Betablock

Uses

Betablock is used for:

• essential and renal hypertension
• angina pectoris
• long term prophylaxis after recovery from acyte myocardial infarction
• cardiac dysrhythmia
• prophylaxis of migraine
• essential tremor
• anxiety and anxiety tachycardia
• adjunctive management of thyrotoxicosis and thyrotoxic crisis
• hypertrophic obstructive cardiomyopathy
• phaeochromocytoma (with α-blocker)

Betablock is also used to associated treatment for these conditions: Akathisia caused by antipsychotic use, Angina Pectoris, Atrial Fibrillation, Cardiovascular Mortality, Gastroesophageal variceal hemorrhage prophylaxis, Hemangiomas, High Blood Pressure (Hypertension), Migraine, Myocardial Infarction, Obstructive Hypertrophic Cardiomyopathy, Performance Anxiety, Pheochromocytomas, Proliferating Infantile Hemangioma, Supraventricular Arrhythmias, Tachyarrhythmia caused by Digitalis intoxication, Tachyarrhythmia caused by catecholamine excess, Thyroid Crisis, Thyrotoxicosis, Tremor caused by lithium, Tremor, Essential, Ventricular Tachycardia (VT)

How Betablock works

Betablock is a nonselective β-adrenergic receptor antagonist. Blocking of these receptors leads to vasoconstriction, inhibition of angiogenic factors like vascular endothelial growth factor (VEGF) and basic growth factor of fibroblasts (bFGF), induction of apoptosis of endothelial cells, as well as down regulation of the renin-angiotensin-aldosterone system.

Dosage

Betablock dosage

Tablet:

Adults:

• Hypertension: A starting dose of 80 mg twice a day may increased at weekly intervals according to response. The usual dose range is 160-320 mg per day. With concurrent diuretic or other antihypertensive drugs a further reduction of blood pressure is obtained.
• Angina, anxiety, migraine and essential tremor: A staring dose of 40 mg two or three times daily may be increased by the same amount at weekly intervals according to patients response. An adequate response in anxiety, migraine and essential tremor is usually seen in the range 80-160 mg/day and an angina in the range 120-240 mg/day.
• Situational and generalized anxiety: A dose of 40 mg daily may provide short term relief of acute situational anxiety. Generalized anxiety require long term therapy, usually responds adequately to 40 mg twice daily which ,which individual cases, may be increased to 40 mgthree times daily. Treatment should be continued according to responses. Patients should reviewed after 6 to 12 months treatment.
• Dysrhythmias, anxiety tachycardia, hypertrophic obstructive cardiomyopathy and thyrotoxicosis: A dosage range of 10-40 mg three or four times a day usually achieves the required response.
• Post myocardial infarction: Treatment should be started between days 5 and after 21 after myocardial infarction, with an initial dose of 40 mg four times a day for 2 or 3 days. In order to improve compliance the total daily doses three after be given as 80 mg twice a day. Phaeochromocytoma (Used only with an alpha receptor blocking drug).
• Pre-operative: 60 mg daily for three days.
• Non-operable malignant cases: 30 mg daily.
• Migraine: Under 12 years: 20 mg two or three times daily.Over 12 years : The adult dose.

Children:

• Sysrhythmias, Phaeochromocytoma, Thyrotoxicisis: Dosage should be individually determined and the following is only a guide 0.25-0.5 mg/kg three or four times daily as required.

Sustained Release Capsule:

Adult:

• Hypertension: The usual initial dose is 80mg Betablock SR once daily, whether used alone or added to a diuretic. The usual maintenance dosage is 120 to 160 mg once daily.
• Angina pectoris: Starting with 80mg Betablock SR once daily, dosage should be gradually increased three to seven day intervals until optimum response is obtained.
• Migraine: The initial oral dose is 80 mg Betablock SR once daily. T he usual effective dose range is 160 to 240 mg once daily. It may be advisable to withdraw the drug gradually over a period of several weeks.
• Hypertrophic subaortic stenosis: 80 mg Betablock SR once daily

Injection:

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

The usual dose is 1 to 3 mg administered under careful monitoring, such as electrocardiography and central venous pressure. The rate of administration should not exceed 1 mg (1 mL) per minute to diminish the possibility of loweringblood pressureand causing cardiac standstill.

Sufficient time should be allowed for the drug to reach the site of action even when a slow circulation is present. If necessary, a second dose may be given after two minutes. Thereafter, additional drug should not be given in less than four hours. Additional propranolol hydrochloride should not be given when the desired alteration in rate or rhythm is achieved.

Transfer to oral therapy as soon as possible.

Side Effects

Betablock is usually well tolerated. Minor side effects such as cold extremities, nausea, diarrhea, sleep disturbances and lassitude are often transient. There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenergic blocking drugs.

Toxicity

Symptoms of overdose include hypotension, hypoglycemic seizure, restlessness, euphoria, insomnia. Patients with asthma may develop bronchospasm. In case of overdose, monitor vital signs, mental status, and blood glucose. Treat hypotension with intravenous fluids, bradycardia with atropine, and isoproterenol and aminophylline for bronchospasm. If patients do not respond to intravenous fluids, follow up with glucagon 50-150µg/kg intravenously, then 1-5mg/hour, followed by catecholamines. Dialysis will not be useful as propranolol is highly protein bound.

Precaution

Beta-adrenoceptor blocking drugs should be avoided in over heart failure. Betablock modifies the tachycardia of hypoglycaemic therapy in diabetic patients. Betablock may prolong the hypoglycaemic response to insulin.

Interaction

Beta-adrenoceptor blocking drugs interact with clonidine.If beta-adrenoceptor blocking drugs and clonidine are given concurrently, clonidine should be discontinued until several days after withdrawal of beta-adrenoceptor blocking drug. Care should be taken in prescribing a beta-adrenoceptor blocking drugs with class 1 antidysrhythmic agents (disopyramide).Beta-adrenoceptor blocking drugs should be used with caution in combination with verapamil in patients with impaired ventricular function.

Food Interaction

• Avoid alcohol. Alcohol increases propranolol plasma concentrations.
• Avoid natural licorice. Natural licorice inhibits the metabolism of propranolol, increasing drug exposure.
• Take with food.

[Moderate] ADJUST DOSING INTERVAL: The bioavailability of propranolol may be enhanced by food.

MANAGEMENT: Patients may be instructed to take propranolol at the same time each day, preferably with or immediately following meals.

Betablock Alcohol interaction

[Moderate]

Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation.

Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

Caution and close monitoring for development of hypotension is advised during coadministration of these agents.

Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs.

Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

Betablock Cholesterol interaction

[Moderate] Beta-adrenergic receptor blocking agents (aka beta-blockers) may alter serum lipid profiles.

Increases in serum VLDL and LDL cholesterol and triglycerides, as well as decreases in HDL cholesterol, have been reported with some beta-blockers.

Patients with preexisting hyperlipidemia may require closer monitoring during beta-blocker therapy, and adjustments made accordingly in their lipid-lowering regimen.

Betablock multivitamins interaction

[Moderate] ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers.

The exact mechanism of interaction is unknown.

In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively.

The elimination half-life increased by 44%.

Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone.

However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments.

The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours.

Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.

Betablock Drug Interaction

Moderate: aripiprazole, diphenhydramine, duloxetine, clonazepam, fluoxetine, quetiapine, alprazolam, sertralineMinor: levothyroxine, ascorbic acidUnknown: amphetamine / dextroamphetamine, omega-3 polyunsaturated fatty acids, lamotrigine, escitalopram, pregabalin, topiramate, cyanocobalamin, cholecalciferol, lisdexamfetamine, cetirizine

Betablock Disease Interaction

Major: bradyarrhythmia/AV block, cardiogenic shock/hypotension, CHF, diabetes, hypersensitivity, ischemic heart disease, PVD, asthma/COPD, liver diseaseModerate: cerebrovascular insufficiency, glaucoma, hyperlipidemia, hyperthyroidism, hyperthyroidism PKs, myasthenia gravis, pheochromocytoma, psoriasis, tachycardia, Prinzmetal's variant angina, renal impairment

Volume of Distribution

The volume of distribution of propranolol is approximately 4L/kg or 320L.

Elimination Route

Patients taking doses of 40mg, 80mg, 160mg, and 320mg daily experienced C_max values of 18±15ng/mL, 52±51ng/mL, 121±98ng/mL, and 245±110ng/mL respectively. Betablock has a T_max of approximately 2 hours, though this can range from 1 to 4 hours in fasting patients. Taking propranolol with food does not increase T_max but does increase bioavailability.

Half Life

The elimination half life of propranolol is approximately 8 hours. The plasma half life of propranolol is 3 to 6 hours.

Clearance

The clearance of propranolol is 2.7±0.03L/h/kg in infants 90 days. Betablock clearance increases linearly with hepatic blood flow. Propanolol has a clearance in hypertensive adults of 810mL/min.

Elimination Route

91% of an oral dose of propranolol is recovered as 12 metabolites in the urine.

Pregnancy & Breastfeeding use

There are no adequate and controlled studies in pregnant women. Betablock is excreted in human milk. Caution should be exercised when propranolol is administered to a nursing mother.

Contraindication

Betablock Hydrochloride is contraindicated in patients with known Hypersensitivity to any component of the formulation. If there is a history of bronchial asthma of bronchospasm.

Acute Overdose

The symptoms of over dosage may include bradycardia, hypotension, acute cardiac insufficiency and bronchospasm. Treatment of over dosage include close supervision, treatment in an intensive care ward, he use of gastric lavage, activated charcoal and a laxative to prevent absorption of any drug still present in the gastrointestinal tract, the use of plasma or plasma substitutes to treat hypotension and shock.

Storage Condition

Store in a cool dry place. Protect from light.

Innovators Monograph

You find simplified version here Betablock