What types of injections are used to treat ED?
Oral medications don't work for everyone. Many men may be prescribed medicines that go directly, via injection, into the penis. Injection therapy may use a single drug or a combination of drugs. Single drug injection therapy uses alprostadil, a type of prostaglandinE1 (PGE1), and is called either Caverject® or Edex®. Combination therapies, called "bi-mix" (for 2 drugs mixtures) or "tri-mix" (for 3 drugs mixtures), are a mixture of either two, or all three, of the following most commonly used drugs: papaverine, phentolamine and/or alprostadil. Not all bi-mix or tri-mix medications are identical - the amount of the individual drugs may vary from pharmacy to pharmacy.
Alprostadil is a vasoactive agent that is a synthetic version of the chemical prostaglandin E. This chemical helps relax the smooth muscle tissue in the penis to enhance blood flow needed for an erection.
Papaverine and phentolamine also belong to this group of medicines called vasodilators (drugs that relax smooth muscle tissue, causing arteries to open and allowing an influx of blood flow).
Most men who do not respond to oral drug therapies used to treat ED find injection therapies to be effective. Success rates with self-injection are roughly 85 percent of patients. Injections may also be helpful for men who are taking other medications, such as oral nitrates, that should not be used at the same time as some oral medications for ED.