Consideration should be given to the following: ED Patients should be stable on alpha-blocker therapy prior to initiating a PDE5 inhibitor. In some patients, concomitant use of these two drug classes can lower blood pressure significantly [see Drug Interactions 7. Safety of combined use of PDE5 inhibitors and alpha-blockers may be affected by other variables, including intravascular volume depletion and other antihypertensive drugs. When you are deciding on which ED medication to commit to, it is often advised for you to try both Viagra and Cialis to see which you prefer. Hypersensitivity reactions have been reported, including Stevens-Johnson syndrome and exfoliative dermatitis [see Adverse Reactions 6. When mild vasodilators are taken in combination, blood-pressure-lowering effects of each individual compound may be increased. Both Tadalafil and Sildenafil are licensed and safe to use.Learn more about Cialis oral. 1. This is a generic drug. The average cost for 30 Tablet(s), 5mg each of the generic (tadalafil) is $ You can buy tadalafil at the discounted . Published on October 18, warning This article is no longer being updated and some information may not be current. Visit the GoodRx Healthhomepage for our latest articles. .  · The usual as-needed Cialis dosage for ED ranges from 5 mg to 20 mg by mouth, taken at least 30 minutes before sex. You’ll typically start with the 10 mg dose, .