Summary of Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem contradictory. For clarification, read the full article for details about the summarized interactions.
Avoid: Reduced drug absorption/bioavailability—Avoid these supplements when taking this medication since the supplement may decrease the absorption and/or activity of the medication in the body. |
Food |
Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results. |
High-potassium foods*
Pleurisy root*
Potassium supplements*
|
| Depletion or interference |
None known |
| Side effect reduction/prevention |
None known |
| Supportive interaction |
None known |
An asterisk (*) next to an item in the summary
indicates that the interaction is supported only by weak, fragmentary,
and/or contradictory scientific evidence.
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 (for example, bananas), unless directed to do so by their doctor.
Interactions with Herbs
Pleurisy root
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
Interaction with Foods and Other Compounds
Food
Taking acebutolol with food slows the rate of absorption and reduces the maximum blood levels of the drug, though overall absorption is not affected.4 However, the blood level of an active breakdown product of acebutolol is reduced.5 Though the activity of acebutolol is affected by food, people taking the drug on a daily basis are not likely to experience a reduction in the effectiveness of the drug if it is taken with a meal.
Grapefruit juice
In a study of healthy volunteers, drinking 200 ml of grapefruit juice at the same time as taking acebutolol caused a small decrease in blood levels of the drug by interfering with its absorption.6 Although the researchers who performed this study felt that the effect was unlikely to be clinically significant in most cases, it would seem prudent not to take grapefruit juice at the same time as acebutolol.
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. Sifton DW, ed. Physicians Desk Reference. Montvale. NJ: Medical Economics Company, Inc., 2000, 3317–9.
5. Zaman R, Wilkins MR, Kendall MJ, Jack DB. The effect of food and alcohol on the pharmacokinetics of acebutolol and its metabolite, diacetolol. Biopharm Drug Dispos 1984;5:91–5.
6. Lilja JJ, Raaska K, Neuvonen PJ. Effects of grapefruit juice on the pharmacokinetics of acebutolol. Br J Clin Pharmacol 2005;60:659–63.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.
2007-09-01