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The incidence of adverse events was derived from two controlled efficacy and safety trials involving 1473 BPH patients. In Study 1, CARDURA XL (doxazosin mesylate extended release tablets) (n=317) was compared to doxazosin IR tablets (n=322) and to placebo (n=156). In Study 2, CARDURA XL (doxazosin mesylate extended release tablets) (n=350) was compared just to doxazosin IR tablets (n=330). In both these studies, CARDURA XL (doxazosin mesylate extended release tablets) was initiated at a dose of 4 mg, which could be increased by the investigator to 8 mg after seven weeks if an adequate response was not seen (see CLINICAL PHARMACOLOGY; Clinical Studies). Similarly, doxazosin IR was begun at a dose of 1 mg, which was increased in all patients to 2 mg after 1 week, followed by the option to increase to 4 mg after 4 weeks, and 8 mg after 7 weeks.

In these two studies, 6% of patients receiving CARDURA XL (doxazosin mesylate extended release tablets) withdrew from the study due to adverse events, compared to 7% receiving doxazosin IR, and 3% receiving placebo. The most commonly reported adverse events leading to discontinuation in the CARDURA XL (doxazosin mesylate extended release tablets) group were: dizziness, dyspnea, asthenia, headache, hypotension, postural hypotension, and somnolence.

The incidence rates presented below (Table 4) are based on combined data from the two controlled studies (Studies 1 and 2). Adverse events with an incidence in the CARDURA XL (doxazosin mesylate extended release tablets) group of at least 1% and reported more frequently than with placebo are summarized in Table 4.

TABLE 4 :Treatment-Emergent Adverse Events Occurring in ≥ 1% of BPH Patients Treated with CARDURA XL (doxazosin mesylate extended release tablets) and Reported More Frequently Than with Placebo in the Two Controlled Clinical Studies

Body System CARDURA XL
(N = 666)
Doxazosin IR
(N = 651)
(N = 156)
  Abdominal Pain 1.8% 2.3% 0.6%
  Asthenia 3.9% 6.9% 1.3%
  Back Pain 2.9% 1.7% 2.6%
  Headache 6.0% 5.1% 4.5%
  Hypotension 1.7% 1.8% 0.0%
  Postural Hypotension 1.2% 2.2% 0.6%
  Dyspepsia 1.4% 1.2% 0.0%
  Nausea 1.2% 2.3% 0.6%
  Myalgia 1.4% 0.5% 0.0%
  Dizziness 5.3% 9.1% 1.9%
  Somnolence 1.5% 1.2% 0.0%
  Vertigo 1.5% 4.1% 0.6%
  Dyspnea 1.2% 1.2% 0.0%
  Respiratory Tract Infection 4.8% 4.5% 1.9%
  Urinary Tract Infection 1.4% 0.8% 0.6%

Additional adverse events reported with CARDURA XL (doxazosin mesylate extended release tablets) at an incidence of less than 1% and those of clinical interest include: Cardiovascular System: angina pectoris, syncope, tachycardia, chest pain, palpitations; Digestive System: diarrhea; Musculoskeletal System: arthralgia; Nervous System: libido decreased; Urogenital System: impotence, dysuria. Of these, the following events were reported more frequently with CARDURA XL (doxazosin mesylate extended release tablets) than with placebo: syncope, tachycardia, palpitations, and dysuria.

In general, the adverse events reported in the open-label safety extension, in approximately 295 BPH patients treated for up to 37 weeks, were similar in type and frequency to the events described above in the 13-week controlled trials.

In post-marketing experience, the following additional adverse reactions have been reported with doxazosin IR: Autonomic Nervous System: priapism; Cardiovascular System: cerebrovascular accidents, dizziness postural, myocardial infarction; Central and Peripheral Nervous System: hypoesthesia, paresthesia; Endocrine System: gynecomastia; Gastrointestinal System: vomiting; General Body System: fatigue, hot flushes, malaise; Heart Rate/Rhythm: bradycardia, cardiac arrhythmias; Hematopoietic: leukopenia, purpura, thrombocytopenia; Liver/Biliary System: abnormal liver function tests, hepatitis, hepatitis cholestatic, jaundice; Musculoskeletal System: muscle cramps, muscle weakness; Psychiatric: agitation, anorexia, nervousness; Respiratory System: bronchospasm aggravated; Skin Disorders: alopecia, urticaria; Special Senses: blurred vision, Intraoperative Floppy Iris Syndrome (see PRECAUTIONS, Cataract Surgery); Urinary System: hematuria, micturition disorder, micturition frequency, nocturia, polyuria.

There have been rare reports of gastrointestinal irritation and gastrointestinal bleeding with use of another drug in this non-deformable sustained release formulation, although causal relationship to the drug is uncertain.