Get your patient on Cardura xl - Doxazosin Mesylate tablet, Film Coated, Extended Release (Doxazosin Mesylate)

The initial dose of CARDURA XL, 4 mg given once daily, should be administered with breakfast. Depending on the patient’s symptomatic response and tolerability, the dose may be increased to 8 mg, the maximum recommended dose. The recommended titration interval is 3-4 weeks. If CARDURA XL administration is discontinued for several days, therapy should be restarted using the 4 mg once daily dose. Tablets should be swallowed whole, and must not be chewed, divided, cut, or crushed.

If switching from CARDURA immediate-release (IR) to CARDURA XL, therapy should be initiated with the lowest dose (4 mg once daily). Prior to starting therapy with CARDURA XL, the final evening dose of CARDURA should not be taken.

Concomitant administration of CARDURA XL with a PDE-5 inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension; therefore, PDE-5 inhibitor therapy should be initiated at the lowest dose in patients taking CARDURA XL.

The safety and effectiveness of CARDURA XL in pediatric patients have not been established.

The incidence of hypotension with CARDURA XL use appears to be age related and more prevalent in patients 70 years or older. At steady state, increases of 27% in maximum plasma concentrations (C _max ) and 34% in the area under the concentration-time curve (AUC) were seen in the elderly (> 65 years old) compared to the young [see Clinical Pharmacology (12.3) ] .

Of the 666 patients with BPH who received CARDURA XL in the two controlled clinical efficacy and safety studies, 325 patients (49%) were 65 years of age or older. One hundred thirty-six patients treated with CARDURA XL (20%) were > 70 years of age.

In these two studies, the cumulative incidence of hypotension appeared to be age related. The reason for an increased incidence of hypotension in patients older than 70 years of age may be related to a modest increase in systemic exposure to doxazosin [see Clinical Pharmacology (12.3) ] , to an increased propensity to orthostasis in the elderly, or to an enhanced sensitivity to vasodilatory agents in the elderly. The incidence of hypotension reported as an adverse reaction was higher in patients 70 years of age and older (4/136; 2.9%) as compared to patients < 70 years of age (7/530; 1.3%).

Since there is no clinical experience in patients with severe hepatic impairment, use in these patients is not recommended. CARDURA XL should be administered with caution to patients with mild or moderate hepatic impairment [see Warnings and Precautions (5.6) , Clinical Pharmacology (12.3) ] .

Postural hypotension with or without symptoms (e.g., dizziness) may develop within a few hours following administration of CARDURA XL. However, infrequently, symptomatic postural hypotension has also been reported later than a few hours after dosing. As with other alpha-blockers, there is a potential for syncope, especially after the initial dose or after an increase in dosage strength. Patients should be warned of the possible occurrence of such events and should avoid situations where injury could result should syncope occur. Care should be taken when CARDURA XL is administered to patients with symptomatic hypotension or patients who have had a hypotensive response to other medications.

Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients on or previously treated with alpha ₁ blockers. This variant of small pupil syndrome is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents, progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs, and potential prolapse of the iris toward the phacoemulsification incisions. The patient’s surgeon should be prepared for possible modifications to their surgical technique, such as the utilization of iris hooks, iris dilator rings, or viscoelastic substances. There does not appear to be a benefit from stopping alpha ₁ blocker therapy prior to cataract surgery.

As with any other non-deformable material, caution should be used when administering CARDURA XL to patients with preexisting severe gastrointestinal narrowing (pathologic or iatrogenic). There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of another drug in this non-deformable extended-release formulation. Markedly increased GI retention times, as may occur in patients with chronic constipation, can increase systemic exposure to doxazosin and thereby potentially increase adverse reactions.

Carcinoma of the prostate causes many of the same symptoms associated with BPH and the two disorders frequently co-exist. Carcinoma of the prostate should therefore be ruled out prior to commencing therapy with CARDURA XL.

Concomitant administration of CARDURA XL with a PDE-5 inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension. Pharmacodynamic interactions between CARDURA XL and antihypertensive medications or other vasodilating agents have not been determined.

CARDURA XL is not recommended for patients with severe hepatic impairment and should be administered with caution to patients with mild or moderate hepatic impairment [see Use in Specific Populations (8.6) , Clinical Pharmacology (12.3) ] .

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 should be discontinued.

Caution should be exercised when concomitantly administering CARDURA XL with a strong CYP 3A4 inhibitor, such as atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, or voriconazole.

Rarely (probably less frequently than once in every several thousand patients), alpha-1 antagonists, including doxazosin, have been associated with priapism (painful penile erection, sustained for hours and unrelieved by sexual intercourse or masturbation). Because this condition can lead to permanent impotence if not promptly treated, patients must be advised about the seriousness of the condition.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The incidence of adverse reactions was derived from two controlled efficacy and safety trials involving 1473 BPH patients. In Study 1, CARDURA XL (n = 317) was compared to doxazosin IR tablets (n = 322) and to placebo (n = 156). In Study 2, CARDURA XL (n = 350) was compared just to doxazosin IR tablets (n = 330). In both of these studies, CARDURA XL 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 Studies (14.1) ] . 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.

The most commonly reported adverse reactions leading to discontinuation in the CARDURA XL group were dizziness, dyspnea, asthenia, headache, hypotension, postural hypotension, and somnolence. The rates of discontinuation for adverse reactions were 6%, 7% and 3% in the CARDURA XL, doxazosin IR, and placebo groups, respectively.

Table 1 lists the incidence rates of adverse reactions derived from all reported adverse events in the two controlled studies (Studies 1 and 2) combined, at a rate greater than placebo and in 1% or more of patients treated with CARDURA XL.

Additional adverse events reported with CARDURA XL, reported by less than 1% of patients, 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.

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 controlled trials.

The following adverse events have been identified during post-approval use of doxazosin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Autonomic Nervous System: priapism;

Cardiovascular System: cerebrovascular accidents, dizziness postural, myocardial infarction;

Central and Peripheral Nervous System: hypoesthesia, paresthesia;

Endocrine System: gynecomastia;

Gastrointestinal System: gastrointestinal obstruction, 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, skin rash, pruritus;

Special Senses: blurred vision, Intraoperative Floppy Iris Syndrome [see Warnings and Precautions (5.2) ] ;

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.

No in vivo drug interaction studies were conducted with CARDURA XL.

In vitro studies suggest that doxazosin is a substrate of CYP 3A4. Caution should be exercised when concomitantly administering CARDURA XL with a strong CYP 3A4 inhibitor, such as atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, or voriconazole [see Clinical Pharmacology (12.3) ] .

Pharmacodynamic interactions between CARDURA XL and antihypertensive medications or other vasodilating agents have not been determined.

Concomitant administration of CARDURA XL with a PDE-5 inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension [see Dosage and Administration (2.3) ] .

The symptoms associated with benign prostatic hyperplasia (BPH), such as urinary frequency, nocturia, weak stream, hesitancy, and incomplete emptying are related to two components, anatomical (static) and functional (dynamic). The static component is related to an increase in prostate size caused, in part, by a proliferation of smooth muscle cells in the prostatic stroma. However, the severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostate. The dynamic component of BPH is associated with an increase in smooth muscle tone in the prostate and bladder neck. The degree of tone in this area is mediated by the alpha ₁ adrenoceptor, which is present in high density in the prostatic stroma, prostatic capsule, and bladder neck. Blockade of the alpha ₁ receptor decreases urethral resistance and may relieve the BPH symptoms and improve urine flow. Doxazosin mesylate is a selective inhibitor of the alpha ₁ -subtype of alpha adrenergic receptors. In the human prostate, doxazosin mesylate antagonizes phenylephrine (alpha ₁ agonist)-induced contractions, in vitro , and binds with high affinity to the alpha _1A adrenoceptor.

Administration of CARDURA XL to patients with symptomatic BPH resulted in a statistically significant improvement in maximum urinary flow rate [see Clinical Studies (14.1) ] .

The pharmacokinetics of CARDURA XL is different from that of doxazosin IR. CARDURA XL provides a controlled release of doxazosin over a 24-hour period.

Studies in Sprague-Dawley rats after 6, 12, and 18 months, and in CD-1 mice after 18 months of dietary administration, showed an increased incidence of myocardial necrosis or fibrosis at doxazosin base exposure of 26-fold above the human exposure (AUC) at the MHRD of 8 mg CARDURA XL. No cardiotoxicity was observed in dogs or Wistar rats after 12 months of oral dosing at doxazosin base exposures of 65- and 85-fold, respectively, above the human exposure (C _max ) at the MHRD of 8 mg CARDURA XL. There is no evidence that similar lesions occur in humans.

Two controlled clinical studies were conducted with CARDURA XL in BPH patients, followed by an open-label extension study. Study 1 was a randomized, double-blind, parallel-group, placebo- and active-controlled study that compared the safety and efficacy of CARDURA XL (4 or 8 mg/day) with that of doxazosin IR (1, 2, 4, or 8 mg/day) and placebo over 13 weeks in 795 BPH patients, of whom 317 were randomized to CARDURA XL. Study 2 was a randomized, double-blind, parallel-group, active-controlled study that compared the safety and efficacy of CARDURA XL (4 or 8 mg/day) with that of doxazosin IR (1, 2, 4, or 8 mg/day) over 13 weeks in 680 BPH patients, of whom 350 were randomized to CARDURA XL.

In both studies, men aged 50-80 years with symptomatic benign prostatic hyperplasia (BPH) were enrolled. Symptomatic BPH was defined as a total score of at least 12 points on the 35-point International Prostate Symptom Score (IPSS) and a maximum urinary flow rate of ≤ 15 mL/sec but no less than 5 mL/sec (total voided volume ≥ 150 mL). In these two studies, conducted in a total of 1475 patients, the mean age was 64 years (range 47-83 years). Patients were Caucasian (96%), Black (1.5%), Asian (1.5%), and of Other ethnicity (1%).

In both studies, CARDURA XL dosing was initiated after a 2-week placebo run-in period at 4 mg per day increasing to 8 mg per day after 7 weeks of treatment if adequate response (defined as having both an increase in maximum urinary flow rate of at least 3 mL/sec and a decrease in total IPSS of at least 30% from baseline) was not seen. Doxazosin IR was titrated from an initial dose of 1 mg daily to 2 mg daily after 1 week with the option to increase to 4 mg daily after 3 weeks and then to a maximum of 8 mg daily after 7 weeks if an adequate response was not seen. The final daily dose of CARDURA XL was 4 mg in 43% of patients and 8 mg in 57% of patients. The final daily dose of doxazosin IR was 1 mg in 1%, 2 mg in 12%, 4 mg in 30%, and 8 mg in 57% of patients.

There were two primary efficacy variables in each of these two controlled clinical studies: the total International Prostate Symptom Score (IPSS) and the peak urinary flow rate (Q _max ). The IPSS consists of seven questions that assess the severity of both irritative (frequency, urgency, nocturia) and obstructive (incomplete emptying, stopping and starting, weak stream, and pushing or straining) symptoms, with possible total scores ranging from 0 to 35. The Q _max was measured in both studies just prior to the next dose. The results for total symptom score are given in Table 3, and for maximum urinary flow rate in Table 4.

Mean changes in IPSS scores for CARDURA XL and placebo in Study 1 are summarized in Figure 2.

Mean changes in maximum urinary flow rate (Q _max ) for both CARDURA XL and placebo in Study 1 are summarized in Figure 3.