erectile dysfunction (ED) is a common medical disorder often affecting the aging male. Nitric oxide (NO) is a physiological signal essential to penile erection. NO synthase (NOS) catalyzes the production of NO from L-arginine. ADMA, a competitive inhibitor of NO synthase increases with age and many disorders that reduce NO in the erectile tissue are commonly associated with ED. Although new pharmacological strategies have been identified for medical treatment of ED, patients often seek alternative therapies for cost or side effect reasons. The aim of the present study is to determine the efficacy of orally administered L-arginine on ED not caused by established organic disease.
This is the most common amino acid in men’s health supplements. L-arginine is converted in the body into a chemical called nitric oxide. Nitric oxide helps the blood vessels to open wider, improving blood flow. Caution is advised when taking L-arginine, or similar supplements, as it can lower blood pressure. It can increase the risk of bleeding when taken with certain drugs. It may also alter blood sugar levels.
L-arginine is classified as a nonessential amino acid, but it may be considered essential or semiessential under conditions of stress, during which L-arginine synthesis becomes compromised. L-arginine has been evaluated for use in cardiovascular disease because of its antiatherogenic, anti-ischemic, antiplatelet, and antithrombotic properties, and for use in renal disease, diabetes, cystic fibrosis, sickle cell disease, and erectile dysfunction. Its immunostimulatory effects and potential benefits in ophthalmic conditions and preeclampsia have also been evaluated.
L-arginine has been studied for a variety of conditions using various dosages and treatment durations; current daily dosage trends range from 6 to 30 g orally in 3 divided doses. Oral and intravenous (IV) formulations have been the most commonly studied.
Contraindications have not been identified. However, L-arginine is not recommended following acute myocardial infarction.
L-arginine supplementation has shown beneficial effects in women with hypertension and in those at risk for preeclampsia. However, due to minimal data regarding safety and efficacy in pregnancy and lactation, L-arginine should only be used in these populations if recommended by and under the supervision of a health care provider.
Caution is warranted in patients concomitantly using L-arginine supplementation and nitrates. L-arginine may potentiate the effects of isosorbide mononitrate and other nitric oxide donors, such as glyceryl trinitrate (ie, nitroglycerin) and sodium nitroprusside. Insulin: Caution is warranted in patients using insulin concomitantly with L-arginine; effects on insulin are unpredictable. Cholesterol-lowering drugs: Caution is warranted in patients using cholesterol-lowering drugs concomitantly with L-arginine; effects on cholesterol-lowering drugs are unpredictable.
Nausea, diarrhea, dyspepsia, palpitations, headache, and numbness have been reported with L-arginine use. Bitter taste may occur with higher doses. Because of L-arginine’s vasodilatory effects, hypotension may occur. IV preparations containing L-arginine hydrochloride have a high chloride content that may increase the risk for metabolic acidosis in patients with electrolyte imbalances. Hyperkalemia and elevations in serum urea nitrogen (BUN) levels may occur in patients with renal and/or hepatic impairment.
Oral prescription medications are often successful in treating ED. There are four primary prescription medications that are FDA-approved and available:
All four medicines help to enhance the effects which the body produces to relax muscles in the penis to allow an increased blood flow. These four drugs are known as PDE-5 inhibitors. They are not magic pills and sexual stimulation is still needed to produce an erection.