The best person to answer this question for you is your GP because he or she knows your medical history. When a drug is being prescribed the doctor has to consider the person’s overall medical condition as well the potential for interaction with other drugs that the person might be taking. It is not just a matter of considering if one drug interferes with another. The overall context of the person’s health, medical history and drug history has to be considered before the prescription is issued. However, there are no published reports of negative interactions between these two drugs. Therefore assuming that there are no negative factors in relation to your medical history it would be safe to take viagra while taking nifedipine concurrently.