Calcium Acetate

Also indexed as: Phosex®, PhosLo®

Calcium acetate is used to prevent high phosphorus blood levels in people with kidney failure.

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.

Beneficial May be Beneficial: Depletion or interference—The medication may deplete or interfere with the absorption or function of the nutrient. Taking these nutrients may help replenish them.

Zinc
Beneficial May be Beneficial: Supportive interaction—Taking these supplements may support or otherwise help your medication work better.

Food
Avoid Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.

Antacids (calcium-containing)

Calcium
Side effect reduction/prevention

None known
Reduced drug absorption/bioavailability

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

Calcium
People with kidney failure may develop high blood levels of calcium while taking calcium acetate. Since calcium acetate is a source of supplemental calcium, people taking the drug should avoid taking additional calcium supplements.1 People experiencing adverse effects of high blood calcium—such as loss of appetite, mental depression, poor memory, and muscle weakness—should notify their healthcare practitioner.

Zinc
People with renal failure or on hemodialysis often have low blood levels of zinc, which may produce symptoms such as abnormal taste or smell, reduced sexual functions, and poor immunity. One controlled study showed that taking zinc at the same time as calcium acetate reduces absorption of zinc.2 Therefore, people should avoid taking calcium acetate and zinc supplements together. Another controlled study revealed that neither short-term nor long-term treatment with calcium acetate results in reduced blood zinc levels.3 Thus, while calcium acetate reduces the amount of zinc absorbed from supplements, long-term treatment with the drug does not appear to affect overall zinc status. However, people with renal failure who experience symptoms of zinc deficiency might benefit from supplementing with zinc, regardless of whether or not they take calcium acetate.

Interaction with Foods and Other Compounds

Food
Taking calcium acetate with food reduces absorption of phosphorus, which is the goal of therapy.4 Therefore, calcium acetate should be taken with a meal.

Antacids (Calcium-containing)
Calcium-containing antacids, when taken together with calcium acetate, may result in abnormally high blood levels of calcium.5 Consequently, people taking calcium acetate should avoid taking calcium-containing antacids.

References

1. Sifton DW, et. Physicians’ Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 811–2.

2. Hwang SH, Lai YH, Chen HC, Tsai JH. Comparisons of the effects of calcium carbonate and calcium acetate on zinc tolerance test in hemodialysis patients. Am J Kidney Dis 1992;19:57–60

3. Hwang SJ, Chang JM, Lee SC, et al. Short- and long-term uses of calcium acetate do not change hair and serum zinc concentrations in hemodialysis patients. Scand J Clin Lab Invest 1999;59:83–7.

4. Schiller LR, Santa Ana CA, Sheikh MS, et al. Effect of the time of administration of calcium acetate on phosphorus binding. N Engl J Med 1989;320:1110–3.

5. Sifton DW, et. Physicians’ Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 811–2.