Calcitriol is a form of vitamin D that is used to treat and prevent low levels of calcium in the blood of patients whose kidneys or parathyroid glands (glands in the neck that release natural substances to control the amount of calcium in the blood) are not working normally. Low blood levels of calcium may cause bone disease. Calcitriol is in a class of medications called vitamins. It works by helping the body to use more of the calcium found in foods or supplements.
Calcitriol comes as a capsule and a solution (liquid) to take by mouth. It usually is taken once a day or once every other day in the morning with or without food. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take calcitriol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Your doctor will probably start you on a low dose of calcitriol and may gradually increase your dose, not more than once every 2 to 8 weeks.
Calcitriol may help to control your condition but will not cure it. Continue to take calcitriol even if you feel well. Do not stop taking calcitriol without talking to your doctor.
Calcitriol is also sometimes used to treat rickets (softening and weakening of bones in children caused by lack of vitamin D), osteomalacia (softening and weakening of bones in adults caused by lack of vitamin D), and familial hypophosphatemia (rickets or osteomalacia caused by decreased ability to break down vitamin D in the body). Calcitriol is also sometimes used to increase the amount of calcium in the blood of premature (born early) babies. Talk to your doctor about the risks of using this medication for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking calcitriol, tell your doctor and pharmacist if you are allergic to calcitriol, other forms of vitamin D such as calcifediol (Calderol), dihydrotachysterol (Hytakerol, DHT), doxercalciferol (Hectorol), ergocalciferol (Drisdol, Calciferol), paricalcitol (Zemplar) or any other medications or vitamins.tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking, especially antacids; calcium supplements; cholestyramine (Questran); colestipol (Colestid); digoxin (Lanoxin); diuretics ('water pills') ketoconazole (Nizoral);lanthanum (Fosrenol); laxatives; oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); other forms of vitamin D; phenobarbital (Luminal, Solfoton); phenytoin (Dilantin);and sevelamer (Renagel). Also tell your doctor or pharmacist if you are taking ergocalciferol (Drisdol, Calciferol) or have stopped taking it in the past few months.Your doctor may need to change the doses of your medications or monitor you carefully for side effects.you should know that many nonprescription medications are not safe to take with calcitriol. Ask your doctor before you take any nonprescription medications while you are taking calcitriol.tell your doctor if you have recently had surgery or are unable to move around for any reason and if you have or have ever had kidney or liver disease.tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking calcitriol, call your doctor. You should not breast-feed while you are taking calcitriol.if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking calcitriol.
Calcitriol will work only if you get the right amount of calcium from the foods you eat. If you get too much calcium from foods, you may experience serious side effects of calcitriol, and if you do not get enough calcium from foods, calcitriol will not control your condition. Your doctor will tell you which foods are good sources of these nutrients and how many servings you need each day. If you find it difficult to eat enough of these foods, tell your doctor. In that case, your doctor can prescribe or recommend a supplement.
If you are being treated with dialysis (process of cleaning the blood by passing it through a machine), your doctor may also prescribe a low-phosphate diet. Follow these directions carefully.
If you do not have kidney disease, you should drink plenty of fluids while taking calcitriol. If you have kidney disease, talk to your doctor about how much fluid you should drink each day.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately: weaknessheadachesluggishnessupset stomachvomitingdry mouthconstipationmuscle painbone painmetallic taste in mouthincreased thirstdecreased appetiteweight lossincreased urination (especially at night)difficult or painful urinationchanges in visionlack of interest in the things around youhallucination (seeing things or hearing voices that do not exist)fever or chillsstomach painpale, fatty stoolsyellowing of the skin or eyesrunny nosedecreased sexual desireirregular heartbeatrashhivesitchingdifficulty breathing or swallowing
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( Web Site) or by phone (1-800-332-1088).
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Protect this medication from light. Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include: weaknessheadachesluggishnessupset stomachvomitingdry mouthconstipationmuscle painbone painmetallic taste in mouthincreased thirstdecreased appetiteweight lossincreased urination (especially at night)difficult or painful urinationchanges in visionlack of interest in the things around youhallucination (seeing things or hearing voices that do not exist)fever or chillsstomach painpale, fatty stoolsyellowing of the skin or eyesrunny nosedecreased sexual desireirregular heartbeat
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to calcitriol.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.