madman
Super Moderator
The efficacy and use of finasteride in women: a systematic review
Abstract
Background Physicians are beginning to use finasteride as a treatment for hair loss, hirsutism, and various other dermatologic conditions in women. However, the reported efficacy and use of finasteride in the female population vary widely. The purpose of this study is therefore to better define the efficacy and use of finasteride in women and identify research gaps that require further investigation.
Methods A systematic review of the current literature describing finasteride use in women.
Results A total of 2,683 patients participated in 65 studies involving finasteride use in women published between January 1997 and July 2017. Most randomized controlled trials (RCTs) evaluated finasteride use in women with hirsutism (48.7%) or female pattern hair loss (34.7%). RCTs recommend finasteride treatment for women with hirsutism or polycystic ovarian syndrome. Meanwhile, other forms of hair loss were studied such as alopecia, lichen planopilaris, and frontal fibrosing alopecia, but no RCTs evaluating finasteride therapy were identified. Other prospective and retrospective studies report that finasteride may improve hair loss in women with female pattern hair loss or frontal fibrosing alopecia. Overall, doses of oral finasteride ranged from 0.5 to 5 mg/day, in females aged 6–88, over a duration of 6–12 months (57.6%), as monotherapy (88.9%), and for continuous use (96.4%).
Conclusion The studies reviewed highlight the finasteride dosage, length of treatment, and candidate conditions that can benefit from finasteride therapy. Future long-term studies are necessary to fully assess the therapeutic mechanisms and potential consequences of finasteride use and to optimize treatment protocols.
Introduction
Finasteride is a competitive inhibitor of 5-alpha-reductase, an enzyme that catalyzes the conversion of testosterone to dihydrotestosterone (DHT). While there are multiple 5-alpha-reductase isotypes in the body, finasteride specifically acts on isoenzyme II, which is found in the uterus, endometrium, fallopian tube, prostate, male genitalia, hair follicle root sheath, and liver.1–8 Because finasteride neither directly inhibits testosterone synthesis nor interacts with the androgen receptor, its physiologic actions are restricted to DHT-dependent tissues.7,9–11 However since finasteride inhibits the conversion of testosterone to DHT, the mean circulating levels of testosterone are concomitantly increased following use. Elevated testosterone may negatively compete with estrogen in the blood. Overall, it is estimated that finasteride use results in a 15% increase in both testosterone and estradiol compared to baseline, which is still considered within the physiologic range.12
Finasteride is clinically indicated for the treatment of conditions associated with pathologic accumulation of DHT, such as symptomatic benign prostatic hyperplasia and male pattern hair loss driven by DHT excess in the prostate and hair follicles, respectively.13 Because of DHT’s critical role in embryonic development, finasteride use may yield adverse consequences. Animal studies have demonstrated external genital abnormalities including hypospadias, in male fetuses exposed to 5-alpha-reductase type II inhibitors.14–16 As such, finasteride and dutasteride are classified in FDA pregnancy category X and are not FDA-approved for use in women. Dutasteride is another competitive inhibitor of 5-alpha-reductase, three times as potent as finasteride at inhibiting type II, and more than 100 times as effective at inhibiting type I.17 Concerns regarding the adverse effects of finasteride and dutasteride used in men has led the NIH to add the controversial “post-finasteride syndrome”, described as a persistent sexual, neurological, and physical adverse reaction, to its Genetic and Rare Diseases Information website.16,18
Despite its potential teratogenicity, finasteride is prescribed to women for off-label use in the treatment of alopecia and hirsutism.7,9–11,19–22 Women are usually informed about the teratogenic risks with finasteride and are often administered a contraceptive to reduce pregnancy potential. To date, research focusing on the efficacy of finasteride treatment in the female patient population varies and is limited.
Results
*Androgen receptor-CAG repeats
*Acne
*Female pattern hair loss (androgenetic alopecia in women)
*Frontal fibrosing alopecia
*Lichen planopilaris
*Hirsutism
*Hyperandrogenic polycystic ovary syndrome
*Hidradenitis suppurativa
*Central serous chorioretinopathy
*Fertility
*Neurologic conditions
Conclusion
Although there have been recent advances in understanding the use of finasteride in women, much remains unclear. The studies reviewed here provide a good starting point for assessing finasteride dosage and length of treatment in the management of candidate conditions that may benefit from finasteride therapy. Additional prospective, long-term studies remain necessary to fully evaluate the efficacy and consequences of chronic finasteride use and to optimize treatment protocols.
Abstract
Background Physicians are beginning to use finasteride as a treatment for hair loss, hirsutism, and various other dermatologic conditions in women. However, the reported efficacy and use of finasteride in the female population vary widely. The purpose of this study is therefore to better define the efficacy and use of finasteride in women and identify research gaps that require further investigation.
Methods A systematic review of the current literature describing finasteride use in women.
Results A total of 2,683 patients participated in 65 studies involving finasteride use in women published between January 1997 and July 2017. Most randomized controlled trials (RCTs) evaluated finasteride use in women with hirsutism (48.7%) or female pattern hair loss (34.7%). RCTs recommend finasteride treatment for women with hirsutism or polycystic ovarian syndrome. Meanwhile, other forms of hair loss were studied such as alopecia, lichen planopilaris, and frontal fibrosing alopecia, but no RCTs evaluating finasteride therapy were identified. Other prospective and retrospective studies report that finasteride may improve hair loss in women with female pattern hair loss or frontal fibrosing alopecia. Overall, doses of oral finasteride ranged from 0.5 to 5 mg/day, in females aged 6–88, over a duration of 6–12 months (57.6%), as monotherapy (88.9%), and for continuous use (96.4%).
Conclusion The studies reviewed highlight the finasteride dosage, length of treatment, and candidate conditions that can benefit from finasteride therapy. Future long-term studies are necessary to fully assess the therapeutic mechanisms and potential consequences of finasteride use and to optimize treatment protocols.
Introduction
Finasteride is a competitive inhibitor of 5-alpha-reductase, an enzyme that catalyzes the conversion of testosterone to dihydrotestosterone (DHT). While there are multiple 5-alpha-reductase isotypes in the body, finasteride specifically acts on isoenzyme II, which is found in the uterus, endometrium, fallopian tube, prostate, male genitalia, hair follicle root sheath, and liver.1–8 Because finasteride neither directly inhibits testosterone synthesis nor interacts with the androgen receptor, its physiologic actions are restricted to DHT-dependent tissues.7,9–11 However since finasteride inhibits the conversion of testosterone to DHT, the mean circulating levels of testosterone are concomitantly increased following use. Elevated testosterone may negatively compete with estrogen in the blood. Overall, it is estimated that finasteride use results in a 15% increase in both testosterone and estradiol compared to baseline, which is still considered within the physiologic range.12
Finasteride is clinically indicated for the treatment of conditions associated with pathologic accumulation of DHT, such as symptomatic benign prostatic hyperplasia and male pattern hair loss driven by DHT excess in the prostate and hair follicles, respectively.13 Because of DHT’s critical role in embryonic development, finasteride use may yield adverse consequences. Animal studies have demonstrated external genital abnormalities including hypospadias, in male fetuses exposed to 5-alpha-reductase type II inhibitors.14–16 As such, finasteride and dutasteride are classified in FDA pregnancy category X and are not FDA-approved for use in women. Dutasteride is another competitive inhibitor of 5-alpha-reductase, three times as potent as finasteride at inhibiting type II, and more than 100 times as effective at inhibiting type I.17 Concerns regarding the adverse effects of finasteride and dutasteride used in men has led the NIH to add the controversial “post-finasteride syndrome”, described as a persistent sexual, neurological, and physical adverse reaction, to its Genetic and Rare Diseases Information website.16,18
Despite its potential teratogenicity, finasteride is prescribed to women for off-label use in the treatment of alopecia and hirsutism.7,9–11,19–22 Women are usually informed about the teratogenic risks with finasteride and are often administered a contraceptive to reduce pregnancy potential. To date, research focusing on the efficacy of finasteride treatment in the female patient population varies and is limited.
Results
*Androgen receptor-CAG repeats
*Acne
*Female pattern hair loss (androgenetic alopecia in women)
*Frontal fibrosing alopecia
*Lichen planopilaris
*Hirsutism
*Hyperandrogenic polycystic ovary syndrome
*Hidradenitis suppurativa
*Central serous chorioretinopathy
*Fertility
*Neurologic conditions
Conclusion
Although there have been recent advances in understanding the use of finasteride in women, much remains unclear. The studies reviewed here provide a good starting point for assessing finasteride dosage and length of treatment in the management of candidate conditions that may benefit from finasteride therapy. Additional prospective, long-term studies remain necessary to fully evaluate the efficacy and consequences of chronic finasteride use and to optimize treatment protocols.
