Carvedilol

carvedilol

(kar vah' da lol)

Coreg

Pregnancy Category C

Drug classes

Alpha- and beta-adrenergic blocker

Antihypertensive

Therapeutic actions

Competitively blocks alpha-, beta-, and beta₂-adrenergic receptors and has some sympathomimetic activity at beta₂-receptors. Both alpha and beta blocking actions contribute to the BP-lowering effect; beta blockade prevents the reflex tachycardia seen with most alpha-blocking drugs and decreases plasma renin activity. Significantly reduces plasma renin activity.

Indications

·        Hypertension, alone or with other oral drugs, especially diuretics

·        Treatment of mild to severe CHF of ischemic or cardiomyopathic origin with digitalis, diuretics, ACE inhibitors

·        Left ventricular dysfunction (LVD) after MI

·        Unlabeled uses: Angina (25–50 mg bid)

Contraindications and cautions

·        Contraindicated with decompensated CHF, bronchial asthma, heart block, cardiogenic shock, hypersensitivity to carvedilol, pregnancy, lactation.

·        Use cautiously with hepatic impairment, peripheral vascular disease, thyrotoxicosis, diabetes, anesthesia, major surgery.

Available forms

Tablets—3.125, 6.25, 12.5, 25 mg

Dosages

ADULTS

·        Hypertension: 6.25 mg PO bid; maintain for 7–14 days, then increase to 12.5 mg PO bid if needed to control BP. Do not exceed 50 mg/day.

·        CHF: Monitor patient very closely, individualize dose based on patient response. Initial dose, 3.125 mg PO bid for 2 wk, may then be increased to 6.25 mg PO bid. Maximum dose, 25 mg PO bid in patients < 85 kg or 50 mg PO bid in patients > 85 kg.

·        LVD following MI: 6.25 mg PO bid, increase after 3–10 days to target dose of 25 mg bid.

PEDIATRIC PATIENTS

Safety and efficacy not established.

PATIENTS WITH HEPATIC IMPAIRMENT

Do not administer to any patient with severe hepatic impairment.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral	Rapid	30 min	8–10 hr

Metabolism: Hepatic; T_1/2: 7–10 hr

Distribution: Crosses placenta; may enter breast milk

Excretion: Bile, feces

Adverse effects

·        CNS: Dizziness, vertigo, tinnitus, fatigue, emotional depression, paresthesias, sleep disturbances

·        CV: Bradycardia, orthostatic hypertension, CHF, cardiac arrhythmias, pulmonary edema, hypotension

·        GI: Gastric pain, flatulence, constipation, diarrhea, hepatic failure

·        Respiratory: Rhinitis, pharyngitis, dyspnea

·        Other: Fatigue, back pain, infections

Interactions

Drug-drug

·        Increased effectiveness of antidiabetics; monitor blood glucose and adjust dosages appropriately

·        Increased effectiveness of clonidine; monitor patient for potential severe bradycardia and hypotension

·        Increased serum levels of digoxin; monitor serum levels and adjust dose accordingly

·        Increased plasma levels of carvedilol with rifampin

·        Potential for dangerous conduction system disturbances with verapamil or diltiazem; if this combination is used, closely monitor ECG and BP

Drug-food

·        Slowed rate of absorption but not decreased effectiveness with food

Nursing considerations

Assessment

·        History: CHF, bronchial asthma, heart block, cardiogenic shock, hypersensitivity to carvedilol, pregnancy, lactation, hepatic impairment, peripheral vascular disease, thyrotoxicosis, diabetes, anesthesia or major surgery

·        Physical: Baseline weight, skin condition, neurologic status, P, BP, ECG, respiratory status, LFTs, renal and thyroid function tests, blood and urine glucose

Interventions

·        WARNING: Do not discontinue drug abruptly after chronic therapy (hypersensitivity to catecholamines may have developed, causing exacerbation of angina, MI, and ventricular arrhythmias); taper drug gradually over 2 wk with monitoring.

·        Consult with physician about withdrawing drug if patient is to undergo surgery (withdrawal is controversial).

·        Give with food to decrease orthostatic hypotension and adverse effects.

·        Monitor for orthostatic hypotension and provide safety precautions.

·        Monitor patients with diabetes closely; drug may mask hypoglycemia or worsen hyperglycemia.

·        WARNING: Monitor patient for any sign of liver dysfunction (pruritus, dark urine or stools, anorexia, jaundice, pain); arrange for LFTs and discontinue drug if tests indicate liver injury. Do not restart carvedilol.

Teaching points

·        Take drug with meals.

·        Do not stop taking drug unless instructed to do so by a health care provider.

·        Avoid use of over-the-counter medications.

·        You may experience these side effects: Depression, dizziness, light-headedness (avoid driving or performing dangerous activities; getting up and changing positions slowly may help ease dizziness).

·        Report difficulty breathing, swelling of extremities, changes in color of stool or urine, very slow heart rate, continued dizziness.

Adverse effects in Italic are most common; those in Bold are life-threatening.