Finasteride adverse effects

Treatment for at least 3-6 months is necessary to see increased hair growth or prevent further hair loss. Continued treatment with finasteride is necessary to sustain benefit. Reported adverse effects include decreased libido, ejaculation disorders, and erectile dysfunction, which resolve in most men who remain on therapy and in all men who discontinue finasteride. 

Adverse effects are reported with an incidence of 1-3%. The most common include gastrointestinal upset, hypertension, decreased libido, abdominal pain, impotence, back pain, urinary retention, and headache. In comparison to tamsulosin and finasteride, saw palmetto was claimed to be less likely to affect sexual function (eg, ejaculation). 

The effect of adding finasteride 5 mg/day to high-dose bicalutamide 150 mg/ day has been studied in 41 men with advanced prostate cancer treated over a mean of 3.9 years (21). The serum prostate-specific antigen (PSA) concentration was measured every 2 weeks until disease progression. At the first nadir of PSA, the median fall from baseline was 96.5% a second nadir occurred in 30 of 41 patients, with a median fall of 98.5% from baseline. The median times to each nadir were 3.7 and 5.8 weeks respectively. The median time to treatment failure was 21 months. Adverse effects were minor, including gynecomastia. Sex drive was normal in 17 of 29 men at baseline and in 12 of 24 men at the second PSA nadir, but one-third of the men had spontaneous erections at both times. The authors concluded that finasteride provided additional intracellular androgen blockade when added to bicalutamide. The duration of control was comparable to that achieved with castration, with preserved sexual function in some patients. 

In an open comparative study of androgenetic alopecia in 90 men oral finasteride (1 mg/day for 12 months n = 65) was compared with 5% topical minoxidil solution twice daily (n = 25) (22). The cure rates were 80% for oral finasteride and 52% for topical minoxidil. The adverse effects were all mild, and did not lead to withdrawal of treatment. Of the 65 men given oral finasteride, six had loss of libido, and one had an increase in body hair at other sites irritation of the scalp was seen in one of those who used minoxidil. These adverse events disappeared as soon as the treatment was withdrawn. The laboratory data did not show any statistically or clinically significant changes from baseline values to the endpoint, except for the serum total testosterone concentration, which was increased, and free testosterone and serum prostate-specific antigen in the finasteride group which were reduced from baseline values. 

The benefit of combining an alpha-adrenoceptor antagonist with a 5-alpha-reductase inhibitor has been assessed in men with benign prostatic hyperplasia (23). Modified-release alfuzosin was more effective than finasteride, with no additional benefit in combining the drugs. The adverse effects of alpha-blockade were postural hypotension, hypotension, headache, dizziness, and malaise the adverse effects of finasteride were ejaculatory disorders and impotence. 

The therapeutic and adverse effects of dibenyline, finasteride, and a combination of the two in 190 patients with symptomatic benign prostatic hyperplasia have been evaluated (24). Adverse effects were more common with dibenyline than with finasteride alone or in combination with dibenyline. The drop-out rate was higher with dibenyline (16%) than finasteride alone (7.5%) or the two in combination (4.6%). The reported adverse effects are listed in Table 1. 

Table 1 Adverse effect of finasteride with or without dibenyline in benign prostatic hyperplasia...

In 44 women with polycystic ovary syndrome treated with finasteride or flutamide for 6 months the adverse effects of flutamide were reduced libido, gastrointestinal disorders, and dry skin (29). Finasteride caused reduced libido, headache, and dry skin. Dry skin was reported in 68% of users of flutamide and in only 27% of users of finasteride. 

The long-term effects and adverse effects of finasteride have been studied in a multicenter study of 3270 men... 

At an oral dose of 1 mg/day finasteride has no major adverse effects on measures of semen production or quality (57), although it can cause a slight reduction in the volume of ejaculate (15). 

The effects of finasteride (n = 545), tamsulosin, or the proprietary herbal remedy Permixon on sexual function have been studied in patients with lower urinary tract symptoms due to benign prostatic hyperplasia (64). At 6 months tamsulosin and finasteride caused slight increases in sexual disorders and Permixon caused a slight improvement. Ejaculation disorders were the most frequently reported adverse effects after tamsulosin or finasteride. 

However, an Italian investigation of sexual and erectile function, using questionnaires directed to 186 patients treated at various centers with finasteride 1 mg/day for 4-6 months has challenged the accepted wisdom the authors concluded that (as judged by the five-item International Index of Erectile Function) there was no adverse effect on erection after this period of time (65). 

Reversible painful gynecomastia has been reported as an adverse effect of finasteride in a dose as low as 1 mg/day (67) it can be unilateral (68) or bilateral (69). Some reports of gynecomastia in users of finasteride relate to doses as low as 1 mg/day (70). 

A systematic review and meta-analysis of randomized trials of S. repens in men with benign prostatic hyperplasia showed that saw palmetto extracts improve urinary symptoms and flow measures to a greater extent than placebo, and similar improvements in urinary symptoms and flow measures to the 5-alpha-reductase inhibitor finasteride with fewer adverse effects (6). 

Clinical studies have reported very few adverse effects that are of a mild nature (usually gastric distress or headache) following saw palmetto administration at normal doses. One randomized, double-blind study of finasteride, tamsulosin, and saw palmetto for 3 months observed no differences among the three treatments in terms of the effectiveness measures and no change in sexual function in those individuals receiving saw palmetto, though ejaculation disorders were noted as the most common side effect in those individuals receiving either tamsulosin or finasteride (26). 

A meta-analysis (Wilt et al., 1998) of randomized trials comparing saw palmetto to placebo or other therapy was recently published. The authors concluded that despite methodology problems, saw palmetto appears to improve urologic symptoms and urinary flow to an extent similar to that of finasteride, but with fewer adverse effects. 

In a randomised study, 17 healthy subjects were given a single 400-microgram dose of digoxin while taking finasteride 5 mg daily for 10 days. Finasteride had no significant effect on the pharmacokinetics of digoxin. No adverse effects are expected on concurrent use. 

In a meta-analysis of saw palmetto clinical trials, data from 3139 men in 21 randomized trials lasting 4 to 48 weeks were assessed. Adverse effects in the saw palmetto groups were reported as generally minor and similar to those of placebo. Withdrawal rates in the studies were 8.9% for saw palmetto, 7.1% for placebo, and 9.0% for the drug finasteride. Specific adverse events were reported in 11 of the clinical trials. The most common event was impotence, with incidences reported at 1.1% for saw palmetto, 0.7% for placebo, and 4.9% for finasteride. Gastrointestinal side effects were reported in 1.3% of men on saw palmetto, 0.9% on placebo, and 1.5% on finasteride (Wilt et al. 2002). 

Teratogenicity Women using finasteride should maintain effective contraception in view of the drug s adverse effects on the fetus [49. ... 

Sexual function Adverse effects of finasteride on male sexual function are not uncommon (SEDA-30, 480). These effects are dose related, and in the low doses used to treat hair loss (1 mg/day) they are unusual. However, they can occur in certain instances, as in two patients with azoospermia and severe oligospermia resulting in infertility when they took finasteride 1 mg/ day for hair loss the drug was withdrawn and the sperm count recovered within 3-6 months [112 ]. 

Psychiatric Finasteride has recently been associated with persistent sexual side effects. In addition, depression has recently been added to tiie product labelling as an adverse effect. This is because finasteride reduces the levels of several neuroactive steroids linked to sexual fxmction and depression. In 2010-2011, former users of finasteride (n = 61) with persistent sexual side effects for >3 months were revised and psychologically evaluated and compared to a healthy group of men (n = 29) recruited from the community dwelling [99 ]. The primary outcomes were the prevalence of depressive symptoms and the prevalence of suicidal thoughts as determined by the Beck depression inventory II (BDI-II). The results of this study revealed that rates of depressive symptoms (BDI-II score >14) were significantly higher in the former finasteride users (75% 46/61) as compared to that in the controls (10% 3/29)... 

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