Potential Side Effects and Interactions While Cialis is generally safe, like all medications, it can have side effects. It should not be taken more than once a day. Buy from pharmacies that send spam emails or unsolicited advertisements. How long does Cialis last? If you experience any of the following symptoms, they could indicate an overdose of this medication and must be reported to your healthcare provider: flushing, headache, runny or stuffy nose, heartburn, chest pain, indigestion, prolonged erection, and back pain. Stepwise increase in alpha-blocker dose may be associated with further lowering of blood pressure when taking a PDE5 inhibitor. Cialis has a longer duration of action, up to 36 hours, compared to other ED medications.As with most generic medications, tadalafil is generally cheaper than the branded version Cialis. A person can expect to pay around $ per month for tadalafil. 60 mg x pills. $ $ − +. Add to Cart. Tadalafil is effective for the treatment of men erection problems and symptoms of benign prostate enlargement, pulmonary hypertension. 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.