V-bloc

V-bloc

carvedilol

Manufacturer:

Kalbe Farma
Full Prescribing Info
Contents
Carvedilol.
Action
Pharmacology: Carvedilol is a β-adrenoceptor antagonist which also causes peripheral vasodilatation primarily via α1-adrenergic blockade. It produces its antihypertensive effect partly by reducing total peripheral resistance by blocking α1-adrenoceptor and by preventing β-adrenoceptor-mediated compensatory mechanisms.
Pharmacokinetics: Carvedilol is rapidly and completely absorbed when administered orally with maximum plasma concentrations (Cmax) reached within 1-2 hrs after single 25- or 50-mg doses in healthy volunteers and hypertensive patients. Carvedilol undergoes extensive first-pass hepatic metabolism resulting in a low and variable absolute bioavailability of about 25%. The rate of absorption (as indicated by absorption) is decreased by food. Carvedilol is highly lipophilic and is widely distributed into extravascular tissues with volume of distribution of 1.5-2 L/kg in healthy volunteers.
Metabolism is primarily hepatic with <2% of the dose excreted unchanged in urine. Some metabolites appear to be active but whether this is of any clinical relevance is uncertain.
Elimination is primarily biliary with 60% of the dose excreted in faeces. Thus, a dosage adjustment in renally impaired patients is not required. However, peak plasma carvedilol concentrations and bioavailability are significantly increased in patients with severe hepatic impairment (eg, cirrhosis) and the use of carvedilol in these patients is not recommended.
Indications/Uses
Management of congestive heart failure (CHF) and essential hypertension. It can be used alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.
Dosage/Direction for Use
Essential Hypertension: Once-daily dosing is recommended.
Adults and the Elderly: The recommended dose for initiation of therapy is 12.5 mg once a day (or 6.25 mg twice daily) for the first 2 days. Thereafter, the recommended dosage is 25 mg once a day. If necessary, the dosage may subsequently be increased at intervals of at least 2 weeks up to the recommended maximum daily dose of 50 mg given a day.
Congestive Heart Failure (CHF): The recommended starting dose is 3.125 mg twice daily for 2 weeks, may be increased to 6.25 mg twice daily. Maximum dose in patients <85 kg is 25 mg twice daily; >85 kg is 50 mg twice daily.
V-bloc is taken with food.
Contraindications
V-bloc must not be used in patients with: New York Heart Association (NYHA) Class IV decompensated heart failure requiring IV inotropic support; bronchial asthma; chronic obstructive pulmonary disease (COPD) with a bronchospastic component; clinically manifest liver dysfunction; 2nd- and 3rd-degree AV-block; severe bradycardia (<50 beats/min); shock, including cardiogenic shock and hypovolaemic shock; sick sinus syndrome (including sino-atrial block); severe hypotension (systolic blood pressure <85 mm Hg); hypersensitivity to carvedilol. Allergic disorders (including asthma and rhinitis) which may suggest a predisposition to bronchospasm.
Special Precautions
V-bloc should not be used in the case of the following diseases since there is a lack of experience in these situations: Markedly reduced performance of the heart, labile or secondary (organically induced) high blood pressure, unstable angina pectoris, impulse conduction disturbances in the heart (complete bundle branch blocks), final stages of peripheral artery disease, impaired renal function (serum creatinine concentration >1.8 mg/dL or creatinine clearance <30 mL/min), recent heart attack (<6 months old), tendency to drop in blood pressure-lowering drugs (α1-receptor antagonists).
Particularly close medical surveillance is required in diabetes mellitus patients with pronounced fluctuations in blood sugar levels and in the event of strict fasting. In older patients, a sharper drop in blood pressure can occur after administration of the 1st dose of V-bloc. This applies especially to patients already taking diuretics. Diuretics should therefore be discontinued before beginning treatment with V-bloc. Drugs with β-blocking properties may trigger psoriasis vulgaris in isolated cases, cause the symptoms of this disease to deteriorate or produce rashes resembling psoriasis (psoriasiform). Patients with personal or familial history of psoriasis should only take drugs with β-blocking properties (eg, V-bloc) after careful consideration of the benefit-to-risk ratio.
Treatment with V-bloc is not to be stopped abruptly but must be gradually tapered off over a few days. This is particularly important in the case of patients with concomitant coronary artery disease (angina pectoris).
Treatment of hypertension requires regular medical surveillance.
During treatment with V-bloc, the eyes must be examined regularly at 6 monthly intervals. Patients with mild to moderate occlusive vascular disease should be carefully monitored during initiation of therapy and β-blockers should be avoided in patients with severe occlusive vascular disease, particularly those with rest pain.
V-bloc should only be used in patients with chronic obstructive pulmonary disease (COPD) with a bronchospastic component not receiving oral or inhaled medication if the potential benefit outweighs the potential risk. In patients with a tendency to bronchospasm, respiratory distress can occur as a result of a possible increase in airway resistance. Patients should be closely monitored during initiation and up-titration of V-bloc and the dose of V-bloc reduced if any evidence of bronchospasm is observed during treatment.
Carvedilol, like other agents with β-blocking properties, may obscure the symptoms of thyrotoxicosis.
Care should be taken in the administration of V-bloc to patients with a history of serious hypersensitivity reactions and in those undergoing desensitization therapy as β-blockers may increase both the sensitivity towards allergens and the seriousness of anaphylactic reactions.
In patients with phaeochromocytoma, an α-blocking agent should be initiated prior to the use of any β-blocking agent. Although, carvedilol has both α- and β-blocking pharmacological activities, there is no experience with its use in this condition. Therefore, caution should be taken in the administration of V-bloc to patients suspected of having phaeochromocytoma.
Agents with nonselective β-blocking activity may provoke chest pain in patients with Prinzmetal's variant angina. There is no clinical experience with carvedilol in these patients, although the α-blocking activity of carvedilol may prevent such symptoms. However, caution should be taken in the administration of V-bloc to patients suspected of having Prinzmetal's variant angina.
In patients suffering from peripheral circulatory disorders (Raynaud's phenomenon), there may be exacerbation of symptoms. Caution should be exercised in patients undergoing general surgery, because of the synergistic negative inotropic and hypotensive effects of carvedilol and anaesthetic drugs.
V-bloc may induce bradycardia. If the pulse rate decreases to <55 beats/min, the dosage of V-bloc should be reduced.
In patients receiving concomitant therapy with calcium channel blockers of the verapamil- or diltiazem-type, or other antiarrhythmic drugs, careful monitoring of ECG and blood is necessary.
V-bloc should be used with caution in patients with labile or secondary hypertension until further clinical experience is available.
Effects on the Ability to Drive or Operate Machinery: Individually varying reactions can impair the ability to drive or operate machinery. This applies particularly when beginning the treatment or starting a new preparation and in conjunction with alcohol.
Use in children: V-bloc should not be used in children <18 years.
Use In Pregnancy & Lactation
V-bloc should not be used during pregnancy or lactation.
There is no adequate experience with V-bloc in pregnant women. Animal reproduction studies have revealed no teratogenic potential for carvedilol. β-Blockers reduce placental perfusion, which may result in intrauterine fetal death, immature and premature deliveries. In addition, adverse effects (especially hypoglycemia and bradycardia) may occur in the fetus and neonate. There is increased risk of cardiac and pulmonary complications in the neonate and in the postnatal period. Therefore, V-bloc should not be used during pregnancy. Carvedilol and/or its metabolites are excreted in breast milk. Therefore, breastfeeding is not recommended during administration of V-bloc.
Adverse Reactions
The most common adverse reaction in this and other studies were oedema, dizziness, bradycardia, hypotension, nausea, diarrhea and blurred vision. There may occasionally be dizziness, headaches and tiredness. These symptoms are usually mild and occur particularly at the beginning of the treatment. There may also be a considerably slowed pulse rate, gastrointestinal upset (nausea, abdominal pain, diarrhea, constipations and in isolated cases, vomiting) or flu-like symptoms. As a result of a possible increase in airway resistance, breathing problems can occur in patients with a tendency towards bronchial constriction (bronchospastic reactions).
Occasionally, particularly after taking the 1st dose of carvedilol, also when changing position from lying down to standing up, there can be an excessive drop in blood pressure (postural hypotension), with symptoms eg, dizziness, going black before the eyes or in rare cases, fainting (syncope). In rare occasions, there may be angina pectoris or conduction disturbances from the atrium to the ventricle of the heart. Rarely, there can be an exacerbation of symptoms in patients suffering from intermittent claudication or vascular spasms in fingers or toes (Raynauds' phenomenon).
Cold hands and feet have only been observed in isolated cases.
It is also possible for latent diabetes to become manifest, for already existing diabetes to become aggravated or for blood sugar counter-regulation to be inhibited. The signs of low blood sugar (eg, a rapid heart rate) may be masked.
There have been reports of isolated cases of allergic skin reactions (eg, rashes and itching), depressed moods, sleep disturbances, disturbances of vision, eye irritation, disturbances of sensation (paraesthesia), pain in the limbs, potency disturbances, intensification of existing heart failure, increases in certain liver values in the blood (serum transaminases) and reduced platelets and white blood corpuscles (thrombopenia, leucopenia). Users of contact lenses should be aware of the possibility of reduced lacrimation.
Drug Interactions
When carvedilol is used at the same time as other drugs, the following must be taken into account: The effect of other blood pressure-lowering drugs may be intensified.
Simultaneous therapy with reserpine, guanethidine, methyldopa, clonidine or guanfacine may cause an intensified blood pressure- and heart rate-lowering effect.
Rifampicin reduces the systemic availability of carvedilol and thus possibly its blood pressure-lowering action.
Clonidine must be stopped gradually after treatment with carvedilol has been stopped a few days previously.
When nifedipine and carvedilol are used simultaneously, there may be a more abrupt drop in blood pressure. When calcium channel blockers of the verapamil- or diltiazem-type or other antiarrhythmic drugs are used simultaneously, careful monitoring of blood pressure and ECG are indicated since there may be a sharp drop in blood pressure, a reduced heart rate (bradycardia) or other rhythm disturbances of the heart. Calcium-channel blockers and antiarrhythmic drugs should therefore not be administered IV during treatment with carvedilol.
When carvedilol and anaesthetic drugs are used simultaneously, attention must be paid to a decrease in heart rate, the cardiac effects (negative inotropism) of the 2 drugs and stimulus conductions in the heart may be delayed. If the patient is required to undergo anaesthesia, the doctor must be informed that carvedilol is being taken.
Carvedilol can cause clinically relevant elevation of plasma digoxin concentrations.
The effects of insulin or oral blood sugar-lowering drugs may be intensified. The signs of low blood sugar (hypoglycaemia) may be masked or attenuated (especially increase in heart rate). Regular monitoring of blood sugar is therefore required in diabetics. Certain sedative (barbiturates, phenothiazines) and drugs for treating depression (acyclic antidepressants), vasodilating drugs and alcohol may intensify the blood pressure-lowering effect.
Storage
Store below 30°C. Protect from light.
MIMS Class
ATC Classification
C07AG02 - carvedilol ; Belongs to the class of alpha and beta blocking agents. Used in the treatment of cardiovascular diseases.
Presentation/Packing
Tab 25 mg x 3 x 10's. 6.25 mg x 3 x 10's.
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