The dose of CIALIS for use as needed should be limited to 10 mg no more than once every 72 hours in patients taking potent inhibitors of CYP3A4 such as ritonavir, ketoconazole, and itraconazole [see Drug Interactions 7. As with other PDE5 inhibitors, tadalafil has mild systemic vasodilatory properties that may result in transient decreases in blood pressure. If you are intending to take either of these drugs for ED treatment, talk to an online clinician. Patients who demonstrate hemodynamic instability on alpha-blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of PDE5 inhibitors. CIALIS for Use as Needed for ED In eight primary placebo-controlled clinical studies of 12 weeks duration, mean age was 59 years range 22 to 88 and the discontinuation rate due to adverse events in patients treated with tadalafil 10 or 20 mg was 3.10 results for “tadalafil 20 mg tablet” Results Prescription Required Tadalafil (Generic for Cialis) Tablets · 20mg · 6-day supply With insurance est. $ Estimated insurance . not available over-the-counter (OTC) Was this helpful? How does Cialis work? Cialis works by increasing blood flow to the penis to help a person get and Missing: amazon. Amazon Prime members get additional benefits including FREE 2-Day Delivery and low prices on medications. About this medication. TADALAFIL (tah DA la fil) treats erectile .