Tadalafil may not be safe for people with certain medical conditions, including people who have had a stroke , have coronary heart disease or retinitis pigmentosa an eye disease. If you take nitrates in any form, or are on treatment for pulmonary hypertension , you should not take tadalafil. This applies to very high-fat meals too. Is Cialis for men only? Cialis should be taken at least 30 minutes before sex with or without food. Call your doctor for medical advice about side effects. If you get an erection that lasts over 4 hours you should go to the hospital.CIALIS for Use as Needed. Creatinine clearance 30 to 50 mL/min: A starting dose of 5 mg not more than once per day is recommended, and the maximum dose is 10 mg not more than once in every 48 hours. Creatinine clearance less than 30 mL/min or on hemodialysis: The maximum dose is 5 mg not more than once in every 72 hours [see . 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. A GoodRx coupon can help you save up to 97% off the average retail price of generic cialis, depending on the pharmacy you choose. You can use GoodRx to compare prices at different pharmacies and get the best price in your area. 3. Ask your doctor for a tablet prescription.