SIR – My cat is having thyroid drops, 2.5mg twice a day, and I see in the accompanying leaflet that an overdose of ‘up to 30mg’ given to ‘young healthy cats’ caused, among other things, anorexia, vomiting, and haemolytic anaemia.

Unlike the two recently poisoned humans who received all the care it is possible to give, these cats would merely have been observed, no matter how they were suffering, and their reactions noted, with no care given at all.

They would have either died or been killed at the end of the experiment.

Why such a huge overdose? There’s no hint of an antidote so I fail to see any relevance.

We are happy to believe that tests on other animals will ensure the safety and efficacy of medicines for humans because those who carry them out tell us so.

This cat medicine was tested on cats, not the usual mice, suggesting perhaps that they know that species differences render the results in one species irrelevant to another.

When asked how soon it will be available for human use it’s generally about 10 years because at the moment we only know how it works in mice. 10 years later it is forgotten and we never hear that it failed in humans.

Roberta Balfour

Malvern