Basic Summary: Raloxifene is a second generation SERM that has been shown to reverse pre-existing gyno as well as show all benefits of first generation SERMs.
**Taken from Superior Muscle**
Selective estrogen receptor modulators (SERMs) are a relatively new family of drugs designed to act as estrogens on some, but not all, tissues.2 Tamoxifen is a first-generation SERM. Raloxifene, a second-generation SERM, has been extensively studied on postmenopausal women, and is indicated for the treatment of postmenopausal osteoporosis.3 It is an alternative to estrogen replacement therapy in women with a history of breast cancer.4, 5 Its anti-proliferative effect on mammary tissue is such that prolonged use reduces the risk of breast cancer among osteoporotic women.6
In a recent placebo-controlled short-term trial, the drug was administered to 34 healthy males (mean age, 48 years) at the dose of 60 mg/day for one month; no subject developed gynocomastia. Besides, serum testosterone increased 20%, and serum estradiol decreased slightly.7
We decided to evaluate the effect of raloxifene in a series of patients with gynocomastia. Twelve patients aged 18-84 years were treated. Breast enlargement was unilateral in 5 cases; its duration ranged from a few weeks (7 cases) to several years (5 cases). Four patients were hypogonadal by clinical criteria, and had low serum testosterone. In two patients there was a possible drug effect (prasterone in one, ranitidine in the other). The size of breast tissue ranged between 1.5 and 6.0 cm. All patients had normal testes by palpation, and normal serum levels of estradiol, LH, FSH, prolactin, and alpha-hCG. Liver function tests and serum creatinine also were normal. The dose of raloxifene was 60 mg every other day in 4 elderly patients (age 70 years or more), and 60 mg daily in the remaining; the medication was given for 2-12 months. Hypogonadal patients received, in addition, i.m. injections of testosterone enanthate, 100 mg twice a month.
Raloxifene was well tolerated; only one young patient reported a slight decrease in sexual potency. No subject complained of hot flushes; there were no episodes of thrombophlebitis during follow-up. The analgesic effect of treatment was fast (2-4 weeks) and sustained among 9 patients with pain and tenderness. The size of the gynocomastia was evaluated monthly by means of a caliper (all patients), and ultrasonography (7 patients). All patients responded: there was an average reduction in size of 61% (range: 34-100%); in 2 patients gynocomastia disappeared. Six of 8 eugonadal patients (75%) had a reduction in the size of breast tissue of at least 50% (average, 73%). Among hypogonadal patients (all of them followed with ultrasonography) gynocomastia disappeared in one, and size reduction in the remaining subjects ranged between 46 and 67% (this is particularly noteworthy, since testosterone replacement not infrequently causes or aggravates gynocomastia due to local aromatization to estrogens by mammary tissue). Maximal effect was observed during the first 2 months of treatment.
This open, observational study suggests that raloxifene may be a safe, well tolerated and effective therapeutic alternative for drug-induced or idiopathic gynocomastia in men of all ages.
Zulema Man, MD.
TIEMPO, Buenos Aires, Argentina
Ariel S??nchez, MD, PhD;
Hugo Carretto, MD;
Ricardo Parma, MD.
Centro de Endocrinolog??a, Rosario, Argentina
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