Lopressor
Buy LopressorLopressor Information
Generic Name: Metoprolol Tartrate
Brand Names: Metoprolol, Lopressor
Lopressor (metoprolol tartrate) is a beta blocker used to treat high blood pressure, angina (chest pain), and decreases the risk of having a repeat heart attack.
Lopressor (metoprolol tartrate) is indicated for the treatment of the following conditions:
Hypertension
Lopressor (metoprolol tartrate) tablets are indicated for the treatment of hypertension. They may be used alone or in combination with other antihypertensive agents.
Angina Pectoris:
Lopressor (metoprolol tartrate) is indicated in the long-term treatment of angina pectoris.
Myocardial Infarction:
Lopressor (metoprolol tartrate) ampuls and tablets are indicated in the treatment of hemodynamically stable patients with definite or suspected acute myocardial infarction to reduce cardiovascular mortality. Treatment with intravenous metoprolol tartrate can be initiated as soon as the patient's clinical condition allows. Alternatively, treatment can begin within 3 to 10 days of the acute event.
Lopressor Ingredients and Composition
How Does Lopressor Work?
Lopressor (metoprolol tartrate) is a beta-adrenergic receptor blocking agent. In vitro and in vivo animal studies have shown that it has a preferential effect on beta1 adrenoreceptors, chiefly located in cardiac muscle. This preferential effect is not absolute, however, and at higher doses, metoprolol tartrate also inhibits beta2 adrenoreceptors, chiefly located in the bronchial and vascular musculature.
Clinical pharmacology studies have confirmed the beta-blocking activity of Lopressor (metoprolol tartrate) in man, as shown by (1) reduction in heart rate and cardiac output at rest and upon exercise, (2) reduction of systolic blood pressure upon exercise, (3) inhibition of isoproterenol-induced tachycardia, and (4) reduction of reflex orthostatic tachycardia.
Relative beta1 selectivity has been confirmed by the following: (1) In normal subjects, Lopressor (metoprolol tartrate) is unable to reverse the beta2-mediated vasodilating effects of epinephrine. This contrasts with the effect of nonselective (beta1 plus beta2) beta blockers, which completely reverse the vasodilating effects of epinephrine. (2) In asthmatic patients, metoprolol tartrate reduces FEV1 and FVC significantly less than a nonselective beta blocker, propranolol, at equivalent beta1-receptor blocking doses.
Lopressor (metoprolol tartrate) has no intrinsic sympathomimetic activity, and membrane-stabilizing activity is detectable only at doses much greater than required for beta blockade. Metoprolol tartrate crosses the blood-brain barrier and has been reported in the CSF in a concentration 78% of the simultaneous plasma concentration. Animal and human experiments indicate that metoprolol tartrate slows the sinus rate and decreases AV nodal conduction.
In controlled clinical studies, Lopressor (metoprolol tartrate) has been shown to be an effective antihypertensive agent when used alone or as concomitant therapy with thiazide-type diuretics, at dosages of 100-450 mg daily. In controlled, comparative, clinical studies, metoprolol tartrate has been shown to be as effective an antihypertensive agent as propranolol, methyldopa, and thiazide-type diuretics, and to be equally effective in supine and standing positions.
The mechanism of the antihypertensive effects of beta-blocking agents has not been elucidated. However, several possible mechanisms have been proposed: (1) competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic neuron sites, leading to decreased cardiac output; (2) a central effect leading to reduced sympathetic outflow to the periphery; and (3) suppression of renin activity.
By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction, and in blood pressure, Lopressor (metoprolol tartrate) reduces the oxygen requirements of the heart at any given level of effort, thus making it useful in the long-term management of angina pectoris. However, in patients with heart failure, beta-adrenergic blockade may increase oxygen requirements by increasing left ventricular fiber length and end-diastolic pressure.
Although beta-adrenergic receptor blockage is useful in the treatment of angina and hypertension, there are situations in which sympathetic stimulation is vital. In patients with severely damaged hearts, adequate ventricular function may depend on sympathetic drive. In the presence of AV block, beta blockade may prevent the necessary facilitating effect of sympathetic activity on conduction. Beta2-adrenergic blockade results in passive bronchial constriction by interfering with endogenous adrenergic blockade results in passive bronchial constriction by interfering with endogenous adrenergic bronchodilator activity in patients subject to bronchospasm and may also interfere with exogenous bronchodilators in such patients.
How To Take Lopressor and Lopressor Dosage and Administration
Hypertension
The dosage of Lopressor (metoprolol tartrate) should be individualized. Metoprolol tartrate should be taken with or immediately following meals.
The usual initial Lopressor dosage is 100 mg daily in single or divided doses, whether used alone or added to diuretic. The dosage may be increased at weekly (or longer) intervals until optimum blood pressure reduction is achieved. In general, the maximum effect of any given dosage level will be apparent after 1 week of therapy. The effective Lopressor dosage range is 100-450 mg per day. Dosages above 450 mg per day have not been studied. While once-daily dosing is effective and can maintain a reduction in blood pressure throughout the day, lower doses (especially 100 mg) may not maintain a full effect at the end of the 24-hour period, and larger or more frequent daily doses may be required. This can be evaluated by measuring blood pressure near the end of the dosing interval to determine whether satisfactory control is being maintained throughout the day. Beta1 selectivity diminishes as the dose of Lopressor (metoprolol tartrate) is increased.
Angina Pectoris
The dosage of Lopressor (metoprolol tartrate) should be individualized. Metoprolol tartrate should be taken with or immediately following meals.
The usual initial Lopressor dosage is 100 mg daily, given in two divided doses. The dosage may be gradually increased at weekly intervals until optimum clinical response has ben obtained or there is pronounced slowing of the heart rate. The effective Lopressor dosage range is 100-400 mg per day. Dosages above 400 mg per day have not been studied. If treatment is to be discontinued, the dosage should be reduced gradually over a period of 1 to 2 weeks.
Myocardial Infarction
Early Treatment: During the early phase of definite or suspected acute myocardial infarction, treatment with Lopressor (metoprolol tartrate) can be initiated as soon as possible after the patient's arrival in the hospital. Such treatment should be initiated in a coronary care or similar unit immediately after the patient's hemodynamic condition has stabilized.
Treatment in this early phase should begin with the intravenous administration of three bolus injections of 5 mg of metoprolol tartrate each; the injections should be given at approximately 2-minute intervals. During the intravenous administration of metoprolol tartrate, blood pressure, heart rate, and electrocardiogram should be carefully monitored.
In patients who tolerate the full intravenous dose (15 mg), metoprolol tartrate tablets, 50 mg every 6 hours, should be initiated 15 minutes after the last intravenous dose and continued for 48 hours. Thereafter, patients should receive a maintenance dosage of 100 mg twice daily
Patients who appear not to tolerate the full intravenous dose should be started on Lopressor (metoprolol tartrate) tablets either 25 mg or 50 mg every 6 hours (depending on the degree of intolerance) 15 minutes after the last intravenous dose or as soon as their clinical condition allows. In patients with severe intolerance, treatment with Lopressor (metoprolol tartrate) should be discontinued.
Late Treatment: Patients with contraindications to Lopressor treatment during the early phase of suspected or definite myocardial infarction, patients who appear not to tolerate the full early treatment, and patients in whom the physician wishes to delay therapy for any other reason should be started on Lopressor (metoprolol tartrate) tablets, 100 mg twice daily, as soon as their clinical condition allows. Therapy should be continued for at least 3 months. Although the efficacy of Lopressor (metoprolol tartrate) beyond 3 months has not been conclusively established, data from studies with other beta blockers suggest that treatment should be continued for 1 to 3 years.
If you suspect a Lopressor Overdose
Acute Toxicity
Several cases of Lopressor overdosage have been reported, some leading to death. Oral LD50's (mg/kg): mice, 1158-2460; rats, 3090-4670.
Signs and Symptoms
Potential signs and symptoms associated with Lopressor overdosage with metoprolol tartrate are bradycardia, hypotension, bronchospasm, and cardiac failure.
Treatment
There is no specific antidote.
In general, patients with acute or recent myocardial infarction may be more hemodynamically unstable than other patients and should be treated accordingly.
On the basis of the pharmacologic actions of Lopressor (metoprolol tartrate), the following general measures should be employed.
Elimination of Lopressor
Gastric lavage should be performed.
Bradycardia: Atropine should be administered. If there is no response to vagal blockade, isoproterenol should be administered cautiously.
Hypotension: A vasopressor should be administered (e.g., levarterenol or dopamine).
Bronchospasm: A beta2-stimulating agent and/or a theophylline derivative should be administered.
Cardiac Failure: A digitalis glycoside and diuretic should be administered. In shock resulting from inadequate cardiac contractility, administration of dobutamine, isoproterenol, or glucagon may be considered.
Lopressor Side Effects
Lopressor Warnings
Lopressor Precautions and Contraindications
Lopressor should be taken even if you feel fine because high blood pressure may not produce physical symptoms. Do not discontinue Lopressor suddenly without consulting with your physician. Inform your physician if you are pregnant or nursing. Lopressor should be taken at the same time each day and may be taken with or without food. Lopressor may cause dizziness, drowsiness, or blurred vision; use caution while driving or operating hazardous machinery. Do not take other medications which may contain alpha-adrenergic stimulants (nasal decongestants, over-the-counter cold preparations) without consulting your physician or pharmacist. Notify your physician if you experience difficulty breathing, pulse rate, or swelling of legs or ankles. Lopressor may alter blood sugar levels or cover up symptoms of very low blood sugar (hypoglycemia) in patients with diabetes.
Contraindications to Lopressor
Hypertension and Angina
Lopressor (metoprolol tartrate) is contraindicated in sinus bradycardia, heart block greater than first degree, cardiogenic shock, and overt cardiac failure.
Myocardial Infarction
Lopressor (metoprolol tartrate) is contraindicated in patients with a heart rate <45 beats/min; second-and-third-degree heart block; significant first-degree heart block (P-R interval <0.24 sec); systolic blood pressure <100 mmhg; or moderate-to-severe cardiac failure.
NURSING MOTHERS
Metoprolol tartrate, the active ingredient in Lopressor, is excreted in breast milk in very small quantity. An infant consuming 1 liter of breast milk daily would receive a dose of less than 1 mg of the drug. Caution should be exercised when metoprolol tartrate is administered to a nursing woman.
Lopressor Drug Interactions
Catecholamine-depleting drugs (e.g., reserpine) may have an additive effect when given with beta-blocking agents. Patients treated with Lopressor (metoprolol tartrate) plus a catecholamine depletor should, therefore, be closely observed for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension.
While taking beta-blockers such as Lopressor, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.
Lopressor Clinical Trials and Studies
Storing Lopressor
Store Lopressor between 15-30°C (59-86°F).
Protect from light and moisture.
