§ Mr. Ashleyasked the Secretary of State for Social Services (1) how the number and proportion of reported adverse reactions to the drug Halcion compares in each of its first three years with those of the first three years of the drug Dalmane;
(2) how many National Health Service prescriptions there have been for the drug Halcion in each of the years it has been available;
(3) what is the proportion of reported adverse reactions to the drug Halcion in each of the years it has been available on the National Health Service, and how this compares with the proportion of reported adverse reactions to similar drugs serving the same purpose in each of the first three years they were available;
(4) how many official reports of adverse reactions there have been for the drug Halcion in each of the years it has been available on the National Health Service.
§ Mr. Geoffrey Finsberg[pursuant to his reply, 17 May 1982, c. 46]: The following table compares the adverse reaction reports for a number of short-acting benzodiazepine tranquilisers with those for triazolam—Halcion. Information on flurazepam—Dalmane—is also included as requested, but may not be strictly comparable as it is a long-acting benzodiazepine, unlike triazolam which is short-acting. The figures are expressed as a comparison of the number of adverse reaction reports—where the drug was suspected of having caused the adverse reaction—per million prescriptions in Great Britain, using the figure for triazolam as the base—given value 1—in each case, because prescribing figures for individual drugs are confidential for commercial reasons. The table, as requested, compares the drugs for the first three years of their marketing; it also compares the sum of the first two years of marketing which is regarded as giving a more accurate picture.
reaction reports for triazolam was incorrect. The number of reports recorded by the CSM which mentioned 391W triazolam was 162 to the end of 1981, 54 for each of the years 1979, 1980 and 1981; the total to date is 191. Of these, 185 are reports where triazolam was suspected, by the reporting doctor, of causing an adverse reaction.
For reasons of commercial confidentiality, I am unable to give the information requested on the number of prescriptions for triazolam.
The Committee on Safety of Medicines is keeping the safety of this drug and other drugs in this class under continued review and if any new evidence comes to light it will be drawn to its attention.