Coreg

Action

Blocks stimulation of cardiac beta₁-adrenergic receptor sites and pulmonary beta₂-adrenergic receptor sites. Shows intrinsic sympathomimetic activity, causing slowing of heart rate, decreased myocardial excitability, reduced cardiac output, and decreased renin release from kidney.

Availability

Capsules (extended-release): 10 mg, 20 mg, 40 mg, 80 mg

Tablets: 3.125 mg, 6.25 mg, 12.5 mg, 25 mg

Indications and dosages

➣ Hypertension

Adults: Initially, 6.25 mg P.O. b.i.d. (Coreg). May be increased q 7 to 14 days to a maximum dosage of 25 mg b.i.d. Or, 20 mg P.O. daily (Coreg CR). If tolerated, using standing systolic pressure about 1 hour after dosing, maintain dosage of Coreg CR for 7 to 14 days; then increase to 40 mg once daily if needed based on trough systolic standing blood pressure. Maintain this dosage for 7 to 14 days and adjust to 80 mg once daily if tolerated and needed. Total daily dose of Coreg CR shouldn't exceed 80 mg.

➣ Heart failure caused by ischemia or cardiomyopathy

Adults: Initially, 3.125 mg P.O. b.i.d. (Coreg) for 2 weeks. May increase to 6.25 mg b.i.d. Dosage may be doubled q 2 weeks as tolerated, not to exceed 25 mg b.i.d. in patients weighing less than 85 kg (187 lb) or 50 mg b.i.d. in patients weighing more than 85 kg. Or, 10 mg P.O. daily (Coreg CR) for 2 weeks. If tolerated, increase dosage to 20 mg, 40 mg, and 80 mg over successive intervals of at least 2 weeks.

➣ Left ventricular dysfunction following myocardial infarction

Adults: Initially, 6.25 mg P.O. b.i.d. (Coreg); increase after 3 to 10 days to 12.5 mg b.i.d. (based on tolerability), then increase to target dosage of 25 mg b.i.d. A lower starting dose (3.125 mg b.i.d.) or slower titration may be used if clinically indicated. Or, 20 mg P.O. once daily (Coreg CR); increase after 3 to 10 days to 40 mg daily (based on tolerability), then increase to target dose of 80 mg daily. A lower starting dose may be used (10 mg daily) or the rate of up titration may be slowed if clinically indicated.

Off-label uses

• Angina pectoris

• Idiopathic cardiomyopathy

Contraindications

• Hypersensitivity to drug

• Uncompensated heart failure

• Pulmonary edema

• Cardiogenic shock

• Bradycardia or heart block

• Severe hepatic impairment

• Bronchial asthma, bronchospasm

Precautions

Use cautiously in:

• renal or hepatic impairment, pulmonary disease, diabetes mellitus, hypoglycemia, thyrotoxicosis, peripheral vascular disease, hypotension, respiratory depression

• elderly patients

• pregnant or breastfeeding patients

• children.

Administration

• Ensure that patient is hemodynamically stable and fluid retention has been minimized before starting therapy.

• Give immediate-release form with food to slow absorption and minimize orthostatic hypotension.

• Give extended-release form in the morning with food and instruct patient to swallow capsule whole.

• For patients who can't swallow capsules whole, carefully open capsules and sprinkle contents on applesauce; have patient swallow contents immediately without chewing. Don't use warm applesauce; doing so could affect the modified-release properties of this formulation.

• When drug is used to treat heart failure, check apical pulse before administering. If it's below 60 beats/minute, withhold dosage and contact prescriber.

• When drug is used for hypertension, check standing systolic pressure about 1 hour after dosing for use as a guide for patient tolerance.

• Be aware that addition of diuretic may cause additive effects and may worsen orthostatic hypotension.

• Know that full antihypertensive effect takes 7 to 14 days.

See Don't withdraw drug abruptly, because this may lead to withdrawal phenomenon (angina exacerbation, myocardial infarction, ventricular arrhythmias, and even death).

Adverse reactions

CNS: dizziness, fatigue, anxiety, depression, insomnia, memory loss, nightmares, headache, pain

CV: orthostatic hypotension, peripheral vasoconstriction, angina pectoris, chest pain, hypertension, bradycardia, heart failure, atrioventricular block

EENT: blurred or abnormal vision, dry eyes, stuffy nose, rhinitis, sinusitis, pharyngitis

GI: nausea, diarrhea, constipation

GU: urinary tract infection, hematuria, albuminuria, decreased libido, erectile dysfunction, renal dysfunction

Hematologic: bleeding, purpura, thrombocytopenia

Metabolic: hypovolemia, hypervolemia, hyperglycemia, hyponatremia, hyperuricemia, glycosuria, gout, hypoglycemia

Musculoskeletal: arthralgia, back pain, muscle cramps

Respiratory: wheezing, upper respiratory tract infection, dyspnea, bronchitis, bronchospasm, pulmonary edema

Skin: pruritus, rash

Other: weight gain, lupuslike syndrome, viral infection, anaphylaxis

Interactions

Drug-drug. Antihypertensives: additive hypotension

Calcium channel blockers, general anesthetics, I.V. phenytoin: additive myocardial depression

Cimetidine: increased carvedilol toxicity

Clonidine: increased hypotension and bradycardia, exaggerated withdrawal phenomenon

Digoxin: additive bradycardia

Dobutamine, dopamine: decrease in beneficial cardiovascular effects

Insulin, oral hypoglycemics: altered efficacy of these drugs

MAO inhibitors: hypertension

Nonsteroidal anti-inflammatory drugs: decreased antihypertensive action

Rifampin, thyroid preparations: decreased carvedilol efficacy

Theophyllines: reduced theophylline elimination, antagonistic effect that decreases theophylline or carteolol efficacy

Drug-diagnostic tests. Antinuclear antibodies: increased titers

Blood urea nitrogen, glucose, lipoproteins, potassium, triglycerides, uric acid: increased levels

Drug-food. Any food: delayed drug absorption

Drug-behaviors. Acute alcohol ingestion: additive hypotension

Patient monitoring

• Watch for signs and symptoms of hypersensitivity reaction.

• Assess baseline CBC and kidney and liver function test results.

• Monitor vital signs (especially blood pressure), ECG, and exercise tolerance. Drug may alter cardiac output and cause ineffective airway clearance.

• Weigh patient daily and measure fluid intake and output to detect fluid retention.

• Measure blood glucose regularly if patient has diabetes mellitus. Drug may mask signs and symptoms of hypoglycemia.

Patient teaching

• Instruct patient to take drug with food exactly as prescribed.

• Tell patient to take extended-release capsule in the morning with food, to swallow capsule whole, and not to chew, crush, or divide its contents.

• Instruct patient who can't swallow capsule whole to carefully open capsule, sprinkle contents on cool or cold applesauce, and swallow contents immediately without chewing. Tell patient not to store mixture for future use.

See Caution patient not to stop taking drug abruptly, because serious reactions may result.

• Advise patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from sudden blood pressure drop.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Inform male patient that drug may cause erectile dysfunction. Advise him to discuss this issue with prescriber.

• Advise patient to use soft-bristled toothbrush and electric razor to avoid gum and skin injury.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and behaviors mentioned above.