International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

3: Migraine Pill's Horrific Side Effect

The British National Formulary (1993) warns that methysergide, a treatment for migraine, should only be administered under hospital supervision because of dangerous side-effects resulting from abnormal formation of fibrous tissue. This condition, known medically as retroperitoneal fibrosis, can lead to obstruction of abdominal blood vessels and blockage of the tube carrying urine from the kidneys to the bladder. Fibrotic damage to the heart valves has also been reported and can result in heart failure.

Methysergide's life-threatening side-effects were not predicted by animal tests,(1) nor could they be induced during subsequent experimentation, and a report in the British Medical Journal notes that "Attempts to reproduce these fibrotic lesions in animals have been unsuccessful."(2)


I ) R.Heywood in Animal Toxicity Studies: Their Relevance for Man, Eds. C.E. Lumley & S.R.Walker (Quay Publications, 1990).
2) K.A.Misch, British Medical Journal, 1974, May 18, 365-366.

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