Alternative Administration
The capsules may be carefully opened and the beads sprinkled over a spoonful of applesauce. The applesauce should not be warm because it could affect the modified-release properties of this formulation. The mixture of drug and applesauce should be consumed immediately in its entirety. The drug and applesauce mixture should not be stored for future use. Absorption of the beads sprinkled on other foods has not been tested.
Heart Failure
The following information describes the safety experience in heart failure with immediate-release carvedilol.
Carvedilol has been evaluated for safety in heart failure in more than 4,500 subjects worldwide of whom more than 2,100 participated in placebo-controlled clinical trials. Approximately 60% of the total treated population in placebo-controlled clinical trials received carvedilol for at least 6 months and 30% received carvedilol for at least 12 months. In the COMET trial, 1,511 subjects with mild-to-moderate heart failure were treated with carvedilol for up to 5.9 years (mean 4.8 years). Both in U.S. clinical trials in mild-to-moderate heart failure that compared carvedilol in daily doses up to 100 mg (n = 765) with placebo (n = 437), and in a multinational clinical trial in severe heart failure (COPERNICUS) that compared carvedilol in daily doses up to 50 mg (n = 1,156) with placebo (n = 1,133), discontinuation rates for adverse experiences were similar in carvedilol and placebo subjects. In placebo-controlled clinical trials, the only cause of discontinuation greater than 1% and occurring more often on carvedilol was dizziness (1.3% on carvedilol, 0.6% on placebo in the COPERNICUS trial).
Table 2 shows adverse events reported in subjects with mild-to-moderate heart failure enrolled in U.S. placebo-controlled clinical trials, and with severe heart failure enrolled in the COPERNICUS trial. Shown are adverse events that occurred more frequently in drug-treated subjects than placebo-treated subjects with an incidence of greater than 3% in subjects treated with carvedilol regardless of causality. Median trial medication exposure was 6.3 months for both carvedilol and placebo subjects in the trials of mild-to-moderate heart failure and 10.4 months in the trial of subjects with severe heart failure. The adverse event profile of carvedilol observed in the long-term COMET trial was generally similar to that observed in the U.S. Heart Failure Trials.
Table 2. Adverse Events (%) Occurring More Frequently with Immediate-Release Carvedilol than with Placebo in Subjects with Mild-to-Moderate Heart Failure (HF) Enrolled in U.S. Heart Failure Trials or in Subjects with Severe Heart Failure in the COPERNICUS Trial (Incidence >3% in Subjects Treated with Carvedilol, Regardless of Causality)| Body System/Adverse Event | Mild-to-Moderate HF | Severe HF |
|---|
| Carvedilol | Placebo | Carvedilol | Placebo |
|---|
| (n = 765) | (n = 437) | (n = 1,156) | (n = 1,133) |
|---|
| Body as a Whole | | | | |
| Asthenia | 7 | 7 | 11 | 9 |
| Fatigue | 24 | 22 | — | — |
| Digoxin level increased | 5 | 4 | 2 | 1 |
| Edema generalized | 5 | 3 | 6 | 5 |
| Edema dependent | 4 | 2 | — | — |
| Cardiovascular | | | | |
| Bradycardia | 9 | 1 | 10 | 3 |
| Hypotension | 9 | 3 | 14 | 8 |
| Syncope | 3 | 3 | 8 | 5 |
| Angina pectoris | 2 | 3 | 6 | 4 |
| Central Nervous System | | | | |
| Dizziness | 32 | 19 | 24 | 17 |
| Headache | 8 | 7 | 5 | 3 |
| Gastrointestinal | | | | |
| Diarrhea | 12 | 6 | 5 | 3 |
| Nausea | 9 | 5 | 4 | 3 |
| Vomiting | 6 | 4 | 1 | 2 |
| Metabolic | | | | |
| Hyperglycemia | 12 | 8 | 5 | 3 |
| Weight increase | 10 | 7 | 12 | 11 |
| BUN increased | 6 | 5 | — | — |
| NPN increased | 6 | 5 | — | — |
| Hypercholesterolemia | 4 | 3 | 1 | 1 |
| Edema peripheral | 2 | 1 | 7 | 6 |
| Musculoskeletal | | | | |
| Arthralgia | 6 | 5 | 1 | 1 |
| Respiratory | | | | |
| Cough increased | 8 | 9 | 5 | 4 |
| Rales | 4 | 4 | 4 | 2 |
| Vision | | | | |
| Vision abnormal | 5 | 2 | — | — |
Cardiac failure and dyspnea were also reported in these trials, but the rates were equal or greater in subjects who received placebo.
The following adverse events were reported with a frequency of greater than 1% but less than or equal to 3% and more frequently with carvedilol in either the U.S. placebo-controlled trials in subjects with mild-to-moderate heart failure or in subjects with severe heart failure in the COPERNICUS trial.
Incidence greater than 1% to less than or equal to 3%
Body as a Whole: Allergy, malaise, hypovolemia, fever, leg edema.
Cardiovascular: Fluid overload, postural hypotension, aggravated angina pectoris, AV block, palpitation, hypertension.
Central and Peripheral Nervous System: Hypesthesia, vertigo, paresthesia.
Gastrointestinal: Melena, periodontitis.
Liver and Biliary System: SGPT increased, SGOT increased.
Metabolic and Nutritional: Hyperuricemia, hypoglycemia, hyponatremia, increased alkaline phosphatase, glycosuria, hypervolemia, diabetes mellitus, GGT increased, weight loss, hyperkalemia, creatinine increased.
Musculoskeletal: Muscle cramps.
Platelet, Bleeding and Clotting: Prothrombin decreased, purpura, thrombocytopenia.
Psychiatric: Somnolence.
Reproductive, male: Impotence.
Special Senses: Blurred vision.
Urinary System: Renal insufficiency, albuminuria, hematuria.
Left Ventricular Dysfunction Following Myocardial Infarction
The following information describes the safety experience in left ventricular dysfunction following acute myocardial infarction with immediate-release carvedilol.
Carvedilol has been evaluated for safety in survivors of an acute myocardial infarction with left ventricular dysfunction in the CAPRICORN trial which involved 969 subjects who received carvedilol and 980 who received placebo. Approximately 75% of the subjects received carvedilol for at least 6 months and 53% received carvedilol for at least 12 months. Subjects were treated for an average of 12.9 months and 12.8 months with carvedilol and placebo, respectively.
The most common adverse events reported with carvedilol in the CAPRICORN trial were consistent with the profile of the drug in the U.S. heart failure trials and the COPERNICUS trial. The only additional adverse events reported in CAPRICORN in >3% of the subjects and more commonly on carvedilol were dyspnea, anemia, and lung edema. The following adverse events were reported with a frequency of >1% but ≤3% and more frequently with carvedilol: flu syndrome, cerebrovascular accident, peripheral vascular disorder, hypotonia, depression, gastrointestinal pain, arthritis, and gout. The overall rates of discontinuations due to adverse events were similar in both groups of subjects. In this database, the only cause of discontinuation >1% and occurring more often on carvedilol was hypotension (1.5% on carvedilol, 0.2% on placebo).
Hypertension
COREG CR were evaluated for safety in an 8-week double-blind trial in 337 subjects with essential hypertension. The profile of adverse events observed with COREG CR was generally similar to that observed with immediate-release carvedilol tablets. The overall rates of discontinuations due to adverse events were similar between COREG CR and placebo.
Table 3. Adverse Events (%) Occurring More Frequently with COREG CR than with Placebo in Subjects with Hypertension (Incidence ≥1% in Subjects Treated with Carvedilol, Regardless of Causality)| Adverse Event | COREG CR (n = 253) | Placebo (n = 84) |
|---|
| Nasopharyngitis | 4 | 0 |
| Dizziness | 2 | 1 |
| Nausea | 2 | 0 |
| Edema peripheral | 2 | 1 |
| Nasal congestion | 1 | 0 |
| Paresthesia | 1 | 0 |
| Sinus congestion | 1 | 0 |
| Diarrhea | 1 | 0 |
| Insomnia | 1 | 0 |
The following information describes the safety experience in hypertension with immediate-release carvedilol.
Carvedilol has been evaluated for safety in hypertension in more than 2,193 subjects in U.S. clinical trials and in 2,976 subjects in international clinical trials. Approximately 36% of the total treated population received carvedilol for at least 6 months. In general, carvedilol was well tolerated at doses up to 50 mg daily. Most adverse events reported during carvedilol therapy were of mild to moderate severity. In U.S. controlled clinical trials directly comparing carvedilol monotherapy in doses up to 50 mg (n = 1,142) with placebo (n = 462), 4.9% of carvedilol subjects discontinued for adverse events versus 5.2% of placebo subjects. Although there was no overall difference in discontinuation rates, discontinuations were more common in the carvedilol group for postural hypotension (1% versus 0). The overall incidence of adverse events in U.S. placebo-controlled trials was found to increase with increasing dose of carvedilol. For individual adverse events this could only be distinguished for dizziness, which increased in frequency from 2% to 5% as total daily dose increased from 6.25 mg to 50 mg as single or divided doses.
Table 4 shows adverse events in U.S. placebo-controlled clinical trials for hypertension that occurred with an incidence of greater than or equal to 1% regardless of causality and that were more frequent in drug-treated subjects than placebo-treated subjects.
Table 4. Adverse Events (% Occurrence) in U.S. Placebo-Controlled Hypertension Trials with Immediate-Release Carvedilol Tablets (Incidence ≥1% in Subjects Treated with Carvedilol, Regardless of Causality)Shown are events with rate >1% rounded to nearest integer.
| Adverse Event | Carvedilol (n = 1,142) | Placebo (n = 462) |
|---|
| Cardiovascular | | |
| Bradycardia | 2 | — |
| Postural hypotension | 2 | — |
| Peripheral edema | 1 | — |
| Central Nervous System | | |
| Dizziness | 6 | 5 |
| Insomnia | 2 | 1 |
| Gastrointestinal | | |
| Diarrhea | 2 | 1 |
| Hematologic | | |
| Thrombocytopenia | 1 | — |
| Metabolic | | |
| Hypertriglyceridemia | 1 | — |
Dyspnea and fatigue were also reported in these trials, but the rates were equal or greater in subjects who received placebo.
The following adverse events not described above were reported as possibly or probably related to carvedilol in worldwide open or controlled trials with carvedilol in subjects with hypertension or heart failure.
Incidence greater than 0.1% to less than or equal to 1%
Cardiovascular: Peripheral ischemia, tachycardia.
Central and Peripheral Nervous System: Hypokinesia.
Gastrointestinal: Bilirubinemia, increased hepatic enzymes (0.2% of hypertension patients and 0.4% of heart failure patients were discontinued from therapy because of increases in hepatic enzymes) [see Adverse Reactions (6.2)].
Psychiatric: Nervousness, sleep disorder, aggravated depression, impaired concentration, abnormal thinking, paranoia, emotional lability.
Respiratory System: Asthma [see Contraindications (4)].
Reproductive, male: Decreased libido.
Skin and Appendages: Pruritus, rash erythematous, rash maculopapular, rash psoriaform, photosensitivity reaction.
Special Senses: Tinnitus.
Urinary System: Micturition frequency increased.
Autonomic Nervous System: Dry mouth, sweating increased.
Metabolic and Nutritional: Hypokalemia, hypertriglyceridemia.
Hematologic: Anemia, leukopenia.
The following events were reported in less than or equal to 0.1% of subjects and are potentially important: complete AV block, bundle branch block, myocardial ischemia, cerebrovascular disorder, convulsions, migraine, neuralgia, paresis, anaphylactoid reaction, alopecia, exfoliative dermatitis, amnesia, GI hemorrhage, bronchospasm, pulmonary edema, decreased hearing, respiratory alkalosis, increased BUN, decreased HDL, pancytopenia, and atypical lymphocytes.
Laboratory Abnormalities
Reversible elevations in serum transaminases (ALT or AST) have been observed during treatment with carvedilol. Rates of transaminase elevations (2- to 3-times the upper limit of normal) observed during controlled clinical trials have generally been similar between subjects treated with carvedilol and those treated with placebo. However, transaminase elevations, confirmed by rechallenge, have been observed with carvedilol. In a long-term, placebo-controlled trial in severe heart failure, subjects treated with carvedilol had lower values for hepatic transaminases than subjects treated with placebo, possibly because carvedilol-induced improvements in cardiac function led to less hepatic congestion and/or improved hepatic blood flow.
Carvedilol therapy has not been associated with clinically significant changes in serum potassium, total triglycerides, total cholesterol, HDL cholesterol, uric acid, blood urea nitrogen, or creatinine. No clinically relevant changes were noted in fasting serum glucose in hypertensive subjects; fasting serum glucose was not evaluated in the heart failure clinical trials.
Risk Summary
Available data regarding use of COREG CR in pregnant women are insufficient to determine whether there are drug-associated risks of adverse developmental outcomes. There are risks to the mother and fetus associated with poorly controlled hypertension in pregnancy. The use of beta blockers during the third trimester of pregnancy may increase the risk of hypotension, bradycardia, hypoglycemia, and respiratory depression in the neonate (see Clinical Considerations). In animal reproduction studies, there was no evidence of adverse developmental outcomes at clinically relevant doses (see Data). Oral administration of carvedilol to pregnant rats during organogenesis resulted in post-implantation loss, decreased fetal body weight, and an increased frequency of delayed fetal skeletal development at maternally toxic doses that were 50 times the maximum recommended human dose (MRHD). In addition, oral administration of carvedilol to pregnant rabbits during organogenesis resulted in increased post-implantation loss at doses 25 times the MRHD (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated populations are unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Clinical Considerations
Disease-Associated Maternal and/or Embryo/Fetal Risk: Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section and post-partum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Pregnant women with hypertension should be carefully monitored and managed accordingly.
Fetal/Neonatal Adverse Reactions: Neonates of women with hypertension who are treated with beta-blockers during the third trimester of pregnancy may be at increased risk for hypotension, bradycardia, hypoglycemia, and respiratory depression. Observe newborns for symptoms of hypotension, bradycardia, hypoglycemia, and respiratory depression and manage accordingly.
Data
Animal Data: Studies performed in rats and rabbits given carvedilol during fetal organogenesis revealed increased post-implantation loss in rats at a maternally toxic dose of 300 mg per kg per day (50 times the MRHD as mg per m2) and in rabbits (in the absence of maternal toxicity) at doses of 75 mg per kg per day (25 times the MRHD as mg per m2). In the rats, there was also a decrease in fetal body weight at 300 mg per kg per day (50 times the MRHD as mg per m2) accompanied by an increased incidence of fetuses with delayed skeletal development. In rats, the no-effect level for embryo-fetal toxicity was 60 mg per kg per day (10 times the MRHD as mg per m2); in rabbits, it was 15 mg per kg per day (5 times the MRHD as mg per m2). In a pre- and post-natal development study in rats administered carvedilol from late gestation through lactation, increased embryo-lethality was observed at a maternally toxic dose of 200 mg per kg per day (approximately 32 times the MRHD as mg per m2), and pup mortality and delays in physical growth/development were observed at 60 mg per kg per day (10 times the MRHD as mg per m2) in the absence of maternal toxicity. The no-effect level was 12 mg per kg per day (2 times the MRHD as mg per m2). Carvedilol was present in fetal rat tissue.
Risk Summary
There are no data on the presence of carvedilol in human milk, the effects on the breastfed infant, or the effects on milk production. Carvedilol is present in the milk of lactating rats. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for COREG CR and any potential adverse effects on the breastfed infant from COREG CR or from the underlying maternal condition.
Heart Failure and Left Ventricular Dysfunction following Myocardial Infarction
The basis for the beneficial effects of carvedilol in patients with heart failure and in patients with left ventricular dysfunction following an acute myocardial infarction is not known. The concentration-response relationship for β1-blockade following administration of COREG CR is equivalent (±20%) to immediate-release carvedilol tablets.
Hypertension
The mechanism by which β-blockade produces an antihypertensive effect has not been established.
β-adrenoreceptor blocking activity has been demonstrated in animal and human studies showing that carvedilol (1) reduces cardiac output in normal subjects, (2) reduces exercise- and/or isoproterenol-induced tachycardia, and (3) reduces reflex orthostatic tachycardia. Significant β-adrenoreceptor blocking effect is usually seen within 1 hour of drug administration.
α1-adrenoreceptor blocking activity has been demonstrated in human and animal studies, showing that carvedilol (1) attenuates the pressor effects of phenylephrine, (2) causes vasodilation; and (3) reduces peripheral vascular resistance. These effects contribute to the reduction of blood pressure and usually are seen within 30 minutes of drug administration.
Due to the α1-receptor blocking activity of carvedilol, blood pressure is lowered more in the standing than in the supine position, and symptoms of postural hypotension (1.8%), including rare instances of syncope, can occur. Following oral administration, when postural hypotension has occurred, it has been transient and is uncommon when immediate-release carvedilol is administered with food at the recommended starting dose and titration increments are closely followed [see Dosage and Administration (2)].
In a randomized, double-blind, placebo-controlled trial, the β1-blocking effect of COREG CR, as measured by heart rate response to submaximal bicycle ergometry, was shown to be equivalent to that observed with immediate-release carvedilol tablets at steady state in adult subjects with essential hypertension.
In hypertensive subjects with normal renal function, therapeutic doses of carvedilol decreased renal vascular resistance with no change in glomerular filtration rate or renal plasma flow. Changes in excretion of sodium, potassium, uric acid, and phosphorus in hypertensive patients with normal renal function were similar after carvedilol and placebo.
Carvedilol has little effect on plasma catecholamines, plasma aldosterone, or electrolyte levels, but it does significantly reduce plasma renin activity when given for at least 4 weeks. It also increases levels of atrial natriuretic peptide.
Absorption
Carvedilol is rapidly and extensively absorbed following oral administration of immediate-release carvedilol tablets, with an absolute bioavailability of approximately 25% to 35% due to a significant degree of first-pass metabolism. COREG CR have approximately 85% of the bioavailability of immediate-release carvedilol tablets. For corresponding dosages [see Dosage and Administration (2)], the exposure (AUC, Cmax, trough concentration) of carvedilol as COREG CR is equivalent to those of immediate-release carvedilol tablets when both are administered with food. The absorption of carvedilol from a COREG CR is slower and more prolonged compared with the immediate-release carvedilol tablet with peak concentrations achieved approximately 5 hours after administration. Plasma concentrations of carvedilol increase in a dose-proportional manner over the dosage range of COREG CR 10 to 80 mg. Within-subject and between-subject variability for AUC and Cmax is similar for COREG CR and immediate-release carvedilol.
Effect of Food: Administration of COREG CR with a high-fat meal resulted in increases (~20%) in AUC and Cmax compared with COREG CR administered with a standard meal. Decreases in AUC (27%) and Cmax (43%) were observed when COREG CR was administered in the fasted state compared with administration after a standard meal. COREG CR should be taken with food.
In a trial with adult subjects, sprinkling the contents of the COREG CR on applesauce did not appear to have a significant effect on overall exposure (AUC) compared with administration of the intact capsule following a standard meal but did result in a decrease in Cmax (18%).
Distribution
Carvedilol is more than 98% bound to plasma proteins, primarily with albumin. The plasma-protein binding is independent of concentration over the therapeutic range. Carvedilol is a basic, lipophilic compound with a steady-state volume of distribution of approximately 115 L, indicating substantial distribution into extravascular tissues.
Metabolism and Excretion
Carvedilol is extensively metabolized. Following oral administration of radiolabelled carvedilol to healthy volunteers, carvedilol accounted for only about 7% of the total radioactivity in plasma as measured by AUC. Less than 2% of the dose was excreted unchanged in the urine. Carvedilol is metabolized primarily by aromatic ring oxidation and glucuronidation. The oxidative metabolites are further metabolized by conjugation via glucuronidation and sulfation. The metabolites of carvedilol are excreted primarily via the bile into the feces. Demethylation and hydroxylation at the phenol ring produce 3 active metabolites with β-receptor blocking activity. Based on preclinical studies, the 4'-hydroxyphenyl metabolite is approximately 13 times more potent than carvedilol for β-blockade.
Compared with carvedilol, the 3 active metabolites exhibit weak vasodilating activity. Plasma concentrations of the active metabolites are about one-tenth of those observed for carvedilol and have pharmacokinetics similar to the parent.
Carvedilol undergoes stereoselective first-pass metabolism with plasma levels of R(+)-carvedilol approximately 2 to 3 times higher than S(-)-carvedilol following oral administration of COREG CR in healthy subjects. Apparent clearance is 90 L per h and 213 L per h for R(+)- and S(-)-carvedilol, respectively.
The primary P450 enzymes responsible for the metabolism of both R(+) and S(-)-carvedilol in human liver microsomes were CYP2D6 and CYP2C9 and to a lesser extent CYP3A4, 2C19, 1A2, and 2E1. CYP2D6 is thought to be the major enzyme in the 4'- and 5'-hydroxylation of carvedilol, with a potential contribution from 3A4. CYP2C9 is thought to be of primary importance in the O-methylation pathway of S(-)-carvedilol.
Carvedilol is subject to the effects of genetic polymorphism with poor metabolizers of debrisoquin (a marker for cytochrome P450 2D6) exhibiting 2- to 3-fold higher plasma concentrations of R(+)-carvedilol compared with extensive metabolizers. In contrast, plasma levels of S(-)-carvedilol are increased only about 20% to 25% in poor metabolizers, indicating this enantiomer is metabolized to a lesser extent by cytochrome P450 2D6 than R(+)-carvedilol. The pharmacokinetics of carvedilol do not appear to be different in poor metabolizers of S-mephenytoin (patients deficient in cytochrome P450 2C19).
Heart Failure
Following administration of immediate-release carvedilol tablets, steady-state plasma concentrations of carvedilol and its enantiomers increased proportionally over the dose range in subjects with heart failure. Compared with healthy subjects, subjects with heart failure had increased mean AUC and Cmax values for carvedilol and its enantiomers, with up to 50% to 100% higher values observed in 6 subjects with NYHA class IV heart failure. The mean apparent terminal elimination half-life for carvedilol was similar to that observed in healthy subjects.
For corresponding dose levels [see Dosage and Administration (2)], the steady-state pharmacokinetics of carvedilol (AUC, Cmax, trough concentrations) observed after administration of COREG CR to subjects with chronic heart failure (mild, moderate, and severe) were similar to those observed after administration of immediate-release carvedilol tablets.
Hypertension
For corresponding dose levels [see Dosage and Administration (2)], the pharmacokinetics (AUC, Cmax, and trough concentrations) observed with administration of COREG CR were equivalent (±20%) to those observed with immediate-release carvedilol tablets following repeat dosing in subjects with essential hypertension.
Geriatric
Plasma levels of carvedilol average about 50% higher in the elderly compared with young subjects after administration of immediate-release carvedilol.
Hepatic Impairment
No trials have been performed with COREG CR in subjects with hepatic impairment. Compared with healthy subjects, subjects with severe liver impairment (cirrhosis) exhibit a 4- to 7-fold increase in carvedilol levels. Carvedilol is contraindicated in patients with severe liver impairment.
Renal Impairment
No trials have been performed with COREG CR in subjects with renal impairment. Although carvedilol is metabolized primarily by the liver, plasma concentrations of carvedilol have been reported to be increased in patients with renal impairment after dosing with immediate-release carvedilol. Based on mean AUC data, approximately 40% to 50% higher plasma concentrations of carvedilol were observed in subjects with hypertension and moderate to severe renal impairment compared with a control group of subjects with hypertension and normal renal function. However, the ranges of AUC values were similar for both groups. Changes in mean peak plasma levels were less pronounced, approximately 12% to 26% higher in subjects with impaired renal function.
Consistent with its high degree of plasma protein binding, carvedilol does not appear to be cleared significantly by hemodialysis.
Amiodarone
In a pharmacokinetic trial conducted in 106 Japanese subjects with heart failure, coadministration of small loading and maintenance doses of amiodarone with carvedilol resulted in at least a 2-fold increase in the steady-state trough concentrations of S(-)-carvedilol [see Drug Interactions (7.6)].
Cimetidine
In a pharmacokinetic trial conducted in 10 healthy male subjects, cimetidine (1,000 mg per day) increased the steady-state AUC of carvedilol by 30% with no change in Cmax [see Drug Interactions (7.5)].
Digoxin
Following concomitant administration of carvedilol (25 mg once daily) and digoxin (0.25 mg once daily) for 14 days, steady-state AUC and trough concentrations of digoxin were increased by 14% and 16%, respectively, in 12 subjects with hypertension [see Drug Interactions (7.4)].
Glyburide
In 12 healthy subjects, combined administration of carvedilol (25 mg once daily) and a single dose of glyburide did not result in a clinically relevant pharmacokinetic interaction for either compound.
Hydrochlorothiazide
A single oral dose of carvedilol 25 mg did not alter the pharmacokinetics of a single oral dose of hydrochlorothiazide 25 mg in 12 subjects with hypertension. Likewise, hydrochlorothiazide had no effect on the pharmacokinetics of carvedilol.
Rifampin
In a pharmacokinetic trial conducted in 8 healthy male subjects, rifampin (600 mg daily for 12 days) decreased the AUC and Cmax of carvedilol by about 70% [see Drug Interactions (7.5)].
Torsemide
In a trial of 12 healthy subjects, combined oral administration of carvedilol 25 mg once daily and torsemide 5 mg once daily for 5 days did not result in any significant differences in their pharmacokinetics compared with administration of the drugs alone.
Warfarin
Carvedilol (12.5 mg twice daily) did not have an effect on the steady-state prothrombin time ratios and did not alter the pharmacokinetics of R(+)- and S(-)-warfarin following concomitant administration with warfarin in 9 healthy volunteers.
Mild-to-Moderate Heart Failure
Carvedilol was studied in 5 multicenter, placebo-controlled trials, and in 1 active-controlled trial (COMET trial) involving subjects with mild-to-moderate heart failure.
Four U.S. multicenter, double-blind, placebo-controlled trials enrolled 1,094 subjects (696 randomized to carvedilol) with NYHA class II-III heart failure and ejection fraction less than or equal to 0.35. The vast majority were on digitalis, diuretics, and an ACE inhibitor at trial entry. Subjects were assigned to the trials based upon exercise ability. An Australia-New Zealand double-blind, placebo-controlled trial enrolled 415 subjects (half randomized to immediate-release carvedilol) with less severe heart failure. All protocols excluded subjects expected to undergo cardiac transplantation during the 7.5 to 15 months of double-blind follow-up. All randomized subjects had tolerated a 2-week course on immediate-release carvedilol 6.25 mg twice daily.
In each trial, there was a primary end point, either progression of heart failure (1 U.S. trial) or exercise tolerance (2 U.S. trials meeting enrollment goals and the Australia-New Zealand trial). There were many secondary end points specified in these trials, including NYHA classification, patient and physician global assessments, and cardiovascular hospitalization. Other analyses not prospectively planned included the sum of deaths and total cardiovascular hospitalizations. In situations where the primary end points of a trial do not show a significant benefit of treatment, assignment of significance values to the other results is complex, and such values need to be interpreted cautiously.
The results of the U.S. and Australia-New Zealand trials were as follows:
Slowing Progression of Heart Failure: One U.S. multicenter trial (366 subjects) had as its primary end point the sum of cardiovascular mortality, cardiovascular hospitalization, and sustained increase in heart failure medications. Heart failure progression was reduced, during an average follow-up of 7 months, by 48% (P = 0.008).
In the Australia-New Zealand trial, death and total hospitalizations were reduced by about 25% over 18 to 24 months. In the 3 largest U.S. trials, death and total hospitalizations were reduced by 19%, 39%, and 49%, nominally statistically significant in the last 2 trials. The Australia-New Zealand results were statistically borderline.
Functional Measures: None of the multicenter trials had NYHA classification as a primary end point, but all such trials had it as a secondary end point. There was at least a trend toward improvement in NYHA class in all trials. Exercise tolerance was the primary end point in 3 trials; in none was a statistically significant effect found.
Subjective Measures: Health-related quality of life, as measured with a standard questionnaire (a primary end point in 1 trial), was unaffected by carvedilol. However, patients' and investigators' global assessments showed significant improvement in most trials.
Mortality: Death was not a pre-specified end point in any trial but was analyzed in all trials. Overall, in these 4 U.S. trials, mortality was reduced, nominally significantly so in 2 trials.
The COMET Trial
In this double-blind trial, 3,029 subjects with NYHA class II-IV heart failure (left ventricular ejection fraction less than or equal to 35%) were randomized to receive either carvedilol (target dose: 25 mg twice daily) or immediate-release metoprolol tartrate (target dose: 50 mg twice daily). The mean age of the subjects was approximately 62 years, 80% were males, and the mean left ventricular ejection fraction at baseline was 26%. Approximately 96% of the subjects had NYHA class II or III heart failure. Concomitant treatment included diuretics (99%), ACE inhibitors (91%), digitalis (59%), aldosterone antagonists (11%), and "statin" lipid-lowering agents (21%). The mean duration of follow-up was 4.8 years. The mean dose of carvedilol was 42 mg per day.
The trial had 2 primary end points: all-cause mortality and the composite of death plus hospitalization for any reason. The results of COMET are presented in Table 5 below. All-cause mortality carried most of the statistical weight and was the primary determinant of the trial size. All-cause mortality was 34% in the subjects treated with carvedilol and was 40% in the immediate-release metoprolol group (P = 0.0017; hazard ratio = 0.83, 95% CI: 0.74 to 0.93). The effect on mortality was primarily due to a reduction in cardiovascular death. The difference between the 2 groups with respect to the composite end point was not significant (P = 0.122). The estimated mean survival was 8.0 years with carvedilol and 6.6 years with immediate-release metoprolol.
Table 5. Results of COMET| End Point | Carvedilol n = 1,511 | Metoprolol n = 1,518 | Hazard Ratio | (95% CI) |
|---|
| All-cause mortality | 34% | 40% | 0.83 | 0.74 – 0.93 |
| Mortality + all hospitalization | 74% | 76% | 0.94 | 0.86 – 1.02 |
| Cardiovascular death | 30% | 35% | 0.80 | 0.70 – 0.90 |
| Sudden death | 14% | 17% | 0.81 | 0.68 – 0.97 |
| Death due to circulatory failure | 11% | 13% | 0.83 | 0.67 – 1.02 |
| Death due to stroke | 0.9% | 2.5% | 0.33 | 0.18 – 0.62 |
It is not known whether this formulation of metoprolol at any dose or this low dose of metoprolol in any formulation has any effect on survival or hospitalization in patients with heart failure. Thus, this trial extends the time over which carvedilol manifests benefits on survival in heart failure, but it is not evidence that carvedilol improves outcome over the formulation of metoprolol (TOPROL-XL) with benefits in heart failure.
Severe Heart Failure (COPERNICUS)
In a double-blind trial, 2,289 subjects with heart failure at rest or with minimal exertion and left ventricular ejection fraction less than 25% (mean 20%), despite digitalis (66%), diuretics (99%), and ACE inhibitors (89%), were randomized to placebo or carvedilol. Carvedilol was titrated from a starting dose of 3.125 mg twice daily to the maximum tolerated dose or up to 25 mg twice daily over a minimum of 6 weeks. Most subjects achieved the target dose of 25 mg. The trial was conducted in Eastern and Western Europe, the United States, Israel, and Canada. Similar numbers of subjects per group (about 100) withdrew during the titration period.
The primary end point of the trial was all-cause mortality, but cause-specific mortality and the risk of death or hospitalization (total, cardiovascular [CV], or heart failure [HF]) were also examined. The developing trial data were followed by a data monitoring committee, and mortality analyses were adjusted for these multiple looks. The trial was stopped after a median follow-up of 10 months because of an observed 35% reduction in mortality (from 19.7% per patient-year on placebo to 12.8% on carvedilol: hazard ratio 0.65, 95% CI: 0.52 to 0.81, P = 0.0014, adjusted) (see Figure 1). The results of COPERNICUS are shown in Table 6.
Table 6. Results of COPERNICUS Trial in Subjects with Severe Heart Failure| End Point | Placebo (n = 1,133) | Carvedilol (n = 1,156) | Hazard Ratio (95% CI) | % Reduction | Nominal P value |
|---|
| Cardiovascular = CV; Heart failure = HF |
| Mortality | 190 | 130 | 0.65 (0.52 – 0.81) | 35 | 0.00013 |
| Mortality + all hospitalization | 507 | 425 | 0.76 (0.67 – 0.87) | 24 | 0.00004 |
| Mortality + CV hospitalization | 395 | 314 | 0.73 (0.63 – 0.84) | 27 | 0.00002 |
| Mortality + HF hospitalization | 357 | 271 | 0.69 (0.59 – 0.81) | 31 | 0.000004 |
Figure 1. Survival Analysis for COPERNICUS (Intent-to-Treat)
The effect on mortality was principally the result of a reduction in the rate of sudden death among subjects without worsening heart failure.
Patients' global assessments, in which carvedilol-treated subjects were compared with placebo, were based on pre-specified, periodic patient self-assessments regarding whether clinical status post-treatment showed improvement, worsening, or no change compared with baseline. Subjects treated with carvedilol showed significant improvements in global assessments compared with those treated with placebo in COPERNICUS.
The protocol also specified that hospitalizations would be assessed. Fewer subjects on immediate-release carvedilol than on placebo were hospitalized for any reason (372 versus 432, P = 0.0029), for cardiovascular reasons (246 versus 314, P = 0.0003), or for worsening heart failure (198 versus 268, P = 0.0001).
Immediate-release carvedilol had a consistent and beneficial effect on all-cause mortality as well as the combined end points of all-cause mortality plus hospitalization (total, CV, or for heart failure) in the overall trial population and in all subgroups examined, including men and women, elderly and non-elderly, blacks and non-blacks, and diabetics and non-diabetics (see Figure 2).
Figure 2. Effects on Mortality for Subgroups in COPERNICUS
Although the clinical trials used twice-daily dosing, clinical pharmacologic and pharmacokinetic data provide a reasonable basis for concluding that once-daily dosing with COREG CR should be adequate in the treatment of heart failure.
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Waylis Therapeutics LLC
Wixom, MI 48393
October 2023
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