Carvedilol

1. Introduction

Carvedilol, marketed under brand names such as Coreg and Dilatrend, is a non-selective beta-blocker with alpha-blocking activity. It is used to manage hypertension, heart failure, and left ventricular dysfunction after a myocardial infarction. Its dual mechanism of action reduces heart rate, lowers blood pressure, and improves cardiac output in heart failure.

2. Indications

  • Approved Indications:
    • Hypertension.
    • Symptomatic heart failure.
    • Left ventricular dysfunction following a myocardial infarction.
  • Off-Label Uses:
    • Atrial fibrillation with rapid ventricular response (rate control).

3. Dosage

  • Hypertension:
    • Initial dose: 6.25 mg twice daily.
    • Maintenance dose: 25 mg twice daily.
    • Maximum dose: 50 mg/day in divided doses.
  • Heart Failure:
    • Initial dose: 3.125 mg twice daily.
    • Gradually increase every 2 weeks to a maximum dose of 25 mg twice daily (for patients ≤85 kg) or 50 mg twice daily (for patients >85 kg).
  • Post-Myocardial Infarction:
    • Initial dose: 6.25 mg twice daily.
    • Maintenance dose: 25 mg twice daily.

4. Administration

  • Take with food to reduce the risk of orthostatic hypotension.
  • Tablets should be swallowed whole; do not crush or chew.

5. Forms Available

  • Tablets: 3.125 mg, 6.25 mg, 12.5 mg, 25 mg.
  • Extended-release capsules: 10 mg, 20 mg, 40 mg, 80 mg.

6. Side Effects

6.1. Common Side Effects

  • Dizziness.
  • Fatigue.
  • Hypotension.
  • Bradycardia (slow heart rate).

6.2. Less Common Side Effects

  • Peripheral oedema.
  • Diarrhoea.
  • Weight gain.

6.3. Rare but Serious Side Effects

  • Bronchospasm in patients with asthma or chronic obstructive pulmonary disease (COPD).
  • Severe bradycardia or heart block.
  • Hepatotoxicity.

7. Warnings

  • Contraindicated in patients with severe hepatic impairment.
  • Avoid in patients with decompensated heart failure requiring inotropic support.
  • Use cautiously in patients with diabetes, as carvedilol can mask symptoms of hypoglycaemia (e.g., tachycardia).
  • Avoid abrupt discontinuation, as it may lead to rebound hypertension or angina.

8. Precautions

  • Monitor closely in patients with bronchospastic diseases, as carvedilol may worsen symptoms.
  • Use cautiously in patients with a history of severe allergic reactions, as beta-blockers may reduce the effectiveness of epinephrine.

9. Interactions

  • Drug-Drug Interactions:
    • Calcium channel blockers (e.g., verapamil, diltiazem): May increase the risk of bradycardia and hypotension.
    • CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): May increase carvedilol plasma levels.
    • Antidiabetic agents: Enhanced risk of hypoglycaemia or delayed recognition of symptoms.
  • Drug-Food Interactions:
    • Take with food to reduce the risk of orthostatic hypotension.

10. Monitoring Parameters

  • Blood pressure and heart rate regularly.
  • Signs of heart failure exacerbation (e.g., weight gain, dyspnoea).
  • Blood glucose levels in diabetic patients.
  • Liver function tests periodically in long-term use.

11. Use in Children

  • Safety and efficacy in children have not been established; not typically recommended.

12. Use in Pregnancy

  • Category C: Limited data available; use only if the potential benefit outweighs the risk to the foetus.
  • May cause foetal bradycardia, hypoglycaemia, or hypotension.

13. Use in Elderly

  • Use with caution, as elderly patients are more prone to side effects such as dizziness and hypotension.

14. Use in Kidney Disease

  • No specific dose adjustments required; use cautiously in patients with severe renal impairment.

15. Use in Liver Disease

  • Contraindicated in severe hepatic impairment due to increased risk of toxicity.

16. Patient Counselling Points

  • Take carvedilol with food to reduce dizziness or light-headedness.
  • Do not abruptly stop taking the medication, as this may worsen heart conditions or cause rebound hypertension.
  • Inform patients about the potential side effects, including dizziness, fatigue, or slow heart rate, and advise them to report severe symptoms.
  • Diabetic patients should monitor blood glucose closely, as symptoms of hypoglycaemia may be masked.
  • Avoid alcohol, as it may enhance the hypotensive effects of the medication.

17. Table of Brand Names, Manufacturers, and Prices

Brand NameManufacturerPrice (USD)
CoregGlaxoSmithKline$25–40 (30 tablets, 25 mg)
DilatrendRoche$30–50 (30 tablets, 25 mg)
Generic OptionsVarious$10–20 (30 tablets, 25 mg)

18. FAQs (15 Questions)

  1. What is carvedilol used for?
    Carvedilol is used to treat hypertension, heart failure, and left ventricular dysfunction after a heart attack.
  2. How does carvedilol work?
    It is a beta-blocker with alpha-blocking activity that reduces heart rate, lowers blood pressure, and improves blood flow.
  3. What are the common side effects of carvedilol?
    Dizziness, fatigue, bradycardia, and hypotension.
  4. Can carvedilol cause weight gain?
    Yes, weight gain may occur, particularly in patients with heart failure.
  5. How should carvedilol be taken?
    It should be taken with food to reduce the risk of orthostatic hypotension.
  6. Is carvedilol safe for children?
    Safety and efficacy in children have not been established.
  7. Can pregnant women take carvedilol?
    It should only be used during pregnancy if the benefits outweigh the risks.
  8. Can carvedilol cause low blood sugar?
    It can mask symptoms of hypoglycaemia in diabetic patients, so caution is needed.
  9. What should I do if I miss a dose?
    Take the missed dose as soon as you remember, but skip it if it’s close to the next dose. Do not double up.
  10. Can I stop taking carvedilol suddenly?
    No, sudden discontinuation may worsen heart conditions or cause rebound hypertension.
  11. Does carvedilol interact with other medications?
    Yes, it interacts with calcium channel blockers, CYP2D6 inhibitors, and antidiabetic drugs.
  12. Can carvedilol be used for heart failure?
    Yes, it is commonly used to manage heart failure and improve symptoms.
  13. How long does it take for carvedilol to work?
    Effects on blood pressure may be seen within hours, but full benefits for heart failure may take weeks to months.
  14. Does carvedilol cause tiredness?
    Yes, fatigue is a common side effect, especially during the initial phase of treatment.
  15. How should carvedilol be stored?
    Store at room temperature, away from moisture and heat.