tamsulosin (Rx)

Brand and Other Names:Flomax
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsule

  • 0.4mg

Benign Prostatic Hypertrophy

Indicated for treatment of signs and symptoms of benign prostatic hyperplasia (BPH)

0.4 mg PO qDay; take 30 minutes after same meal each day

If inadequate response after 2-4 weeks, may increase to 0.8 mg qDay

If therapy interrupted or discontiniued for several days, resume at 0.4 mg/day and increase if needed

Bladder Outlet Obstruction (Off-label)

Relief of symptoms

0.4 mg PO qDay

Ureteral Stones (Off-label)

Facilitation of kidney stone expulsion

0.4 mg PO qDay; discontinued after successful expulsion (average, 1-2 weeks)

Double-blind, placebo-controlled trial found tamsulosin did not significantly increase stone passage rate compared with placebo for stones <9 mm (JAMA Intern Med. 2018 Aug 1;178(8):1051-1057)

Dosing Modifications

Renal impairment

  • CrCl ≥10 mL/min: Dosage adjustment not necessary
  • CrCl <10 mL/min: Not studied

Hepatic impairment

  • Mild to moderate: Dosage adjustment not necessary
  • Severe: Not studied

Dosing Considerations

Not indicated for hypertension

Safety and efficacy not established

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Interactions

Interaction Checker

and tamsulosin

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            Headache (19-21%)

            Orthostatic hypotension (6-19%)

            Rhinitis (13-18%)

            Abnormal ejaculation (8-18%)

            Dizziness (15-17%)

            Arthralgia (11%)

            Infection (9-11%)

            1-10%

            Asthenia (8%)

            Back pain (7-8%)

            Skin rash (7%)

            Pharyngitis (5-6%)

            Diarrhea (4-6%)

            Myalgia (5%)

            Chest pain (4%)

            Cough (3-4%)

            Somnolence (3-4%)

            Nausea (2-4%)

            Sinusitis (2-4%)

            Abdominal discomfort (2-3%)

            Bitter taste (2-3%)

            Decreased libido (1-2%)

            Insomnia (1-2%)

            Postmarketing Reports

            Priapism (rare)

            Signs and symptoms of orthostasis, including syncope

            Infrequent reports of dyspnea, palpitations, hypotension, atrial fibrillation, arrhythmia, and tachycardia

            Visual impairment

            During cataract and glaucoma surgery, a variant of small pupil syndrome known as Intraoperative Floppy Iris Syndrome (IFIS) has been reported in association with alpha1 blocker therapy

            Skin desquamation including reports of Stevens-Johnson syndrome, erythema multiforme, and dermatitis exfoliative

            Constipation, vomiting, and epistaxis

            Allergic-type reactions (eg, skin rash, urticaria, pruritus, angioedema, respiratory symptoms) have been reported with positive rechallenge

            Dry mouth

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            Warnings

            Contraindications

            Hypersensitivity

            Cautions

            Use with caution in coronary artery disease, liver disease, general anesthesia

            Orthostatic hypotension may occur

            Priapism rarely reported

            Prostatic cancer should be ruled out before therapy is initiated

            May cause syncope (first-dose effect)

            Discontinue if angina symptoms occur or worsen

            Intraoperative floppy iris syndrome has been reported in patients receiving alpha1 blockers at time of cataract surgery; association is unclear

            Patients with sulfa allergy have rarely developed allergic reaction; avoid use if previous sulfa allergy reactions have been life-threatening

            Not for use as antihypertensive drug

            May exacerbate heart failure

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            Pregnancy & Lactation

            Pregnancy

            No data are available on use in pregnant women

            No adverse developmental effects observed in animal studies administering tamsulosin to rats or rabbits during organogenesis

            Infertility

            • Males: Abnormal ejaculation including ejaculation failure, ejaculation disorder, retrograde ejaculation, and ejaculation decrease has been associated with therapy; studies in rats revealed significantly reduced fertility in males considered to be due to impairment of ejaculation, which was reversible
            • Females: Drug is not indicated for use in women; female fertility in rats was significantly reduced, considered to be due to impairment of fertilization

            Lactation

            There are no data on presence of drug in human milk, effects on breastfed infant, or on milk production

            No data are available; owing to potential of tamsulosin to cause hypotension, breastfeeding is not recommended if taking tamsulosin

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Blocks alpha1a adrenergic receptor in smooth muscle of prostate, decreasing bladder neck and urethral resistance

            Absorption

            Bioavailability: Fasting, 30%

            Onset: 4-8 hr

            Peak plasma time: With food, 6-7 hr; fasting, 4-5 hr

            Distribution

            Protein bound: 90%

            Vd: 0.2 L/kg or 16 L

            Metabolism

            Metabolized in liver

            Metabolites: Glucuronide and sulfate conjugates (inactive)

            Elimination

            Half-life: 14-15 hr

            Excretion: Urine (76%), feces (21%)

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            Administration

            Oral Administration

            Administer 30 minutes after same meal each day

            Do not crush, chew, or open capsules

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.