Addition of metformin to sildenafil treatment for erectile dysfunction in eugonadal nondiabetic men with insulin resistance. A prospective, randomized, double-blind pilot study.
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. The aim of this paper is to evaluate the effect of treatment  with metformin on the response to sildenafil in patients with erectile  dysfunction (ED) and IR enrolled in a prospective, randomized, controlled,  double-blind placebo study. We included 30 male patients with ED, IR, and poor  response to sildenafil. Exclusion criteria included 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 homeostasis model assessment (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  month 2 (IIEF-5: 17.0 ± 6.0 vs 14.3 ± 3.9, P = .01;  HOMA: 3.9 ± 1.6 vs 5.5 ± 2.4, P = .01) to 4 of  treatment (IIEF-5: 19.8 ± 3.8 vs 14.3 ± 3.9, P = .005;  HOMA: 4.5 ± 1.9 vs 5.5 ± 2.4, P = .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%  compared with 7.7%, P = .03, respectively. Adverse events 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.
Urology Division, Hospital Italiano de Buenos Aires, Gascón 450, Buenos Aires C1181ACH, Argentina. gaston.rey@hospitalitaliano.org.ar
Gastón J
GJ
Rey-Valzacchi
Pablo R
PR
Costanzo
Luis A
LA
Finger
Alberto O
AO
Layus
Guillermo M
GM
Gueglio
León E
LE
Litwak
Pablo
P
Knoblovits
D000368:Aged; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008687:Metformin / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D008954:Models, Biological; D010410:Penile Erection / Q000187:drug effects; D010865:Pilot Projects; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*
D010879:Piperazines; D011687:Purines; D013450:Sulfones; D008687:Metformin; D000068677:Sildenafil Citrate