Since Cialis is used as needed, you are not likely to miss a dose. Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. Side Effects What are the side effects of Cialis Tadalafil? These PDE5 inhibitors may cause headache, flushing, drop in blood pressure, or other adverse effects. That’s not to say there aren’t just as many illegitimate sites.Keep in mind that online pharmacies used to fill ED prescriptions may not accept insurance. So online prices for Cialis may be higher than the price of getting Cialis through a mail-order pharmacy. MNT ‘s review. Lemonaid sells Cialis in these forms: Cialis: available in doses of 5, 10, and 20 mg, starting at $65 per tablet. Daily Cialis: 5 mg tablet with pricing starting from $50 per tablet. 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.