In , Pfizer scientists discovered that sildenafil, which also inhibits the PDE5 enzyme, caused penile erection in males participating in a clinical study of a heart medicine. Counterfeit medicines can be very dangerous. Persons surnamed “Cialis” objected to Eli Lilly and Company’s so naming the drug, but the company has maintained that the drug’s trade name is unrelated to the surname. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa an inherited eye condition that causes loss of vision or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Tell your doctor if tadalafil is not working well or if you are experiencing side effects.Tadalafil – STADA T20 – 20 Milligramm. Tadalafil, sold under the brand name Cialis among others, is a medication used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. It is taken by mouth. Onset is typically within half an hour and the duration is up to 36 hours. Common side effects include headache, muscle pain, . AdIt’s super shopping time. Don’t miss out. It’s super shopping time. Don’t miss out on special Black Friday offer! Side Effects. Headache, stomach upset, back pain, muscle pain, stuffy nose, flushing, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To.