Carvedilol

From Ask Dr Wiki

Contents 1 Mechanism of action 2 Therapeutic uses 3 Dose 3.1 Hypertension 3.2 Congestive heart failure 4 Contraindications 5 Side effects 6 Drug interactions (not inclusive) 7 Comments 8 Pharmacokinetics

Mechanism of action

• Non-selective beta and alpha blocker antagonize both beta₁ and beta₂ and alpha₁ receptors thus inhibiting the effects of catecholamines on these receptors
• Cardiovascular effects include
• Reduced contractility
• Decreased heart rate
• Vasodilation

Therapeutic uses

• Hypertension
• Heart failure

Dose

Hypertension

• Initial dose: 6.25 mg PO two times daily
• Increase dose every 7 – 14 days
• Maximum dose: 25 mg PO two times daily

Congestive heart failure

• Initial dose: 3.125 mg PO two times daily
• Double dose every 2 weeks as tolerated
• Maximum dose
  • < 85 kg: 25 mg PO twice daily
  • > 85 kg: 50 mg PO twice daily
• Severe heart failure: 25 mg PO twice daily

Contraindications

• Hypersensitivity to beta blockers
• Asthma
• Heart block greater than first degree
• Insulin dependent diabetics with frequent hypoglycemic episodes
• Overt heart failure/cardiogenic shock
• Severe sinus bradycardia
• Sick sinus syndrome

Side effects

• Fatigue
• Bradycardia
• Heart block
• Bronchospasm
• Depression
• Lipid abnormalities
• May mask the symptoms of hypoglycemia
• Rebound effect with abrupt discontinuation
• Precipitation of heart failure
• Impotence

Drug interactions (not inclusive)

• Rifampin
• Clonidine
• Cimetidine
• Cyclosporine
• Medications that slow AV nodal conduction such as
  • Digoxin
  • Diltiazem
  • Verapamil
  • Amiodarone
  • Other beta blockers
• Non-steroidal anti-inflammatory drugs
• Other medications that lower blood pressure
• Other medications that produce a decrease in contractility
• Medications that inhibit the CYP 2D6 and CYP 2C9 enzyme

Comments

• Patients should be informed that they should not stop taking beta blockers abruptly because this can lead to a rebound effect.
• Diabetic patients should be informed that they need to monitor their blood glucose more frequently when starting a beta blocker since beta blockers can mask signs and symptoms of hypoglycemia
• Patients with bronchospastic lung disease should not receive beta blockers unless the benefits outweigh the risks

Pharmacokinetics

• Onset: 1 hour
• Half-life: 6 – 10 hours
• Elimination: hepatic