once per day. What side effects are found when taking these 2 meds. The tadalafil seems to be helping her slowly become more active with her B P remaining good, average 120/70. Last 4 days she has awaken 2 mornings with severe headaches resulting with B P readings 146 to 177/81. The headaches have persisted from slight to severe. She has been taking Tylenol when Headaches are severe. Is Amlodipine causing this problem or are headaches the result of taking the Tadalafil tablets?