It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. Oral medicine for ED also might not be safe or work well if you have: Very low blood pressure, called hypotension, or uncontrolled high blood pressure, called hypertension. Counterfeit medicines can be very dangerous. Read more on male sexual health on the Sexual Health Australia site. Because patients with recent heart attacks or stroke, heart pains angina , heart failure, uncontrolled blood pressure or uncontrolled irregular heart beats, severe liver disease, and retinal eye problems were not studied with Cialis, Cialis is not recommended for these patients. Avanafil Stendra.The most common side effects with Cialis are: headache, indigestion, back pain, muscle aches, flushing, and stuffy or runny nose. These side effects usually go away after a few hours. Men who get back pain and muscle aches usually get it 12 to 24 hours after taking Cialis. Back pain and muscle aches usually go away within 2 days.  · The approved dosages of Cialis for ED, BPH symptoms, or both, are between mg and 20 mg a day or as needed. Dosages higher than 20 mg a day haven’t been studied, and it’s not known what. Cialis can cost around $ to $ per month out of pocket, depending on the dosage you need. The first generic version of Cialis was released in October , and other manufacturers have released generic versions since then. This has increased market competition, driving prices down.