Meds and you

Updated 11 February 2013


Carvedilol is a beta blocker indicated for the treatment of mild to moderate congestive heart failure and to reduce high blood pressure.


Carvedilol is the active ingredient of Carloc, Carvedilol-Hexal, Carvetrend, Dilatrend and Merck-Carvedilol.

General Information

Carvedilol is a beta blocker indicated for the treatment of mild to moderate congestive heart failure and to reduce high blood pressure. It does not cure any of these conditions, but simply keeps them under control and is therefore prescribed long-term.

For carvedilol to be effective it has to be taken regularly, even if you do not notice an immediate effect. Blood pressure declines gradually and it may take a few weeks before you get the full benefit. Carvedilol can be used on its own, or in combination with certain other medication for high blood pressure.

The first couple of doses of this medication may cause a sudden drop in blood pressure, which may cause dizziness or blackouts when you get up quickly. It is therefore advised that one should be resting when starting treatment and lie down for 2 hours afterwards.

Carvedilol is a nonselective beta blocker and is less likely to affect the airways. It may provoke breathing difficulties due to its effect on receptors in the lungs. If you suffer from asthma or other respiratory conditions, carvedilol should be taken with caution.

Carvedilol may be prescribed after a heart attack to protect the heart from further damage.

How does carvedilol work?

Carvedilol reduces the stimulating effect of noradrenalin. As a result it lowers the force and speed at which the heart is beating. This assists in stabilising fast and abnormal heart rhythms, reduces chest pain and lowers blood pressure.

Fast facts

Drug schedule: Schedule 3

Available as: Carvedilol is available in tablet form.

What does it do? Carvedilol lowers blood pressure and reduces the heart's workload.

Overdose risk: Medium

Dependence risk: Low

Is carvedilol available as a generic? Yes

Is carvedilol available on prescription only? Yes

User information

Dietary advice: Dietary advice

Stopping this medicine: Carvedilol should never be discontinued suddenly after prolonged use. This may markedly increase blood pressure, cause chest pain and may cause fast or irregular hearth rhythms. A heart attack may even be provoked. When treatment with this medication needs to be stopped, the dosage should be gradually reduced under medical supervision.

Prolonged use: No problems expected. Your doctor may request periodic tests if you use this medication for extended periods of time.

Special precautions

Consult your doctor before using this drug if:

  • you have pheochromocytoma
  • you had an allergic reaction to carvedilol before.
  • you have asthma, or a history of obstructive airways disease
  • you have heart disease
  • you have known liver or kidney disease
  • you have diabetes. Carvedilol may mask some of the warning signs of low
  • blood sugar, such as a fast heart rate.
  • you have an overactive thyroid .Carvedilol may mask symptoms of this
  • condition.
  • you have a medical emergency, or before you undergo any surgery
  • you have low blood pressure.

Pregnancy: Avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.

Breastfeeding: Avoid. It is unknown how this medication may affect your baby. Consult your doctor before use.

Porphyria: This medication is safe use.

Infants and children: and efficacy of this medication has not been established for children

Elderly: Caution is advised in the elderly as adverse effects may be more likely. A reduced dose may be needed.

Driving and hazardous work: Caution is advised, as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.

Alcohol: Avoid concomitant use of alcohol with this medication, as it may cause a dangerous drop in blood pressure.

Possible side effects

Side effect


Consult your doctor



Only if severe

In all cases




Dizziness/ tiredness/ weakness












Chest pain or tightness



Difficulty breathing/ shortness of breath



Swelling of ankles




Non-steroidal anti-inflammatory drugs (NSAID's) e.g. Ibuprofen

May reduce the drug’s antihypertensive effect.

Certain blood pressure medications e.g. reserpine

Severe low blood pressure or slow heart rate may occur.

Certain drugs for malaria/malaria prevention

Risk of serious heart problems may be increased.


Increase potential for carvedilol toxicity

Certain over-the-counter cold and flu remedies

Risk of severe high blood pressure


May decrease carvedilol effectiveness.


Severe high blood pressure may occur.


Reduced efficacy of carvedilol


Increased risk of warfarin toxicity


Further reduction in heart rate


Increase risk of theophylline toxicity

Overdose action

An overdose of this medication can be fatal. Seek immediate emergency medical attention. Symptoms of overdose may include swelling of the legs, feet and ankles; shortness of breath; difficulty breathing and a slow heartbeat.

Recommended dosage

Adults: 12.5-50 mg once daily


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