Calcium supplements are used for people with kidney disease to lower high phosphate levels or to prevent low calcium.
Some people with chronic kidney disease (CKD) need to take calcium supplements. Results of your blood tests will guide your healthcare provider’s decisions about whether or not you need extra calcium. Don't take calcium supplements without checking with your healthcare provider. Read more about chronic kidney disease (CKD).
When are calcium supplements used in people with CKD?
For high phosphate levels
Calcium supplements may be used as a ‘phosphate binder’ when phosphate levels in the blood are high. Kidney disease can cause phosphate levels to rise. High phosphate levels can cause weakened bones and may also increase the risk of a heart attack and stroke.
The aim of treatment is to achieve a normal phosphate level for your age, and avoid high calcium levels (hypercalcaemia). When treating high phosphate levels (hyperphosphataemia) with calcium supplements, the total daily calcium intake from food and medication should not be more than two times the recommended daily nutrient intake for calcium.
To prevent low calcium
Calcium supplements are also used to prevent low calcium caused by kidney disease or for management of hungry bone syndrome after a parathyriodectomy (operation to remove the parathyroid glands).
Ongoing low levels of calcium can cause seizures, irregular heartbeat, severe muscle spasms and cramping, and can affect brain function.
Calcium supplements are available as tablets, dissolvable tablets or capsules, such as Calcium Carbonate, Calci-Tab. It is also available as an injection, which is used in hospital.
- The dose of calcium will be different for different people, depending on the levels of calcium and phosphate in your blood.
- The dose of your calcium supplement may change over time depending on the results of your blood tests and the effects of your diet.
How to take calcium supplements
- Take calcium tablets and capsules as directed with food and a glass of water.
- Dissolve the effervescent tablets in a glass of water before swallowing.
- If you miss a dose, take the missed dose as soon as possible. If it is close to the time for your next dose, skip the missed dose and carry on as usual. Don't take 2 doses at the same time.
- Calcium supplements can interfere with the way your body absorbs other medicines so you may need to take these at a different time to your calcium – ask your pharmacist for advice.
- Calcium supplements can cause constipation. Talk to your healthcare provider if this is causing problems for you.
Things to consider while you are taking calcium supplements
Be aware of calcium from the foods you eat
Calcium is found naturally in many foods, including dairy products. Unfortunately, these same foods are often very high in phosphate and are not good choices for people with kidney disease who require a low phosphate diet. If your calcium is low, your dietitian will advise you on calcium containing foods to include in your diet. If your doctor prescribes a supplement, ask your dietitian to discuss the best time to take it.
Be aware of the signs of low calcium (hypocalcaemia)
The symptoms of hypocalcaemia depend on if it’s mild or severe.
- People who have mild hypocalcaemia often have no symptoms.
- Symptoms of mild hypocalcaemia can include:
- muscle cramps, especially in your back and legs
- dry, scaly skin
- brittle nails
- more coarse hair than is normal for you.
- If left untreated, over time hypocalcaemia can affect the nervous system producing symptoms such as confusion, memory problems, irritability or restlessness, depression and hallucinations.
- Severe hypocalcaemia (very low levels of calcium in your blood) can cause the following symptoms:
- tingling in your lips, tongue, fingers and/or feet.
- muscle aches
- muscle spasms in your throat that make it difficult to breathe
- stiffening and spasms of your muscles
- abnormal heart rhythms (arrhythmia)
- congestive heart failure.
Calcium and phosphate balance with kidney disease Kidney Health, Australia
Chronic kidney disease and nutrition Kidney Health NZ