Google
 
Web www.vitaminlore.com
www.eniva.com
. 

Metoprolol

Also indexed as: Lopressor®, Toprol® XL

Combination drugs: Co-Betaloc SA®, Co-Betaloc®, Lopressor® HCT

Metoprolol is a beta-blocker drug used to reduce the symptoms of angina pectoris (chest pain), lower blood pressure in people with hypertension, and treat people after heart attacks. Metoprolol is available alone and in a combination product used to lower blood pressure.

Interactions with Dietary Supplements

Potassium
Some beta-adrenergic blockers (called “nonselective” beta blockers) decrease the uptake of potassium from the blood into the cells,1 leading to excess potassium in the blood, a potentially dangerous condition known as hyperkalemia.2 People taking beta-blockers should therefore avoid taking potassium supplements, or eating large quantities of fruit (e.g., bananas), unless directed to do so by their doctor.

Interactions with Herbs

Pleurisy root (Asclepius tuberosa)
As pleurisy root and other plants in the Aesclepius genus contain cardiac glycosides, it is best to avoid use of pleurisy root with heart medications such as beta-blockers.3

Interactions with Foods and Other Compounds

Food
Food increases the absorption of metoprolol.4 Metoprolol should be taken at the same time every day5 always with or always without food.

Alcohol
Metoprolol may cause drowsiness, dizziness, lightheadedness, or blurred vision.6 Alcohol may intensify these effects and increase the risk of accidental injury. To prevent problems, people taking metoprolol should avoid alcohol.

Summary of Interactions for Metoprolol

Depletion or interference High-potassium foods*
Pleurisy root*
Potassium supplements*
Adverse interaction Alcohol
High-potassium foods*
Pleurisy root*
Potassium supplements*
Side effect reduction/prevention None known
Supportive interaction None known
Reduced drug absorption/bioavailability None known

For the convenience of the reader, the information in the summary is categorized as follows: “Depletion or interference” indicates the drug may deplete or interfere with the absorption or function of the supplement or herb. “Adverse interaction” indicates that the supplement or herb used together with the drug may result in undesirable effects. “Side effect reduction/prevention” indicates the supplement or herb may reduce the likelihood and/or severity of a potential side effect caused by the drug. “Supportive interaction” indicates the supplement or herb may support or aid the function of the drug. “Reduced drug absorption/bioavailability” indicates that the supplement or herb may decrease the absorption and/or activity of the drug in the body. An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

References:

1. Rosa RM, Silva P, Young JB, et al. Adrenergic modulation of extrarenal potassium disposal. N Engl J Med 1980;302:431–4.

2. Lundborg P. The effect of adrenergic blockade on potassium concentrations in different conditions. Acta Med Scand Suppl 1983;672:121–6 [review].

3. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health-Care Professionals. London: Pharmaceutical Press, 1996, 213–4.

4. Melander A, Danielson K, Schersten B, Wahlin E. Enhancement of the bioavailability of propranolol and metoprolol by food. Clin Pharmacol Ther 1977;22:108–12.

5. Threlkeld DS, ed. Diuretics and Cardiovasculars, Beta-Adrenergic Blocking Agents. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Oct 1992, 158p–8q.

6. Threlkeld DS, ed. Diuretics and Cardiovasculars, Beta-Adrenergic Blocking Agents. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Feb 1993, 158p–8q.