Terazosin (Hytrin): Uses and Applications
Terazosin is primarily used to treat benign prostatic hyperplasia (BPH) and hypertension, with its mechanism of action as an alpha-1 blocker that relaxes smooth muscles in the prostate and blood vessels.
Use in Benign Prostatic Hyperplasia (BPH)
Terazosin works by blocking alpha-1 receptors in the prostate, which:
- Relaxes smooth muscle in the prostate and bladder neck
- Reduces urinary obstruction and improves urine flow
- Decreases lower urinary tract symptoms (LUTS)
According to the American Urological Association guidelines, terazosin is an effective treatment option for men with moderate to severe BPH symptoms 1. Clinical trials have shown that terazosin improves:
- International Prostate Symptom Score (IPSS) by 3.7 points
- Peak urinary flow rate
- Quality of life scores related to urinary symptoms
Use in Hypertension
Terazosin is also indicated for the treatment of hypertension, though it is not considered a first-line agent according to current guidelines 1. As an alpha-1 blocker, terazosin:
- Relaxes blood vessels throughout the body
- Reduces peripheral vascular resistance
- Lowers both systolic and diastolic blood pressure
The American College of Cardiology/American Heart Association guidelines note that terazosin can be used as an add-on therapy in resistant hypertension, particularly when other medications have failed 1.
Dosing and Administration
For BPH:
- Starting dose: 1 mg once daily at bedtime
- Gradual titration: Can be increased to 2,5, and 10 mg based on response
- Maximum dose: 20 mg daily
For Hypertension:
- Starting dose: 1 mg once daily
- Gradual titration based on blood pressure response
- Typical maintenance dose: 1-5 mg daily
- Maximum dose: 20 mg daily
Important Considerations and Side Effects
First-dose phenomenon
- Risk of significant hypotension with the first dose
- First dose should be taken at bedtime to minimize risk of syncope 2
- Patients should be warned about possible dizziness and syncope
Common side effects
- Dizziness (reported in 14-20% of patients) 3
- Asthenia (weakness)
- Postural hypotension
- Headache
- Peripheral edema
Special populations
- Elderly patients may be more sensitive to hypotensive effects
- Use caution in patients with cardiovascular disease
- May cause intraoperative floppy iris syndrome during cataract surgery 2
Comparative Efficacy
When comparing alpha blockers for BPH:
- Terazosin improves IPSS scores by approximately 3.7 points compared to placebo 1
- Similar efficacy to other alpha blockers like doxazosin
- May have more significant blood pressure effects than more uroselective agents like tamsulosin 4
For hypertension:
- Not recommended as first-line therapy
- Other agents (ACE inhibitors, ARBs, calcium channel blockers, thiazide diuretics) are preferred for initial treatment 1
Conclusion
Terazosin (Hytrin) serves dual purposes in treating both BPH and hypertension through its alpha-1 blocking mechanism. While effective for both conditions, it requires careful initiation and monitoring, particularly for first-dose hypotension. For BPH, it significantly improves urinary symptoms, while for hypertension, it's typically used as an add-on therapy rather than first-line treatment.