Ergocalciferol is used in the treatment of hypoparathyroidism (condition in which the body does not produce enough parathyroid hormone), refractory rickets (softening and weakening of bones that does not respond to treatment), and familial hypophosphatemia (rickets or osteomalacia caused by an inherited condition with a decreased ability to break down vitamin D in the body). Ergocalciferol is in a class of medications called vitamin D analogs. It works by helping the body to use more of the calcium found in foods or supplements.

Side Effects Of Ergocalciferol

Ergocalciferol may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • pale skin
  • tiredness

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • feeling tired, difficulty thinking clearly, loss of appetite, nausea, vomiting, constipation, increased thirst, increased urination, or weight loss
  • drowsiness
  • muscle aches, stiffness, and weakness

Ergocalciferol may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before taking ergocalciferol:

  • tell your doctor and pharmacist if you are allergic to ergocalciferol, aspirin, tartrazine (a yellow dye in some processed foods and drugs), any other medications, or any of the ingredients in ergocalciferol capsules. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: calcium supplements; other vitamin D supplements and fortified foods; or thiazide diuretics (‘water pills’) such as chlorothiazide (Diuril), hydrochlorothiazide (in many blood pressure medications), indapamide, and metolazone (Zaroxolyn). You and your caregiver should know that many nonprescription medications are not safe to take with ergocalciferol. Ask your doctor before you take any nonprescription medications while you are taking ergocalciferol. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have high blood levels of calcium and vitamin D, an abnormal sensitivity to high levels of vitamin D, or if you have malabsorption syndrome (problems absorbing food). Your doctor will probably tell you not to take ergocalciferol.
  • tell your doctor 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 ergocalciferol, call your doctor.

Ergocalciferol Dosage

Ergocalciferol comes as a capsule to take by mouth. It is usually taken once daily. Take ergocalciferol at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take ergocalciferol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the capsules whole; do not chew or crush them.

Your doctor may change your dose depending on your body’s response to ergocalciferol.


Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests before and during your treatment with ergocalciferol.

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.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.