Calcium Acetate: What it does and how to use it

Calcium acetate is a prescription medicine most often used to lower phosphate levels in people with chronic kidney disease who are on dialysis. High phosphate can cause itchy skin, bone problems, and raise the risk of calcification in blood vessels. Calcium acetate binds phosphate from food inside your gut so it leaves your body instead of building up in the blood.

How calcium acetate works and when it's used

You take calcium acetate with meals because it needs food phosphate to work. When calcium meets phosphate in your stomach, they form a compound that your body can’t absorb. That compound is passed out in stool. Doctors usually prescribe it when diet and other measures haven’t kept phosphate low enough. It’s not a replacement for dialysis or for a phosphate-controlled diet—think of it as one tool in the toolkit.

Practical tips, dosing, and safety

Follow your prescription exactly. Doses vary by patient, diet, and lab results, so doctors tweak it based on your blood phosphate and calcium tests. A common approach is to take tablets or chewables with every meal, but don’t change the number of tablets without checking labs or talking to your care team.

Separate calcium acetate from certain medicines. Calcium can reduce absorption of antibiotics like tetracyclines and fluoroquinolones, thyroid medicine (levothyroxine), and some osteoporosis drugs. Give those other meds a gap of a few hours if your doctor recommends it.

Watch for signs of too much calcium: nausea, constipation, muscle weakness, or confusion. Your provider will monitor blood calcium and phosphorus regularly. If calcium gets too high, they may cut the dose or switch you to a different phosphate binder that doesn’t contain calcium.

Don’t combine calcium acetate with extra calcium supplements or a high-calcium diet without advice. People with certain conditions—like high blood calcium (hypercalcemia), severe hyperparathyroidism, or specific heart and vascular issues—may need a different treatment plan.

If you miss a dose, take it with your next meal unless it’s almost time for the next scheduled dose. Don’t double up. Store tablets at room temperature and keep them away from children.

Common side effects include mild stomach upset, gas, or constipation. Serious problems are less common but do happen—if you have severe abdominal pain, persistent vomiting, sudden muscle weakness, or signs of an allergic reaction, seek medical help right away.

Alternatives exist. Non-calcium phosphate binders (like sevelamer or lanthanum) avoid extra calcium and may be better for some people. Your doctor will weigh pros and cons based on your labs, calcium levels, heart risk, and budget or insurance coverage.

Questions are normal. Ask your nephrologist or pharmacist about timing with meals, other meds, and what tests will track progress. Small changes in diet or timing often make a big difference in how well this treatment works.