Although not all of these side effects may occur, if they do occur they may need medical attention. Patients who have an erection lasting greater than 4 hours, whether painful or not, should seek emergency medical attention. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. Do not keep outdated medicine or medicine no longer needed.AdLooking for Tadalfil? We have almost everything on eBay. No matter what you love, you’ll find it here. Search Tadalfil and more.1M+ visitors in the past monthTop Brands · >80% Items Are New · Money Back Guarantee · Daily DealsPopular Links: Gucci · Casual Shoes · Women’s Shoes · Aftershave · Casual · Bibs · SHORTS. CVS Pharmacy. $ retail. Save 67%. $ Get free savings. Select this if your pharmacy isn’t listed above. Other pharmacies. $ Viagra (sildenafil) tends to get all the attention. After all, it was the first FDA-approved oral erectile dysfunction (ED) medication, and it became a household name soon after. But its close cousin, Cialis (tadalafil), is also an effective option for many men who experience ED. Cialis is a longer-acting option that some men prefer over other ED .