Side Effects Common side effects of Cialis include the following: Headache. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Dosing is as follows: As needed for ED: 5 to 20 mg by mouth as a one-time dose, with a maximum of one dose in 24 hours. Though this growth is not cancerous, prostate cancer and BPH can co-occur. You can take this medicine with or without food 30 minutes before sex, depending on the dose. Healthcare providers have experience talking about ED and providing treatment options without any judgment or shame.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, . Extra 15% off $30 sitewide with code SAVE15; Clip your mystery deal! BOGO 50% off select Walgreens health & wellness. Cialis doesn’t work right away. For the as-needed dose, plan to take Cialis at least 30 minutes before sexual activity, but bear in mind it may take as long as 2 hours to take effect.