Viagra – the fastest selling drug in history – can be given by prescription or bought over the counter in 25mg, 50mg and 100mg doses. It designed to help impotent men by inhibiting an enzyme, which widens blood vessels and improves blood flow to the penis. Doctors are warning, that taking the strongest dose of Viagra, could cause a form of blindness for up to three weeks. [Details will be available during ‘The Dr. Bob Martin Show’]
