Aromatase Inhibitors in Erectile Dysfunction

Hyperestrogenism may cause erectile dysfunction(ED) by impeding normal penile development,increasing venous vascular permeability and leakage(via VEGF) and by inhibiting testosterone(T)production. Estrogen excess can impair spermatogenesis and may increase the risk of estrogen-sensitive cancers(viz.breast cancer)[1,2]Weekly and biweekly letrozole(2.5 mg),an aromatase inhibitor,has been reported to normalize serum T in males with obesity related hypogonadism and poor sperm quality,respectively.[3,4]A 40-year old insulin requiring,normotensive,obese(BMI-26.9),diabetic(12 years duration) was evaluated for ED.T was 187 ng/dl and estradiol(E2) was 69 pg/ml(normal-11-44 pg/ml) with normal LH and prolactin levels. There was normalization of T(increased to 487 ng/dl) with 2.5 mg letrozole every 3 weeks. Another patient,55 year old male, insulin requiring,hypertensive,obese(BMI-28.8),diabetic(21 years duration) had normalization of T(401 ng/dl) with baseline low T(224.4 ng/dl) and normal E2(33 pg/ml) with T-E2 ratio of less than 10,with weekly 2.5 mg letrozole. There was one kg weight gain and 0.2 ng/ml increase in PSA in two years. These cases highlight the significance of estimating both T and E2 in the evaluation of ED. Moreover,it also highlights the efficacy and safety of weekly and even every 3-week 2.5 mg letrozole therapy. References: 1. .Schulster M,Bernie AM,Ramasamy R:The role of estradiol in male reproductive function.Asian Journal of Andrology,2016,18(3),435-440. 2. Goldfrank LR and Flomenbaum N:Goldfrank’s Toxicologic Emergencies,McGraw- Hill Professional,2006,p443. 3.Loves S,Ruinemans-Koerts,de Boer H:Letrozole once a week normalizes serum testosterone in obesity-related male hypogonadism. Eur J Endocrinol,2008,158,741-747.4. Singh SK:Aromatase inhibitors in male sex. Indian J Endocrinol Metab,2013,17,S259-261.