ALFUZOSIN

ALFUZOSIN
(al-fuz'o-sin)
UroXatral, Xatral

Classifications: alpha-adrenergic antagonist;
Therapeutic: antagonist of alpha-1 receptors
Prototype: Prazosin
Pregnancy Category: B

Availability

10 mg extended-release tablet

Action

Alfuzosin is a short-acting, selective antagonist at alpha-1 receptors with a low incidence of hypotension and sexual dysfunction at therapeutic doses. Alpha-1 receptors cause contraction of smooth muscle in the prostate, prostatic capsule, prostatic urethra, bladder base, and bladder neck. Both alpha-1a (70%) and alpha-1b receptors exist in the prostate.

Therapeutic Effect

Blockade of alpha-1 receptors by alfuzosin causes smooth muscles in the bladder neck and prostate to relax, thereby reducing pressure on the urethra and improving urine flow rate. This results in a reduction in BPH symptoms.

Uses

Treatment of symptomatic benign prostatic hypertrophy (BPH).

Contraindications

Hypersensitivity to alfuzosin; severe hepatic insufficiency; concurrent treatment with potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, and ritonavir); angina; QT prolongation.

Cautious Use

Coronary artery disease, cardiac arrhythmias; hepatic disease; dizziness, light-headedness, orthostatic hypotension; pregnancy (category B).

Route & Dosage

Benign Prostatic Hypertrophy
Adult: PO 10 mg q.d.

Administration

Oral

Give immediately after same meal each day.
Ensure that extended-release tablet is not crushed or chewed. It must be swallowed whole.
Store at 15°–30° C (59°–86° F). Protect from light and moisture.

Adverse Effects (≥1%)

Body as a Whole: Fatigue, pain. CNS: Dizziness, headache. GI: Abdominal pain, dyspepsia, constipation, nausea. Respiratory: Upper respiratory infection, bronchitis, sinusitis, pharyngitis. Urogenital: Impotence, priapism.

Interactions

Drug: Increased risk of hypotension with other antihypertensive agents or sildenafil, vardenafil, and tadalafil; ketoconazole, itraconazole, protease inhibitors may increase alfuzosin levels and toxicity.

Pharmacokinetics

Absorption: 49% when taken with food. Peak: 8 h. Metabolism: In liver by CYP3A4. Elimination: 69% in feces, 24% in urine. Half-Life: 10 h.

Nursing Implications

Assessment & Drug Effects

Monitor CV status and BP, especially if on concurrent treatment with antihypertensive drugs or inhibitors of CYP3A4. See INTERACTIONS.
Check postural vital signs to evaluate for orthostatic hypotension within a few hours following administration.
Withhold drug and report new or worsening angina to physician.
Lab tests: Baseline and periodic LFTs.

Patient & Family Education

Inform physician about all other prescription, nonprescription, or herbal drugs being taken.
Make position changes slowly to minimize dizziness.
Do not drive or engage in other hazardous activities until reaction to drug is known.
Moderate or eliminate grapefruit juice consumption while on this drug.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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