Erection depends largely on the release of nitric oxide (NO) by vascular endothelial cells.
Insulin resistance (IR) is a metabolic abnormality that produces endothelial dysfunction characterized by decreased synthesis and release of NO.
To evaluate the effect of treatment with metformin on the response to sildenafil in patients with erectile dysfunction (ED) and IR.
Prospective, randomized, controlled, double-blind placebo study. We included 30 male patients with ED, IR and poor response to sildenafil. Exclusion criteria: pharmacologic, anatomic or endocrine ED, diabetes, prostatic surgery or chronic illnesses. Erectile function was rated according to the International Index of Erectile Function 5 (IIEF-5). IR was measured by HOMA (IR=HOMA 3). Patients were randomized to receive metformin (n=17) or placebo (n=13).
After treatment with metformin, patients with ED showed a significant increase in IIEF-5 score and a significant decrease in HOMA both occurring at months 2 (IIEF-5: 17.0±6.0 vs. 14.3±3.9, p=0.01 and HOMA: 3.9±1.6 vs. 5.5±2.4, p=0.01) to 4 of treatment (IIEF-5: 19.8±3.8 vs. 14.3±3.9, p=0.005 and HOMA: 4.5±1.9 vs. 5.5±2.4, p=0.04), with no changes in these parameters in patients with ED receiving placebo. Patients treated with metformin had more adverse events than those who received placebo: 61.5% versus 7.7%, p=0.03, respectively. AEs were mild, mainly gastrointestinal, and did not cause discontinuation of treatment.
Treatment with metformin in patients with ED and poor response to sildenafil reduced the IR and improved erectile function.
Written by:
Gastón J. Rey Valzacchi, Pablo R. Costanzo, Luis A. Finger, Alberto O. Layus, Guillermo M. Gueglio, León E. Litwak, and Pablo Knoblovits. Are you the author?
Reference: J Androl. 2011 Oct 20. Epub ahead of print.
doi: 10.2164/jandrol.111.013714
PubMed Abstract
PMID: 22016348
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