Calcitriol belongs to the group of medications called vitamin D3 metabolites. Calcitriol is a form of vitamin D that is active in the body. It helps to maintain the balance of calcium and phosphorus in the blood. It also helps bones absorb calcium.

Calcitriol is used to help increase the amount of calcium in the blood and help with proper bone formation for people with chronic kidney failure that are undergoing dialysis. It is also used to increase the amount of calcium in the blood for people whose parathyroid glands are not working effectively, such as after surgery. Calcitriol may also be used to treat vitamin D-resistant rickets, a bone disease caused by too little vitamin D.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended starting dose of calcitriol for adults is 0.25 µg daily. Your doctor will adjust the dose based on blood tests and the amount of calcium in your blood.

While you are taking calcitriol, it is important that you follow any dietary suggestions your doctor has provided. Do not increase or decrease the amount of calcium in your diet without discussing the change with your doctor first.

Ensure that you are drinking enough fluid and do not become dehydrated while taking calcitriol. Your doctor or pharmacist should be able to tell you how much fluid you need to be taking in.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store all forms of this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

0.25 µg
Each brown-orange to red-orange (first half)/white to grey-yellow or grey-orange (second half), opaque, oval soft gelatin capsule contains 0.25 µg of calcitriol. Nonmedicinal ingredients: butylhydroxyanisole, butylhydroxytoluene, medium-chain triglycerides, gelatin, glycerol 85%, hydrogenated products of partially hydrolysed starch, titanium dioxide E171, red and yellow iron oxide E172.

0.50 µg
Each brown-orange to red-orange, opaque, oval, soft gelatin capsule contains 0.50 µg of calcitriol. Nonmedicinal ingredients: butylhydroxyanisole, butylhydroxytoluene, medium-chain triglycerides, gelatin, glycerol 85%, hydrogenated products of partially hydrolysed starch, titanium dioxide E171, red and yellow iron oxide E172.

Oral Solution

Do not use calcitriol if you:

• are allergic to calcitriol, vitamin D or forms of vitamin D, or any ingredients of the medication
• have high levels of calcium in the blood
• have high levels of vitamin D in the blood

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal cramps
• agitation
• constipation
• difficulty sleeping
• extremity pain
• headache
• insomnia
• metallic taste
• nausea
• red, irritated eyes
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• symptoms of an allergic reaction (e.g., itchiness, rash, redness)
• symptoms of high blood calcium
• bone pain
• decreased appetite
• drowsiness
• dry mouth
• fatigue
• fever
• frequent urination
• headache
• itchiness
• metallic taste in the mouth
• muscle pain
• stomach ache or cramps
• thirst
• trouble sleeping
• weakness
• weight loss
• symptoms of irregular heartbeat (e.g., shortness of breath, rapid or pounding heartbeat, unusual sweating)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood tests: Calcitriol causes changes to the amounts of calcium, magnesium, and phosphate in the blood. Your doctor will schedule regular blood tests to ensure that the levels of these minerals continue to be appropriate while you are taking this medication.

Heart arrhythmias: Calcitriol increases the amount of calcium in the bloodstream. Too much calcium can interfere with the regular rhythm of the heart. If you have irregular heartbeat (arrhythmia) discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Hypercalcemia: It is important to follow your doctor's instructions for taking this medication. Hypercalcemia, or high blood calcium levels, can occur. To help prevent the risk of this, follow any dietary suggestions your doctor has provided. Do not increase or decrease the amount of calcium in your diet without discussing the change with your doctor first. Also, keep your appointments for blood tests to monitor your calcium levels. Symptoms of high blood calcium include bone pain, decreased appetite, drowsiness, dry mouth, fatigue, headache, metallic taste in mouth, muscle pain, stomach ache, thirst, weakness, and weight loss. If you experience any of these symptoms, stop taking the medication and contact your doctor immediately.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are a breast-feeding mother and are taking calcitriol, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and efficacy of this medication have not been established for children under the age of 18 years.

There may be an interaction between calcitriol and any of the following:

• aluminum hydroxide
• apalutamide
• "azole" antifungals (e.g., fluconazole, itraconazole, voriconazole)
• calcium supplements
• carbamazepine
• cholestyramine
• clarithromycin
• cobicistat
• colestipol
• corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
• danazol
• digoxin
• diltiazem
• enzalutamide
• grapefruit juice
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• idelalisib
• magnesium (supplements or antacids)
• mifepristone
• multivitamins
• orlistat
• other forms of vitamin D (e.g., alfacalcidol, calcifediol, cholecalciferol)
• phenobarbital
• phenytoin
• phosphate
• primidone
• rifampin
• sevelamer
• sucralfate
• thiazide diuretics (e.g., hydrochlorothiazide, indapamide)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.