What is the recommended use and dosage of Terazosin (alpha-blocker) for treating benign prostatic hyperplasia (BPH) and hypertension?

Terazosin for Benign Prostatic Hyperplasia and Hypertension

Terazosin is an effective alpha-blocker for BPH that should be started at 1 mg at bedtime and titrated to 10 mg daily over 4-6 weeks, producing a clinically meaningful 4-6 point improvement in urinary symptoms, though it carries significant risks of orthostatic hypotension and dizziness that require careful dose escalation. 1

Dosing Algorithm for BPH

Initial Dosing

• Start at 1 mg at bedtime for all patients—this initial dose must not be exceeded 1
• Close monitoring during initial administration is mandatory to minimize severe hypotensive responses 1
• If therapy is discontinued for several days, restart at the initial 1 mg dose 1

Dose Titration

• Increase in a stepwise fashion: 1 mg → 2 mg → 5 mg → 10 mg once daily 1
• 10 mg daily is generally required for clinical response 1
• Treat for a minimum of 4-6 weeks at 10 mg to assess therapeutic benefit 1
• Some patients may require 20 mg daily, though evidence is limited at this dose 1
• Doses above 20 mg are not supported by adequate data 1

Expected Clinical Outcomes

• Produces an average 4-6 point improvement in AUA Symptom Index, which patients perceive as meaningful change 2
• Increases peak urinary flow rates by approximately 50% and mean flow rates by 46% 3
• Improves obstructive symptoms by 67% and total symptom scores by 54% 3

Critical Safety Considerations

Cardiovascular Adverse Events

• Primary adverse events include orthostatic hypotension, dizziness, tiredness (asthenia), ejaculatory problems, and nasal congestion 2
• Only 0.6% of patients experience syncopal episodes, typically at initiation or dose escalation 4
• Orthostatic hypotension occurred in only 4 of 163 patients in major trials 3

Hypertension Management Caveat

• In men with hypertension and cardiac risk factors, alpha-blocker monotherapy should not be assumed to constitute optimal hypertension management 2
• Terazosin reduces blood pressure significantly in untreated hypertensive patients but causes minimal changes in normotensive or controlled hypertensive patients 5, 4
• Patients with hypertension may require separate antihypertensive management 2

Drug Interactions

• Exercise caution when combining with other antihypertensives, especially verapamil 1
• Hypotension reported when used with PDE-5 inhibitors 1
• Dosage reduction and retitration of either agent may be necessary with concomitant antihypertensives 1

Comparative Effectiveness

Versus Other Alpha-Blockers

• Terazosin, doxazosin, tamsulosin, and alfuzosin are similarly effective for symptom relief 2
• Tamsulosin has lower probability of orthostatic hypotension but higher probability of ejaculatory dysfunction 2
• Terazosin is significantly more effective than tamsulosin in improving symptom scores at standard doses 6
• If tiredness is problematic, tamsulosin is preferred due to fewer systemic cardiovascular effects including fatigue 7

Versus 5-Alpha Reductase Inhibitors

• Alpha-blockers like terazosin are more effective than finasteride for improving lower urinary tract symptoms 2
• Finasteride produces only a 3-point improvement in AUA Symptom Index compared to terazosin's 4-6 point improvement 2
• Finasteride is only appropriate for patients with demonstrable prostatic enlargement 2

Dosing for Hypertension

Initial and Maintenance Dosing

• Start at 1 mg at bedtime 1
• Titrate slowly to achieve desired blood pressure response 1
• Usual dose range: 1-5 mg once daily, though some patients benefit from up to 20 mg daily 1
• Doses over 20 mg provide no additional blood pressure benefit 1

Monitoring Strategy

• Monitor blood pressure at end of dosing interval to ensure 24-hour control 1
• Measure blood pressure 2-3 hours post-dose to assess maximum response and evaluate symptoms like dizziness or palpitations 1
• If response diminishes at 24 hours, consider increased dose or twice-daily regimen 1

Common Pitfalls to Avoid

• Never exceed 1 mg as initial dose—this is the most critical safety measure 1
• Do not assume adequate hypertension control in patients with cardiac risk factors using terazosin alone 2
• Do not discontinue and restart without returning to 1 mg initial dosing 1
• Avoid premature discontinuation before completing 4-6 weeks at 10 mg dose 1
• Do not use in patients without prostatic enlargement if considering 5-alpha reductase inhibitors as alternative 2