No

Alpha₁ Blockers

Treatment of signs and symptoms of benign prostatic hyperplasia (BPH)

B

Hypersensitivity to tamsulosin or any component

Not intended for use as an antihypertensive drug. May cause orthostasis, syncope or dizziness. Patients should avoid situations where injury may occur as a result of syncope. Rule out prostatic carcinoma before beginning therapy with tamsulosin. Anticipate a similar effect if therapy is interrupted for a few days, if dosage is rapidly increased, or if another antihypertensive drug is introduced.

Orthostatic hypotension (by testing criteria): First-dose orthostatic hypotension at 4 hours postdose has been observed in 7% of patients following a 0.4 mg dose as compared to 3% in a placebo group. Overall, at least one positive test was observed in 16% of patients receiving 0.4 mg and 19% of patients receiving the 0.8 mg dose as compared to 11% in a placebo group. Percentages correspond to the 0.4 mg and 0.8 mg doses, respectively.

>10%:

Central nervous system: Headache (19.3% to 21.1%), dizziness (14.9% to 17.1%)

Genitourinary: Abnormal ejaculation (8.4% to 18.1%)

Respiratory: Rhinitis (13.1% to 17.9%)

1% to 10%:

Cardiovascular: Chest pain (4.0% to 4.1%)

Central nervous system: Weakness (7.8% to 8.5%), somnolence (3.0% to 4.3%), insomnia (1.4% to 2.4%)

Endocrine & metabolic: Decreased libido (1.0% to 2.0%)

Gastrointestinal: Diarrhea (6.2% to 4.3%), nausea (2.6% to 3.9%), stomach discomfort (2% to 3%), bitter taste (2% to 3%)

Neuromuscular & skeletal: Back pain (7.0% to 8.3%)

Ocular: Amblyopia (0.2% to 2.0%)

Respiratory: Pharyngitis (5.8% to 5.1%), cough (3.4% to 4.5%), sinusitis (2.2% to 3.7%)

Miscellaneous: Infection (9.0% to 10.8%), tooth disorder (1.2% to 2.0%)

<1% (Limited to important or life-threatening symptoms): Orthostasis (symptomatic) (0.2% to 0.4%), syncope (0.2% to 0.4%), vertigo (0.6% to 0.1%)

Case reports: Elevated transaminases

Symptoms of overdose include headache and hypotension. Treatment is supportive.

Alpha-adrenergic blockers; should not be used in combination with other alpha-adrenergic blocking agents.

warfarin: Use caution with concomitant administration of warfarin and tamsulosin.

Cimetidine resulted in a significant decrease (26%) in the clearance of tamsulosin which resulted in a moderate increase in tamsulosin AUC (44%); therefore, use with caution when used in combination with cimetidine (especially doses >0.4 mg).

No dosage adjustments necessary if administered with atenolol, enalapril, or Procardia XL®.

An antagonist of alpha_1A adrenoceptors in the prostate. Three subtypes identified: alpha_1A, alpha_1B, alpha_1D have distribution that differs between human organs and tissue. Approximately 70% of the alpha₁-receptors in human prostate are of alpha_1A subtype. The symptoms associated with benign prostatic hyperplasia (BPH) are related to bladder outlet obstruction, which is comprised of two underlying components: static and dynamic. Static is related to an increase in prostate size, partially caused by a proliferation of smooth muscle cells in the prostatic stroma. Severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostate. Dynamic is a function of an increase in smooth muscle tone in the prostate and bladder neck leading to constriction of the bladder outlet. Smooth muscle tone is mediated by the sympathetic nervous stimulation of alpha₁ adrenoceptors, which are abundant in the prostate, prostatic capsule, prostatic urethra, and bladder neck. Blockade of these adrenoceptors can cause smooth muscles in the bladder neck and prostate to relax, resulting in an improvement in urine flow rate and a reduction in symptoms of BPH.

Absorption: >90%

Bioavailability: Fasting: 30% increase

Protein binding: Extensively to human plasma protein (94% to 99%), primarily alpha₁ acid glycoprotein (AAG); not affected by amitriptyline, diclofenac, glyburide, simvastatin plus simvastatin-hydroxy acid metabolite, warfarin, diazepam, propranolol, trichlormethazide, or chlormadinone, nor does tamsulosin effect extent of binding of these drugs

Metabolism: Cytochrome P-450 enzymes in the liver; profile of metabolites in humans has not been established

Steady-state: By the fifth day of once daily dosing

Peak concentrations: C_max: Fasting: 40% to 70% increase; T_max: Fasting: 4-5 hours; With food: 6-7 hours

Half-life: Healthy volunteers: 9-13 hours; Target population: 14-15 hours

Elimination: <10% excreted unchanged in urine; metabolites undergo extensive conjugation to glucuronide or sulfate prior to renal excretion

Oral: Adults: 0.4 mg once daily approximately 30 minutes after the same meal each day

The time to maximum concentration (T_max) is reached by 4-5 hours under fasting conditions and by 6-7 hours when administered with food. Taking it under fasted conditions results in a 30% increase in bioavailability and 40% to 70% increase in peak concentrations (C_max) compared to fed conditions.

Tamsulosin should not be used as an antihypertensive agent despite its alpha-blocking properties. It may induce significant orthostatic hypotension with lightheadedness and possible loss of consciousness.

Dizziness is common; may cause drowsiness or insomnia

None reported

No information available to require special precautions

No effects or complications reported

Take as directed 30 minutes, after same meal each day. Do not skip dose or discontinue without consulting prescriber. You may experience drowsiness, dizziness, or impaired judgment (use caution when driving or engaging in tasks that require alertness until response to drug is known); postural hypotension (use caution when rising from sitting or lying position or when climbing stairs); nausea (frequent mouth care or sucking lozenges may help); urinary incontinence (void before taking medication); ejaculatory disturbance (reversible, may resolve with continued use); diarrhea (boiled milk or yogurt may help); palpitations or rapid heartbeat; difficulty breathing, unusual cough, or sore throat; or other persistent side effects.

Capsule, as hydrochloride: 0.4 mg