"There is good evidence for the efficacy of Orlistat (Alli) in weight reduction but it should not be used as the sole element of weight management, " says Dr Colin Cable of the Royal Pharmaceutical Society of Great Britain, who reviewed the products.

BBC: Slimming pills: Do the claims add up?

Riluzole, a treatment for Motor Neurone Disease, was provided by 94% of authorities, the obesity treatment Orlistat 96% and flu drug Relenza, 96%.

BBC: Drug prescribing methods queried