Doxazosin Mesylate
BPH & Drugs for Urinary Retention · Selective alpha-1 blocker
Indications
Urinary outflow obstruction and symptoms associated with benign prostatic hyperplasia. Hypertension.
Dosage
Adults: BPH: Initially 1 mg once daily, increasing if necessary after 1-2 wk to 2 mg once daily and then 4 mg once daily if required; max 8 mg daily for urinary outflow obstruction & symptoms associated with BPH. Hypertension: Initial: 1 mg once daily. Titrate: May double the dose every 1-2 wk. Max: 16 mg/day. Children: Not recommended.
Adverse Effects
Postural effects, dizziness, vertigo, headache, fatigue, asthaenia, oedema, nausea, rhinitis, somnolence, palpitation, tachycardia, anxiety, insomnia, nervousness, paraesthesia, hypotension, RTI, cough, dyspnoea, GI upset, anorexia, dry mouth, pruritus, back pain, myalgia, UTI, urinary incontinence, chest pain, flu-like symptoms, malaise.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Contraindicated or not recommended. Contraindications: History of postural hypotension and micturition syncope. BPH with upper urinary tract congestion, chronic UTI or bladder stones. Severe hepatic impairment. History of oesophageal or GI obstruction (XL preps only). Precautions: Hypertension; monitor BP regularly, particularly at start of treatment. Pulmonary oedema due to aortic or mitral stenosis, high-output cardiac failure, right sided heart failure due to pulmonary embolism or pericardial effusion, left ventricular heart failure with low filling pressure. Hepatic impairment. Cataract surgery. Risk of priapism; warn patients to seek immediate medical assistance.
Interactions
Beta-blockers, diuretics, ACE inhibitors, calcium channel blockers, sildenafil, tadalafil, vardenafil, PDE5 inhibitors, other antihypertensives.
Advice to Patient
Take with or without meals. Take as advised by prescriber, at bedtime. Contact prescriber if there is rapid weight gain, increased depression or nervousness, constant swelling of ankles/feet/extremities, rapid heartbeat or palpitations, muscle weakness, pain, fatigue. Avoid standing for long time, exercising, alcohol and going outside in hot weather. Change position slowly when climbing stairs and from lying or sitting to standing position. Check weight once a week at the same time in same clothes.
Pharmacokinetics
Duration: >24 hrs. Metabolism: Extensively hepatic. Bioavailability: Immediate release: Approx. 65%. Extended release relative to immediate release: 54%-59%. Half-life elimination: Immediate release: Approx. 22 hrs. Extended release: 15-19 hrs. Time to peak, serum: Immediate release: 2-3 hrs. Extended release: 8 ± 3.7-9 ± 4.7 hrs. Excretion: Faeces (approx. 63%). Urine (9%).
Unlicensed Use
Children: Dysfunctional voiding: 4-12 yr, initially 0.5 mg daily increased at mthly intervals according to response; max 2 mg daily; 12-18 yr, initially 1 mg daily, dose may be doubled at intervals of 1 mth according to response; usual maintenance 2-4 mg daily, max 8 mg daily. Hypertension: 6-12 yr, 500 mcg once daily, increased at 1-wk intervals to 2-4 mg daily; 12-18 yr, 1 mg daily, increased after 1-2 wk to 2 mg once daily and thereafter to 4 mg once daily if necessary, usual max 4 mg daily, rarely up to 16 mg daily may be required.
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
Always consult a pharmacist or doctor.