There is no doubt that lots of commercially aware patients are doing this with Viagra

A number of shrewd chaps have spotted it works out a great deal cheaper if you are on 50mg Viagra to buy 100mg Viagra which only costs a tiny bit more, and split it in two.

It's just possible that Viagra is not evenly distributed through the tablet and the side effects could be increased or it won't work properly and the patient will be disappointed."

Side effects of Viagra include headaches, facial flushing, upset stomach and, in a few users, blurred or blue-tinged vision.

Impotence specialist Douglas Savage told Doctor: "I am sure it's widespread. Patients are not at any increased danger but they may get more Side effects of Viagra".

Viagra is available in 25mg, 50mg and 100mg and most users start on the 50mg size.

At first the Government ruled only people suffering impotence from certain conditions - such as spinal cord injuries, diabetes or multiple sclerosis - could obtain prescriptions for ED medication although some doctors have defied the ruling.

Phil Johnson, editor of Doctor, said: "This is the kind of thing that happens when governments take irrational decisions on the rationing drugs like Viagra."

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