- What is vitamin D-oral, and how does it work (mechanism of action)?
- What are the uses for vitamin D-oral?
- What are the side effects of vitamin D-oral?
- What is the dosage for vitamin D-oral?
- Which drugs or supplements interact with vitamin D-oral?
- Is vitamin D-oral safe to take if I'm pregnant or breastfeeding?
- What else should I know about vitamin D-oral?
What is vitamin D-oral, and how does it work (mechanism of action)?
Vitamin D is a necessary vitamin for the growth and development of bones. Vitamin D is commonly known as ergocalciferol (Vitamin D2) and cholecalciferol (Vitamin D3). Vitamin D2 and D3 are broken down to their active form, calcitriol, in the body. Calcitriol works by increasing absorption of calcium and phosphorus in the body. Calcitriol also prevents loss of calcium and phosphorus from kidneys so they are absorbed back in the body to maintain sufficient levels.
What brand names are available for vitamin D-oral?
Ergocalciferol (Vitamin D2), Cholecalciferol (Vitamin D3), Cholecalciferol (Vitamin D3)
Is vitamin D-oral available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for vitamin D-oral?
Vitamin D2 and D3 50000 IU are available with a prescription. Vitamin D2 and D3 400 – 5000 IU are available over-the-counter (OTC).
What are the uses for vitamin D-oral?
Vitamin D is used for treating hypoparathyroidism, vitamin D resistant rickets, and low vitamin D levels. Over-the-counter Vitamin D preparations are commonly used for low Vitamin D levels.
What are the side effects of vitamin D-oral?
Side effects of Vitamin D include:
- nausea,
- vomiting,
- constipation,
- weight loss,
- weakness, and
- increased calcium levels (hypercalcemia).
What is the dosage for vitamin D-oral?
- Hypoparathyroidism: Take 25000 to 200000 IU vitamin D by mouth once daily with 4 grams of calcium lactate 6 times daily.
- Vitamin D resistant rickets: Take 12000 to 500000 IU Vitamin D by mouth once daily.
- Daily intake of vitamin D: Take 600 IU daily.
Which drugs or supplements interact with vitamin D-oral?
Vitamin D should be used with caution with mineral oil because mineral oil slows down the absorption of Vitamin D and reduces its therapeutic benefits.
Thiazide diuretics like hydrochlorothiazide (Microzide) and chlorthalidone (Thalitone) should be used with caution in people with hypoparathyroid taking Vitamin D, because thiamine diuretics may increase calcium levels.

QUESTION
According to the USDA, there is no difference between a “portion” and a “serving.” See AnswerIs vitamin D-oral safe to take if I'm pregnant or breastfeeding?
There are no adequate studies done on Vitamin D to determine safe and effective use in pregnant women.
Vitamin D enters breast milk. Therefore, it is best to be cautious before using it in nursing mothers.
What else should I know about vitamin D-oral?
What preparations of vitamin D-oral are available?
PREPARATIONS: Vitamin D2 and D3 are available in 400, 800, 1000, 2000, 2400, and 5000 international units (IU) tablets and capsules. Vitamin D2 is available in 50000 IU (1.25 mg) softgels. Vitamin D3 is available in 50000 IU capsules.
How should I keep vitamin D-oral stored?
Vitamin D capsules and tablets are stored at room temperature between 15 C - 30 C (59 F - 86 F).
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Summary
Vitamin D (Ergocalciferol [Vitamin D2], Cholecalciferol [Vitamin D3]) is required for the maintanence for bones and teeth. It works to increase absorption of calcium and to prevent its loss through the kidneys.
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Related Disease Conditions
-
Vitamin D Deficiency
Vitamin D deficiency has been linked with rickets, cancer, cardiovascular disease, severe asthma in children and cognitive impairment in older adults. Causes include not ingesting enough of the vitamin over time, having limited exposure to sunlight, having dark skin, and obesity. Symptoms include bone pain and muscle weakness. Treatment for vitamin D deficiency involves obtaining more vitamin D through supplements, diet, or exposure to sunlight.
-
Vitamins and Calcium Supplements
Vitamins are organic substances that are essential for the proper growth and functioning of the body. Calcium is a mineral essential for healthy bones and is also important for muscle contraction, heart action, and normal blood clotting.
-
Thyroid Cancer
There are four major types of thyroid cancer: papillary, follicular, medullary, and anaplastic thyroid cancer. Tumors on the thyroid are referred to as thyroid nodules. Symptoms of thyroid cancer include swollen lymph nodes, pain in the throat, difficulty swallowing, hoarseness, and a lump near the Adam's apple. Treatment usually involves chemotherapy, surgery, radioactive iodine, hormone treatment or external radiation and depends upon the type of thyroid cancer, the patient's age, the tumor size, and whether the cancer has metastasized.
-
Rickets
Rickets is caused by a deficiency of vitamin D, calcium, or phosphate. Infants and children who are exclusively breastfed, have dark skin, and infants born to mothers who are vitamin D deficient are most at risk for developing rickets. Symptoms and signs of rickets include bone pain, delayed teeth formation, short stature, skeletal deformities (bowlegs, abnormally shaped skull), and decreased muscle strength. Treatment of rickets depends upon the cause, but the first step usually involves correcting any abnormal levels of calcium, phosphate, or vitamin D with supplements.
-
Giant Cell Arteritis (GCA or Temporal Arteritis)
Giant cell arteritis, inflammation of blood vessel walls, affects 10%-15% of polymyalgia rheumatica patients. Symptoms of giant cell arteritis include fatigue, weight loss, low-grade fever, jaw pain when chewing, scalp tenderness, and headaches. High doses of cortisone medications are used to treat giant cell arteritis.
-
Hypoparathyroidism
In hypoparathyroidism, the parathyroid gland does not produce enough parathyroid hormone. Causes of hypoparathyroidism include injury to the parathyroid glands, autoimmune disorder association, or may be present ab birth. Symptoms of hypoparathyroidism include: tingling fingers, toes, and lips, brittle nails, dry, coarse skin, dry hair; memory loss, headaches, severe muscle cramps, cataracts, malformed teeth, and convulsions. Treatment of hypoparathyroidism is to restore the calcium and phosphorus to normal levels in the body.
-
Cancer Prevention
Certain behavioral, lifestyle, and environmental factors contribute to cancer. Cancer prevention involves modifying these factors to decrease cancer risk. Tobacco use, alcohol consumption, physical inactivity, inadequate fruit and vegetable intake, and obesity increase the risk of certain cancers. Vaccines, genetic testing, and cancer screening also play a role in cancer prevention.
Treatment & Diagnosis
Medications & Supplements
Prevention & Wellness
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