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Health Blog :: Getting To Know Your Medicines - Phosphate Binders

October 03, 2022


Phosphate is a mineral in the body used to form bone and teeth. Phosphate is also used in your body cells in substances used for energy, cell membranes, and your DNA. The body gets phosphate from foods and gets rid of its excess in the urine and stool. People with kidney failure tend to have higher phosphate levels as they cannot get rid of it normally. This can lead to bone problems, cell malfunction and itching. Long-term, high levels of phosphorus can deposit in blood vessels and cause problems for the heart. Higher phosphorus levels increase risk of complications and death.

Treatment of high phosphorus includes eating a diet low in phosphate and taking medicines called phosphate binders. Dialysis treatment also helps to remove some phosphate from the body.

There are 3 main types of phosphate binders on the market – aluminum-containing binders (used very rarely these days due to aluminum toxicity), calcium containing binders which are cheaper medicines and have been around for many years, and the non-calcium-based binders (sevelamer, lanthanum, sucroferric oxyhydroxide, and ferric citrate) which are considerably more expensive. The doctor and the dietitian will help you decide which one is best for you to take depending on your insurance coverage, blood results and how easy you find it to take your tablets without side effects.

  • Calcium Carbonate is a phosphate binder which contain calcium. These binders have been an appealing first choice for a long time, because they also address the low calcium that is often seen with high phosphate in patients with chronic kidney disease. However, higher calcium levels and accelerated calcification of the blood vessels are the main concerns with calcium-containing phosphate binders, particularly when they are combined with vitamin D treatment. Side effects include a chalky taste in the mouth, or sometimes the higher level of calcium in the blood. Calcium Carbonate should be swallowed whole or chewed, 10-15 minutes before meals.
  • Phoslo (calcium acetate) are phosphate binders which contain calcium as well like above. They should be swallowed whole and taken 10-15 mins before meals.
  • Renagel/Renvela (sevelamer) are phosphate binders which do not contain calcium or aluminum but another mineral called sevelamer. It is the most prescribed non-calcium-based phosphate binder. It also helps lower bad cholesterol and decrease calcification of the vessels. The disadvantages are its high price and high pill burden. It may also reduce the fat-soluble vitamins and should not be taken together. Its main adverse effect is gastrointestinal intolerance The tablets should be swallowed whole with meals. Renvela is also available as a powder form to make into a solution for easier intake.
  • Fosrenol (lanthanum) is a phosphate binder which contains a mineral lanthanum. It should be chewed and taken immediately after meals. It is roughly twice as strong of a binder as calcium and sevelamer. Lanthanum powder is available and more effective than chewable tablets. Side effects include nausea if taken before food. It comes in three different doses, so the dose is always one tablet per meal. This drug is expensive.
  • Velphoro (sucroferric oxyhydroxide) is a phosphate binder which contains iron as a binder. Common side effects include diarrhea and change in stool color. It is also one pill per meal. It should be chewed and not swallowed whole. Tablets can be crushed and broken into piece before taking.
  • Auryxia (ferric citrate) is an iron containing phosphate binder as well. Common side effects are gastrointestinal related, like constipation, diarrhea, nausea. 5% of patients can develop higher potassium levels. It can darken the stool like Velphoro. It has a higher pill burden and needs several tablets per meal to control the phosphorus. Tablets should be swallowed whole and not crushed.

Reducing the amount of phosphate in your body can only be done in combination with controlling your diet for processed foods, fast foods, nuts and cola drinks, as these tablets will not work alone.


The best time to take the binder tablets is about ten minutes before meals. Except for Renagel, Renvela, and Phoslo, Auryxia that should be swallowed whole, the others could be chewed or dissolved in the mouth before swallowing.

Phosphate binders only work if they are taken with foods containing phosphate like meat, fish, eggs, cheese, dairy, nuts and legumes, and are NOT necessary with meals or snacks which do not include protein foods, such as toast, jam or salad sandwiches, biscuits or fruit. This may mean that you take more binders with a main meal or include one with a snack. Your doctor will prescribe the number of binders you need each day.


The most common side effects with the phosphate binders are constipation or diarrhea, nausea and a metal or chalky taste in your mouth.

If you do not like the taste, most phosphate binders can be swallowed whole, 15 minutes before meals. Fosrenol should always be taken after meals. Velphoro and Auryxia can make your stools appear black.


Keep the tablets in their original packet in a cool, dry place out of the reach of children. Do not throw out any expired or unwanted medicine by flushing them down the toilet or throwing them away. Take them to your local pharmacy which will dispose of them for you. For any further information on binders, ask your doctor, pharmacist, dietitian or nurse.

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