DrugindexOnline^{2nd edition}

Pronouncation: (al-FEW-zoe-sin HIGH-droe-KLOR-ide)
Class: Antiadrenergic agent, peripherally acting

Trade Names:
Uroxatral
- Tablets, extended release 10 mg

Mechanism of Action

Pharmacology

Selective blockade for alpha ₁ -adrenergic receptors in the lower urinary tract, which cause smooth muscle in the bladder neck and prostate to relax, resulting in improved urine flow and a reduction in symptoms of benign prostatic hyperplasia (BPH).

Pharmacokinetics

Absorption

Bioavailability is about 49%. Time to reach C _max is about 8 h. The C _max and AUC are about 13.6 ng/mL and 194 ng•h/mL, respectively.

Distribution

Following IV administration, the Vd is about 3.2 L/kg. Protein binding is 82% to 90%.

Metabolism

Extensive hepatic metabolism with only 11% excreted unchanged in the urine. The major isozyme responsible for metabolism is CYP3A4.

Elimination

After 7 days, 69% is recovered in the feces and 24% in the urine.

Renal function impairment

The mean C _max and AUC values were increased about 50% in patients with mild, moderate, or severe renal function impairment.

Hepatic function impairment

In patients with moderate or severe hepatic function impairment, plasma concentrations of alfuzosin were increased 3- to 4-fold.

Indications and Usage

Treatment of signs and symptoms of benign prostatic hyperplasia.

Contraindications

Patients with moderate or severe hepatic function impairment; coadministration with potent CYP3A4 inhibitors (eg, itraconazole, ketoconazole, ritonavir); hypersensitivity to any component of the product.

Dosage and Administration

Adults

PO 10 mg/day, immediately after the same meal each day. Do not cut, chew, or crush tablet. Instruct patient to swallow tablet whole.

Storage/Stability

Store at controlled room temperature (59° to 86°F). Protect from light and moisture.

Drug Interactions

Atenolol

Plasma levels may be elevated by alfuzosin, increasing the pharmacologic and adverse reactions

Cimetidine

Alfuzosin levels may be elevated, increasing the pharmacologic and adverse reactions

Moderate CYP3A4 inhibitors (eg, diltiazem)

Alfuzosin plasma levels may be elevated, increasing the pharmacologic and adverse reactions

Potent CYP3A4 inhibitors (eg, itraconazole, ketoconazole, ritonavir)

Because plasma concentrations of alfuzosin may be increased more than 2-fold, coadministration of these agents is contraindicated.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Orthostatic hypotension (7%); tachycardia (postmarketing).

CNS

Dizziness (6%); headache, fatigue (3%).

Dermatologic

Rash (postmarketing).

EENT

Sinusitis, pharyngitis (1% to 2%).

GI

Abdominal pain, constipation, dyspepsia, nausea (1% to 2%).

Genitourinary

Impotence (1% to 2%); priapism (postmarketing).

Respiratory

Upper respiratory tract infection (3%); bronchitis (1% to 2%).

Miscellaneous

Pain (1% to 2%); chest pain (postmarketing).

Precautions

Monitor Orthostatic hypotension Monitor patient for orthostatic hypotension. Notify health care provider if symptomatic orthostatic hypotension or new onset or worsening of angina pectoris is noted. Urinary symptoms Assess changes in urinary symptoms such as frequency, hesitancy, weak stream, volume, dribbling, and nocturia.

Pregnancy

Category B .

Lactation

Use not indicated.

Children

Safety and efficacy not established.

Renal Function

Use with caution.

Hepatic Function

Do not administer to patients with moderate or severe hepatic function impairment

Alpha-blockers

Do not use in combination with other alpha-blockers.

Coronary insufficiency

Discontinue if symptoms of angina pectoris appear or worsen.

Hypotension

Postural hypotension with or without symptoms may occur within a few h following administration of alfuzosin.

Prostate carcinoma

Rule out presence of carcinoma of the prostate before starting alfuzosin.

QT prolongation

Use with caution and monitor patients with a known history of QT prolongation or patients taking medication known to prolong the QT interval.

Overdosage

Symptoms

Hypotension.

Patient Information

• Advise patient to take prescribed dose every day immediately after the same meal each day.
• Advise patient not to cut, crush, or chew tablet and to swallow the tablet whole with a full glass of water.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
• Caution patient that drug may cause dizziness or fainting and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
• Advise patient to contact health care provider if urinary symptoms do not improve or worsen while taking this medication.
• Instruct patient to report the following symptoms to health care provider: dizziness, fainting, chest pain, prolonged or painful erection, or bothersome side effects.