Terazosin for BPH

Clinical bottom line

Terazosin improves urinary symptoms and maximum urinary flow rate in men with benign prostatic obstruction. Men taking terazosin can expect prompt relief that does not improve further with time. Over a mean of 42 weeks about one man in four discontinues, and about 1 in 10 discontinues because of adverse events.

Reference

TJ Wilt et al. Terazosin for treating symptomatic benign prostatic obstruction: a systematic review of efficacy and adverse effects. BJU International 2002 89: 214-225.

Systematic review

The search strategy was extensive and based on Cochrane strategies. Several databases, including the Cochrane Library and special registries were searched to the end of 2001. For inclusion studies had to have symptomatic benign prostatic obstruction, compare terazosin with placebo or other therapies, be randomised, and of at least four weeks duration. The primary outcome measure was symptom score improvement, but peak urinary flow rate, specific symptoms, prostate volume and adverse effects were also analysed.

Results

There were 10 placebo-controlled studies, all randomised and double blind, and conducted over 8 to 52 weeks with terazosin doses of 2.5, 5 or 10 mg, often with dose adjustment. One trial had a comparison with finasteride plus a combination over a year, six compared terazosin with other alpha-blockers, but were short and small, and one study compared terazosin with transurethral microwave therapy.

Symptom scores

The 10 placebo-controlled trials used different symptom scoring, but typically men had moderate to severe symptoms at baseline. With terazosin there was generally an improvement that was significantly better than with placebo, by 31-69% for terazosin and 10-58% with placebo.

Maximum urinary flow rate

At baseline maximum urinary flow rate was 8-14 mL/second. The maximum flow rate increased with terazosin by about 2-3 mL/second in most studies (Figure 1), though not in studies with the highest flow rates (Figure 2). There was no increase in flow rate with time (Figure 1).

Figure 1: Change in maximum flow rate with terazosin 2.5 to 10 mg

Figure 2: Change in maximum flow rate according to initial maximum flow rate

For placebo, the change in maximum flow rate was an improvement of about 1 mL/second for studies where the initial maximum flow rate was under 13 mL/second (Figure 3). There was no increase in flow rate with time.

The difference between terazosin and placebo was between 1 and 2 mL/second, again with no evidence of any change over one year (Figure 4).

Figure 3: Change in maximum flow rate with placebo

Figure 4: Change in maximum flow rate (terazosin-placebo)

Discontinuations and adverse events

The results for all cause discontinuations, discontinuations because of adverse effects, and specific adverse events for terazosin versus placebo are shown in Table 1.

There were fewer all cause discontinuations with terazosin (27%), so that for every 15 men treated one fewer discontinued than with placebo. There were more adverse event discontinuations with terazosin (13%), so that for every 26 men treated one more discontinued with adverse events than with placebo.

There was more dizziness with terazosin (14%), so that for every 13 men treated with terazosin one more suffered dizziness than with placebo.

There was more asthenia (loss of strength) with terazosin (9%), so that for every 21 men treated with terazosin one more suffered asthenia than with placebo.

There was more postural hypotension with terazosin (3%), so that for every 34 men treated with terazosin one more suffered postural hypotension than with placebo.

There was no significant difference with headache (5%), or erectile dysfunction (6%) with terazosin. For the erectile dysfunction there was information on relatively few men, making any comment about statistical significance tentative.

Table 1: Discontinuations and adverse events

Comment

The evidence we have is that terazosin improves urinary symptoms and maximum urinary flow rate in men with benign prostatic obstruction. Men taking terazosin can expect prompt relief that does not improve further with time. Over a mean of 42 weeks about one man in four discontinues, and about 1 in 10 discontinues because of adverse events.

		Percent with		Relative risk	NNT/ NNH
Adverse event	Number of men	Terazosin	Placebo	(95% CI)	(95% CI)
All cause discontinuation	3525	27	34	0.8 (.07 to 0.9)	15 (10 to 26)
Adverse event discontinuation	3424	13	9	1.5 (1.2 to 1.8)	26 (17 to 55)
Dizziness	3388	14	6	2.3 (1.8 to 2.8)	13 (10 to 17)
Asthenia	3302	9	4	2.2 (1.7 to 3.0)	21 (15 to 31)
Headache	1304	5	5	1.2 (0.7 to 1.9)
Postural hypotension	3142	3	1	6.4 (3.0 to 13)	34 (26 to 51)
Erectile dysfunction	770	6	4	1.6 (0.9 to 3.0)