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Terazosin Uses, Dosage, Side Effects & Benefits | DrugsAtlas

Authoritative Clinical Reference

DRUG NAME: Terazosin

Therapeutic Class: Alpha-adrenergic blocker

Subclass: Alpha-1 adrenergic receptor antagonist

Speciality: Urology

Schedule (India): Schedule H

Route(s): Oral

Formulations Available in India:
• Tablets: 1 mg, 2 mg, 5 mg, 10 mg

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India):

1. Benign Prostatic Hyperplasia (BPH) — Symptomatic Relief

Parameter	Recommendation
Starting dose	1 mg once daily at bedtime
Titration	Increase to 2 mg, then 5 mg, then 10 mg at intervals of 1–2 weeks based on symptom response and tolerability
Usual maintenance dose	5–10 mg once daily
Maximum dose	20 mg once daily

Key Clinical Notes:
• Bedtime dosing minimises first-dose hypotensive effect
• Standing blood pressure monitoring advised during titration
• Provides symptomatic relief only — not disease-modifying
• Reduce dose or discontinue if significant postural symptoms occur

2. Hypertension (Adjunct Therapy)

Parameter	Recommendation
Starting dose	1 mg once daily at bedtime
Titration	Increase by 1–2 mg increments every 1–2 weeks based on blood pressure response
Usual maintenance dose	5–10 mg once daily
Maximum dose	20 mg once daily

Key Clinical Notes:
• Not first-line antihypertensive per Indian guidelines
• Consider as adjunct therapy or in patients with coexisting BPH
• Monitor for orthostatic hypotension especially when added to existing antihypertensives

Secondary Indications – Adults Only (Off-label):

Indication	PTSD-associated Nightmares / Sleep Disturbance — OFF-LABEL
Dose	1–5 mg once daily at bedtime
Duration	Chronic as needed
Specialist input	Required (Psychiatry)
Evidence basis	International RCTs; off-label use in treatment-resistant cases

Indication	Ureteric Stone Expulsion (Medical Expulsive Therapy) — OFF-LABEL
Dose	2–5 mg once daily
Duration	2–4 weeks or until stone passage
Specialist input	Urology guidance recommended
Evidence basis	RCTs supporting alpha-blocker facilitated stone passage

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India):

No approved paediatric indications in India. Not recommended below 18 years due to limited safety and efficacy data.

Secondary Indications – Paediatric Doses (Off-label):

Indication	Paediatric Hypertension — OFF-LABEL
Starting dose	0.05 mg/kg/day once daily
Titration	Increase gradually based on blood pressure response
Maximum dose	0.4 mg/kg/day or 20 mg/day (whichever is lower)
Specialist input	Required (Paediatric Nephrology/Cardiology)
Evidence basis	Limited case series; extrapolated from adult data

Not recommended below 18 years except under specialist supervision.

Safety Monitoring:
• Regular blood pressure (supine and standing)
• Orthostatic vital signs assessment
• Monitor for dizziness, sedation, syncope

RENAL ADJUSTMENT

eGFR (mL/min/1.73m²)	Recommendation
≥30	No dose adjustment required
<30 (Severe impairment)	Use with caution; initiate at lowest dose (1 mg); titrate slowly with close blood pressure monitoring
Haemodialysis	Not significantly dialysed; no supplemental dose required

HEPATIC ADJUSTMENT

Child-Pugh Class	Recommendation
A (Mild)	Start at 1 mg; titrate cautiously with blood pressure monitoring
B (Moderate)	Use with caution; slower titration; monitor for enhanced hypotensive effect
C (Severe)	Avoid — insufficient pharmacokinetic data; risk of prolonged drug effect

CONTRAINDICATIONS

• Known hypersensitivity to terazosin or any quinazoline derivative

• History of syncope attributable to alpha-blocker therapy

• Concurrent use with other alpha-adrenergic blockers (additive hypotension)

CAUTIONS

• Elderly patients — increased risk of falls and syncope

• First-dose phenomenon — marked hypotension possible; initiate at bedtime

• Orthostatic hypotension — particularly during initial dosing and titration

• Impaired renal or hepatic function

• Planned cataract surgery — risk of Intraoperative Floppy Iris Syndrome (IFIS); inform ophthalmologist

• Concurrent antihypertensive therapy — additive blood pressure lowering

• Does not reduce prostate size — provides symptomatic relief only; rule out prostate malignancy before initiating BPH therapy

PREGNANCY

Parameter	Recommendation
Safety category	Limited human data; safety not established
Preferred alternatives	Methyldopa, labetalol, nifedipine for gestational hypertension
When to use	Avoid unless potential benefit justifies risk; specialist supervision required
Monitoring	Maternal blood pressure (supine and standing); fetal growth assessment

LACTATION

Parameter	Recommendation
Compatibility	Limited data; avoid if possible due to lack of safety information
Preferred alternatives	Nifedipine, labetalol for hypertensive nursing mothers
Drug levels in milk	Unknown; likely low based on pharmacokinetic profile
Infant monitoring	Sedation, poor feeding, hypotension (if exposure unavoidable)

ELDERLY

• Starting dose: 0.5–1 mg once daily at bedtime

• Titration: Slow increments every 2 weeks; smaller dose increases (1 mg steps)

• Additional risks: Higher susceptibility to orthostatic hypotension, syncope, and falls

• Monitoring: Regular standing blood pressure checks; fall risk assessment

• Consider tamsulosin as alternative if tolerability is poor (more uroselective)

MAJOR DRUG INTERACTIONS

Interacting Drug	Mechanism / Effect	Recommendation
PDE-5 inhibitors (sildenafil, tadalafil, vardenafil)	Additive vasodilation → severe hypotension	AVOID co-initiation; if both required, separate dosing by ≥4–6 hours; use lowest PDE-5 inhibitor dose
Other alpha-blockers (prazosin, doxazosin, tamsulosin)	Additive alpha-blockade → profound hypotension	AVOID combination
Strong CYP3A4 inhibitors (ketoconazole, itraconazole)	May increase terazosin exposure	Use with caution; monitor for hypotension

MODERATE DRUG INTERACTIONS

Interacting Drug	Effect	Management
Antihypertensives (beta-blockers, CCBs, diuretics, ACE inhibitors)	Enhanced blood pressure lowering	Monitor blood pressure; may need dose adjustment
Diuretics	Increased risk of orthostatic hypotension	Initiate terazosin at lower dose
NSAIDs	May attenuate antihypertensive effect via sodium retention	Monitor blood pressure
Alcohol	Additive CNS depression and hypotension	Counsel on moderation
Verapamil	Increased terazosin bioavailability	Monitor for enhanced effect

COMMON ADVERSE EFFECTS

• Dizziness

• Postural hypotension

• Fatigue and asthenia

• Headache

• Nasal congestion

• Palpitations

• Peripheral oedema

• Somnolence

SERIOUS ADVERSE EFFECTS

• Syncope — especially first-dose; may require discontinuation

• Intraoperative Floppy Iris Syndrome (IFIS) — during cataract surgery

• Severe hypotension with falls — may necessitate hospitalisation in elderly

• Priapism (rare) — requires urgent urological intervention

• Angioedema (rare)

MONITORING REQUIREMENTS

Phase	Parameters
Baseline	Blood pressure (supine and standing); heart rate; assess fall risk; symptom severity score (IPSS for BPH)
After initiation/dose change	Blood pressure 2–4 hours after first dose; standing blood pressure daily during titration; assess for dizziness/syncope
Long-term	Periodic blood pressure monitoring; fall risk reassessment in elderly; BPH symptom reassessment; PSA if indicated

BRANDS AVAILABLE IN INDIA

• Hytrin (Abbott)

• Terazin (Cipla)

• Olyster (Sun Pharma)

• Terazopress (various manufacturers)

PRICE RANGE (INR)

• 1 mg tablet: ₹2–₹5 per tablet

• 2 mg tablet: ₹3–₹6 per tablet

• 5 mg tablet: ₹5–₹8 per tablet

• Not listed under NLEM 2022; not under NPPA price control

• Government procurement prices significantly lower

CLINICAL PEARLS

• Always initiate at bedtime with 1 mg dose to minimise first-dose hypotensive effect — counsel patients to rise slowly from bed

• Useful dual-benefit agent for elderly men with both BPH and mild hypertension

• Inform ophthalmologist before cataract surgery — IFIS risk persists even after drug discontinuation

• Rule out prostate malignancy with PSA and DRE before attributing LUTS to BPH

• Tamsulosin may be preferred in patients at high risk for hypotension (more uroselective profile)

• If therapy interrupted for several days, re-titrate from 1 mg to avoid hypotensive episodes

Clinical Responsibility

This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.

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