Generic Medicine Info
Indications and Dosage
Benign prostatic hyperplasia
Adult: Initially, 1 mg at bedtime, increased gradually at weekly intervals according to patient’s response. Maintenance: 5-10 mg once daily.

Adult: As monotherapy or in combination with diuretics or other antihypertensive agents: Initially, 1 mg at bedtime, increased gradually at weekly intervals according to patient’s response. Maintenance: 2-10 mg once daily. Max: 20 mg daily in 1 or 2 divided doses.
May be taken with or without food.
History of micturition syncope in the treatment of BPH.
Special Precautions
Patient with permanent erectile dysfunction and male impotence; severe coronary heart disease, pulmonary oedema due to aortic or mitral valve stenosis, high output cardiac insufficiency, right-sided cardiac insufficiency due to pulmonary embolism or pericardial effusion, left-sided cardiac insufficiency with low filling pressure. Hepatic impairment. Pregnancy and lactation.
Adverse Reactions
Significant: First-dose hypotensive episodes (e.g. postural hypotension, syncope), orthostatic hypotension, priapism, floppy iris syndrome during cataract surgery, drowsiness, somnolence.
Blood and lymphatic system disorders: Thrombocytopenia.
Cardiac disorders: Palpitations, tachycardia, arrythmia, atrial fibrillation, chest pain.
Endocrine disorders: Tinnitus.
Eye disorders: Blurred vision, amblyopia, visual impairment, conjunctivitis.
General disorders and administration site conditions: Asthenia, pyrexia, flu symptoms.
Immune system disorders: Anaphylactoid reaction, angioedema, face oedema.
Investigations: Weight increased, decreased hematocrit, decreased Hb, decreased WBC count, decreased total protein, decreased blood albumin.
Metabolism and nutrition disorders: Peripheral oedema, oedema,
Musculoskeletal and connective tissue disorders: Back pain, pain in extremity, neck pain, shoulder pain, gout, arthralgia, arthritis, joint disorders, myalgia.
Nervous system disorders: Headache, paraesthesia, vertigo.
Psychiatric disorders: Depression, nervousness, anxiety, insomnia.
Renal and urinary disorders: Pollakiuria, UTI, urinary incontinence.
Reproductive system and breast disorders: Libido decreased, erectile dysfunction.
Respiratory, thoracic and mediastinal disorders: Nasal congestion, rhinitis, dyspnea, sinusitis, bronchitis, pharyngitis, cold symptoms, cough.
Skin and subcutaneous tissue disorders: Pruritus, rash, hyperhidrosis.
Vascular disorders: Vasodilation, epistaxis.
Patient Counseling Information
This drug may cause dizziness, drowsiness, and visual disturbances, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor blood pressure. Rule out prostate cancer before starting therapy for benign prostatic hyperplasia (BPH).
Symptoms: Acute hypotension. Management: Symptomatic and cardiovascular supportive treatment. Restore normal blood pressure and heart rate by keeping the patient in supine position. May give volume expanders in case of shock, then vasopressors, if necessary. Monitor renal function.
Drug Interactions
Increased adverse effects with ACE inhibitors (e.g. captopril, enalapril); and diuretics (e.g. hydrochlorothiazide, furosemide). Additive hypotensive effect with other antihypertensive agents. Increased concentration and significant hypotension with verapamil. Additive blood pressure lowering effect and symptomatic hypotension with phosphodiesterase type 5 (PDE5) inhibitors (e.g. sildenafil, tadalafil).
Description: Terazosin is an α1-adrenergic antagonist. It competitively inhibits post-synaptic α-receptors resulting to relaxation of peripheral blood vessels leading to gradual decrease in blood pressure followed by sustained antihypertensive action.
Onset: Antihypertensive effect: Within 15 minutes.
Duration: 24 hours.
Absorption: Rapidly and completely absorbed from the gastrointestinal tract. Bioavailability: Approx 90%. Time to peak plasma concentration: Approx 1 hour.
Distribution: Plasma protein binding: 90-94%.
Metabolism: Metabolised in the liver via demethylation and conjugation; undergoes minimal first pass metabolism.
Excretion: Via faeces (approx 60%, approx 20% as unchanged drug); urine (approx 40%, approx 10% as unchanged drug). Half-life: Approx 12 hours.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Terazosin, CID=5401, https://pubchem.ncbi.nlm.nih.gov/compound/Terazosin (accessed on Jan. 23, 2020)

Store below 25°C. Protect from light and moisture.
MIMS Class
Drugs for Bladder & Prostate Disorders / Other Antihypertensives
ATC Classification
G04CA03 - terazosin ; Belongs to the class of alpha-adrenoreceptor antagonists. Used in the treatment of benign prostatic hypertrophy.
Anon. Terazosin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 03/04/2019.

Buckingham R (ed). Terazosin Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/01/2014.

Hytrin Tablets. U.S. FDA. https://www.fda.gov/. Accessed 09/01/2014.

Joint Formulary Committee. Terazosin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 03/04/2019.

McEvoy GK, Snow EK, Miller J et al (eds). Terazosin Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 09/01/2014.

Terazosin (Jubilant Cadista Pharmaceuticals Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 09/01/2014.

Terazosin Hydrochloride Capsule (Sandoz Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 03/04/2019.

Disclaimer: This information is independently developed by MIMS based on Terazosin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2022 MIMS. All rights reserved. Powered by MIMS.com
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