Calcifediol (Oral)

Since calcifediol decreases the body's level of parathyroid hormone (PTH), it can be effective in treating kidney patients whose bodies manufacture too much PTH.


Calcifediol is a vitamin D analog which helps increase the body's level of calcium and phosphorus, while at the same time reducing levels of parathyroid hormone (PTH). Kidney disease patients sometimes suffer from hyperparathyroidism, which is overactivity of the parathyroid gland, and calcifediol can be very effective in helping to treat this condition. Because these patients generally have low vitamin D levels, calcifediol can help to make up for the deficiency, as well as any deficiency of calcium or phosphorus which may exist. Vitamin D also assists with the body's absorption of calcium and the general functioning of phosphorus in the body, so calcifediol provides an added boost to these functions as well. Although very helpful for kidney patients in general, calcifediol is not indicated for patients who are undergoing regular dialysis.

Condition Treated

  • Hyperparathyroidism (in adults with Stage 3/Stage 4 kidney disease)
  • Hypocalcemia
  • Renal Osteodystrophy

Type of Medicine

  • Vitamin D analog

Side Effects

Along with its intended beneficial effects, it is at least possible that calcifediol may also trigger some unwanted side effects in patients who use it for the treatment of kidney disease. For the most part, calcifediol has very few side effects which will cause discomfort or pain to the patient using it. In addition, most doctors will prescribe calcifediol only when they deem that the benefits delivered to a patient significantly outweigh any side effects which might accompany usage of the medication. The vast majority of patients using calcifediol experience either no side effects whatsoever or very mild side effects.

Probably the most important side effect to watch for is an allergic reaction because this could cause some very serious issues with your body. You should immediately get emergency medical attention if you observe allergic signs such as hives, a noticeable difficulty with breathing, or severe swelling which becomes apparent in the tongue, throat, lips, or facial area.

Side effects which are not quite so severe as an allergic reaction call for contacting your family doctor as soon as possible to discuss any of the following symptoms:

  • swelling in areas of the body below the neck
  • sudden unexplained weight gain
  • persistent shortness of breath, in the absence of strenuous exertion
  • high calcium content in your blood
  • nausea and vomiting
  • abnormal constipation
  • continuous thirst
  • increased desire to urinate
  • muscle weakness
  • lethargic or fatigued feeling over a long period of time
  • confusion or disorientation
  • unexplained bone pain
  • low count of red blood cells
  • unusual paleness of the skin
  • lightheadedness which makes you feel like you might faint
  • shortness of breath
  • irregular or rapid heartbeat
  • persistent difficulty with focusing or concentrating.

There are also some relatively minor side effects which can occur in patients on a treatment program which includes calcifediol such as occasional constipation, runny nose or stuffy nose, much more frequent sneezing than normal, and sore throat that does not go away.


Although your doctor will almost certainly review all directions for taking calcifediol, you can also consult the information on the prescription label if you should forget those instructions. Do not use more or less than the prescribed amount with each dosage, and do not use calcifediol longer than your doctor has prescribed it for.

The medication should be taken at bedtime every day, partly because this helps the body acclimate itself to a regular schedule of ingestion so that it's not always adapting itself to different times and dosage schedules.

Calcifediol capsules should always be swallowed whole, and the capsules themselves should never be broken open, nor should they be chewed or crushed prior to ingestion. If you should miss a regularly scheduled dosage of calcifediol, take the missed dosage as soon as you remember it unless it is nearly time for your next regularly scheduled dosage, in which case you should skip it altogether and just take the next one.

You should never double up on dosages of calcifediol to try to get back on schedule as this could possibly overwhelm the body with an excess of the ingredients in the medication. You should also not transfer any of your unused calcifediol to a friend or relative, and you should completely use up your calcifediol medication until the entire prescription is gone.


You should consult with your doctor or pharmacist prior to taking any vitamins, herbal supplements, or mineral supplements because the possibility exists that these may interact with calcifediol. There are a number of non-prescription dietary supplements which do contain significant amounts of vitamin D or calcium, and when taken in conjunction with calcifediol, you may be ingesting too much of some of these ingredients.

There are also certain other medications which should not be used at the same time you are taking calcifediol because it can affect your blood levels, and can have an impact on the other drugs themselves. When interactions like this take place, it is possible for some unusual side effects to occur, some of which may be severe. This makes it important that you compile a complete list of all medications you are taking, as well as all vitamins and herbal supplements, and the dosages of everything on your list. This should be reviewed with your doctor thoroughly so that all possible interactions can be considered, and if necessary, certain medications can be either discontinued or dosages can be lowered.

Some of the medications which are known to interact with calcifediol are the following:

  • any kinds of heart medications
  • any kinds of diuretics
  • antibiotics or antifungal medications
  • cholestyramine
  • digoxin or digitalis
  • phenobarbital and other medications used in the treatment of seizures
  • antiviral medications which are used to treat HIV/AIDS or hepatitis C
  • any mineral supplements or other medications which contain either calcium or vitamin D in any amounts.


There are a number of warnings to be aware of when taking calcifediol. There is a risk of developing hypercalcemia, and this, in turn, may boost the risk of cardiac arrhythmias or seizures, and it can also have an impact on the effect of digitalis on the heart.

If chronic hypercalcemia develops, it can lead to a vascular calcification or a soft tissue calcification, and in its most severe manifestations, hypercalcemia may require emergency medical attention. In order to monitor for these kinds of impacts, it may be necessary for patients to have their blood levels checked relatively often, and any patient with a history of hypercalcemia would have to be monitored for the possibility of a recurrence during calcifediol therapy.

As stated above, with the development of hypercalcemia, there is an increased risk of digitalis toxicity, which will also have to be monitored in blood levels. It may become necessary to modify dosages of calcifediol or to discontinue its usage entirely if impacts are severe enough.

There is a potential for PTH levels in the body to be decreased to a level low enough that adynamic bone disease could develop and increase the risk of bone fractures. This can be monitored by carefully assessing PTH levels in the body and adjusting calcifediol dosages if necessary.

There is no extensive research and no data available to make positive conclusions about pregnant women taking calcifediol, although studies in animals suggest that there could be notable side effects. For this reason, calcifediol should only be used during pregnancy under a doctor's recommendation, and in such cases, there should be careful monitoring of potential impacts.

Any woman who is breastfeeding or planning to breastfeed while taking calcifediol should discuss this with the family doctor because it is known that the medication can come through in breast milk, in which case it would be passed on to the infant. This is not definitely dangerous because the amounts passed through breastmilk are known to be small, so the advisability of breastfeeding while taking calcifediol should be thoroughly considered beforehand.


Calcifediol should be stored at room temperature, away from extremes of heat, humidity, or cold. If exposed to extreme heat or cold, the capsules may become damaged, and the medication inside could then be degraded, or it could be reduced in effectiveness. This medication should be stored out of the reach of children and pets, and it should not be kept in a pill reminder container where children can access it. These kinds of containers do not generally have adequate security to keep unwanted hands away from medication, so they are easily broken into. If you have any unused calcifediol, you should dispose of it properly, and if you're unsure about how to do this, contact your doctor or pharmacist for instructions.


Calcifediol is a Vitamin D analog and is generally used as a supplement in the treatment of patients who have low levels of vitamin D in their bodies, usually as a result of serious kidney disease. It works by decreasing the level of parathyroid hormone (PTH) and, at the same time, increasing the levels of calcium and phosphorus. Usually, the more serious cases of kidney disease are the ones treated with calcifediol, although patients undergoing dialysis are not good candidates for calcifediol treatment.

There are relatively few side effects from usage of calcifediol, and the side effects which do appear are often fairly mild - many patients using the medication experience no side effects at all. Anyone allergic to calcifediol or any of its ingredients must avoid taking the medication, since as with all medication allergies, some very serious symptoms may develop.

Calcifediol is rather easily ingested, coming in the form of a capsule which must be swallowed whole for a regular dosage. Capsules should not be transferred to other patients, and should not be crushed, chewed, or broken in any way prior to ingestion. If a calcifediol capsule has been broken, it should not be ingested, because its effectiveness would be of questionable value.

This medication is only administered in response to a patient's medical condition and the patient's response to the medication itself. It should be taken regularly and at the same time each day in order to derive the maximum benefit from usage.

Last Reviewed:
December 22, 2017
Last Updated:
April 04, 2018
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