An article published online on August 17, 2009 in the Journal of Sexual Medicine describes research conducted at the University of Rome which found that it may be necessary to reduce homocysteine before treatment with erectile dysfunction (ED) can be effective. The study included 75 men aged 25 to 65 with erectile dysfunction who were treated with sildenafil citrate (“Viagra”) for 2 months. Nonresponders to the drug were treated with a course of 600 milligrams vitamin B6 per week and 15 milligrams folic acid per day along with sildenafil for 6 weeks. Questionnaires concerning erectile function were administered before and after treatment. Participants were evaluated for the presence of the MTHFR 677T mutation which is present in a higher percentage of heart disease patients than in those without the disease. Individuals with two copies of the mutation have levels of homocysteine that average 25 percent higher than the rest of the population, and which increase significantly when blood levels of folate are low. Twenty-seven percent of the subjects had both copies of the MTHFR 677T mutation and 48 percent had one copy, which is a greater frequency than the general populace. All of the 18 patients who initially failed to respond to drug treatment had high levels of homocysteine and low folic acid levels. Subsequent to the 6 week course of vitamin therapy, folic acid levels increased, homocysteine concentrations declined, and all but two participants experienced improvement in ED. The association of hyperhomocysteinemia with vascular disease supports the mechanism for homocysteine-reducing agents in improving ED, which is caused primarily by the same factors that affect the coronary arteries. “Measurement of plasma homocysteine and folic acid levels and molecular analysis of the MTHFR genotype should be added to the ED diagnostic procedure, especially in young patients or in those with a family history of cardiovascular disease," the authors conclude. "When this mechanism is implicated, treatment should first aim to reduce homocysteine levels through administration of folic acid, alone or in combination with vitamin B6 or B12, and then proceed to treatment with phosphodiesterase-5 inhibitors.” |