How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. This medication is taken with or without food an hour before sex. Oral medicine for ED also might not be safe or work well if you have: Very low blood pressure, called hypotension, or uncontrolled high blood pressure, called hypertension. They include dutasteride Avodart, Jalyn and finasteride Propecia, Proscar. These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. Which Is More Effective? It might work longer if you have mild to moderate erectile dysfunction.Dosage. The dose of Cialis you need will depend on whether you’re taking it daily or as needed. Daily doses are often between and 5 milligrams (mg). The as-needed dose is usually 10 mg but can range from 5–20 mg. The typicaldose of Viagra is 50 mg. However, the dosage can range from 25– mg. Learn how your medication interacts with other prescriptions, over-the-counter (OTC) drugs and/or supplements. Check Drug Interactions. Email Newsletter Signup. Sign up for our .  · Descriptions. Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where .