UROXATRAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for UROXATRAL (UROXATRAL).
Selective antagonist of postsynaptic alpha1A-adrenoceptors in the prostate, bladder base, and prostatic urethra, leading to relaxation of smooth muscle and improved urinary flow.
| Metabolism | Primarily hepatic via CYP3A4, with minor contributions from CYP1A2, CYP2D6, and CYP2C8. Extensive first-pass metabolism. |
| Excretion | After oral administration, approximately 11% of the dose is excreted unchanged in urine, while 49% is excreted as metabolites in urine and 22% in feces. Overall, renal elimination accounts for about 60% of total clearance. |
| Half-life | The terminal elimination half-life is approximately 5 to 9 hours in healthy young subjects, and 6 to 10 hours in elderly patients. This supports once-daily dosing, with steady state achieved after 3-5 days. |
| Protein binding | Alfuzosin is approximately 82-90% bound to plasma proteins, primarily to alpha-1-acid glycoprotein (AAG). Binding is concentration-independent within therapeutic range. |
| Volume of Distribution | The volume of distribution after oral administration is about 2.5 L/kg, indicating extensive distribution into extravascular tissues. This large Vd contributes to its prolonged duration of action. |
| Bioavailability | The absolute oral bioavailability of alfuzosin is approximately 49% (range 44-53%) when taken under fed conditions. Food increases Cmax by about 50% and AUC by 20-30% compared to fasting; therefore, it should be taken with food. |
| Onset of Action | The onset of clinical effect (improvement in urinary symptoms) occurs within 1 to 2 weeks of starting oral therapy, as determined by the International Prostate Symptom Score (IPSS). The peak effect is observed after 4-6 weeks. |
| Duration of Action | The duration of action supports once-daily dosing. After discontinuation, symptom relief may persist for several days but gradual return to baseline is expected within 1-2 weeks. |
| Molecular Weight | 389.5 |
10 mg orally once daily, immediately after the same meal each day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment (CrCl ≥30 mL/min). For severe renal impairment (CrCl <30 mL/min), contraindicated. |
| Liver impairment | Contraindicated in moderate to severe hepatic impairment (Child-Pugh class B or C). No data for mild impairment (Child-Pugh A); use with caution. |
| Pediatric use | Not approved; safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dosage adjustment required; monitor for orthostatic hypotension and dizziness. |
| 1st trimester | UROXATRAL (alfuzosin) is not recommended during the first trimester due to limited data; animal studies have not shown teratogenic effects, but human data are insufficient. |
| 2nd trimester | Use during second trimester is not recommended unless clearly needed; avoid due to potential risk of maternal hypotension and unknown fetal effects. |
| 3rd trimester | Use during third trimester is not recommended; may cause maternal hypotension and reduced placental perfusion, potentially affecting fetal oxygenation. |
Clinical note
Comprehensive clinical and safety monograph for UROXATRAL (UROXATRAL).
| Placental transfer | Alfuzosin is known to cross the placenta in animals; human data are limited but suggest transfer occurs. The degree is likely moderate based on molecular weight and pharmacokinetics. |
| Breastfeeding | Alfuzosin is excreted into breast milk in low amounts; however, effects on the nursing infant are unknown. Due to the potential for adverse effects such as hypotension, caution is advised. Use only if clearly needed and monitor the infant. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to alfuzosin or any component of the formulationSevere hepatic impairment (Child-Pugh Class C)Concomitant use with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir)History of orthostatic hypotension or syncope with alpha-blockers
| Precautions | Orthostatic hypotension and syncope (especially with dose escalation or use with other alpha-blockers or antihypertensives), Use with caution in patients with renal impairment (CrCl < 30 mL/min), Intraoperative floppy iris syndrome (IFIS) during cataract surgery, Priapism (rare), Hepatic impairment |
| Food/Dietary | Take UROXATRAL with food to reduce the risk of orthostatic hypotension. Avoid grapefruit juice as it may increase drug levels. No other specific food restrictions. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | UROXATRAL (alfuzosin HCl) is classified as FDA Pregnancy Category B. Animal studies have not shown fetal harm, but no adequate human studies exist. Risk cannot be ruled out, especially in the first trimester. Use only if clearly needed. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to risk of orthostatic hypotension. Assess for syncope, especially during dose initiation. Fetal monitoring as per standard obstetric care; no specific fetal monitoring required by drug. |
| Fertility Effects | No human studies on fertility. Animal studies showed no impairment of fertility. Theoretical effect on ejaculation (abnormal ejaculation reported in males); relevance to female fertility unknown. |
| Clinical Pearls | UROXATRAL (alfuzosin HCl) is a selective alpha-1 adrenergic receptor antagonist indicated for the treatment of benign prostatic hyperplasia (BPH). Unlike tamsulosin, alfuzosin has lower affinity for alpha-1A receptors, reducing the risk of intraoperative floppy iris syndrome (IFIS). Administer immediately after the same meal each day to maintain consistent bioavailability. Avoid use in patients with moderate to severe hepatic impairment. Do not use with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir). |
| Patient Advice | Take UROXATRAL exactly as prescribed, usually once daily after the same meal. · Swallow the tablet whole; do not crush, chew, or split. · Avoid driving or operating heavy machinery until you know how UROXATRAL affects you, as dizziness or orthostatic hypotension may occur. · Do not take with other alpha-blockers or medications for erectile dysfunction (e.g., sildenafil) without consulting your doctor. · Report any symptoms of fainting, dizziness upon standing, or prolonged painful erection (priapism). · Continue taking UROXATRAL even if you feel well, as it controls symptoms but does not cure BPH. |