Adult: As conventional tab: 2.5 mg tid. Max: 10 mg daily. As extended-release tab: 10 mg once daily. 1st dose should be given at bedtime. Elderly: As conventional tab: Initially, 2.5 mg bid, adjust according to response. Max: 10 mg daily. As extended-release tab: Initially, 5 mg daily, increase to 10 mg daily if necessary. 1st dose should be given at bedtime.
Oral Acute urinary retention associated with benign prostatic hyperplasia
Elderly: As extended-release tab: 10 mg once daily for 2-3 days during catheterisation, and 1 day after removal. Max: 4 days.
Renal Impairment
Benign prostatic hyperplasia:
As conventional tab: Initially, 2.5 mg bid, adjust according to response. As extended-release tab: Mild to moderate: 5 mg once daily, adjust according to response. Severe (CrCl <30 mL/min): Contraindicated.
Acute urinary retention associated with benign prostatic hyperplasia:
Elderly: Severe (CrCl <30 mL/min): Contraindicated.
Hepatic Impairment
Benign prostatic hyperplasia:
As conventional tab: Mild to moderate: Initially, 2.5 mg once daily, may increase to bid according to response. As extended-release tab: Severe (Child-Pugh class C): Contraindicated.
Acute urinary retention associated with benign prostatic hyperplasia:
Elderly: Severe (Child-Pugh class C): Contraindicated.
Administration
Should be taken with food. extended-release: Should be taken with food. Take immediately after the same meal each day. Swallow whole, do not chew/crush.
Contraindications
History of orthostatic hypotension. Severe hepatic and renal impairment. Concomitant use with other α1-receptor blockers and potent CYP3A4 inhibitors.
Special Precautions
Patient with acute cardiac failure, history of tachyarrhythmia or certain CV disease (e.g. myocardial ischaemia), QT prolongation (congenital or acquired), or taking medications that prolong QT interval. Patient undergoing cataract surgery. Mild to moderate renal and hepatic impairment. Not intended for the treatment of hypertension. Not intended for use in women and children. Elderly.
Adverse Reactions
Significant: Angina, CNS depression, intraoperative floppy iris syndrome (cataract surgery patients), orthostatic hypotension, syncope, risk of cerebral ischaemic disorders. Rarely, priapism. Cardiac disorders: Tachycardia. Eye disorders: Visual disturbances. Gastrointestinal disorders: Nausea, diarrhoea, dry mouth, abdominal pain, dyspepsia. General disorders and admin site conditions: Asthenia, malaise, oedema, chest pain. Nervous system disorders: Dizziness, vertigo, headache. Respiratory, thoracic and mediastinal disorders: Rhinitis. Skin and subcutaneous tissue disorders: Rash, pruritus. Vascular disorders: Flushing.
This drug may cause dizziness or weakness, if affected, do not drive or operate machinery.
Monitoring Parameters
Rule out prostatic carcinoma before initiation of therapy (many symptoms of BPH and prostate cancer are similar). Monitor blood pressure (regularly, especially at the beginning of therapy), urine flow, and prostate-specific antigen (PSA).
Overdosage
Symptom: Hypotension. Management: Maintain the patient in a supine position to restore blood pressure and normalise the heart rate. IV fluids and/or vasopressors may also be needed.
Drug Interactions
May enhance the hypotensive effect of antihypertensive agents, nitrates (e.g nitroglycerin, isosorbide dinitrate,) and phosphodiesterase-5 inhibitors (e.g. sildenafil, tadalafil). Administration with general anaesthesia may result in blood pressure instability. Potentially Fatal: Enhanced hypotensive effect with other α1-blockers (e.g. tamsulosin). Increased serum concentration with potent CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, ritonavir, clarithromycin, telithromycin, nefazodone, nelfinavir).
Food Interaction
Food increases the extent of absorption.
Action
Description: Alfuzosin, a quinazoline derivative that selectively blocks α1-receptors in the lower urinary tract which causes smooth muscle relaxation in the prostate and bladder neck, resulting in the improvement of urine flow and reduction of symptoms in benign prostatic hyperplasia (BPH). Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Food increases absorption. Bioavailability: 49% following a meal. Time to peak plasma concentration: 8 hours following a meal. Distribution: Volume of distribution: 3.2 L/kg. Plasma protein binding: 82-90%. Metabolism: Extensively metabolised in the liver by CYP3A4 isoenzymes via oxidation, O-demethylation, and N-dealkylation into inactive metabolites. Excretion: Mainly via faeces (69%); urine (24%; 11% as unchanged drug). Elimination half-life: 10 hours.
Chemical Structure
Alfuzosin Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 2092, Alfuzosin. https://pubchem.ncbi.nlm.nih.gov/compound/Alfuzosin. Accessed Mar. 29, 2022.
Storage
Store below 30°C. Protect from light and moisture.
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