International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

58: Obesity Drug's Horrific Side Effects

During the 1960s Swiss doctors noticed a sudden and unexpected rise in a dangerous lung disease called obstructive pulmonary hypertension. The cause was traced to aminorex which had been used since 1965 for the treatment of obesity.(1) The drug produces an increase in lung pressure leading to chest pains, difficulty breathing, fainting spells, heart problems and, in some cases, death.(2) Aminorex's deadly side effect had not been predicted by animal experiments (3) and in 1968 the drug was withdrawn from sale.

Animal experiments continued even after withdrawal but long term administration to rats still failed to induce the disease.(2) In dogs, aminorex did increase lung pressure (1) but its relevance to the human condition is unclear since a later analysis concluded that “pulmonary hypertension cannot be induced in experimental animals even with aminorex...”(4)


1) F.Follath et al, British Medical Journal, 1971, January 30, 265-266.
2) E.H.Ellinwood & W.J.K.Rockwell in Meyler’s Side Effects of Drugs, 11th edition,Ed.M.N.G.Dukes (Elsevier, 1988)
3) A.D.Dayan in Risk-Beneft Analysis in Drug Research, Ed. J.F.Cavalla (MTP Press, 1981).
4) P.H.Connell in Side Effects of Drugs Annual - 3, Ed. M.N.G.Dukes (Excerpta Medica, 1979)

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