Calcium Acetate: What It Is and How to Use It

Calcium acetate is a medicine most often used to lower phosphate levels in people with kidney failure who are on dialysis. It works by binding phosphate from food in your gut so less is absorbed into the blood. That simple action helps prevent high phosphate, which can cause bone pain, itching, and heart problems over time.

Doctors prescribe calcium acetate when diet and dialysis alone don't keep phosphate in the target range. Clinical studies and routine practice show it is effective at reducing serum phosphate when taken with meals. It is not a substitute for dialysis or for following a renal diet—think of it as one part of a plan your care team sets up.

How to take calcium acetate

Take calcium acetate exactly as your doctor tells you, usually with or right after meals. The tablets are often chewed or swallowed; follow the product instructions. Typical starting doses are one or two 667 mg tablets with each meal, but your doctor will adjust the dose based on regular blood tests of phosphate and calcium. Never take extra doses on your own to try to speed results.

Don’t take calcium acetate at the same time as other medicines that need stomach absorption, like levothyroxine, certain antibiotics (quinolones and tetracyclines), or bisphosphonates. Space those drugs at least two hours apart if possible. Also avoid taking extra calcium supplements unless your care team says it’s okay.

Side effects, warnings, and interactions

Common side effects include constipation, stomach upset, and stomach pain. A key risk is hypercalcemia—too much calcium in the blood—which can cause nausea, weakness, confusion, and irregular heartbeat. Your care team monitors blood calcium and phosphate regularly so doses can be adjusted promptly.

Tell your provider about all prescription drugs, over-the-counter meds, and supplements you take. Calcium acetate can reduce the absorption of several medicines, so timing matters. If you have a history of severe high calcium, kidney stones, or parathyroid problems, your doctor may choose a different phosphate binder.

Practical tips and when to call your doctor

Store calcium acetate at room temperature and keep it out of reach of children. If you miss a dose, take it with your next meal—don’t double up. Watch for symptoms like extreme weakness, severe constipation, confusion, or fast heartbeat and get medical help if they occur. Keep regular lab appointments to track phosphate, calcium, and parathyroid hormone levels.

Talk openly with your dialysis team about side effects, pill burden, and cost. There are alternatives to calcium-based binders if problems arise. Your care team can help you pick the safest, most practical option to keep phosphate under control and protect your bones and heart.

If cost or side effects are an issue, ask about non-calcium binders like sevelamer or lanthanum carbonate. They work differently and may avoid extra calcium. Insurance coverage varies, so check copays and patient assistance programs. Sticking to the plan and reporting problems early gives the best results. Ask questions often.