Side Effects of Coreg (carvedilol)

Coreg (carvedilol) is a beta-adrenergic blocking agent (beta-blocker) used to treat high blood pressure (hypertension), congestive heart failure, and angina (chest pain from heart disease). Coreg blocks receptors of the adrenergic nervous system, the system of nerves in which adrenalin (epinephrine) is active. 

Nerves from the adrenergic system enter the heart and release an adrenergic chemical (norepinephrine) that attaches to receptors on the heart's muscle and stimulates the muscle to beat more rapidly and forcefully. By blocking the receptors, Coreg reduces the heart's rate and force of contraction and thereby reduces the work of the heart. 

Coreg also blocks adrenergic receptors on arteries and causes the arteries to relax and the blood pressure to fall. The drop in blood pressure further reduces the work of the heart since it is easier to pump blood against a lower pressure.

Common side effects of Coreg include

• dizziness,
• fluid accumulation (edema),
• decreased heart rate,
• low blood pressure,
• weight gain,
• diarrhea,
• postural hypotension (a rapid decrease in blood pressure when going from the seated to the standing position that causes lightheadedness and/or fainting), and
• vision abnormalities.

Serious side effects of Coreg include

• lightheadedness,
• irregular heart rhythm,
• cold feeling or numbness in fingers or toes,
• chest pain,
• dry cough,
• wheezing,
• chest tightness,
• heart problems, and
• increased blood glucose levels (hyperglycemia).

Drug interactions of Coreg include medications that lower blood sugar such as insulin or oral anti-diabetic medications, because Coreg can mask early warning symptoms of low blood sugar (hypoglycemia) such as tremors and increased heart rate.

• Patients with diabetes taking medications that lower blood sugar may need to monitor their blood sugar more often. Coreg taken with calcium channel blockers (CCBs) such as diltiazem or verapamil may trigger an irregular heart rhythm or an increase in blood pressure.
• Reserpine, monoamine oxidase inhibitors, and clonidine, because they have similar mechanisms of action as Coreg, may greatly accentuate the effects of Coreg and cause a steep decline in blood pressure and/or heart rate.
• Close monitoring of blood pressure and heart rate may be needed.
• Coreg may cause an increase in digoxin blood levels. Digoxin blood levels should be monitored if Coreg is started, adjusted, or discontinued. Rifampin can sharply decrease the Coreg blood level and in patients taking rifampin, the dose of Coreg may need to be increased.
• Coreg shares a common pathway for elimination by the liver with several other drugs such as quinidine, fluoxetine, paroxetine, or propafenone. Use of these drugs may block the elimination of Coreg.
• Coreg blood levels may be increased (along with the risk for Coreg's side effects) if patients are taking any of these drugs.
• Coreg may increase cyclosporin blood levels. The dose of cyclosporin may need to be adjusted when the two drugs are used together.
• Amiodarone may increase Coreg levels in the blood, increasing the effects and potential for toxicity of Coreg. 

Safe use of Coreg during pregnancy has not been established. No studies with Coreg are available in nursing mothers; however, use of Coreg while breastfeeding is not recommended due to the risk of a slow heart rate in the infant.

The most common side effects of carvedilol are:

• Dizziness
• Edema (fluid accumulation)
• Decreased heart rate
• Low blood pressure
• Weight gain
• increased blood glucose levels (hyperglycemia)
• Diarrhea

Postural hypotension (a rapid decrease in blood pressure when going from the seated to the standing position that causes lightheadedness and/or fainting). Taking carvedilol with food minimizes the risk of postural hypotension.

Other common side effects of carvedilol are an irregular heart rhythm and vision abnormalities.

Carvedilol should be used cautiously in patients who use diuretics or who are elderly or that have:

• Cirrhosis
• Asthma
• Peripheral vascular disease
• Hyperthyroidism
• Prinzmetal's variant angina (angina at rest)
• Kidney disease.

Clinical Studies Experience

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

• Coreg has been evaluated for safety in subjects with heart failure (mild, moderate, and severe), in subjects with left ventricular dysfunction following myocardial infarction and in hypertensive subjects.
• The observed adverse event profile was consistent with the pharmacology of the drug and the health status of the subjects in the clinical trials.
• Adverse events reported for each of these patient populations are provided below.
• Excluded are adverse events considered too general to be informative, and those not reasonably associated with the use of the drug because they were associated with the condition being treated or are very common in the treated population.
• Rates of adverse events were generally similar across demographic subsets (men and women, elderly and non-elderly, blacks and non-blacks).

Heart Failure

• Coreg 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 Coreg for at least 6 months and 30% received Coreg for at least 12 months. In the COMET trial, 1,511 subjects with mild-to-moderate heart failure were treated with Coreg for up to 5.9 years (mean: 4.8 years).
• Both in U.S. clinical trials in mild-to-moderate heart failure that compared Coreg 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 Coreg 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 1 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 Coreg observed in the long-term COMET trial was generally similar to that observed in the U.S. Heart Failure Trials.

Table 1. Adverse Events (%) Occurring More Frequently with Coreg 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)

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 Coreg 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

• Coreg 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 Coreg and 980 who received placebo.
• Approximately 75% of the subjects received Coreg for at least 6 months and 53% received Coreg for at least 12 months.
• Subjects were treated for an average of 12.9 months and 12.8 months with Coreg and placebo, respectively.
• The most common adverse events reported with Coreg 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 greater than 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 greater than 1% but less than or equal to 3% and more frequently with Coreg:
  •  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 greater than 1% and occurring more often on carvedilol was hypotension (1.5% on carvedilol, 0.2% on placebo).

Hypertension

• Coreg 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 Coreg for at least 6 months.
• Most adverse events reported during therapy with Coreg were of mild to moderate severity.
• In U.S. controlled clinical trials directly comparing Coreg in doses up to 50 mg (n = 1,142) with placebo (n = 462), 4.9% of subjects receiving Coreg 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 increased with increasing dose of Coreg.
• 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.
• Table 2 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 2. Adverse Events (%) Occurring in U.S. Placebo-Controlled Hypertension Trials (Incidence ≥1%, Regardless of Causality)^a

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 Coreg in worldwide open or controlled trials with Coreg 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 Postmarketing Experience].
• Psychiatric: Nervousness, sleep disorder, aggravated depression, impaired concentration, abnormal thinking, paroniria, emotional lability.
• Respiratory System: Asthma [see CONTRAINDICATIONS].
• 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 Coreg. 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 Coreg and those treated with placebo.
• However, transaminase elevations, confirmed by rechallenge, have been observed with Coreg. In a long-term, placebo-controlled trial in severe heart failure, subjects treated with Coreg had lower values for hepatic transaminases than subjects treated with placebo, possibly because improvements in cardiac function induced by Coreg led to less hepatic congestion and/or improved hepatic blood flow.
• Coreg 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 patients; fasting serum glucose was not evaluated in the heart failure clinical trials.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Coreg. 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.

Blood And Lymphatic System Disorders

• Aplastic anemia.

Immune System Disorders

• Hypersensitivity (e.g., anaphylactic reactions, angioedema, urticaria).

Renal And Urinary Disorders

• Urinary incontinence.

Respiratory, Thoracic, And Mediastinal Disorders

• Interstitial pneumonitis.

Skin And Subcutaneous Tissue Disorders

• Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme.

CYP2D6 Inhibitors And Poor Metabolizers

• Interactions of carvedilol with potent inhibitors of CYP2D6 isoenzyme (such as quinidine, fluoxetine, paroxetine, and propafenone) have not been studied, but these drugs would be expected to increase blood levels of the R(+) enantiomer of carvedilol.
• Retrospective analysis of side effects in clinical trials showed that poor 2D6 metabolizers had a higher rate of dizziness during up-titration, presumably resulting from vasodilating effects of the higher concentrations of the α-blocking R(+) enantiomer.

Hypotensive Agents

• Patients taking a β-blocker and a drug that can deplete catecholamines (e.g., reserpine and monoamine oxidase inhibitors) should be observed closely for signs of hypotension and/or severe bradycardia.
• Concomitant administration of clonidine with a β-blocker may cause hypotension and bradycardia.
• When concomitant treatment with a β-blocker and clonidine is to be terminated, the β-blocker should be discontinued first. Clonidine therapy can then be discontinued several days later by gradually decreasing the dosage.

Cyclosporine

• Modest increases in mean trough cyclosporine concentrations were observed following initiation of carvedilol treatment in 21 renal transplant subjects suffering from chronic vascular rejection.
• In about 30% of subjects, the dose of cyclosporine had to be reduced in order to maintain cyclosporine concentrations within the therapeutic range, while in the remainder no adjustment was needed.
• On the average for the group, the dose of cyclosporine was reduced about 20% in these subjects.
• Due to wide interindividual variability in the dose adjustment required, it is recommended that cyclosporine concentrations be monitored closely after initiation of carvedilol therapy and that the dose of cyclosporine be adjusted as appropriate.

Digitalis Glycosides

• Both digitalis glycosides and β-blockers slow atrioventricular conduction and decrease heart rate.
• Concomitant use can increase the risk of bradycardia. Digoxin concentrations are increased by about 15% when digoxin and carvedilol are administered concomitantly. Therefore, increased monitoring of digoxin is recommended when initiating, adjusting, or discontinuing Coreg.

Inducers/Inhibitors Of Hepatic Metabolism

• Rifampin reduced plasma concentrations of carvedilol by about 70%. Cimetidine increased AUC by about 30% but caused no change in Cmax.

Amiodarone

• Amiodarone and its metabolite desethyl amiodarone, inhibitors of CYP2C9, and P-glycoprotein increased concentrations of the S(-)-enantiomer of carvedilol by at least 2 fold.
• The concomitant administration of amiodarone or other CYP2C9 inhibitors such as fluconazole with Coreg may enhance the β-blocking activity, resulting in further slowing of the heart rate or cardiac conduction.
• Patients should be observed for signs of bradycardia or heart block, particularly when one agent is added to pre-existing treatment with the other.

Calcium Channel Blockers

• Conduction disturbance (rarely with hemodynamic compromise) has been observed when Coreg is coadministered with diltiazem.
• As with other β-blockers, if Coreg is administered with calcium channel blockers of the verapamil or diltiazem type, it is recommended that ECG and blood pressure be monitored.

Insulin Or Oral Hypoglycemics

• β-blockers may enhance the blood-sugar-reducing effect of insulin and oral hypoglycemics. Therefore, in patients taking insulin or oral hypoglycemics, regular monitoring of blood glucose is recommended.

Anesthesia

• If treatment with Coreg is to be continued perioperatively, particular care should be taken when anesthetic agents that depress myocardial function, such as ether, cyclopropane, and trichloroethylene, are used.