McClellan K J, Markham A
Adis International Limited, Mairangi Bay, Auckland, New Zealand.
Drugs. 1999 Jan;57(1):111-26. doi: 10.2165/00003495-199957010-00014.
The 5alpha-reductase inhibitor finasteride blocks the conversion of testosterone to dihydrotestosterone (DHT), the androgen responsible for male pattern hair loss (androgenetic alopecia) in genetically predisposed men. Results of phase III clinical studies in 1879 men have shown that oral finasteride 1 mg/day promotes hair growth and prevents further hair loss in a significant proportion of men with male pattern hair loss. Evidence suggests that the improvement in hair count reported after 1 year is maintained during 2 years' treatment. In men with vertex hair loss, global photographs showed improvement in hair growth in 48% of finasteride recipients at 1 year and in 66% at 2 years compared with 7% of placebo recipients at each time point. Furthermore, hair counts in these men showed that 83% of finasteride versus 28% of placebo recipients had no further hair loss compared with baseline after 2 years. The clinical efficacy of oral finasteride has not yet been compared with that of topical minoxidil, the only other drug used clinically in patients with male pattern hair loss. Therapeutic dosages of finasteride are generally well tolerated. In phase III studies, 7.7% of patients receiving finasteride 1 mg/day compared with 7.0% of those receiving placebo reported treatment-related adverse events. The overall incidence of sexual function disorders, comprising decreased libido, ejaculation disorder and erectile dysfunction, was significantly greater in finasteride than placebo recipients (3.8 vs 2.1%). All sexual adverse events were reversed on discontinuation of therapy and many resolved in patients who continued therapy. No other drug-related events were reported with an incidence > or =1% in patients receiving finasteride. Most events were of mild to moderate severity. Oral finasteride is contraindicated in pregnant women because of the risk of hypospadias in male fetuses.
Oral finasteride promotes scalp hair growth and prevents further hair loss in a significant proportion of men with male pattern hair loss. With its generally good tolerability profile, finasteride is a new approach to the management of this condition, for which treatment options are few. Its role relative to topical minoxidil has yet to be determined.
5α-还原酶抑制剂非那雄胺可阻止睾酮转化为双氢睾酮（DHT），DHT是导致遗传易感性男性出现男性型脱发（雄激素性脱发）的雄激素。对1879名男性进行的III期临床研究结果表明，每天口服1毫克非那雄胺可促进大量男性型脱发男性的头发生长并防止进一步脱发。有证据表明，治疗1年后报告的头发数量增加情况在2年治疗期间得以维持。在头顶脱发的男性中，整体照片显示，1年后非那雄胺治疗组中48%的患者头发生长有所改善，2年后为66%，而安慰剂组在每个时间点的改善率均为7%。此外，这些男性的头发计数显示，2年后，非那雄胺治疗组中83%的患者与基线相比未出现进一步脱发，而安慰剂组这一比例为28%。口服非那雄胺的临床疗效尚未与局部用米诺地尔进行比较，米诺地尔是临床上用于男性型脱发患者的唯一其他药物。非那雄胺的治疗剂量一般耐受性良好。在III期研究中，每天接受1毫克非那雄胺治疗的患者中有7.7%报告了与治疗相关的不良事件，而接受安慰剂治疗的患者这一比例为7.0%。性功能障碍（包括性欲减退、射精障碍和勃起功能障碍）的总体发生率在非那雄胺治疗组中显著高于安慰剂组（3.8%对2.1%）。所有性方面的不良事件在停药后均会逆转，许多在继续治疗的患者中也会缓解。在接受非那雄胺治疗的患者中，未报告其他发生率≥1%的与药物相关的事件。大多数事件的严重程度为轻度至中度。由于存在男性胎儿患尿道下裂的风险，孕妇禁用口服非那雄胺。
口服非那雄胺可促进大量男性型脱发男性的头皮头发生长并防止进一步脱发。非那雄胺总体耐受性良好，是治疗这种治疗选择有限的疾病的一种新方法。其相对于局部用米诺地尔的作用尚未确定。
