L-Arginine and Antidepressants

L-Arginine is an amino acid -- a chemical building block of protein. It is a precursor to nitric oxide, a gas known as a vasodilator. Vasodilators are agents that widen and relax blood vessels. Arginine supplements are promoted for athletic performance and conditions that benefit from vasodilation, such as erectile dysfunction. Although research is ongoing, evidence suggests that L-arginine may interact with certain antidepressants. You should consult your doctor before taking L-arginine.

Arginine helps your body make nitric oxide. Evidence suggests that arginine may help conditions that benefit from from improved vasodilation, according to MayoClinic.com. These conditions include chest pain, heart failure, atherosclerosis and vascular headaches. Because nitric oxide increases blood flow, arginine is commonly marketed for weight training. Arginine is considered a semiessential amino acid:your body typically makes enough to meet your needs, but under certain circumstances supplementation is beneficial.

Although antidepressants are commonly prescribed to treat depression, the scientific community does not fully understand the mechanisms involved in their effectiveness. Science does know that antidepressants work in part because they augment mood-regulating brain chemicals such as serotonin, dopamine, epinephrine and norepinephrine. Research is revealing that other mechanisms, such as nitric oxide regulation, are partially responsible for the antidepressant effects of some medications.

A study published in the March 2011 issue of the journal Behavioural Brain Research found that nitric oxide suppression has antidepressant effects and that the antidepressants Effexor, generically known as venlafaxine, and Tofranil, generically known as imipramaine, work in part because they suppress the production of nitric oxide. Researchers found that administering L-arginine blocked the antidepressant effects of these drugs. This data suggests that L-arginine may decrease the effectiveness of certain antidepressants. Arginine did not block the antidepressant effects of Prozac, generically fluoxetine, and Wellbutrin, or bupropion.

Although more studies are needed, preliminary evidence suggests that you should avoid taking L-arginine if you are prescribed certain antidepressants, such as Effexor or Tofranil. If you decide to take it despite this information, you should do so only after discussing it with your physician. Arginine can cause other side effects, including bloating, diarrhea and stomach discomfort. Arginine may also increase bleeding risk and inflammatory response. You should use caution if you have diabetes, since arginine can lower blood sugar levels.