Prescription Drug Name:

Metoprolol Tartrate Tablets, USP, Rx only






id: b4764915-3c44-48dd-bc6e-26c51e1c39d7
displayName: Description Section
FDA Article Code: 34089-3

Metoprolol tartrate USP is a selective beta1-adrenoreceptor blocking agent, available as 25, 50 and 100 mg tablets for oral administration. Metoprolol tartrate is (±)-1-(isopropylamino)-3-[p-(2-methoxyethyl)phenoxy]-2-propanol (2:1) dextro-tartrate salt. Its structural formula is:

Metoprolol tartrate USP is a white, practically odorless, crystalline powder with a molecular weight of 684.82. It is very soluble in water; freely soluble in methylene chloride, in chloroform, and in alcohol; slightly soluble in acetone; and insoluble in ether.

Each tablet for oral administration contains 25 mg, 50 mg or 100 mg of metoprolol tartrate.

The tablets contain the following inactive ingredients: microcrystalline cellulose, corn starch, sodium starch glycollate, colloidal silicon dioxide, sodium lauryl sulfate, talc, magnesium stearate, hypromellose, titanium dioxide, polyethylene glycol and polysorbate 80. In addition, 50 mg tablet contains D&C Red #30 Aluminium Lake and 100 mg tablet contains FD&C Blue #2 Aluminium Lake as coloring agents.


id: 1919a9c9-1799-4586-a175-f3c3433fda23
displayName: Clinical Pharmacology Section
FDA Article Code: 34090-1

Mechanism of Action

Metoprolol tartrate is a beta1-selective (cardioselective) adrenergic receptor blocker. This preferential effect is not absolute, however, and at higher plasma concentrations, metoprolol also inhibits beta2-adrenoreceptors, chiefly located in the bronchial and vascular musculature.

Clinical pharmacology studies have demonstrated the beta-blocking activity of metoprolol, 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.


The mechanism of the antihypertensive effects of beta-blocking agents has not been fully 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.

Angina Pectoris

By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction, and in blood pressure, metoprolol 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.

Myocardial Infarction

The precise mechanism of action of metoprolol in patients with suspected or definite myocardial infarction is not known.


Relative beta1 selectivity is demonstrated by the following: (1) In healthy subjects, metoprolol 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 reduces FEV1 and FVC significantly less than a nonselective beta-blocker, propranolol, at equivalent beta1-receptor blocking doses.

Metoprolol has no intrinsic sympathomimetic activity, and membrane-stabilizing activity is detectable only at doses much greater than required for beta-blockade. Animal and human experiments indicate that metoprolol slows the sinus rate and decreases AV nodal conduction.

Significant beta-blocking effect (as measured by reduction of exercise heart rate) occurs within 1 hour after oral administration, and its duration is dose-related. For example, a 50% reduction of the maximum effect after single oral doses of 20, 50, and 100 mg occurred at 3.3, 5, and 6.4 hours, respectively, in normal subjects. After repeated oral dosages of 100 mg twice daily, a significant reduction in exercise systolic blood pressure was evident at 12 hours. When the drug was infused over a 10-minute period, in normal volunteers, maximum beta-blockade was achieved at approximately 20 minutes. Equivalent maximal beta-blocking effect is achieved with oral and intravenous doses in the ratio of approximately 2.5:1.

There is a linear relationship between the log of plasma levels and reduction of exercise heart rate. However, antihypertensive activity does not appear to be related to plasma levels. Because of variable plasma levels attained with a given dose and lack of a consistent relationship of antihypertensive activity to dose, selection of proper dosage requires individual titration.

In several studies of patients with acute myocardial infarction, intravenous followed by oral administration of metoprolol caused a reduction in heart rate, systolic blood pressure and cardiac output. Stroke volume, diastolic blood pressure and pulmonary artery end diastolic pressure remained unchanged.

In patients with angina pectoris, plasma concentration measured at 1 hour is linearly related to the oral dose within the range of 50 to 400 mg. Exercise heart rate and systolic blood pressure are reduced in relation to the logarithm of the oral dose of metoprolol. The increase in exercise capacity and the reduction in left ventricular ischemia are also significantly related to the logarithm of the oral dose.


id: d726f38e-34ae-48c1-b600-bc35613e2260
displayName: Precautions Section
FDA Article Code: 42232-9

Risk of Anaphylactic Reactions

While taking beta blockers, 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.


id: 9f6b3bac-57fa-4e3a-8067-a2c9fc557d27
displayName: Overdosage Section
FDA Article Code: 34088-5

Acute Toxicity

Several cases of overdosage have been reported, some leading to death.

Oral LD50’s (mg/kg): mice, 1158 to 2460; rats, 3090 to 4670.


id: 3a706ebd-5c7a-4115-8fae-5b4413147d1a
displayName: How Supplied Section
FDA Article Code: 34069-5

Product: 50090-2149 NDC: 50090-2149-4 90 TABLET, FILM COATED in a BOTTLE NDC: 50090-2149-5 180 TABLET, FILM COATED in a BOTTLE NDC: 50090-2149-0 30 TABLET, FILM COATED in a BOTTLE NDC: 50090-2149-1 60 TABLET, FILM COATED in a BOTTLE Product: 50090-2207 NDC: 50090-2207-0 180 TABLET, FILM COATED in a BOTTLE NDC: 50090-2207-3 30 TABLET, FILM COATED in a BOTTLE NDC: 50090-2207-1 60 TABLET, FILM COATED in a BOTTLE NDC: 50090-2207-2 90 TABLET, FILM COATED in a BOTTLE Product: 50090-2260 NDC: 50090-2260-4 180 TABLET, FILM COATED in a BOTTLE NDC: 50090-2260-0 30 TABLET, FILM COATED in a BOTTLE NDC: 50090-2260-1 60 TABLET, FILM COATED in a BOTTLE NDC: 50090-2260-3 90 TABLET, FILM COATED in a BOTTLE

Metoprolol Tartrate

id: 55ce9fe9-67db-4ae0-ac81-1bc69c902dea
FDA Article Code: 51945-4

Metoprolol Tartrate

id: 1ee8d0e6-4041-4374-ba00-207293ba6c99
FDA Article Code: 51945-4

Metoprolol Tartrate

id: 239ff440-7d0f-49a5-809f-b9974d79df80
FDA Article Code: 51945-4