Drug manufacturers Sanofi and Eli Lilly are looking forward to seek permission from health regulators to allow over-counter sales of Cialis, the world's top-selling erectile dysfunction drug, without a prescription. A combined statement was made on Wednesday by the pharmaceutical companies.

The drug can be currently purchased through prescription only. The drug was first approved by the European Medicines Agency in 2002 and the US Food and Drug Administration gave it a green signal in 2003.

However, it has to be seen now if regulators will allow selling Cialis without a prescription. It is feared that Cialis can cause a dangerous fall in blood pressure if taken with nitrates, a class of heart drugs that includes nitroglycerin.

The proposal made by Eli Lilly and the French pharmaceutical company Sanofi to seek approval for over-the-counter sale of Cialis that is intended to better the plight of men with erectile dysfunction.

Sanofi wants to buy rights to seek approval to sell Cialis over-the-counter in the United States, Europe, Canada and Australia after certain patents expire.

Cialis will lose its patent protection in the United States and Europe in 2017 and it is believed that this will bring a huge decline in the sales. Also, cheaper generic alternatives will only make the situation for Sanofi worse.

"Millions of men worldwide trust Cialis to treat E. D. We are pleased to work with Sanofi to pursue a path that could allow more men who suffer from E. D. to obtain convenient access to a safe and reliable product without a prescription", said David A. Ricks, president of Lilly Bio-Medicines, the unit of Lilly that oversees Cialis.

Lilly said more than 45 million men have been recommended Cialis and the drug has not shown any side-effects to them. Only precaution that has to be taken while taking Cialis is that it should not be taken with some heart medications as it can lead to unsafe drop in blood pressure.