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Overview: Paricalcitol is a form of vitamin D used to treat and prevent hyperparathyroidism (a condition with high parathyroid hormone blood levels) in people with chronic kidney disease. Common side effects include diarrhea, nausea, vomiting, dizziness, and high blood pressure. Make sure to keep all appointments, including those for lab work. Tell your health care provider right away if you get nausea, increased thirst, appetite loss, constipation, or confusion.

Uses

What is paricalcitol used for?

Paricalcitol is commonly used to treat and prevent high levels of parathyroid hormone (hyperparathyroidism) in people with chronic kidney disease.

Paricalcitol may also be used for other conditions as determined by your health care provider.

How does paricalcitol work (mechanism of action)?

People with chronic kidney disease may not make enough active vitamin D. Active vitamin D helps you absorb calcium from foods and drinks. Without enough active vitamin D, your calcium levels can get too low. Low calcium levels can cause parathyroid hormone (PTH) levels to get too high, which can weaken bones over time. Paricalcitol is a form of vitamin D. It gives the body more of the kind of vitamin D it can turn into the active form. This helps the body absorb more calcium, lower PTH levels, and prevent bone problems.

How is paricalcitol supplied (dosage forms)?

Brands and other names

  • Zemplar

Dosage forms and strengths

  • 1 mcg, 2 mcg, 4 mcg oral capsules

    Paricalcitol is also available in injectable forms.

How should I store paricalcitol?

Paricalcitol should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of paricalcitol?

The most common side effects of paricalcitol are listed below. These side effects may vary depending on the condition that is being treated. Tell your health care provider if you have any of these side effects that bother you.

  • Diarrhea
  • Common cold symptoms
  • Dizziness
  • Nausea or vomiting
  • High blood pressure 
  • Allergic reactions (see below)
  • Fluid retention (edema)

There may be other side effects of paricalcitol that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of paricalcitol?

While less common, the most serious side effects of paricalcitol are described below, along with what to do if they happen.

Severe Allergic Reactions. Paricalcitol may cause allergic reactions, which can be serious. Stop using paricalcitol and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

High Calcium Levels (Hypercalcemia). Paricalcitol can cause high calcium levels, also called hypercalcemia. Hypercalcemia can lead to serious problems with your kidneys, heart, or bones. Stop using paricalcitol and call your health care provider if you have any of the following symptoms.

  • Peeing frequently
  • Feeling thirsty
  • Tiredness
  • Confusion or dizziness
  • Poor appetite
  • Nausea or vomiting
  • Constipation
  • Weight loss

Bone Problems. Paricalcitol may cause bone problems and increase your risk of bone fractures. Keep any appointments, including those for lab work or other tests while you are using paricalcitol. Tell your health care provider if you break a bone.

Warnings & Precautions

Who should not use paricalcitol?

Allergies to Ingredients. People who are allergic to any of the following should not use paricalcitol.

  • Paricalcitol
  • Zemplar
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific paricalcitol products they stock.

High Calcium Levels. You should not use paricalcitol if you have too much calcium in your body (hypercalcemia). See the Serious Side Effects section for more information.

Vitamin D Toxicity. You should not use paricalcitol if you have too much vitamin D in your body.

What should I know about paricalcitol before using it?

Do not use paricalcitol unless it has been prescribed to you by a health care provider. Use it as prescribed.

Do not share paricalcitol with other people, even if they have the same condition as you. It may harm them.

Keep paricalcitol out of the reach of children.

Follow your health care provider's instructions regarding diet and phosphorus restriction.

Your health care provider will likely check blood levels of calcium, parathyroid hormone (PTH), and vitamin D before starting this medicine and while you are using it. Make sure to keep all appointments, including those for lab work.

Paricalcitol can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how paricalcitol affects you.

What should I tell my health care provider before using paricalcitol?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if paricalcitol is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Heart failure
  • History of broken bones or bone problems
  • History of kidney stones

Other Medicines and Supplements. Paricalcitol may interact with other medicines and supplements. Before using paricalcitol, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how paricalcitol could affect pregnancy or harm an unborn baby. Tell your health care provider if you are or plan to become pregnant.

Breastfeeding. It is not known if paricalcitol passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will advise you if you should use paricalcitol while breastfeeding.

Interactions

Does paricalcitol interact with foods or drinks?

The risk of serious side effects may be increased if you drink grapefruit juice while using paricalcitol.

It is unknown if drinking alcohol will affect paricalcitol.

Does paricalcitol interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. 

In particular, make sure that you discuss if you are using any of the following before using paricalcitol.

  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • A thiazide diuretic, also called a water pill,  such as hydrochlorothiazide, which is a medicine used to reduce edema (fluid retention) and blood pressure
  • Cholestyramine, a medicine used to lower cholesterol
  • A vitamin, supplement, or product containing calcium or vitamin D
  • Mineral oil, which is a medicine used to treat constipation
  • Fluconazole (Diflucan), itraconazole (Sporanox, Tolsura), ketoconazole, posaconazole (Noxafil), or voriconazole (Vfend), which are used for fungal infections
  • Nefazodone, which is a medicine used to treat depression
  • Clarithromycin, which is a medicine used for bacterial infections
  • A protease inhibitor, such as atazanavir (Reyataz), nelfinavir (Viracept), or ritonavir (Norvir), which is a medicine commonly used to treat HIV
  • An antacid containing aluminum

Many other medicines may alter the blood levels of paricalcitol. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with paricalcitol. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much paricalcitol?

If you or someone else has used too much paricalcitol, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of paricalcitol?

If you miss a dose, use it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only use the next dose. Do not use double or extra doses.