Propranolol and atenlol are two drugs from the beta blocker class of drugs. They block the beta receptors, which are found predominately on the heart (beta1 receptors), lungs (beta2 receptors) and vasculature (beta2 receptors). Propranolol blocks both beta1 and beta2 receptors. Atenolol blocks only beta1 receptors. Although they have been prescribed for many years for the treatment of hypertension, recent evidence suggests that they are not as effective as other blood pressure-lowering medications and should probably not be used as first-line therapy in hypertension.
Side effects include (but are not limited to): dizzyness/lightheadedness, hypotension, insomnia, fatigue, bradycardia, etc. These are usually mild though. Also, termination of therapy must be gradual.
2007-05-24 01:44:10
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answer #3
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answered by jcwis22 1
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Propranolol is a non-selective beta-adrenergic receptor blocking agent. It has no other autonomic nervous system activity.
SIDE EFFECTS:
Warnings
Cardiac Failure:
Sympathetic stimulation is a vital component supporting circulatory function in congestive heart failure; therefore, inhibition by means of beta-adrenergic blockade is a potential hazard as it may further depress myocardial contractility and precipitate cardiac failure. Propranolol acts selectively without abolishing the inotropic action of digitalis on the heart muscle (i.e., that of supporting the strength of myocardial contractions). In patients already receiving digitalis, the positive inotropic action of digitalis may be reduced by propranolol's negative inotropic effect. The effects of propranolol and digitalis are additive in depressing AV conduction.
Patients without a History of Cardiac Failure:
Continued depression of the myocardium over a period of time can, in some patients, lead to cardiac failure. In rare instances, this has been observed during propranolol therapy. Therefore, at the first sign or symptom of impending cardiac failure, patients should be fully digitalized and/or given a diuretic, and the response observed closely: A) if cardiac failure continues, despite adequate digitalization and diuretic therapy, propranolol should be withdrawn immediately; b) if tachyarrhythmia is being controlled, patients should be maintained on combined therapy and closely followed until threat of cardiac failure is over.
Abrupt Cessation of Therapy in Angina Pectoris:
Severe exacerbation of angina and the occurrence of myocardial infarction have been reported in some patients with angina pectoris following abrupt discontinuation of propranolol therapy. Therefore, when discontinuation of propranolol is planned in patients with angina pectoris, the dosage should be gradually reduced over a period of about 2 weeks and the patient should be carefully observed. For patients receiving Inderal tablets, the same frequency of administration should be maintained. For patients on Inderal-LA, discontinuation can be achieved by substituting Inderal-LA 60, 80, 120 and 160 mg by the equivalent dosage of conventional Inderal tablets spread throughout the day, and then gradually reducing the dose. In situations of greater urgency, propranolol dosage should be reduced stepwise, in 4 days under close observation. If angina markedly worsens, or acute coronary insufficiency develops, it is recommended that treatment with propranolol be reinstituted promptly, at least temporarily. In addition, patients with angina pectoris should be warned against abrupt discontinuation of propranolol.
Oculomucocutaneous Syndrome:
Various skin rashes and conjunctival xerosis have been reported in patients treated with beta-blockers including propranolol. A severe oculomucocutaneous syndrome, whose signs include conjunctivitis sicca and psoriasiform rashes, otitis, and sclerosing serositis has occurred with the long-term use of one beta-adrenergic blocking agent. This syndrome has not been observed with propranolol, however, physicians should be alert to the possibility of such reactions and discontinue treatment if they occur.
Patients with Thyrotoxicosis:
Possible deleterious effects from long-term use of propranolol have not yet been adequately appraised. Special consideration should be given to propranolol's potential for aggravating congestive heart failure. Propranolol may mask the clinical signs of developing or continuing hyperthyroidism or its complications, and give a false impression of improvement. Therefore, abrupt withdrawal of propranolol may be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm. This may be another instance where propranolol should be withdrawn slowly by reducing dosage. Propranolol does not distort thyroid function tests.
Patients with Wolff-Parkinson-White Syndrome:
Propranolol should be used with caution since several cases have been reported in which, after propranolol treatment, the tachycardia was replaced by a severe bradycardia requiring a demand pacemaker. In one patient, this occurred after an initial dose of 5 mg of propranolol.
Patients Undergoing Elective or Emergency Surgery:
The management of patients with angina, being treated with beta-blockers and undergoing elective or emergency surgery, is controversial because beta-adrenergic receptor blockade impairs the ability of the heart to respond to beta-adrenergically mediated reflex stimuli, but abrupt discontinuation of therapy with propranolol may be followed by severe complications (see Warnings). Some patients receiving beta-adrenergic blocking agents have been subject to protracted severe hypotension during anesthesia. Difficulty in restarting and maintaining the heartbeat has also been reported.
For these reasons, in patients with angina undergoing elective surgery, propranolol should be withdrawn gradually (see Warnings). According to available evidence, all clinical and physiologic effects of beta-blockade are no longer present 48 hours after cessation of medication.
In emergency surgery, since propranolol is a competitive inhibitor of beta-adrenergic receptor agonists, its effects may be reversed, if necessary, by sufficient doses of such agonists as isoproterenol or dobutamine.
Anesthesia with agents which maintain cardiac contractility by virtue of their effect on catecholamine release (e.g. ether) should be avoided in patients on propranolol therapy.
Patients prone to nonallergic Bronchospasm (e.g., chronic bronchitis, emphysema, bronchiectasis):
Propranolol should be administered with caution since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta-adrenergic receptors.
Patients with Diabetes and in those subject to Hypoglycemia:
Because of its beta-adrenergic blocking activity, propranolol may block premonitory signs and symptoms (pulse rate and pressure changes) of acute hypoglycemia. This is especially important to keep in mind in patients with labile diabetes. Hypoglycemic attacks may be accompanied by a precipitous elevation of blood pressure.
Pregnancy:
The safe use of propranolol in pregnancy has not been established. Use of any drug in pregnancy or in women of childbearing potential requires that the possible risk to mother and/or fetus be weighed against the expected therapeutic benefit. Perinatal complications, such as small placenta and intrauterine growth retardation, have been reported in a few cases where the mother took propranolol during pregnancy. Some infants born to mothers treated with propranolol were reported to have hypoglycemia and/or bradycardia.
Children:
While experience with propranolol in children under 12 is limited, the indications for which this drug is recommended occur infrequently in childhood. Although reports fail to indicate that children respond in a manner different from the adult, physicians are advised to undertake treatment with caution.
ATENOLOL:
USES: This medication is a beta-blocker used to treat chest pain (angina) and high blood pressure. It is also used after an acute heart attack to improve survival. High blood pressure reduction helps prevent strokes, heart attacks and kidney problems. This drug works by blocking the action of certain natural chemicals in your body such as epinephrine on the heart and blood vessels. This results in a lowering of the heart rate, blood pressure, and strain on the heart.
OTHER USES: This medication may also be used for irregular heartbeats, heart failure, migraine headache prevention, tremors and other conditions as determined by your doctor.
If you have chest pain (angina) or have heart disease (e.g., coronary artery disease, ischemic heart disease, high blood pressure), do not stop using this drug without first consulting your doctor. Your condition may become worse when the drug is suddenly stopped. If your doctor decides you should no longer use this drug, you must gradually decrease your dose according to your doctor's instructions.
When gradually stopping this medication, it is recommended that you temporarily limit physical activity to decrease the work on the heart. Seek immediate medical attention if you develop: worsening chest pain, tightness or pressure in the chest, chest pain spreading to the jaw/neck/arm, sweating, trouble breathing or fast/irregular heartbeat.
2007-05-24 05:28:53
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answer #10
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answered by Dr.Qutub 7
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