What is the recommended dosage and treatment protocol for Terazosin (alpha-blocker) in patients with benign prostatic hyperplasia (BPH) or hypertension?

Terazosin Dosage and Treatment Protocol for BPH and Hypertension

For patients with benign prostatic hyperplasia (BPH), terazosin should be initiated at 1 mg at bedtime, with gradual titration to 10 mg once daily for optimal clinical response, as this dose is generally required for therapeutic effect. 1

Dosing Protocol for BPH

Initial Dosing

• Start with 1 mg at bedtime (this initial dose should never be exceeded)
• Close monitoring during initial administration is essential to minimize risk of severe hypotensive response

Dose Titration

• Increase in stepwise fashion: 1 mg → 2 mg → 5 mg → 10 mg once daily
• Titrate based on symptom improvement and/or flow rate changes
• Allow 4-6 weeks at 10 mg daily to properly assess clinical response
• Some patients may require up to 20 mg daily, though data supporting doses above 20 mg are insufficient 1

Efficacy

• Alpha-blockers like terazosin produce on average a 4-6 point improvement in the AUA Symptom Index, which patients generally perceive as meaningful improvement 2
• Studies show terazosin can produce a mean reduction of 55% in overall symptom scores 3
• Terazosin increases peak urinary flow rate by approximately 2 ml/s 4

Dosing Protocol for Hypertension

Initial Dosing

• Same as BPH: 1 mg at bedtime initially
• Strict adherence to initial dosing is critical to minimize hypotensive effects

Dose Titration

• May slowly increase to achieve desired blood pressure response
• Usual recommended dose: 1-5 mg once daily
• Some patients may benefit from doses up to 20 mg daily
• Doses above 20 mg provide no additional blood pressure benefit 1

Monitoring

• Monitor blood pressure at the end of dosing interval
• Consider measuring BP 2-3 hours post-dose to evaluate maximum/minimum responses
• If response diminishes at 24 hours, consider increased dose or twice-daily regimen 1

Special Considerations

Restarting After Discontinuation

• If terazosin is discontinued for several days or longer, therapy must be reinitiated using the initial dosing regimen (1 mg at bedtime) 1

Concomitant Medication

• Use caution when administering with other antihypertensive agents, especially calcium channel blocker verapamil
• Dosage reduction and retitration of either agent may be necessary when using multiple antihypertensive medications
• Hypotension has been reported when used with PDE-5 inhibitors 1

Effect on Blood Pressure in BPH Patients

• Produces clinically significant blood pressure reductions in hypertensive patients
• Minimal, clinically insignificant blood pressure changes in normotensive patients 5
• In patients with untreated hypertension, substantial decreases in both systolic and diastolic blood pressure can occur 6

Adverse Effects

• Primary adverse events: orthostatic hypotension, dizziness, tiredness (asthenia), ejaculatory problems, nasal congestion 2
• Side effects are generally mild to moderate and resolve after stopping therapy 6
• Dizziness (2.0%) and headache (1.1%) are the most common symptoms leading to treatment discontinuation 6
• Syncopal episodes occur in approximately 0.6% of patients, typically during initiation or dose escalation 6

Clinical Pearls

• Terazosin can safely treat both BPH and hypertension simultaneously in patients with both conditions 3
• Efficacy is dose-dependent—higher doses generally produce greater improvement 2
• Alpha-blockers like terazosin are more effective than 5-alpha reductase inhibitors for improving LUTS 2
• In men with hypertension and cardiac risk factors, alpha-blocker monotherapy may not constitute optimal management of hypertension 2