Table 4

Adverse effects reported in double blind, placebo controlled trials of 3–48 months duration Significantly fewer adverse effects with finasteride than with placebo.

Adverse effect

Number of studies

Time point (months)

Harmed with finasteride 5 mg

Harmed with placebo

Relative risk (95% CI)

NNT (95% CI)

Number

Percent

Number

Percent

Serious adverse effects

2

12

437/3557

12

150/1175

13

1.0 (0.8 to 1.1)

n/c

Any sexual dysfunction

1

12

239/1736

14

38/579

7

2.1 (1.5 to 2.9)

14 (10 to 22)

Decreased libido

5

12

269/5688

5

86/3296

3

2.0 (1.6 to 2.5)

47 (35 to 74)

Impotence

6

12

439/5394

8

117/3551

3

2.2 (1.8 to 2.7)

24 (20 to 31)

Ejaculation disorder

5

12

137/5688

2

19/3296

0.6

3.6 (2.2 to 6.0)

55 (43 to 74)

Acute urinary retention

3

12

17/3803

0.4

9/1430

0.6

0.8 (0.4 to 1.9)

n/c

1

24

24/1450

2

54/1452

4

0.5 (0.3 to 0.7)

49 (31 to 112)

1

48

42/1542

3

99/1516

7

0.4 (0.3 to 0.6)

26 (19 to 44)

BPH related surgery

5

12

54/4410

1

24/2035

1

1.1 (0.7 to 1.7)

n/c

2

24

85/1760

5

142/1755

8

0.6 (0.5 to 0.8)

31 (21 to 61)

1

48

69/1542

4

152/1516

10

0.5 (0.3 to 0.6)

18 14 to 27)

Prostate cancer

2

12

9/3557

0.3

5/1175

0.4

0.6 (0.2 to 0.8)

n/c

1

24

3/310

1

6/303

2

0.5 (0.1 to 1.9)

n/c

1

48

76/1524

0.5

76/1516

0.5

1.0 (0.7 to 1.4)

n/c

n/c Not calculable NB: For acute urinary retention, prostate surgery, and prostate cancer the NNT represents the number-needed-to-treat to prevent one episode of acute urinary retention or prostate surgery

Edwards and Moore BMC Urology 2002 2:14   doi:10.1186/1471-2490-2-14