Calcitriol is a form of vitamin D3. Vitamin D helps your body absorb calcium from the stomach.

Calcitriol is used to treat hyperparathyroidism (overactive parathyroid glands) and metabolic bone disease in people who have chronic kidney failure and are not receiving dialysis.

Calcitriol is also used to treat calcium deficiency in people with hypoparathyroidism (underactive parathyroid glands) caused by surgery, disease, or other conditions.

Calcitriol is also used to treat calcium deficiency (hypocalcemia) and metabolic bone disease in people who are receiving dialysis.

Calcitriol may also be used for purposes not listed in this medication guide.

You should not use this medicine if you have high levels of calcium or vitamin D in your blood, or if you have ever had an allergic reaction to calcitriol or other forms of vitamin D.

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 depending on your body's response to calcitriol.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Calcitriol oral is taken by mouth.

Measure oral liquid carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Calcitriol injection is given as an infusion into a vein. A healthcare provider will give your first dose and may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Prepare an injection only when you are ready to give it. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

You will need frequent medical tests.

Drink plenty of fluids unless your doctor has told you to restrict your fluid intake.

You may need to follow a special diet while using calcitriol. Follow all instructions of your doctor or dietitian. Learn about the foods to eat or avoid to help control your condition.

Call your doctor if you are sick with vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking calcitriol. This can lead to very low blood pressure, a serious electrolyte imbalance, or kidney failure.

If you need major surgery or will be on long-term bed rest, your dose or testing needs may change. Follow your doctor's instructions.

Store at room temperature away from moisture, heat, and light.

You should not use calcitriol if:

• you have high levels of calcium or vitamin D in your blood; or

• you have had an allergic reaction to calcitriol or other forms of vitamin D.

Tell your doctor about all your medical conditions or allergies.

It is not known whether calcitriol will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

You should not breastfeed while using calcitriol.

Do not give this medicine to a child without medical advice.

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Early signs of overdose may include headache, weakness, drowsiness, dry mouth, metallic taste, nausea, vomiting, constipation, stomach pain, loss of appetite, muscle pain, or bone pain.

Late signs of overdose may include increased thirst, itching, increased urination (especially at night), severe stomach pain spreading to your back, irregular heartbeats, loss of appetite, weight loss, feeling hot, decreased interest in sex, or being unable to urinate.

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.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

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.

Do not take other vitamin or mineral supplements unless your doctor has told you to.

Ask your doctor before using an antacid or laxative, especially if you are on dialysis. Taking antacids or laxatives that contain magnesium may increase your blood levels of magnesium, which could affect your heart or blood pressure.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Calcitriol may cause serious side effects. Stop using calcitriol and call your doctor at once if you have:

• dehydration symptoms--feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin;

• high calcium levels--nausea, vomiting, constipation, increased thirst or urination, muscle weakness, bone pain, confusion, lack of energy, or tired feeling; or

• low calcium level--muscle spasms or contractions, numbness or tingly feeling (around your mouth, or in your fingers and toes).

Calcitriol can affect growth in children. Tell your doctor if your child is not growing at a normal rate while using calcitriol.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• cholestyramine;

• digoxin, digitalis;

• ketoconazole;

• a diuretic or "water pill"--hydrochlorothiazide, HCTZ, Diovan HCT, Hyzaar, Maxzide, Tenoretic, Zestoretic, and others;

• seizure medicine--phenobarbital, phenytoin; or

• steroid medicine--prednisone, dexamethasone, fluticasone, and others.

This list is not complete. Other drugs may affect calcitriol, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

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.