Pharmacology: Carvedilol significantly reduces systemic blood pressure, pulmonary artery pressure, right atrial pressure, systemic vascular resistance, and heart rate, while stroke volume index is increased.
Mechanism of Action: Carvedilol is a dual action cardiovascular agent with β-blocking and vasodilating properties. The β-blockade is noncardioselective and is devoid of intrinsic sympathomimetic activity. Vasodilation is predominantly mediated through α-receptor antagonism.
Pharmacokinetics: Carvedilol is well absorbed after oral administration, with peak serum levels occurring after approximately 1 hr. The average elimination half-life is 6-7 hrs. Excretion is primarily in bile and significant accumulation of carvedilol or its active metabolites is unlikely in patients with renal impairment.
Management of essential hypertension. Carvedilol can be used alone or in combination with other antihypertensive agents.
Hypertension: The recommended dose for initiation therapy is 6.25 mg once a day for the first 2 days. Thereafter, the recommended dosage is 12.5 mg once a day. Although this is an adequate dose in most patients, if necessary the dose may be titrated up to a recommended maximum daily dose of 50 mg given once a day or in 2 divided doses.
Symptoms: Profound cardiovascular effects eg, hypotension and bradycardia would be expected after massive overdose. Heart failure, cardiogenic shock and cardiac arrest may follow.
Treatment: Gastric lavage or induced emesis may be useful in the first few hours after ingestion.
Patients with 2nd or 3rd degree heart block, severe bradycardia, shock, uncontrolled heart failure, asthma, history of chronic obstructive airways disease, hepatic impairment or those hypersensitive to carvedilol.
Special care should be taken in patients whose cardiac reserve is poor. Heart failure should be satisfactorily controlled with appropriate therapy before carvedilol is started.
Although angina has not been reported on stopping treatment, withdrawal should be gradual in patients with ischaemic heart disease since carvedilol has β-blocking activity.
As with other β-blocking drugs, carvedilol may mask the symptoms of hyperthyroidism and early signs of acute hypoglycemia in patients with diabetes mellitus. Alternatives to β-blocking agents are generally preferred in insulin-dependent diabetic patients.
Effects on the Ability to Drive or Operate Machinery: As for other drugs which produce changes in blood pressure, patients taking carvedilol should be warned not to drive or operate machinery if they experience dizziness or related symptoms. This may be most relevant when starting or changing treatment and when alcohol is taken.
Use in pregnancy & lactation: There is no evidence from animal studies that carvedilol has any teratogenic effects. The relevance of these findings for humans is uncertain. Animal studies have shown that carvedilol crosses the placental barrier and is excreted in breast milk and therefore, the possibility of the consequences of α- and β-blockade in the human fetus and neonate should be borne in mind. Carvedilol, is therefore, not recommended for use during pregnancy or in breastfeeding mothers.
There is no evidence from animal studies that carvedilol has any teratogenic effects. The relevance of these findings for humans is uncertain. Animal studies have shown that carvedilol crosses the placental barrier and is excreted in breast milk and therefore, the possibility of the consequences of α- and β-blockade in the human fetus and neonate should be borne in mind. Carvedilol, is therefore, not recommended for use during pregnancy or in breastfeeding mothers.
Carvedilol is usually well tolerated. Symptomatic postural hypotension, mainly on the initiation of therapy or when increasing the dose may occur, but the incidence is minimized when Carvipress is used as recommended. Dizziness, headache, fatigue, gastrointestinal upset and bradycardia have been observed. These are usually mild, transient and occur early in the course of treatment.
Diminished peripheral circulation, dry eyes and flu-like symptoms have occurred. Occasionally, stuffy nose, wheezing, depressed mood, sleep disturbance, paraesthesiae and progression of heart failure have been reported in isolated cases. There have been isolated reports of changes in serum transaminases, thrombocytopenia and leukopenia.
As with other antihypertensives, there is a potential for pronounced hypotension during general anesthesia.
As with other agents with β-blocking activity, carvedilol may potentiate the effect of other concomitantly administered drugs that are antihypertensive in action or have hypotension as part of their adverse effect profile.
As with other drugs with β-blocking activity, caution should be exercised when administering class I antiarrhythmic drugs or calcium antagonists eg, verapamil. These drugs should not be administered IV.
Store in a dry place below 25°C. Protect from light.
C07AG02 - carvedilol ; Belongs to the class of alpha and beta blocking agents. Used in the treatment of cardiovascular diseases.