Finasteride is used orally to stimulate regrowth of hair in men with mild to moderate androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness). Androgenetic alopecia in men is expressed principally as baldness of the vertex (crown) of the scalp. In clinical trials, oral finasteride therapy has been effective in promoting hair regrowth in young and middle-aged men (18-41 years of age) with mild to moderate androgenetic alopecia and hair loss on the vertex of the scalp and/or anterior mid-scalp area; the effects of finasteride on bitemporal recession have not been established. Improvement in both objective (scalp hair count) and subjective (individuals' self-assessment of appearance) measures of hair regrowth has been demonstrated as early as 3 months following initiation of oral finasteride therapy, and objective improvement was at its maximum during the first 2 years of treatment. Continuation or maintenance of hair regrowth (based on scalp hair count) beyond 2 years of treatment has not been demonstrated; however, slowing of further progression of hair loss has been demonstrated in clinical trials with follow-up periods of up to 5 years. Current evidence indicates that oral finasteride therapy must be continued to sustain initial regrowth and subsequent slowing of hair loss; however, benefit of the drug should be reevaluated periodically. If improvement does not occur within the first year of finasteride therapy, further treatment with the drug is unlikely to provide benefit. Withdrawal of the drug leads to reversal of clinical benefit within 1 year.
Evidence of clinical benefit of finasteride is based principally on the results of 3 randomized, placebo-controlled clinical trials in men with mild to moderate androgenetic alopecia. Two of the trials were conducted in men with predominantly vertex hair loss, and the third trial involved men with hair loss in the anterior mid-scalp, with or without vertex balding. In these trials, efficacy of finasteride therapy was evaluated objectively using hair counts (e.g., number of hairs in a 1-inch diameter circle) and subjectively by investigators' and treated individuals' assessments of cosmetic benefit. All individuals in these clinical trials (both active drug and placebo groups) were instructed to use a specific, medicated, tar-based shampoo (Neutrogena T/Gel shampoo) to prevent seborrheic dermatitis that potentially could influence assessment of hair growth. The 2 trials in men with predominantly vertex hair loss were 1-year controlled trials with 1-year, controlled extension periods. The trials were extended for an additional 3 years in some men. As a result, some men who received finasteride during the first year of the trial continued to receive the drug for periods up to 5 years total, while others were switched to placebo for the second year and then were switched back to finasteride for years 3-5. Of the men who received placebo during the first year of the trial and participated in the extension trials, some continued to received placebo and some were switched to finasteride during the extension trials. The trial in patients with mild-to-moderate anterior mid-scalp area hair loss was a 1-year controlled trial.
In the trials in men with vertex hair loss, hair regrowth (as indicated by increases in hair counts) with finasteride therapy was demonstrated at 6 months and 1 year and was maintained with continued finasteride therapy for up to a total of 2 years, while men receiving placebo continued to have progressive hair loss. Men receiving finasteride for up to 5 years experienced a maximum improvement in hair count during the first 2 years; a gradual decline in hair count occurred in these men after the second year, although hair counts remained above baseline during up to 5 years of finasteride therapy. Men receiving placebo for up to 5 years experienced a decline in hair count that was more rapid than that observed in men receiving finasteride. At 1 year, 14% of men treated with finasteride had hair loss (defined as any decrease in hair count from baseline) compared with 58% of men receiving placebo. In men treated for up to 2 years, 17% of those receiving finasteride had hair loss compared with 72% of those receiving placebo. At 5 years, 35% of those receiving finasteride had hair loss compared with all of those receiving placebo. In men receiving finasteride for the first year who were switched to placebo for the second year, reversal of the increase in hair count was demonstrated at the end of the second year; those switched back to finasteride for years 3-5 experienced an increase in hair count to above baseline during the third year, and hair counts for years 3-5 remained above baseline. Men who were switched from placebo during the first year to finasteride during the second year had a decline in hair count during placebo therapy followed by an increase in hair count to above baseline after 1 year of treatment with finasteride; with continued finasteride therapy during years 3-5 of the trial, a gradual decline in hair count occurred.
Individuals' subjective perceptions of hair growth, hair loss, and appearance were obtained at each clinic visit using a self-administered questionnaire. Evaluation of these self-assessments was consistent with an increase in the amount of hair, a decrease in and slowing of the rate of hair loss, and improvement in appearance in men treated with finasteride. Overall improvement according to individuals' self-assessments was observed as early as 3 months following initiation of finasteride therapy and maintained for up to 5 years.
Investigators' assessments of clinical efficacy were based on a 7-point scale evaluating increases or decreases in scalp hair at each clinic visit. At 1 year, investigators determined that hair growth had increased in 65% of men treated with finasteride compared with 37% of those receiving placebo, while increased hair growth at 2 years occurred in 80 or 47% of men receiving finasteride or placebo, respectively. At 5 years, investigators determined that hair growth had increased in 77% of men receiving finasteride, compared with 15% of men receiving placebo. Increased hair growth as determined by investigators occurred as early as 3 months after initiation of finasteride therapy. Based on blinded evaluation of standardized photographs of the head, an independent panel determined that increased hair growth had occurred in 48 or 66% of men treated with oral finasteride for 1 or 2 years, respectively, compared with 7 or 7% of men receiving placebo for the same periods. The panel also determined that, at 5 years, 48 or 6% of men receiving finasteride or placebo, respectively, had experienced an increase in hair growth; 42 or 19%, respectively, had experienced no change; and 10 or 75%, respectively, had experienced hair loss.
In the year-long study in patients with mild-to-moderate anterior mid-scalp area hair loss, hair counts also increased and were accompanied by patient-rated improvements in appearance.
In the trials in individuals with predominantly vertex baldness, self-assessments of finasteride therapy generally showed improvement in hair growth across racial groups (i.e., in whites, Asians, blacks, and Hispanics); black men reported dissatisfaction with hair growth in the frontal hairline and vertex but were satisfied with overall therapy.
While most men with vertex baldness had some response to finasteride in clinical trials, treatment failures occurred in 17% of men treated for up to 2 years with the drug. Finasteride does not appear to affect nonscalp hair.
Finasteride is not effective for treatment of hair loss in postmenopausal women with androgenetic alopecia and is not indicated for use in women. In a 1-year study in postmenopausal women with androgenetic alopecia, there was no improvement in hair counts, investigators' or treated individuals' assessments of benefit, or ratings based on standardized photographs of the head in women receiving finasteride versus those receiving placebo.
In clinical trials in men with vertex baldness, individuals receiving oral finasteride therapy reported problems in the areas of sexual interest, erections, and perception of sexual problems substantially more frequently than those receiving placebo at the end of 1 year; however, no substantial difference between finasteride and placebo regarding overall satisfaction with sex life was reported. Breast enlargement and tenderness have been reported during clinical trials in men receiving finasteride 5 mg daily for benign prostatic hyperplasia (BPH) and during postmarketing surveillance in men receiving finasteride 1 mg daily for androgenetic alopecia. Breast neoplasm has been reported during clinical trials of 4-7 years' duration in men receiving finasteride 5 mg daily and during postmarketing surveillance in men receiving finasteride 1 mg daily; whether a causal relationship exists between long-term finasteride use and breast neoplasia in men has not been established. Men receiving the drug should be instructed to report any breast changes (e.g., lumps, pain, nipple discharge) to their clinician.
Oral finasteride therapy has been associated with small reductions (from 0.7 to 0.5 ng/mL) in serum prostate-specific antigen (PSA) in men 18-41 years of age receiving the drug at a dosage of 1 mg daily for androgenetic alopecia, and PSA reductions of approximately 50% have been demonstrated in older men receiving the drug at a dosage of 5 mg daily for BPH. Such reductions should be considered when interpreting serum PSA values in men receiving finasteride. Any confirmed increase in serum PSA concentration during finasteride therapy should be evaluated carefully. For further information on effects of 5α-reductase inhibitors on serum PSA concentrations and interpretation of PSA results in patients receiving therapy with these drugs,
5α-Reductase inhibitors may increase the risk of development of high-grade prostate cancer. In 2 placebo-controlled trials evaluating finasteride (5 mg daily for 7 years) or dutasteride (0.5 mg daily for 4 years) for prevention of prostate cancer in men at least 50 years of age, 5α-reductase inhibitor therapy was associated with an overall reduction in prostate cancer occurrence, which reflected a reduction in lower-grade (Gleason score of 6 or less) tumors; however, the incidence of high-grade tumors (Gleason score of 8-10) was increased in men receiving finasteride or dutasteride. Finasteride is not labeled by the US Food and Drug Administration (FDA) for prevention of prostate cancer.
Finasteride is contraindicated in women who are or may potentially be pregnant. Since finasteride inhibits the conversion of testosterone to dihydrotestosterone, the drug could cause abnormalities in the external genitalia of a male fetus if a pregnant woman received the drug, and female patients should be apprised of the potential fetal hazard. In addition, pregnant women should not handle crushed or broken finasteride tablets because of the possibility of absorption and subsequent risk to the male fetus.
For use in the management of benign prostatic hyperplasia,