Objective
A large-scale, multicenter, double-blind study (US 92-03A) was designed to examine the efficacy of tamsulosin in improving maximum urine flow rate (Qmax) and in relieving the symptoms seen with BPH, as well as the side effects of treatment.1
Design
Patients were evaluated for study eligibility during a four-week placebo lead-in period, during which compliance to the study protocol was established, as well as placebo response. A total of 756 patients were then randomized to receive either tamsulosin (0.4 mg/day and 0.8 mg/day) or placebo for 13 weeks. Primary efficacy data were based upon the intent-to-treat (ITT) population. All but one patient met intent-to-treat criteria, and 755 patients were included in the analysis.1
Inclusion/Exclusion Criteria
Patients had to be at least 45 years old to be admitted to the trial. Exclusion criteria included:
- allergy to α or β-blockers
- neurologic or cardiovascular disease
- diastolic blood pressure <65 mm Hg
- prior surgical procedures involving the urinary tract
Findings during the placebo evaluation period that excluded patient participation included poor compliance with the study medication, evidence of urinary infection or renal dysfunction, postural symptoms and evidence of prostate cancer. Patients were required to have a limited Qmax-between 4 and 15 mL/sec-and significant symptoms of BPH as measured by a total AUA Symptom Score ≥13.1
Efficacy Measures
The efficacy of tamsulosin was measured primarily as an improvement in the AUA Symptom Score and an improvement in Qmax. In addition, the percentage of patients responding to treatment (≥25% decrease in symptoms) was also evaluated, and quality of life was also assessed.1
Important Safety Information
Flomax® (tamsulosin HCl) capsules are indicated to treat the signs and symptoms of benign prostatic hyperplasia (BPH). FLOMAX is not indicated to treat hypertension.
FLOMAX is contraindicated in patients who are hypersensitive to tamsulosin HCl or any of its components.
As with other alpha-adrenergic blocking agents, there is a potential risk of syncope. When beginning treatment, or increasing the dose of FLOMAX, patients should be cautioned to avoid driving or performing hazardous tasks where injury could result should syncope occur.
FLOMAX capsules 0.4 mg should not be used in combination with strong inhibitors of CYP3A4 (e.g., ketoconazole).
Rarely (probably less than 1 in 50,000 patients) FLOMAX, like other alpha-1 antagonists, has been associated with priapism. Because this condition can lead to permanent impotence if not properly treated, patients must be advised about the seriousness of the condition.
Carcinoma of the prostate and BPH cause many of the same symptoms. Patients should be evaluated prior to the start of FLOMAX capsules therapy to rule out the presence of carcinoma of the prostate.
Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients treated with alpha-1 blockers, including FLOMAX capsules. Patients should be advised that if they are considering cataract surgery, to tell their ophthalmologist that they have taken FLOMAX capsules.
In patients with sulfa allergy, allergic reaction to FLOMAX capsules has been rarely reported. If a patient reports a serious or life-threatening sulfa allergy, caution is warranted.
FLOMAX capsules should NOT be used in combination with other alpha-adrenergic blocking agents. Caution is advised when alpha-adrenergic blocking agents, including FLOMAX, are co-administered with PDE 5 inhibitors, as this can potentially cause symptomatic hypotension.
FLOMAX capsules (particularly at a dose higher than 0.4 mg) should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers.
Caution should be exercised with concomitant administration of warfarin and FLOMAX and should be used with caution in combination with cimetidine, particularly at doses higher than 0.4 mg.
The most common side effects are dizziness, abnormal ejaculation, and rhinitis.
Before prescribing FLOMAX, please see the Full Prescribing Information.
1. Lepor H for the Tamsulosin Investigator Group. Phase III multicenter placebo-controlled study of tamsulosin in benign prostatic hyperplasia. Urology. 1998;51:892-900.
