Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ALFUZOSIN HYDROCHLORIDE vs FLOMAX
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Selective antagonist of postsynaptic alpha-1 adrenergic receptors in the prostate, bladder base, and prostatic urethra, leading to smooth muscle relaxation and improved urine flow.
Selective antagonist of alpha-1A and alpha-1D adrenergic receptors in the prostate, bladder base, and bladder neck, leading to relaxation of smooth muscle and improved urinary flow.
Treatment of benign prostatic hyperplasia (BPH),Off-label: Management of ureteral stones (medical expulsive therapy)
Treatment of signs and symptoms of benign prostatic hyperplasia (BPH),Off-label: adjunctive therapy for ureteral calculi expulsion
10 mg orally once daily immediately after the same meal each day. Extended-release tablet.
0.4 mg orally once daily, approximately 30 minutes after the same meal each day. If no response after 2-4 weeks, may increase to 0.8 mg once daily.
Terminal elimination half-life: 5-7 hours in patients with benign prostatic hyperplasia; 7-10 hours in elderly; prolonged in hepatic impairment.
Terminal elimination half-life is approximately 14-15 hours (range 6-20 hours) in healthy adults, allowing once-daily dosing.
Extensively metabolized in the liver, primarily via CYP3A4, to inactive metabolites.
Extensively metabolized in the liver via CYP3A4 and CYP2D6 enzymes.
Primarily hepatic metabolism (CYP3A4); 11% renal excretion as unchanged drug; 69% fecal elimination (biliary), 24% urinary (total).
Primarily hepatic metabolism (CYP3A4, CYP2D6) with <10% excreted unchanged in urine; fecal excretion accounts for ~76% of metabolites.
82-90% bound to human serum albumin and alpha-1-acid glycoprotein.
94-99% bound primarily to alpha-1 acid glycoprotein, with high affinity.
Approximately 2.5-3.2 L/kg; indicates extensive extravascular distribution.
Approximately 16 L/kg (or 16 L for an average 70 kg patient), indicating extensive tissue distribution.
Oral immediate-release: 64% (first-pass metabolism); extended-release: 49% relative to immediate-release.
Oral bioavailability is approximately 90% (capsule) due to extensive absorption, with minimal first-pass metabolism.
For Cr Cl 30-49 m L/min: 10 mg once daily; for Cr Cl <30 m L/min: contraindicated.
No adjustment required for GFR ≥10 m L/min; insufficient data for GFR <10 m L/min, use with caution.
Child-Pugh A: 10 mg once daily; Child-Pugh B or C: contraindicated.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Use with caution; consider starting at 0.4 mg once daily. Child-Pugh Class C: Contraindicated.
Not established; safety and efficacy in children <18 years have not been studied.
Not approved for pediatric use; safety and efficacy not established.
No specific dose adjustment recommended; monitor for orthostatic hypotension and dizziness.
Same dosing as adults; monitor for orthostatic hypotension and dizziness. Consider starting at 0.4 mg once daily.
None.
None.
Risk of hypotension, especially orthostatic hypotension, particularly with dose initiation or increase,May cause syncope, especially in patients with predisposing factors (e.g., hypovolemia, concurrent antihypertensives),Use with caution in patients with hepatic impairment,Intraoperative floppy iris syndrome (IFIS) during cataract surgery in patients on or previously treated with alpha-1 blockers,Should not be used in combination with other alpha-1 blockers
Orthostatic hypotension and syncope, especially upon initiation or dose increase,Intraoperative floppy iris syndrome (IFIS) during cataract surgery,Priapism (rare),Hepatic impairment,Consideration of prostate cancer before initiating therapy
Hypersensitivity to alfuzosin hydrochloride or any component of the formulation,Concomitant administration with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir),Moderate to severe hepatic impairment (Child-Pugh B or C)
Hypersensitivity to tamsulosin hydrochloride or any component of the formulation,Concomitant use with strong CYP3A4 inhibitors (e.g., ketoconazole) in patients with moderate to severe hepatic impairment
Take with food to reduce the risk of hypotension. Avoid grapefruit juice as it may increase alfuzosin levels. High-fat meals may alter absorption; consistency in meal timing is advised.
Grapefruit juice may increase tamsulosin levels; avoid concurrent intake. High-fat meals can decrease absorption; administer 30 minutes after the same meal daily.
Alfuzosin hydrochloride is classified as FDA Pregnancy Category B. Animal studies have not shown teratogenic effects, but there are no adequate and well-controlled studies in pregnant women. First trimester: no evidence of fetal harm from animal data. Second and third trimesters: potential risk of maternal hypotension affecting uteroplacental perfusion; limited human data available.
Tamsulosin is FDA Pregnancy Category B. Animal studies revealed no evidence of teratogenicity at doses up to 50 mg/kg/day in rats and 5 mg/kg/day in rabbits (approximately 50 and 30 times the human exposure). There are no adequate and well-controlled studies in pregnant women; use only if clearly needed. First trimester: no known increased risk of major malformations. Second/third trimester: no known specific fetal risks; however, alpha-blockers may cause hypotension in the mother, potentially affecting placental perfusion. No reports of teratogenic effects in humans.
It is unknown if alfuzosin is excreted in human breast milk. The M/P ratio has not been determined. Caution is advised due to potential for adverse effects in nursing infants, including hypotension. Alternative agents with more safety data are preferred during breastfeeding.
Tamsulosin is excreted in rat milk at concentrations 20-fold higher than maternal plasma. No human data exist; M/P ratio is not established. Due to potential for adverse effects (e.g., hypotension) in the nursing infant, breastfeeding is generally not recommended. Discontinue drug or bottle-feed, considering importance of therapy to mother.
No specific dose adjustments are recommended due to lack of pharmacokinetic data in pregnancy. However, increased plasma volume during pregnancy may reduce drug levels; clinical effect should be monitored. Use lowest effective dose if necessary, and avoid in patients with severe hypotension or hypovolemia.
No specific pharmacokinetic studies during pregnancy. Dose adjustments are not routinely recommended; however, hypotension risk may be increased due to pregnancy-related hemodynamic changes. Use the lowest effective dose and monitor for maternal hypotension to avoid fetal compromise.
Alfuzosin is a selective alpha-1 adrenergic antagonist used for benign prostatic hyperplasia (BPH). It has fewer cardiovascular side effects than other alpha-blockers due to its higher affinity for alpha-1a receptors in the prostate. Do not use in patients with moderate to severe hepatic impairment. Avoid use with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir). Use with caution in patients with prolonged QT interval or on QT-prolonging drugs. Administer after the same meal each day to reduce first-dose syncope.
First-dose orthostatic hypotension is common; administer at bedtime. Avoid use in patients with history of cataract surgery due to intraoperative floppy iris syndrome (IFIS). Tamsulosin is not recommended for hypertension. Renal impairment does not require dose adjustment. Use caution with strong CYP3A4 inhibitors (e.g., ketoconazole) and PDE5 inhibitors (e.g., sildenafil) due to enhanced hypotensive effects.
Take this medication immediately after a meal at the same time each day.,Avoid situations that may cause dizziness or fainting, especially after the first dose or when increasing dose.,Do not crush, chew, or open the tablet; swallow whole.,Do not drive or operate heavy machinery until you know how the medication affects you.,Inform your doctor if you experience severe dizziness, fainting, or irregular heartbeat.,Avoid alcohol, which can increase dizziness and blood pressure-lowering effects.,Do not take with other alpha-blockers or medications for erectile dysfunction without consulting your doctor.
Take this medication approximately 30 minutes after the same meal each day to maintain consistent absorption.,Avoid getting up too quickly from a sitting or lying position to minimize dizziness.,Inform your ophthalmologist about tamsulosin use before any cataract surgery due to risk of floppy iris syndrome.,Do not drive or operate heavy machinery until you know how this medication affects you.,If you miss a dose, skip it and take the next dose at the usual time; do not double the dose.
"Alfuzosin, an alpha-1 adrenergic receptor antagonist used for benign prostatic hyperplasia, can enhance the antihypertensive effect of Benidipine, a dihydropyridine calcium channel blocker. This occurs through additive vasodilation, potentially leading to excessive reductions in blood pressure. Clinically, patients may experience orthostatic hypotension, dizziness, or syncope, particularly during initial co-administration or dose adjustments."
"Alfuzosin, an alpha-1 adrenergic receptor antagonist used for benign prostatic hyperplasia, may potentiate the hypotensive effects of lamotrigine, an anticonvulsant. This interaction is primarily due to additive vasodilation, leading to an increased risk of orthostatic hypotension, dizziness, and syncope, particularly at the initiation of therapy or with dose adjustments. Patients, especially those with cardiovascular comorbidities, should be monitored for blood pressure changes and symptoms of hypotension."
"Alfuzosin, an alpha-1 adrenergic receptor antagonist used for benign prostatic hyperplasia, reduces peripheral vascular resistance by blocking alpha-1 receptors on vascular smooth muscle. Pentolinium, a ganglionic blocker, inhibits sympathetic outflow by competitively blocking nicotinic acetylcholine receptors at autonomic ganglia, leading to pronounced hypotension. When combined, their additive vasodilatory effects can cause excessive hypotension, increased risk of syncope, dizziness, and potential cardiovascular collapse, especially during initial therapy or dose escalation."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ALFUZOSIN HYDROCHLORIDE vs FLOMAX, answered by our medical review team.
ALFUZOSIN HYDROCHLORIDE is a Alpha-1 Blocker that works by Selective antagonist of postsynaptic alpha-1 adrenergic receptors in the prostate, bladder base, and prostatic urethra, leading to smooth muscle relaxation and improved urine flow.. FLOMAX is a Alpha-1 Blocker that works by Selective antagonist of alpha-1A and alpha-1D adrenergic receptors in the prostate, bladder base, and bladder neck, leading to relaxation of smooth muscle and improved urinary flow.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ALFUZOSIN HYDROCHLORIDE and FLOMAX depend on the specific clinical indication. These are both Alpha-1 Blocker agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ALFUZOSIN HYDROCHLORIDE is: 10 mg orally once daily immediately after the same meal each day. Extended-release tablet.. The standard adult dose of FLOMAX is: 0.4 mg orally once daily, approximately 30 minutes after the same meal each day. If no response after 2-4 weeks, may increase to 0.8 mg once daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ALFUZOSIN HYDROCHLORIDE and FLOMAX in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ALFUZOSIN HYDROCHLORIDE is classified as Category C. Alfuzosin hydrochloride is classified as FDA Pregnancy Category B. Animal studies have not shown teratogenic effects, but there are no adequate and well-controlled studies in pregn. FLOMAX is classified as Category C. Tamsulosin is FDA Pregnancy Category B. Animal studies revealed no evidence of teratogenicity at doses up to 50 mg/kg/day in rats and 5 mg/kg/day in rabbits (approximately 50 and 3. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.