Note: Tamsulosin capsules should be administered ~30 minutes following the same meal each day. The controlled-release (oral controlled absorption system [OCAS]) tablet formulation [Canadian product] should be administered at the same time each day with or without food.
Benign prostatic hyperplasia (monotherapy or combination therapy):
Note : In patients with moderate to severe predominant storage lower urinary tract symptoms, use in combination with beta-3 agonist or anticholinergic agent. In patients with a significantly enlarged prostate (prostate volume >30 mL, prostate-specific antigen >1.5 ng/dL, or palpable prostate enlargement on digital rectal exam), use in combination with 5-alpha reductase inhibitor (AUA [Lerner 2021]).
Oral:
Capsule: Initial and maintenance: 0.4 mg once daily. If response is inadequate after 2 to 4 weeks, may increase to 0.8 mg once daily. If therapy is discontinued or interrupted for several days, restart with 0.4 mg once daily.
Controlled-release tablet [Canadian product]: Initial and maximum dose: 0.4 mg once daily.
Chronic prostatitis/chronic pelvic pain syndrome in males (off-label use): Oral: Initial: 0.4 mg once daily for 6 weeks as part of an appropriate combination regimen (Pontari 2020; Thakkinstian 2012). If response to initial therapy is inadequate, referral to a urologist is recommended (Anothaisintawee 2011; Nickel 2012; Pontari 2020).
Lower urinary tract symptoms in males (off-label use): Bladder outlet obstruction and low postvoid residual: Oral: Initial: 0.4 mg once daily; may combine with an anticholinergic agent if symptoms of overactive bladder persist (Athanasopoulos 2003; Dimitropoulos 2015; Drake 2015; Van Kerrebroeck 2013).
Ureteral calculi expulsion (off-label use):
Medical expulsive therapy for distal (lower) ureteral calculi to facilitate spontaneous stone passage: Stones >5 and ≤10 mm: Oral: 0.4 mg once daily until stone passage occurs or for up to 4 weeks (Ahmed 2010; Campschroer 2014; Hollingsworth 2016; Ye 2017).
Adjunctive therapy following shock wave lithotripsy to facilitate clearance of residual stones: Oral: 0.4 mg once daily; initiate therapy immediately after extracorporeal shock wave lithotripsy; duration of therapy in trials ranged from 14 days to 3 months (Agrawal 2009; Chen 2015; Falahatkar 2011; Vicentini 2011).
Ureteral stent-related urinary symptoms, treatment (off-label use): Oral: 0.4 mg once daily; treatment was initiated following stent placement and duration of therapy in trials ranged from 1 to 6 weeks (Damiano 2008; Wang 2009a; Wang 2009b; Yakoubi 2011); may also be given in combination with an anticholinergic agent (Dellis 2017).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
The renal dosing recommendations are based upon the best available evidence and clinical expertise. Senior Editorial Team: Bruce Mueller, PharmD, FCCP, FASN, FNKF; Jason Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC; Michael Heung, MD, MS.
Altered kidney function:
CrCl ≥10 mL/minute: No dosage adjustment necessary (Koiso 1996; Miyazawa 2001; Wolzt 1998; manufacturer’s labeling).
CrCl <10 mL/minute: No dosage adjustment likely to be necessary (has not been studied); use with caution (expert opinion).
Hemodialysis, intermittent (thrice weekly): Unlikely to be dialyzed (highly protein bound): No dosage adjustment likely to be necessary (has not been studied); use with caution (expert opinion).
Peritoneal dialysis: Unlikely to be dialyzed (highly protein bound): No dosage adjustment likely to be necessary (has not been studied); use with caution (expert opinion).
Mild-to-moderate impairment: No dosage adjustment is necessary.
Severe impairment: There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied).
(For additional information see "Tamsulosin: Pediatric drug information")
Nephrolithiasis, distal stones: Limited data available; optimal dose not established (Mokhless 2012; Tasian 2014):
Children 2 to 4 years: Oral: 0.2 or 0.4 mg once daily at bedtime
Children >4 years and Adolescents: Oral: 0.4 mg once daily at bedtime
Dosing based on two studies. The larger was a multi-institutional retrospective cohort study of pediatric patients with stones up to 10 mm; patients received either tamsulosin 0.4 mg once daily (n=99, median age: 14.8 years) or analgesics alone (n=175). Spontaneous stone passage was higher in the treatment group (55% vs 44%, p=0.03); treatment group was older and had smaller, more distal stones. When adjusted for stone size and location as part of analysis of 99 case matched pairs, success was also higher in the treatment group (OR 3.31, 95% CI: 1.49 to 7.34) (Tasian 2014). The smaller study was a prospective, randomized controlled trial of pediatric patients with stones up to 12 mm; patients received either tamsulosin 0.4 mg once daily (0.2 mg if ≤4 years old) (n=33, age: 2 to 15 years) or placebo (n=28). In this study, 45% of the treatment group had previously received either extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy, but none in the control group had received these therapies; however, stone size at the start of treatment was similar between groups. Treatment resulted in higher expulsion rate (87.8% vs 64.2%, p<0.01), less days to expulsion (mean: 8.2 vs 14.5 days, p<0.001), less pain episodes (mean: 1.4 vs 2.2, p<0.02) and less need for analgesia (mean: 0.7 vs 1.4, p<0.02) (Mokhless 2012). In both studies, tamsulosin was well tolerated and there were no reported adverse effects.
Primary bladder neck dysfunction: Limited data available: Children ≥3 years and Adolescents: Oral: Initial dose: 0.2 mg once daily, increase by 0.2 mg increments based on response (symptoms and urodynamic studies) and tolerability. Mean effective dose: 0.4 mg daily; maximum reported daily dose: 0.8 mg/day. Dosing based on two trials evaluating treatment with alpha blockers, including over 50 pediatric patients who received tamsulosin. Treatment resulted in improved urine flow rates and decreased post-void residual urine volume; values returned to pretreatment levels when therapy was discontinued. Tamsulosin was well tolerated with no major adverse effects and benefits continued for at least 3 years (Donohoe 2005; Van Batavia 2010).
There are no pediatric-specific recommendations. Based on experience in adult male patients with CrCl ≥10 mL/minute, data suggest no adjustment needed; for more severe renal impairment, use has not been studied.
There are no pediatric-specific recommendations. Based on experience in adult male patients with mild to moderate hepatic impairment, data suggest no adjustment needed; for more severe hepatic impairment, use has not been studied.
Refer to adult dosing.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral, as hydrochloride:
Flomax: 0.4 mg [contains fd&c blue #2 (indigotine)]
Generic: 0.4 mg
Yes
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule Extended Release 24 Hour, Oral:
Generic: 0.4 mg
Tablet Extended Release 24 Hour, Oral:
Flomax CR: 0.4 mg
Generic: 0.4 mg
Oral: Administer capsules 30 minutes after the same mealtime each day. Capsules should be swallowed whole; do not crush, chew, or open. The controlled-release tablet [Canadian product] should be administered at the same time each day with or without food, and should be swallowed whole.
Oral: Per the manufacturer, capsules should be swallowed whole; do not crush, chew, or open. In pediatric trials, capsules were opened and the contents mixed with food (eg, yogurt or pudding) or juice (Donohoe 2005; Tasian 2014).
Benign prostatic hyperplasia: Treatment of signs and symptoms of benign prostatic hyperplasia (BPH)
Limitations of use: Not indicated for the treatment of hypertension.
Chronic prostatitis/chronic pelvic pain syndrome in males; Lower urinary tract symptoms in males; Ureteral calculi expulsion; Ureteral stent-related urinary symptoms, treatment
Flomax may be confused with Flonase, Flovent, Foltx, Fosamax
Tamsulosin may be confused with tacrolimus, tamoxifen, terazosin
Flomax [US, Canada, and multiple international markets] may be confused with Flomox brand name for cefcapene [Japan]; Volmax brand name for salbutamol [multiple international markets]
Flomax: Brand name for tamsulosin [US, Canada, and multiple international markets], but also the brand name for morniflumate [Italy]
Intraoperative floppy iris syndrome has been reported in patients with current or prior use of alpha-1 blockers, particularly tamsulosin, undergoing cataract or glaucoma surgery (Ref).
Mechanism: Unclear; may be related to a combination of the pharmacologic action (ie, inhibition of the iris dilator smooth muscle contraction) and long-term smooth muscle atrophy from accumulation in iris pigment epithelial cells (Ref).
Onset: Varied; may occur with current (within a few weeks of initiation) or prior use (years following discontinuation) (Ref).
Risk factors:
• Individual alpha-1 blocker (particularly tamsulosin) (Ref).
• Hypertension may be an independent risk factor (Ref).
Use may cause orthostatic hypotension, dizziness, and vertigo.
Mechanism: Dose-related; related to the pharmacologic action (ie, inhibition of vascular smooth muscle contraction) (Ref).
Onset: Rapid; “first dose” orthostatic hypotension may occur 4 to 8 hours after dose.
Risk factors:
• Individual alpha-1 blocker (tamsulosin among lowest risk) (Ref)
• First dose or restart after dose interruption (Ref)
• Rapid increase in dose
• Concomitant antihypertensives (especially vasodilators) (Ref)
• Concomitant phosphodiesterase-5 inhibitors (eg, sildenafil)
• Alcohol use (Ref)
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Cardiovascular: Orthostatic hypotension (by orthostatic testing: first dose: 6% to 7% [placebo: 3% to 4%], chronic use: 16% to 19% [placebo: 11%]; symptomatic: <1% [placebo: 0%])
Genitourinary: Ejaculation failure (8% to 18%)
Infection: Infection (9% to 11%)
Nervous system: Dizziness (15% to 17% [placebo: 10%]), headache (19% to 21%)
Respiratory: Rhinitis (13% to 18%)
1% to 10%:
Endocrine & metabolic: Decreased libido (2%)
Gastrointestinal: Diarrhea (6%), nausea (4%)
Nervous system: Drowsiness (3% to 4%), insomnia (1% to 2%), vertigo (1% [placebo: 0.6%])
Neuromuscular & skeletal: Asthenia (8% to 9%), back pain (7% to 8%)
Ophthalmic: Blurred vision (≤2%)
Respiratory: Increased cough (3% to 5%), pharyngitis (6%), sinusitis (4%)
Postmarketing:
Cardiovascular: Atrial fibrillation, tachycardia
Dermatologic: Contact dermatitis (Lijnen 2003), erythema multiforme (Hu 2019), exfoliative dermatitis, skin photosensitivity (Tan 2018), Stevens-Johnson syndrome
Gastrointestinal: Constipation, vomiting, xerostomia
Genitourinary: Priapism (Marconi 2019)
Hypersensitivity: Angioedema, fixed drug eruption (Montazer 2020)
Ophthalmic: Choroidal detachment (Kerimoglu 2010), intraoperative floppy iris syndrome (in patients undergoing cataract or glaucoma surgery) (Keklikci 2009)
Respiratory: Dyspnea, epistaxis
Hypersensitivity (eg, angioedema, rash, urticaria, pruritus, respiratory symptoms) to tamsulosin or any component of the formulation
Canadian labeling: Additional contraindications (not in US labeling): Concomitant use with strong CYP3A4 inhibitors (including ketoconazole)
Concerns related to adverse effects:
• Angina: Discontinue if symptoms of angina occur or worsen.
• Sulfonamide allergy: Rarely, patients with a sulfa allergy have also developed an allergic reaction to tamsulosin; avoid use when previous reaction has been severe or life-threatening.
Disease-related concerns:
• Heart failure: In a scientific statement from the American Heart Association, tamsulosin has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: moderate) (AHA [Page 2016]).
Tamsulosin has been well tolerated in pediatric patients during trials when used for management of nephrolithiasis and primary bladder neck dysfunction (Donohoe 2005; Mokhless 2012; Tasian 2014; Van Batavia 2010). Studies using tamsulosin for the management of elevated detrusor leak point pressure in pediatric patients (ages 2 to 16 years) with a known neurological disorder (eg, spina bifida) failed to show efficacy.
Substrate of CYP2D6 (major), CYP3A4 (major); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
Ajmaline: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Alpha-/Beta-Agonists: Alpha1-Blockers may diminish the vasoconstricting effect of Alpha-/Beta-Agonists. Similarly, Alpha-/Beta-Agonists may antagonize Alpha1-Blocker vasodilation. Risk C: Monitor therapy
Alpha1-Agonists: Alpha1-Blockers may diminish the vasoconstricting effect of Alpha1-Agonists. Similarly, Alpha1-Agonists may antagonize Alpha1-Blocker vasodilation. Risk C: Monitor therapy
Alpha1-Blockers: May enhance the antihypertensive effect of other Alpha1-Blockers. Risk X: Avoid combination
Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When used at chemotherapy doses, hold blood pressure lowering medications for 24 hours before amifostine administration. If blood pressure lowering therapy cannot be held, do not administer amifostine. Use caution with radiotherapy doses of amifostine. Risk D: Consider therapy modification
Amisulpride (Oral): May enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Risk C: Monitor therapy
Artemether and Lumefantrine: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Beta-Blockers: May enhance the orthostatic hypotensive effect of Alpha1-Blockers. The risk associated with ophthalmic products is probably less than systemic products. Risk C: Monitor therapy
Blood Pressure Lowering Agents: May enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Bromperidol: May diminish the hypotensive effect of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may enhance the hypotensive effect of Bromperidol. Risk X: Avoid combination
Calcium Channel Blockers: Alpha1-Blockers may enhance the hypotensive effect of Calcium Channel Blockers. Risk C: Monitor therapy
Cimetidine: May increase the serum concentration of Tamsulosin. Risk C: Monitor therapy
Clofazimine: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
CYP2D6 Inhibitors (Moderate): May increase the serum concentration of Tamsulosin. Risk C: Monitor therapy
CYP2D6 Inhibitors (Strong): May increase the serum concentration of Tamsulosin. Risk C: Monitor therapy
CYP3A4 Inhibitors (Moderate): May increase the serum concentration of Tamsulosin. Risk C: Monitor therapy
CYP3A4 Inhibitors (Strong): May increase the serum concentration of Tamsulosin. Risk X: Avoid combination
Dapoxetine: May enhance the orthostatic hypotensive effect of Alpha1-Blockers. Risk C: Monitor therapy
Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Risk C: Monitor therapy
Erdafitinib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Fexinidazole: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk X: Avoid combination
Fusidic Acid (Systemic): May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk X: Avoid combination
Herbal Products with Blood Pressure Lowering Effects: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Levodopa-Containing Products: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa-Containing Products. Risk C: Monitor therapy
Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Risk C: Monitor therapy
Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Risk D: Consider therapy modification
Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Peginterferon Alfa-2b may increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Risk C: Monitor therapy
Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Phosphodiesterase 5 Inhibitors: Alpha1-Blockers (Uroselective) may enhance the hypotensive effect of Phosphodiesterase 5 Inhibitors. Risk C: Monitor therapy
Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Rilmenidine: Alpha1-Blockers may enhance the hypotensive effect of Rilmenidine. Risk C: Monitor therapy
Capsules: Fasting increases bioavailability by 30% and peak concentration 40% to 70%. Management: Administer 30 minutes after the same meal each day. Note: The controlled-release tablet formulation [Canadian product] is not affected by food and can be taken with or without food at the same time each day.
Ejaculation failure, ejaculation disorder, retrograde ejaculation, and decreased ejaculation has been associated with use of tamsulosin.
Information related to the use of tamsulosin for ureteral calculi expulsion in pregnancy is limited (Bailey 2016; Theriault 2020). Other treatments such as stents or ureteroscopy, are currently recommended if stone removal is needed (AUA/ES [Assimos 2016]; EAU [Türk 2019]; Lloyd 2016).
It is not known if tamsulosin is present in breast milk.
International Prostate Symptom Score (baseline and 4 to 12 weeks after treatment initiation); urinalysis (baseline); BP; prostate cancer screening prior to initiation and then as directed; mental alertness; objective and subjective signs of relief of benign prostatic hyperplasia and lower urinary tract symptoms (AUA [Lerner 2021]; manufacturer’s labeling).
Tamsulosin is an antagonist of alpha1A-adrenoreceptors in the prostate. Smooth muscle tone in the prostate is mediated by alpha1A-adrenoreceptors; blocking them leads to relaxation of smooth muscle in the bladder neck and prostate causing an improvement of urine flow and decreased symptoms of BPH. Approximately 75% of the alpha1-receptors in the prostate are of the alpha1A subtype.
Note: Pharmacokinetics in pediatric patients (ages 2 to 16 years) were found to be similar to adult values (Tsuda 2010).
Absorption: >90%
Distribution: Vd: 16 L
Protein binding: 94% to 99%, primarily to alpha-1 acid glycoprotein (AAG)
Metabolism: Hepatic (extensive) via CYP3A4 and 2D6; metabolites undergo extensive conjugation to glucuronide or sulfate
Bioavailability: Fasting: 30% increase
Steady-state: By the fifth day of once-daily dosing
Half-life elimination: Healthy volunteers: 9 to 13 hours; Target population: 14 to 15 hours
Time to peak: Fasting: 4 to 5 hours; With food: 6 to 7 hours
Excretion: Urine (76%, <10% as unchanged drug); feces (21%)
Geriatric: AUC is 40% higher in subjects 55 to 75 years of age compared with subjects 20 to 32 years of age.
Capsules (Flomax Oral)
0.4 mg (per each): $11.12
Capsules (Tamsulosin HCl Oral)
0.4 mg (per each): $4.20 - $4.22
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.