Generic Cialis helps you get and maintain your erections through a simple, daily dosage. For treatment of pulmonary arterial hypertension: For oral dosage forms suspension or tablets : Adults—20 milligrams mg 3 times a day. When a man is sexually stimulated, his body’s normal response is to increase blood flow to his penis to produce an erection. Tadalafil, the active ingredient in Cialis, is also used to treat pulmonary arterial hypertension, a form of pulmonary hypertension in which blood pressure increases in the arteries that transport blood from your heart to your lungs. Cialis side effects can happen and the drug can interact with other medications causing side effects such as headache, stomach upset, muscle pain, stuffy nose, flushing or dizziness.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 . AdComplete the Online Consultation with our Doctor. Personalize Your Needs. If Appropriate, Get a Prescription for ED from RexMD®. Free Shipping AvailableFree Shipping · Real Doctors · Discreet Packaging · Personalized Plan/5 (3, reviews)Site visitors: Over 10K in the past month. Dosage range: 5 mg to 20 mg; Frequency: one dose at least 30 minutes before sexual activity, with a maximum of one dose per day* Cialis comes as an oral tablet. You’ll take the drug by swallowing it. Questions about taking Cialis. Here’s a list of common questions related to taking Cialis.