Effectiveness of Terazosin for Managing Hypertension
Terazosin is moderately effective for hypertension management, producing average blood pressure reductions of 5-10 mmHg systolic and 3.5-8 mmHg diastolic compared to placebo, but is not recommended as a first-line agent due to its side effect profile. 1
Mechanism of Action and Efficacy
- Terazosin is an alpha-1 adrenergic receptor antagonist that decreases blood pressure by reducing total peripheral vascular resistance through vasodilation 1
- Blood pressure reduction begins within 15 minutes of oral administration and effects persist throughout the 24-hour dosing interval 1
- Clinical trials showed that terazosin produces blood pressure reductions of:
Dosing Considerations
- Initial dose should be 1 mg to avoid large initial blood pressure drops, with subsequent titration to effective doses 1
- Usual effective dose range is 5-20 mg/day, typically administered once daily 1
- Peak blood pressure response (2-3 hours after dosing) is approximately twice the trough (24-hour) response 1
- If blood pressure control is inadequate at the end of the dosing interval, patients may benefit from larger doses or twice-daily dosing 1
Place in Hypertension Treatment
- According to the 2018 ACC/AHA hypertension guidelines, alpha-1 blockers like terazosin are not recommended as first-line agents for hypertension 2
- The guidelines list terazosin in the alpha-1 blocker class with a usual dose range of 1-20 mg/day, administered once or twice daily 2
- Alpha-1 blockers may be considered as second-line agents in patients with concomitant benign prostatic hyperplasia (BPH) 2
Special Populations and Considerations
- In hypertensive patients with BPH, terazosin can effectively treat both conditions simultaneously 3, 4
- In a primary care trial of 5,365 patients with hypertension (including 1,483 with BPH symptoms), terazosin produced significant blood pressure reductions while also improving BPH symptoms 3
- For patients with normal blood pressure or controlled hypertension, terazosin treatment for BPH produces minimal clinically significant blood pressure changes 5, 6
- In patients already on antihypertensive therapy who need BPH treatment, terazosin can be safely added to existing regimens 4
Safety Concerns and Adverse Effects
- The most common adverse events are orthostatic hypotension, dizziness, tiredness (asthenia), ejaculatory problems, and nasal congestion 1
- First-dose effect: Like all alpha blockers, terazosin can cause unusually large falls in blood pressure after the first dose or first few doses 1
- During the first 3 hours after dosing, approximately 12.5% of patients had significant orthostatic hypotension compared to 4% with placebo 1
- In men with hypertension and cardiac risk factors, alpha blockers like doxazosin (similar to terazosin) have been associated with a higher incidence of congestive heart failure compared to other antihypertensive agents 2
Comparative Efficacy
- The magnitude of blood pressure reduction with terazosin is similar to prazosin but less than hydrochlorothiazide 1
- Among alpha blockers used for BPH, tamsulosin appears to have less effect on blood pressure in normotensive and hypertensive patients compared to terazosin 7
- In a comparison study of alpha blockers for BPH, terazosin significantly decreased blood pressure in hypertensive patients, while tamsulosin did not 7
Clinical Recommendations
- For primary hypertension management, terazosin should not be used as a first-line agent due to its side effect profile and the availability of more effective alternatives 2
- Consider terazosin primarily for male patients who have both hypertension and BPH symptoms 3, 4
- Start with 1 mg at bedtime to minimize first-dose hypotension, and titrate gradually to effective doses (typically 5-10 mg) 1
- Monitor for orthostatic hypotension, especially after the first dose and during dose increases 1
- In patients with hypertension and cardiac risk factors, separate management of hypertension with other agents may be necessary 2