Carvedilol lowers blood pressure and increases the output of the heart. It is prescribed for people with congestive heart failure to increase survival and reduce the need for hospitalization. Carvedilol may be prescribed if you have survived a heart attack and now suffer from left ventricular dysfunction, a condition where the left side of the heart no longer pumps properly. It is also used to control high blood pressure. It is often used with other drugs.
In some people, Carvedilol causes a drop in blood pressure when they first stand up, resulting in dizziness or even fainting. If this happens, sit or lie down and notify your doctor. Taking the drug with food reduces the chance of this problem. Even so, during the first month of therapy, or after a change in your dose, be careful about driving and operation of dangerous machinery.
This drug contains the active ingredient carvedilol, which is a type of drug called a beta-blocker.
Beta-blockers block beta-receptors in the heart, lungs and other organs of the body. Blocking these receptors prevents the action of two chemicals called noradrenaline and adrenaline that occur naturally in the body. These are often referred to as the 'fight or flight' chemicals, as they are responsible for the body's reaction to stressful situations.
Carvedilol mainly blocks beta-receptors in the heart, which causes the heart to beat more slowly and with less force. This means that the heart uses less energy and so requires less oxygen from the blood. The pain of angina is caused by not enough oxygen reaching the heart when it's workload is increased, eg during exercise. Carvedilol prevents this pain by decreasing the oxygen demand of the heart, so that it always has a sufficient supply.
Due to the heart beating more slowly and with less force, the pressure at which blood is pumped out of the heart to the rest of the body is reduced. This is one way in which carvedilol reduces blood pressure.
Carvedilol also blocks receptors called alpha-receptors that are present on the walls of blood vessels. Blocking these receptors causes the blood vessels to widen, which means that there is more space and less resistance in the blood vessels. This is another mechanism by which the pressure in the blood vessels is lowered.
The widened blood vessels also allow more blood to reach the heart, which is another way in which carvedilol prevents the pain of angina.
Overall, carvedilol decreases the effort required by the heart to pump blood around the body and so can also be used to treat chronic heart failure, where the pumping action of the heart has become less effective.
Because carvedilol widens the blood vessels and maintains the blood flow to the extremities, it rarely causes the cold extremities (hands and feet) that can occur in people taking other beta-blockers.
Why is this drug prescribed?
- high blood pressure (hypertension);
- chronic heart failure;
- angina pectoris;
- wheezing;
- weight gain;
- weakness;
- vomiting;
- vision changes;
- upper respiratory infection;
- swelling;
- slow heartbeat;
- sinus problems;
- shortness of breath;
- pain;
- nausea;
- low blood pressure;
- joint pain;
- increased cholesterol;
- increased blood sugar levels;
- headache;
- fluid in the lungs;
- fatigue;
- fainting;
- dizziness;
- diarrhea;
- cough;
- bronchitis;
- back pain;
- wheezing;
- weight gain;
- weakness or loss of strength (asthenia);
- visual disturbances;
- slow heart rate (bradycardia);
- rash;
- increased blood cholesterol level;
- impotence;
- headache;
- fatigue;
- excessive fluid retention in the body tissues resulting in swelling (oedema);
- dizziness;
- disturbed sleep;
- disturbances of the gut such as diarrhoea constipation nausea vomiting or abdominal pain;
- depressed mood;
- blockade of the electrical pathways which control the pumping action of the heart (heart block);
- a drop in blood pressure that occurs when going from lying down to sitting or standing which results in dizziness and lightheadedness (postural hypotension);
- anemia;
ADULTS
Hypertension
The starting dose is 6.25 mg twice a day with food. Your doctor may raise the dosage every 1 or 2 weeks to a maximum of 50 mg a day.
Congestive Heart Failure
The starting dose is 3.125 mg twice a day with food. Your doctor may increase the dosage every 2 weeks. The maximum dosage, for people weighing over 187 pounds, is 100 mg a day.
Left Ventricular Dysfunction Following a Heart Attack
The starting dose ranges from 3.125 to 6.25 mg twice a day with food. Your doctor may increase the dosage after 3 to 10 days to 12.5 mg twice a day. Based on your response, the doctor may again increase the dose up to a maximum of 25 mg twice a day.
CHILDREN
The safety and effectiveness of Carvedilol have not been studied in children under 18.
