Last month the Department of Health announced that it intended to withdraw the drug terfenadine from over-the-counter sale because of safety fears.
The Medicines Control Agency is expected to make the drug available on prescription only, following a period of consultation. Experts advising the Government said that other hay fever remedies should be considered for as alternatives if there was any doubt about prescribing terfenadine.
But yesterday doctors in Sweden published the results of a study which showed that some of the suggested alternatives may have similar problems. The study reviewed data from 17 countries on reported side effects by people taking five antihistamines - including terfenadine.
Researchers found that the drugs collectively caused an increased risk of heart abnormalities and death, albeit a small one - less than 0.25 spontaneous adverse reactions per million daily doses sold.
Besides terfenadine, the drugs loratadine and astemizole had the highest rates of adverse reaction. Astemizole is already under close review in the UK because of its potential to upset heart rhythms.
A closer analysis of 57 reports of heart irregularities associated with loratadine showed that in 27 cases there was mention of a reaction caused by interaction with other drugs.
Five of these patients had in fact died, said the paper, which is published in the latest edition of the Lancet medical journal.
The researchers, Professor Ralph Edwards and Marie Lindquist from the World Health Organisation's international drug monitoring centre at Uppsala in Sweden, concluded: "These crude rates reflect doctors' concerns with these products, but do not provide a definite answer.
"Nevertheless, the data indicate that some of the alternatives to terfenadine may have similar problems, suggesting that thorough consideration of the comparative benefit risk profile of all non-sedating antihistamines is wise."
Boots said that both loratadine and astemizole were sold over the counter.
Loratadine was contained in two products, a Boots own brand, Hayfever Relief All Day Antihistamine, and the product Clarityn. Astemizole was sold under the brand names Pollon-eze and Hismanal.
Boots said that new advice 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.
A spokeswoman said: "With any product we obviously keep a close eye open and monitor developments, and should there be any problems we will act accordingly. We do very much take the view that the MCA is the governing body with the expertise and judgment 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