General Articles

Alfuzosin

U.S. BRAND NAMES — Uroxatral®

PHARMACOLOGIC CATEGORY
Alpha 1 Blocker

DOSING: ADULTS — Benign prostatic hyperplasia (BPH): Oral: 10 mg once daily

DOSING: ELDERLY — Refer to adult dosing.

DOSING: RENAL IMPAIRMENT — Bioavailability and maximum serum concentrations are increased by ~50% with mild, moderate, or severe renal impairment.

Note: Safety has not been evaluated in patients with creatinine clearances <30 mL/minute. DOSING: HEPATIC IMPAIRMENT
Mild hepatic impairment: Use has not been studied.

Moderate or severe hepatic impairment (Child-Pugh class B and C): Clearance is decreased 1/3 to 1/4 and serum concentration is increased three- to fourfold; use is contraindicated.

DOSAGE FORMS — Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, extended release, as hydrochloride:
Uroxatral®: 10 mg

DOSAGE FORMS: CONCISE
Tablet, extended release:
Uroxatral®: 10 mg

GENERIC EQUIVALENT AVAILABLE — No

ADMINISTRATION — Tablet should be swallowed whole; do not crush or chew. Administer once daily (with a meal); should be taken at the same time each day.

USE — Treatment of the functional symptoms of benign prostatic hyperplasia (BPH)

ADVERSE REACTIONS SIGNIFICANT
1% to 10%:
Central nervous system: Dizziness (6%), fatigue (3%), headache (3%), pain (1% to 2%)
Gastrointestinal: Abdominal pain (1% to 2%), constipation (1% to 2%), dyspepsia (1% to 2%), nausea (1% to 2%)
Genitourinary: Impotence (1% to 2%)
Respiratory: Upper respiratory tract infection (3%), bronchitis (1% to 2%), pharyngitis (1% to 2%), sinusitis (1% to 2%)

<1% (Limited to important or life-threatening): Angina pectoris (pre-existing CAD), angioedema, chest pain, cholestatic liver injury, diarrhea, edema, flushing, hepatocellular injury, intraoperative floppy iris syndrome (with cataract surgery), jaundice, priapism, pruritus, rash, rhinitis, tachycardia, urticaria CONTRAINDICATIONS — Hypersensitivity to alfuzosin or any component of the formulation; moderate or severe hepatic insufficiency (Child-Pugh class B and C); concurrent use with potent CYP3A4 inhibitors (eg, itraconazole, ketoconazole, ritonavir) WARNINGS / PRECAUTIONS
Concerns related to adverse effects: Angina: Discontinue if symptoms of angina occur or worsen. Floppy iris syndrome: Intraoperative floppy iris syndrome has been observed in cataract surgery patients who were on or were previously treated with alpha1-blockers; causality has not been established and there appears to be no benefit in discontinuing alpha-blocker therapy prior to surgery. Orthostatic hypotension/syncope: May cause significant orthostatic hypotension and syncope, especially with first dose; anticipate a similar effect if therapy is interrupted for a few days, if dosage is rapidly increased, or used with antihypertensives (particularly vasodilators), PDE-5 inhibitors, nitrates or other medications which may result in hypotension. Patients should be cautioned about performing hazardous tasks when starting new therapy or adjusting dosage upward.

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Disease-related concerns: Hepatic impairment: Use with caution in patients with mild hepatic impairment; contraindicated in moderate-to-severe impairment. Prostate cancer: Rule out prostatic carcinoma before beginning therapy (many symptoms of BPH and prostate cancer are similar). QT prolongation: Alfuzosin has been shown to prolong the QT interval alone (minimal) and with other drugs with comparable effects on the QT interval (additive). Use with caution in patients with known QT prolongation (congenital or acquired). Renal impairment: Use with caution in patients with renal impairment.

Special populations: Pediatrics: Not indicated for use in children.

Other warning/precautions: Antihypertensive agent: Not intended for use as an antihypertensive drug.

METABOLISM / TRANSPORT EFFECTS — Substrate of CYP3A4 (major)

DRUG INTERACTIONS
Alpha1-Blockers: May enhance the antihypertensive effect of Alfuzosin. Risk of orthostatic hypotension or syncope may be increased. Alfuzosin may enhance the antihypertensive effect of Alpha1-Blockers. Risk X: Avoid combination

Beta-Blockers: May enhance the orthostatic effect of Alpha1-Blockers. The risk associated with ophthalmic products is probably less than systemic products. Exceptions: Levobunolol; Metipranolol. Risk D: Consider therapy modification

Calcium Channel Blockers: Alpha1-Blockers may enhance the hypotensive effect of Calcium Channel Blockers. Risk C: Monitor therapy

CYP3A4 Inducers (Strong): May increase the metabolism of CYP3A4 Substrates. Risk C: Monitor therapy

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CYP3A4 Inhibitors (Moderate): May decrease the metabolism of CYP3A4 Substrates. Risk C: Monitor therapy

CYP3A4 Inhibitors (Strong): May increase the serum concentration of Alfuzosin. Risk X: Avoid combination

Deferasirox: May decrease the serum concentration of CYP3A4 Substrates. Risk C: Monitor therapy

Herbs (CYP3A4 Inducers): May increase the metabolism of CYP3A4 Substrates. Risk C: Monitor therapy

MAO Inhibitors: May enhance the orthostatic effect of Orthostasis Producing Agents. Risk C: Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Alpha1-Blockers. Management: Ensure patient is stable on alpha 1 blocker before starting PDE5 inhibitor; initiate PDE5 inhibitor at lowest possible dose. If patient stable on PDE5 inhibitor, initiate alpha 1 blocker at lowest dose. Risk D: Consider therapy modification

QTc-Prolonging Agents: Alfuzosin may enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk C: Monitor therapy

Silodosin: Alpha1-Blockers may enhance the adverse/toxic effect of Silodosin. Of particular concern are the risk of postural hypotension, syncope, and/or hypotension. Silodosin may enhance the hypotensive effect of Alpha1-Blockers. Of particular concern are the risk of postural hypotension, syncope, and/or hypotension. Risk X: Avoid combination

Tamsulosin: Alpha1-Blockers may enhance the antihypertensive effect of Tamsulosin. Risk of orthostatic hypotension or syncope may be increased. Tamsulosin may enhance the antihypertensive effect of Alpha1-Blockers. Risk X: Avoid combination

ETHANOL / NUTRITION / HERB INTERACTIONS
Food: Food increases the extent of absorption.

Herb/Nutraceutical: Avoid St John’s wort (may decrease alfuzosin levels).

PREGNANCY RISK FACTOR — B (show table)

PREGNANCY IMPLICATIONS — Teratogenic effects were not observed in animal studies; however, alfuzosin is not indicated for use in women.

LACTATION — Not indicated for use in women

DIETARY CONSIDERATIONS — Take following a meal at the same time each day.

PRICING — (data from drugstore.com)
Tablet, 24-hour (Uroxatral)
10 mg (30): $111.79

MONITORING PARAMETERS — Urine flow; blood pressure

CANADIAN BRAND NAMES — Apo-Alfuzosin; Sandoz-Alfuzosin; Xatral

INTERNATIONAL BRAND NAMES — Alfetim (HN); Alfusin (IN); Benestan (PT); Benestan OD (PT); Dalfaz (AR, ES, PL); Lafuzo (TW); Uroxatral (CN); Uroxatral OD (AR, UY); Uroxatral uno (CH, DE); Xatral (AT, BE, BF, BJ, CH, CI, CL, CZ, DK, ET, FI, FR, GB, GH, GM, GN, GR, IE, IL, IT, KE, LR, MA, ML, MR, MU, MW, NE, NG, NL, NO, SC, SD, SE, SL, SN, TN, TZ, UG, ZA, ZM, ZW); Xatral LP (FR, HK); Xatral OD (BR, CO, CR, DO, EC, GT, HN, MX, NI, PA, PE, PH, PY, SE, SV, VE); Xatral SR (AT, BG, EE, EG, IL, PK, SG); Xatral XL (ID, IL, KP, SG, TH, TW); Xatral XR 10 (SG)

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MECHANISM OF ACTION — An antagonist of alpha1-adrenoreceptors in the lower urinary tract. Smooth muscle tone is mediated by the sympathetic nervous stimulation of alpha1-adrenorecepto

rs, which are abundant in the prostate, prostatic capsule, prostatic urethra, and bladder neck. Blockade of these adrenoreceptors can cause smooth muscles in the bladder neck and prostate to relax, resulting in an improvement in urine flow rate and a reduction in BPH symptoms.

PHARMACODYNAMICS / KINETICS
Absorption: Decreased 50% under fasting conditions

Distribution: Vd: 3.2 L/kg

Protein binding: 82% to 90%

Metabolism: Hepatic, primarily via CYP3A4; metabolism includes oxidation, O-demethylation, and N-dealkylation; forms metabolites (inactive)

Bioavailability: 49% following a meal

Half-life elimination: 10 hours

Time to peak, plasma: 8 hours following a meal

Excretion: Feces (69%); urine (24%; 11% as unchanged drug)

PATIENT INFORMATION — Do not take any new medication during therapy without consulting prescriber. Take exactly as directed, with a meal at the same time each day. Swallow tablet whole; do not crush or chew. May cause drowsiness, dizziness, impaired judgment (use caution when driving or engaging in tasks that require alertness until response to drug is known), or postural hypotension (use caution when rising from sitting or lying position or when climbing stairs). Report unusual chest pain, respiratory difficulty, or any persistent adverse reactions.

May 2010
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