Carvedilol
A non-selective beta blocker that also blocks α1 receptors, used for heart failure, after a heart attack and for high blood pressure.
Drug card
- Class
- Beta blocker, and an alpha-1 blocker
- How it works
- Blocking beta receptors, so the heart beats slower and less forcefully
- Used for
- Chronic heart failure, to improve survival
- Weak left ventricle after a heart attack
- High blood pressure
- Angina
- Known for
- Dizziness on standing (postural hypotension), fainting
- Slow heart rate (bradycardia)
- Its name
- -dilol means a vasodilating beta blocker
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does carvedilol work?
Carvedilol is a racemic mixture: the S(−) form blocks β1 and β2 receptors, and both forms block α1 receptors, which widens blood vessels. Its β effect is stronger than its α1 effect, and it has no intrinsic sympathomimetic activity. First-pass metabolism leaves 25 to 35% bioavailable, and CYP2D6 helps clear it.
Like other beta blockers: They block β-adrenergic receptors, so epinephrine and norepinephrine act less: in the heart (β1) rate and force of contraction fall and AV conduction slows, and the kidneys release less renin. Cardioselective ones (atenolol, bisoprolol, metoprolol) act mainly on β1; non-selective ones also block β2 in airways and vessels; carvedilol and labetalol block α1 as well.
Uses
What is carvedilol used for?
- Chronic heart failure, to improve survival
- Weak left ventricle after a heart attack
- High blood pressure
- Angina
Side effects
Side effects of carvedilol
- Dizziness on standing (postural hypotension), faintingKnown for
- Slow heart rate (bradycardia)Known for
- Dizziness
- Tiredness and weakness
- Raised blood sugar in diabetes
- Weight gain
- Fluid retention while the dose is being raised
- Worsening heart failure while the dose is being raisedSerious
- Diarrhea
- Hidden warning signs of low blood sugarSerious
- Narrowed airways (bronchospasm)Serious
- Floppy iris syndrome during cataract surgery
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Not for asthma, sick sinus syndrome or 2nd- or 3rd-degree AV block unless paced, severe bradycardia, decompensated heart failure or severe liver disease.
- Strong CYP2D6 inhibitors such as fluoxetine and paroxetine can raise its levels.
- Diabetes with heart failure: blood sugar can rise, so glucose is checked when it is started or increased.
- Do not stop suddenly: taper over 1 to 2 weeks to avoid angina and heart attacks.
Good to know: Its α1 blockade adds vasodilation to beta blockade, so dizziness and fainting on standing are typical in the first weeks.
Remember it
A way to remember it
One heart, two lungs: β1 for the heart, β2 for the lungs.
β1 receptors dominate in the heart and β2 receptors in the airways. Cardioselective beta blockers act mainly on β1, so they narrow the airways less than non-selective ones such as propranolol, though all need care in asthma.
A mnemonic widely used in teaching
Its name
-dilol means vasodilating beta blocker
WHO files -dilol under -dil (vasodilators). Carvedilol blocks beta receptors and also alpha-1 receptors, which widens blood vessels.
- Every drug name stem
Its class
Beta blockers
Other beta blockers with a card:
Easily mixed up with alpha-1 blockers and non-dihydropyridine calcium channel blockers.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Blood pressure
Carvedilol is one of 27 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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