Actions of Vitamin D in details
Vitamin D promotes calcium absorption in the intestines and retention at the kidneys thus increasing serum calcium levels. It also increases renal tubule phosphate resorption consequently decreasing serum phosphatase levels, PTH levels and bone resorption.
How should I take Vitamin D?
This section provides information on the proper use of a number of products that contain vitamin d and Related compounds (Vitamin D). It may not be specific to Vitamin D. Please read with care.
For use as a dietary supplement:
- Do not take more than the recommended daily amount. Vitamin D is stored in the body, and taking too much over a period of time can cause poisoning and even death.
If you have any questions about this, check with your health care professional.
For individuals taking the oral liquid form of this dietary supplement:
- This preparation should be taken by mouth even though it comes in a dropper bottle.
- This dietary supplement may be dropped directly into the mouth or mixed with cereal, fruit juice, or other food.
While you are taking alfacalcidol, calcifediol, calcitriol, dihydrotachysterol, doxercalciferol or paricalcitol, your health care professional may want you to follow a special diet or take a calcium supplement. Be sure to follow instructions carefully. If you are already taking a calcium supplement or any medicine containing calcium, make sure your health care professional knows.
Dosing
The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For alfacalcidol
- To treat bone disease in kidney patients undergoing kidney dialysis:
- For oral dosage form (capsules):
- Adults and teenagers—At first, 1 microgram (mcg) a day. Your doctor may change your dose if needed. However, most people will take not more than 3 mcg a day.
- For oral dosage form (drops):
- Adults and teenagers—At first, 1 microgram (mcg) a day. Your doctor may change your dose if needed. However, most people will take not more than 3 mcg a day.
- For oral dosage form (solution):
- Adults and teenagers—At first, 1 mcg a day. Your doctor may change your dose if needed. However, most people will take not more than 3 mcg a day.
- For parenteral dosage form (injection):
- Adults and teenagers—At first, 1 mcg a day. Your doctor may change your dose if needed. However, most people will take not more than 12 mcg a week.
- For oral dosage form (capsules):
- To treat diseases in which calcium is not used properly by the body:
- For oral dosage form (capsules):
- Adults and teenagers—At first, 0.25 microgram (mcg) a day. Your doctor may change your dose if needed. However, most people will take not more than 1 mcg a day.
- For oral dosage form (drops):
- Adults and teenagers—At first, 0.25 microgram (mcg) a day. Your doctor may change your dose if needed. However, most people will take not more than 1 mcg a day.
- For oral dosage form (solution):
- Adults and teenagers—At first, 0.25 mcg a day. Your doctor may change your dose if needed. However, most people will take not more than 1 mcg a day.
- For oral dosage form (capsules):
- For calcifediol
- To treat diseases in which calcium is not used properly by the body or to treat bone disease in kidney patients undergoing kidney dialysis:
- For oral dosage form (capsules):
- Adults, teenagers, and children over 10 years of age—At first, 300 to 350 micrograms (mcg) a week, taken in divided doses either once a day or every other day. Your doctor may change your dose if needed.
- Children 2 to 10 years of age—50 mcg a day.
- Children up to 2 years of age—20 to 50 mcg a day.
- For oral dosage form (capsules):
- To treat diseases in which calcium is not used properly by the body or to treat bone disease in kidney patients undergoing kidney dialysis:
- For oral dosage forms (capsules and solution):
- Adults, teenagers, and children—At first, 0.25 micrograms (mcg) a day. Your doctor may change your dose if needed.
- For parenteral dosage forms (injection):
- Adults and teenagers—At first, 0.5 mcg injected into a vein three times a week. Your doctor may change your dose if needed.
- Children—Use and dose must be determined by your doctor.
- For oral dosage forms (capsules and solution):
- For dihydrotachysterol
- To treat diseases in which calcium is not used properly by the body:
- For oral dosage forms (capsules, solution, or tablets):
- Adults and teenagers—At first, 100 micrograms (mcg) to 2.5 milligrams (mg) a day. Your doctor may change your dose if needed.
- Children—At first, 1 to 5 mg a day. Your doctor may change your dose if needed.
- For oral dosage forms (capsules, solution, or tablets):
- For doxercalciferol
- To treat an overactive parathyroid gland in patients with kidney failure:
- For oral dosage form (capsules):
- Adults—10 micrograms (mcg) three times weekly at dialysis. The doctor may change your dose if needed.
- Children—Use and dose must be determined by your doctor.
- For oral dosage form (capsules):
- For Vitamin D
- The amount of vitamin D to meet normal daily recommended intakes will be different for different individuals. The following information includes only the average amounts of vitamin D.
- To prevent deficiency, the amount taken by mouth is based on normal daily recommended intakes:
- For oral dosage form (capsules):
- For the U.S.
- Adults and teenagers—5 to 10 micrograms (mcg) (200 to 400 Units) per day.
- Pregnant and breast-feeding females—10 mcg (400 Units) per day.
- Children 4 to 10 years of age—10 mcg (400 Units) per day.
- Children birth to 3 years of age—7.5 to 10 mcg (300 to 400 Units) per day.
- For Canada
- Adults and teenagers—2.5 to 5 mcg (100 to 200 Units) per day.
- Pregnant and breast-feeding females—5 to 7.5 mcg (200 to 300 Units) per day.
- Children 7 to 10 years of age—2.5 to 5 mcg (100 to 200 Units) per day.
- Children 4 to 6 years of age—5 mcg (200 Units) per day.
- Children birth to 3 years of age—5 to 10 mcg (200 to 400 Units) per day.
- For oral dosage form (capsules):
- To treat deficiency:
- Adults, teenagers, and children—Treatment dose is determined by prescriber for each individual based on severity of deficiency.
- To treat diseases in which calcium and phosphate are not used properly by the body:
- Adults and teenagers—At first, 1000 to 500,000 Units a day. The doctor may change your dose if needed.
- Children—At first, 1000 to 200,000 Units a day. The doctor may change your dose if needed.
- For paricalcitol
- To treat an overactive parathyroid gland in patients with kidney failure:
- For oral dosage form (capsules):
- Adults—1 to 2 micrograms (mcg) one time per day or 2 to 4 mcg three times a week (not more often than every other day). The doctor may change your dose if needed.
- Children—Use and dose must be determined by your doctor.
- For parenteral dosage form (injection):
- Adults—0.04 to 0.1 micrograms (mcg) per kg no more than every other day during dialysis. The doctor may change your dose if needed.
- Children—Use and dose must be determined by your doctor.
- For oral dosage form (capsules):
Missed Dose
Call your doctor or pharmacist for instructions.
For use as a dietary supplement: If you miss taking a dietary supplement for one or more days there is no cause for concern, since it takes some time for your body to become seriously low in vitamins. However, if your health care professional has recommended that you take this dietary supplement, try to remember to take it as directed every day.
If you are taking this medicine for a reason other than as a dietary supplement and you miss a dose and your dosing schedule is:
- One dose every other day—Take the missed dose as soon as possible if you remember it on the day it should be taken. However, if you do not remember the missed dose until the next day, take it at that time. Then skip a day and start your dosing schedule again. Do not double doses
- One dose a day—Take the missed dose as soon as possible. Then go back to your regular dosing schedule. However, if you do not remember the missed dose until the next day, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
- More than one dose a day—Take the missed dose as soon as possible. Then go back to your regular dosing schedule. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
If you have any questions about this, check with your health care professional.
Storage
Keep out of the reach of children.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Do not keep outdated medicine or medicine no longer needed.
Vitamin D administration
Wafers: Chew or crush before swallowing; do not swallow wafer whole; administer with the largest meal of the day.
Vitamin D pharmacology
Cholecalciferol (vitamin D) is a provitamin. The active metabolite, 1,25-dihydroxyvitamin D (calcitriol), stimulates calcium and phosphate absorption from the small intestine, promotes secretion of calcium from bone to blood; promotes renal tubule phosphate resorption (IOM 2011)
Metabolism
Inactive until hydroxylated hepatically to 25-hydroxyvitamin D [25(OH)D; calcifediol] then renally to the active metabolite 1,25-dihydroxyvitamin D (calcitriol) (IOM 2011)
Excretion
Feces (IOM 2011)
Half-Life Elimination
Circulating: 25(OH)D: 2 to 3 weeks; 1,25-dihydroxyvitamin D: ~4 hours
References
- DailyMed. "ERGOCALCIFEROL: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- DailyMed. "CALCITRIOL: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- DailyMed. "CALCIFEDIOL: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Vitamin D are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Vitamin D. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
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Information checked by Dr. Sachin Kumar, MD Pharmacology
