[Many drugs are prescribed outside their official recommendations, she says. Neurontin, for example, was initially approved only for epilepsy. But, after a slow start, it grew to become a $US2.3 billion ($3 billion today) blockbuster for its owner, Pfizer, in 2003.] About 80 per cent of the prescriptions were for unapproved uses - conditions like bipolar disorder, post-traumatic stress disorder, insomnia, restless legs syndrome, hot flashes, migraines and tension headaches, ... In fact, Neurontin has become a sort of all-purpose restorative for chronic discomfort of almost any type - yet there is almost no good published evidence that it works.