We strive to use primary sources and refrain from using tertiary references. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. They include dutasteride Avodart, Jalyn and finasteride Propecia, Proscar. The typicaldose of Viagra is 50 mg. It works for up to 36 hours.Cialis is taken as an oral tablet, either as a low dose daily medication or as a higher-dose “on-demand” medication. It is the brand name for tadalafil, a medication also used to treat ED. Tadalafil is one of four medications for ED, along with sildenafil (Viagra), vardenafil (Levitra) and avanafil (Stendra). Tadalafil is a widely used medication, mostly prescribed to treat erectile dysfunction and sometimes to treat benign prostatic hyperplasia (BPH). Compared to other ED medications, tadalafil is very long-lasting. heart attack symptoms – chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating. Common Cialis side effects may include: headache; flushing (warmth, redness, or tingly feeling); nausea, upset stomach; stuffy nose; or. muscle pain, back pain, pain in your arms, legs, or back. This is not a complete list of side effects.