Terazosin

Mechanism-of-action class: Adrenergic alpha-Antagonists.

• Terazosin capsules are indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH). There is a rapid response, with approximately 70% of patients experiencing an increase in urinary flow and improvement in symptoms of BPH when treated with terazosin capsules.ICD-10: N40.0

• Terazosin capsules are contraindicated in patients known to be hypersensitive to terazosin hydrochloride.contraindicated

If terazosin capsules administration is discontinued for several days, therapy should be reinstituted using the initial dosing regimen. Benign Prostatic Hyperplasia Initial Dose : 1 mg at bedtime is the starting dose for all patients, and this dose should not be exceeded as an initial dose. Patients should be closely followed during initial administration in order to minimize the risk of severe hypotensive response. Subsequent Doses : The dose should be increased in a stepwise fashion to 2 mg, 5 mg, or 10 mg once daily to achieve the desired improvement of symptoms and/or flow rates. Doses of 10 mg once daily are generally required for the clinical response. Therefore, treatment with 10 mg for a minimum of 4 to 6 weeks may be required to assess whether a beneficial response has been achieved. Some patients may not achieve a clinical response despite appropriate titration. Although some additional patients responded at a 20 mg daily dose, there was an insufficient number of patients studied to draw definitive conclusions about this dose. There are insufficient data to support the use of higher doses for those patients who show inadequate or no response to 20 mg daily. If terazosin administration is discontinued for several days or longer, therapy should be reinstituted using the initial dosing regimen. Use With Other Drugs : Caution should be observed when terazosin capsules are administered concomitantly with other antihypertensive agents, especially the calcium channel blocker verapamil, to avoid the possibility of developing significant hypotension.

Syncope and “First-dose” Effect Terazosin capsules, like other alpha-adrenergic blocking agents, can cause marked lowering of blood pressure, especially postural hypotension, and syncope in association with the first dose or first few days of therapy. A similar effect can be anticipated if therapy is interrupted for several days and then restarted. Syncope has also been reported with other alpha-adrenergic blocking agents in association with rapid dosage increases or the introduction of another antihypertensive drug. Syncope is believed to be due to an excessive postural hypotensive effect, although occasionally the syncopal episode has been preceded by a bout of severe supraventricular tachycardia with heart rates of 120 to 160 beats per minute. Additionally, the possibility of the contribution of hemodilution to the symptoms of postural hypotension should be considered. To decrease the likelihood of syncope or excessive hypotension, treatment should always be initiated with a 1 mg dose of terazosin capsules, given at bedtime. The 2 mg, 5 mg and 10 mg capsules are not indicated as initial therapy. Dosage should then be increased slowly, according to recommendations in the Dosage and Administration section and additional antihypertensive agents should be added with caution. The patient should be cautioned to avoid situations, such as driving or hazardous tasks, where injury could result should syncope occur during initiation of therapy.

Benign Prostatic Hyperplasia The incidence of treatment-emergent adverse events has been ascertained from clinical trials conducted worldwide. All adverse events reported during these trials were recorded as adverse reactions. The incidence rates presented below are based on combined data from six placebo-controlled trials involving once-a-day administration of terazosin at doses ranging from 1 to 20 mg. Table 1 summarizes those adverse events reported for patients in these trials when the incidence rate in the terazosin group was at least 1%, and was greater than that for the placebo group, or where the reaction is of clinical interest. Asthenia, postural hypotension, dizziness, somnolence, nasal congestion/rhinitis, and impotence were the only events that were significantly (p ≤ 0.05) more common in patients receiving terazosin than in patients receiving placebo. The incidence of urinary tract infection was significantly lower in the patients receiving terazosin than in patients receiving placebo. An analysis of the incidence rate of hypotensive adverse events (see PRECAUTIONS ) adjusted for the length of drug treatment has shown that the risk of the events is greatest during the initial seven days of treatment, but continues at all time intervals. TABLE 1. Adverse Reactions During Placebo-Controlled Trials Benign Prostatic Hyperplasia Body System Terazosin (N = 636) Placebo (N = 360) BODY AS A WHOLE Includes weakness, tiredness, lassitude, and fatigue. Asthenia Flu Syndrome Headache 7.4% p ≤ 0.05 comparison between groups.

Pregnancy Teratogenic Effects : Pregnancy Category C Terazosin capsules were not teratogenic in either rats or rabbits when administered at oral doses up to 280 and 60 times, respectively, the maximum recommended human dose. Fetal resorptions occurred in rats dosed with 480 mg/kg/day, approximately 280 times the maximum recommended human dose. Increased fetal resorptions, decreased fetal weight and an increased number of supernumerary ribs were observed in offspring of rabbits dosed with 60 times the maximum recommended human dose. These findings (in both species) were most likely secondary to maternal toxicity. There are no adequate and well-controlled studies in pregnant women and the safety of terazosin in pregnancy has not been established. Terazosin capsules are not recommended during pregnancy unless the potential benefit justifies the potential risk to the mother and fetus. Nonteratogenic Effects : In a peri- and post-natal development study in rats, significantly more pups died in the group dosed with 120 mg/kg/day (> 75 times the maximum recommended human dose) than in the control group during the three-week postpartum period.

Metabolism

Terazosin hydrochloride administered as capsules is essentially completely absorbed in man. Administration of capsules immediately after meals had a minimal effect on the extent of absorption.

Should overdosage of terazosin capsules lead to hypotension, support of the cardiovascular system is of first importance. Restoration of blood pressure and normalization of heart rate may be accomplished by keeping the patient in the supine position. If this measure is inadequate, shock should first be treated with volume expanders. If necessary, vasopressors should then be used and renal function should be monitored and supported as needed. Laboratory data indicate that terazosin is 90-94% protein bound; therefore, dialysis may not be of benefit.

• Mar 30, 1998ANDAANDA074823Senores Pharms
• Jul 28, 2000ANDAANDA075667Bionpharma
• Jan 30, 2001ANDAANDA075614Heritage Pharma Avet
• Dec 20, 2004ANDAANDA075317Jubilant Cadista
• Jul 29, 2024NDANDA218139Novitium Pharma
• May 12, 2025ANDAANDA219482Ajanta Pharma Ltd

1. 1Drug Ineffective5416.2%
2. 2Fatigue5366.1%
3. 3Dyspnoea4955.7%
4. 4Diarrhoea4555.2%
5. 5Dizziness4515.2%
6. 6Asthenia4114.7%
7. 7Death3824.4%
8. 8Off Label Use3594.1%
9. 9Acute Kidney Injury3574.1%
10. 10Fall3453.9%
11. 11Nausea3413.9%
12. 12Chronic Kidney Disease3323.8%
13. 13Renal Failure3303.8%
14. 14Pain3223.7%
15. 15Pneumonia3153.6%

The 10 most recently updated of 40 ClinicalTrials.gov registrations naming Terazosin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Terazosin And Metabolic Energetics in Parkinson's Disease
  Not yet recruiting · Phase 2 · Interventional · 120 enrolled · Nandakumar Narayanan
  NCT07464028updated 2026-03-16
• Terazosin for Dementia With Lewy Bodies
  Not yet recruiting · Phase 1 · Phase 2 · Interventional · 40 enrolled · Qiang Zhang
  NCT04760860updated 2026-03-12
• Effect of Terazosin on ATP Levels in People With Amyotrophic Lateral Sclerosis
  Not yet recruiting · Early phase 1 · Interventional · 20 enrolled · University of Iowa
  NCT07224269updated 2026-03-10
• Terazosin Effect on Cardiac Changes in Early Parkinson's Disease
  Active not recruiting · Phase 2 · Interventional · 15 enrolled · Cedars-Sinai Medical Center
  NCT04386317updated 2026-03-02
• Terazosin and Parkinson's Disease Extension Study
  Active not recruiting · Phase 2 · Interventional · 15 enrolled · Cedars-Sinai Medical Center
  NCT05109364updated 2026-03-02
• Terazosin And Metabolic Engagement in Parkinson's Disease
  Not yet recruiting · Phase 1 · Phase 2 · Interventional · 100 enrolled · Nandakumar Narayanan
  NCT07288450updated 2025-12-18
• Edmond J. Safra Accelerating Clinical Trials in Parkinson's Disease: A Multiarm Multi-stage Platform Trial
  Recruiting · Phase 3 · Interventional · 1,200 enrolled · University College, London
  NCT07207057updated 2025-10-03
• Comparison of Alpha Blockers (Terazosin and Tamsulosin) in Reducing Ureteral Stent Related Symptoms
  Recruiting · Phase 3 · Interventional · 150 enrolled · Penang Hospital, Malaysia
  NCT06966804updated 2025-09-05
• Reduction of Edema With a Specialized Cocktail for Ultra-early Management in Intracerebral Hemorrhage
  Not yet recruiting · Phase 3 · Interventional · 58 enrolled · Second Affiliated Hospital, School of Medicine, Zhejiang University
  NCT06863558updated 2025-05-14
• Reduction of Edema With a Specialized Cocktail for Ultra-early Management in Ischemic Stroke
  Recruiting · Phase 3 · Interventional · 68 enrolled · Second Affiliated Hospital, School of Medicine, Zhejiang University
  NCT06863571updated 2025-04-18

Ranked by 2D fingerprint (Tanimoto) similarity over PubChem structures. Structural proximity only — not a claim of therapeutic equivalence.

• Alfuzosinalpha-Adrenergic Blocker80%
• Doxazosinalpha-Adrenergic Blocker77%

Frequently asked questions

How does Terazosin work?

Mechanism-of-action class: Adrenergic alpha-Antagonists.

What is Terazosin used for?

According to FDA labeling, Terazosin carries indications including: Terazosin capsules are indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH). There is a rapid response, with approximately 70% of patients experiencing an increase in urinary flow and improvement in symptoms of BPH when treated with terazosin capsules.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Terazosin?

Terazosin is classified as Alpha-adrenoreceptor antagonists, alpha-Adrenergic Blocker, Adrenergic alpha-Antagonists, Arterial Vasodilation, Decreased Bladder Sphincter Tone, Decreased Blood Pressure, Venous Vasodilation.

What are the brand names for Terazosin?

Terazosin is marketed under brand names including Tezruly.

What are the contraindications for Terazosin?

Terazosin labeling lists contraindications including: Terazosin capsules are contraindicated in patients known to be hypersensitive to terazosin hydrochloride.. Always consult the full prescribing information and a clinician.