Cialis is already the world's best-selling impotence drug, and its makers hope to significantly ramp up sales by making it available over the counter, reports Reuters. Eli Lilly has struck a deal with French drug-maker Sanofi to sell a non-prescription version, assuming they first win the permission of health regulators in the US and elsewhere. Given its side effects such as a potential drop in blood pressure if taken with heart medicine, that's a "big if," says the Wall Street Journal. In any case, no OTC version would be out until patents expire in 2017. (Pfizer, meanwhile, is now selling Viagra online directly to patients, though they still need a prescription.)