These prescriptions can be delivered to your local pharmacy, or the best ED meds can be sent to you directly. Medicines that you take by mouth are called oral medicines. How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. Getting drugs from a friend or other sources is a recipe for expired, fake or contaminated pills. Common ones include: Flushing of the skin. Recent heart or blood vessel problems.Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles . Often they sell drugs with missing active ingredients or in smaller amounts. The bottom line: It’s safe to take as prescribed. The danger comes from taking it with . Can I buy generic Viagra without a prescription? No. In most countries, including the United.