemizole products. No such advice was recommended for loratadine or cetirizine.
A spokeswoman for Boots said: "We do very much take the view that the MCA is the governing body with the expertise ... to decide what controls to exercise on medicines."
Boots has removed terfenadine products from public display in its stores. Customers are only sold them after consultation with the pharmacist.Reuse content