You can use these resources to answer your questions and prepare for your visit to the Massachusetts General Hospital Division of Gastrointestinal & Oncologic Surgery.

Below are responses to frequently asked questions about calcium supplementation in relation to endocrine surgery:

What is the effect of surgery on my calcium levels?

The parathyroid glands are responsible for controlling the body’s calcium levels. Following surgery, it is common for these glands to not function at normal levels. However, this can result in a decrease in blood calcium levels. This decrease in function is usually temporary—the parathyroid glands almost always make a full recovery.

What are the symptoms of low calcium?

If the calcium level in the blood stream decreases after surgery, you may experience symptoms such as

  • Numbness
  • Tingling
  • Cramps in the fingers, toes, legs or around the mouth
What are calcium supplements?

It is likely you will be instructed to take calcium after thyroid or parathyroid surgery. Each over-the-counter calcium supplement tablet is approximately 500-600 mg. There are several different types of calcium sold over the counter. Some of the more common brands you will see include Tums, Viactiv, Citracal and Caltrate.

The two main forms of calcium in supplements are carbonate and citrate. Calcium carbonate (e.g., Tums, Viactiv and Caltrate) is absorbed most efficiently when taken with food, whereas calcium citrate (e.g., Citracal) is absorbed equally well when taken with or without food.

In general, it is fine to take any form of calcium after thyroid or parathyroid surgery.

How much calcium should I take after surgery?

The exact dose of calcium that is right for you after surgery depends on several factors, including the type and extent of surgery. Some patients will require very little or no additional calcium supplements after surgery.

After a total thyroidectomy, most patients will temporarily require some extra calcium as the parathyroid glands recover. 

A good guideline is to start with 600-1200 mg (one to two over-the-counter supplements) twice a day. If you notice symptoms of numbness or tingling, you may need to take it more frequently (up to three or four times per day). If you have no symptoms, the dose can be decreased and the extra calcium even stopped altogether within a few days following surgery.

What about Vitamin D?

Vitamin D can be very helpful with calcium levels, as adequate vitamin D stores in the body help your body absorb calcium. If you were on vitamin D prior to surgery, this can be resumed post-operatively. Additional vitamin D may be included in your calcium supplement, and this is fine as well.

If you are not on vitamin D and would like to start after surgery, an over-the-counter supplement of 400-800 IU is the usual recommended dosage; however, if you are on other medications or have other health issues, you will want to discuss this with your doctor.

If your surgeon is concerned about your calcium levels, (s)he may prescribe a different form of vitamin D called Rocaltrol (Calcitriol). This should be taken as instructed. Note that this is not a replacement for calcium, and it should be taken in addition to the recommended calcium supplements to help with absorption.

Are there side effects to calcium supplements?

The most common side effects are constipation and an upset stomach. If you are taking high doses of calcium after surgery, be sure to include a stool softener or laxative as needed. Minimize narcotics, as these can also cause constipation. Finally, decrease your calcium supplements if you don't experience symptoms of low calcium as noted above.

Do I need a blood test after surgery to check my calcium levels?

No, not usually. Your body will signal to you that the calcium level is low with the symptoms noted above. If you do not have these symptoms, then most likely your calcium level is just fine. 

How do I take calcium and thyroid medication?

Take the calcium separate from your thyroid medication; the thyroid medication is best absorbed on an empty stomach. If you are hypocalcemic, the calcium regimen takes priority over the thyroid medication following surgery and needs to be taken regularly—especially first thing in the morning. Do not delay in taking calcium due to concerns about thyroid medication and absorption. Simply take the thyroid medication during the day separate from calcium. When your parathyroid glands recover and the extra calcium is stopped, the thyroid medication schedule can be changed.

If you are told your calcium levels are low, and/or you are having hypocalcemic symptoms, please read the additional tips listed below:

  • Keep calcium close by for the first few days after surgery. Take it with you when you leave the house and keep some by the bedside to take at night
  • Be sure to take the calcium at regular intervals (every six to eight hours), rather than three times per day
  • You may be prescribed a special type of vitamin D (e.g., Rocaltrol or Calcitriol). This will help you absorb the calcium
  • Keep a careful record of the dose and timing of calcium supplements and the vitamin D and when/if you are experiencing hypocalcemic symptoms
  • If you are experiencing escalating symptoms of hypocalcemia that does not improve with oral calcium supplements, please contact your surgeon right away, as you may need to go to the emergency room for IV calcium

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