§ Mr. Pavittasked the Secretary of State for Social Services (1) what evidence has been sent to him by the committee on the Safety of Medicines that prolonged cimetidine therapy for duodenal ulcer is without hazard to fertile men, in view of the reported side-effects of gynaecomastia and loss of libido and impotence;
(2) if, in view of the reported effect on leydig cells in rats of doses of the anti-peptic drug cimetidine, he is sponsoring further research with the Medical Research Council to ensure the safety of human dosage;
(3) in view of the reduction in prostate size reported in animal studies with cimetidine, if he has received any evidence of similar effects in humans.
(4) what is the relapse rate of duodenal ulcers after short-term treatment with the antipeptic drug cimetidine;
(5) if he will advise family doctors that the use of the antipeptic drug cimetidine should be limited to short-term treatment in duodenal ulcer disease, as recommended by the Federal Drug Administration Advisory Committee of the United States of America, particularly in view of the reported incidence of gynaecomastia and other endocrine effects with longterm treatment;
(6) if he will issue to prescribers the latest information on any adverse reactions to the new drug, cimetidine, particularly with reference to immune disease, including allergic reactions and any involving the central nervous system;
(7) if he will consult with the Committee on the Safety of Medicines to verify that the new antipeptic drug, cimetidine, is safe to be taken for indefinite periods of time and is free from side effects;
(8) what evidence he has received from the Committee on the Safety of Medicines on the endocrine side effects of the newly-released drug cimetidine;
488W(9) if he will ascertain from the Committee of Safety of Medicines, in view of the withdrawal from clinical trial of the H2-receptor antagonist, metiamide, due to reports of agranulo-cytosis, that similar related adverse reactions have not arisen with the new drug cimetidine.
§ Mr. MoyleCimetidine (Tagamet) is a major advance in the treatment of peptic ulceration. None the less, the manufacturer's data sheet issued to doctors with the product makes clear that the drug's safety and efficacy in prolonged or prophylactic use has not yet been established. The data sheet also specifies several possible adverse reactions including gynaecomastia. This anti-androgen effect of cimetidine was specifically considered by the Committee on Safety of Medicines before it advised that a product licence should be granted; the effect, noted at exceptionally high doses in animals, was reversal. No further research is required.
The product is being carefully monitored and reports of adverse reactions to date do not indicate cause for concern or the need to give further advice to prescribers. The Committe on Safety of Medicines has received no reports of reduction in prostate size or other indication of disturbance of endocrine function. The only report of blood dyscreasia related to a patient who had been treated with a number of drugs, at least one of which is known to be a cause of agrannlocytosis. Information on the relapse rate of duodenal ulcers after short-term treatment is not yet available. At the present time there is no indication that the use of cimetidine is associated with disturbance of immunological mechanisms or of the central nervous system apart from occassional headache.
As with all effective drugs, the full pattern of adverse reactions associated with their use is unlikely to emerge until a particular drug, such as cimetidine, has been in widespread clinical use for a considerable time.