METHODS
A PubMed search was completed in July 2015 to find clinical studies and case reports using finasteride and/or dutasteride to treat FPHL or FFA. Keywords used for these searches included “finasteride,†“dutasteride,†“women,†“hair loss,†“frontal fibrosing alopecia,†and “side effects.†Articles were also selected by reviewing the references of articles from initial searches. Publications were classified by case study, clinical study, or retrospective review. Case studies were classified as such if they contained fewer than 10 study subjects and reported on treatment success after its completion. Clinical studies were publications that initiated, followed, and completed treatment in patients, and reported on its success or failure. Retrospective reviews reported on patients’ treatment success or failure using past medical records.
Ioannidis and Lau provide a framework for evaluating the adequacy of drug safety reporting for clinical trials.21 Belknap et al used this framework to evaluate the adequacy of AE reporting in clinical trials for finasteride in the treatment of androgenic alopecia in men.22 Since our review includes both clinical studies and case reports, adequacy of AE reporting was adapted to investigate the degree of detail to which AEs are described in the literature for finasteride and dutasteride treatment of FPHL and FFA.
First we evaluated if the existence or non-existence of AEs of patients taking finasteride or dutasteride was reported at all in the study or case report. If a publication did not make mention of these events, it was classified as “inadequate.†Those publications which reported that no AEs took place during treatment were classified as “none.†Secondly, if authors reported the existence of AEs, we noted event reporting. If a publication reported the existence of AEs but did not specify which events occurred, it was classified as “partially adequate.†In contrast, if a publication reported the existence of AEs and specified each, it was classified as “adequate.†Thirdly, for clinical studies, we evaluated whether the authors reported if patients withdrew from the study or stopped treatment due to specific AEs during treatment. Finally, we investigated if any of the authors reported patients experiencing a change in libido or sexual function during their treatment with finasteride or dutasteride.
RESULTS
A total of 20 clinical studies and case reports were obtained from the PubMed searches using the previously listed keywords. Four publications were retrospective reviews, 8 were clinical studies, and 8 were case reports. Sixteen of the 20 publications noted the existence or non-existence of AEs (Table 1). Six publications were adequate in their description of adverse events, 3 were partially adequate, 4 were inadequate, and 7 publications reported no AEs (Table 1). Twelve publications had study populations of only postmenopausal patients, 6 had both postmenopausal and premenopausal patients, and 2 had study populations of only premenopausal patients (Table 1). Among the 8 studies that included premenopausal patients, 7 made note of the use of oral contraceptive use and 1 did not (Table 1). A total of 6 publications detailed the specific AEs experienced during treatment (Table 2). Two of the 6 publications evaluating dutasteride treatment for FFA or FPHL reported AEs. The other 4 publications reporting AEs used finasteride. Some of these AEs resolved during treatment while others were consistent throughout. Two clinical studies had patients withdraw (Table 2). The first clinical study had a patient withdraw because of nausea, and another patient withdrew due to colon cancer believed to be unrelated to treatment.19 The second clinical study had a patient withdraw due to headaches.35 Of all 20 publications, only 2 studies write that patients reported a change in libido during treatment with finasteride.36,37
DISCUSSION
Nine of 20 studies where women are treated with 5 α-reductase inhibtiors for hair loss made mention of the existence of side effects or adverse events due to finasteride or dutasteride treatment, and 3 of those studies did not meet the criteria set for being adequate in reporting side effects. The side effects listed in the finasteride package insert include an allergic reaction, breast tenderness, breast enlargement, breast lumps, nipple discharge, and changes in sexual dysfunction or libido. Dutasteride has a similar side effect profile listed on its package insert, with the addition of potential side effects including depression and dizziness. Nearly all of these side effects were reported in the publications we reviewed. Women using finasteride for hair loss report similar side effects to those reported by men using it for hair loss.43,44 In contrast, women who use dutasteride for hair loss have a very different side effect profile than men who use it for the same purpose.43,44 Researchers reporting on use of the 5 α-reductase inihibitors in women should note the side effects they observe so that clinicians are aware of these risks. Given the dearth of publications on the use of these drugs for these conditions, reporting additional information on side effects would assist patients in choosing the treatment that best meets their needs.
The 7 studies that reported the non-existence of AEs had dosing ranging from 2.5-5 mg/day for finasteride, and 0.5 mg/day
