On call. I am 66 years old and have had angina for nearly 5 years. I take aspirin and Zocor, but I haven't needed nitroglycerin for at least 3 years, even though I ride my bike quite hard at least 4 days a week. I've started having trouble with my erections, and now I want to try Viagra. My doctor gave me a prescription, but my wife won't let me fill it. Is Viagra safe for me?