NEW DELHI, Sept 28: At a time when the controversial sexual potency drug Viagra is selling for Rs 500-800 a tablet over the counter, the death on Thursday of a 44-year-old man in Calcutta believed to be on it comes as a timely warning to potential users in the country.The case was reported by Dr K K Aggarwal of the Heart Care Foundation of India (HCFI). It had been brought to his notice by a doctor friend, who contacted him on the Heartline that the HCFI operates with the cellphone service provider Essar. The man was the doctor's brother-in-law.Giving details of the case, Aggarwal said the man, who was not given to exerting himself, decided along with his wife to rev up their sex life with the so-called "wonder drug". When the couple was having sex for the third time on Thursday night, the man collapsed after a massive heart attack.Aggarwal said the man obviously had underlying heart disease that was not known to him - doctors call it an "asymptomatic condition", which results in "sudden death",especially among men between 35 and 50 (even athletes are not immune to it). ``The warning couldn't have come too soon, especially since Indian companies are planning to market the drug from January for Rs 70 a tablet,'' Aggarwal said.A number of cases of death hastened by the indiscriminate use of Viagra have been reported from the US, but, as Aggarwal pointed out, the 44-year-old man was the youngest victim reported so far. Most of the American victims were over 50 and were reported to be having sexual relations with women much younger to them.Commenting on the Calcutta death, Dr Harbans Wasir, Medical Director, Batra Hospital, and former Head, Department of Cardiology, All India Institute of Medical Sciences, said Viagra had become an obsession with a number of men who can afford the market price for it, so much so that the number of users may already be in the thousands.``A number of these men don't tell their wives they are on Viagra, and who knows, some may have died because of misuse of thedrug,'' Wasir averred. ``These cases would have been written off as heart attacks, but in the case of the man from Calcutta, the doctors became suspicious only because his wife knew he was on Viagra.''Wasir, in fact, has been advising doctors ``not to play with the drug.'' Speaking to his fraternity some time back, he had told medicos that Viagra was not ``an aphrodisiac, so it must be used only on the advice of qualified doctors by men suffering from organic impotence.'' The expression `organic impotence' describes the failure of a man to have or maintain an erection for physical, as opposed to psychological, reasons, such as high blood pressure or diabetes.Aggarwal clarified that sudden exertion by a man used to a sedentary life is harmful for his heart, especially if he isn't aware of any underlying problem with it. ``The sex act is like walking briskly for 2 km or spending three minutes on the treadmill,'' he said. ``So, just like we caution people over 40 to avoid doing any exercise they are notaccustomed to before they are vetted by their doctor, a word of advice to Viagra users is in order: Use it only after consulting your doctor.''