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Cardura XL

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Cardura XL

Side Effects


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.

Read the Cardura XL (doxazosin mesylate extended release tablets) Side Effects Center for a complete guide to possible side effects


No in vivo drug interaction studies were conducted with CARDURA XL (see CLINICAL PHARMACOLOGY; Drug-Drug Interactions). In vitro studies suggest that doxazosin is a substrate of CYP3A4. Caution should be exercised when concomitantly administering a potent 3A4 inhibitor, such as atanazavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, or voriconazole with CARDURA XL (doxazosin mesylate extended release tablets) . Pharmacodynamic interactions between CARDURA XL and anti-hypertensive medications or other vasodilating agents have also not been determined.

Concomitant administration of CARDURA XL (doxazosin mesylate extended release tablets) with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension (see DOSAGE AND ADMINISTRATION).

Patients with Coronary Insufficiency

Patients with congestive heart failure, angina pectoris, or acute myocardial infarction within the last 6 months were excluded from the Phase 3 studies. If symptoms of angina pectoris should newly appear or worsen, CARDURA XL (doxazosin mesylate extended release tablets) should be discontinued.

Drug/Laboratory Test Interactions

Doxazosin mesylate does not affect the plasma concentration of prostate specific antigen in patients treated for up to 3 years.

No clinically significant abnormalities in white blood cell (WBC) counts were reported in patients treated with CARDURA XL (doxazosin mesylate extended release tablets) in controlled clinical BPH trials. In previous studies of doxazosin IR in BPH patients, the incidence of clinically significant decreases in WBC counts was 0.4% in patients treated with doxazosin IR and 0% in patients treated with placebo. There was no statistically significant difference between these two groups.

Read the Cardura XL Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 4/1/2010

Side Effects

Cardura XL - User Reviews

Cardura XL User Reviews

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