stopping citalopram cold turkey

Vitamin D has two forms, namely ergocalciferol which is derived from ergosterol in plants, usually yeast, by irradiation, and cholecalciferol which is usually derived from fish, or from the irradiation of 7-dehydrocholesterol from lanolin, or by chemically converting cholesterol.

Some research shows that vitamin D3 is somewhat more effective at higher doses in boosting the concentrations of vitamin D prohormone in the body, and it is usually used nowadays to fortify milk and milk products, as well as to prepare supplements.

The normal supplementation dosage ranges from 400 IU/ mL to 400 IU/drop. Care must be enjoined and demonstrated to avoid overdosage, where to buy cheap strattera next day no prescription especially with the higher concentration, in infants. However, some current research indicates that 800-5000 IU/day improves musculoskeletal health in the elderly, preventing up to 50% of falls.

In those who have vitamin D deficiency, up to 600000 IU administered in several divided doses over a few weeks, such as 50000 IU/week for 8 weeks. This is sufficient to bring the tissue and serum levels back to normal. Following this, 800-1000 IU may be taken daily, either from dietary sources or as a supplement.

Most people maintain a normal vitamin D concentration provided they get 10-15 minutes of sunlight a day on exposed skin. In such a case, supplements are not usually necessary. Indications for vitamin D supplements should be based on measurement of 25-hydroxy-D levels.

Vitamin D supplements may interact with various medications. These include:

  • Steroids – corticosteroids like prednisone, which are widely prescribed for their anti-inflammatory actions, also reduce calcium absorption as well as reduce the metabolism of vitamin D, exacerbating bone loss and speeding up the development of osteoporosis with long-term use.
  • Cholesterol-lowering agents such as cholestyramine can impair the absorption of vitamin D as well as other fat-soluble vitamins by interfering with fat absorption.
  • Anticonvulsants – phenytoin and phenobarbital both induce the hepatic metabolism of vitamin D, leading to increased inactivation, which leads to lower calcium absorption.


  • Vasudevan, D. M., Sreekumari, S., & Vaidyanathan, K. (2013). Textbook of biochemistry for medical students (7th ed.). New Delhi, India: Jaypee Brothers Medical Publishers Pvt Ltd.

Further Reading

  • All Vitamin D Content
  • What is Vitamin D?
  • Vitamin D Biochemistry
  • Vitamin D Deficiency
  • Vitamin D Overdose

Last Updated: Aug 23, 2018

Written by

Dr. Liji Thomas

Dr. Liji Thomas is an OB-GYN, who graduated from the Government Medical College, University of Calicut, Kerala, in 2001. Liji practiced as a full-time consultant in obstetrics/gynecology in a private hospital for a few years following her graduation. She has counseled hundreds of patients facing issues from pregnancy-related problems and infertility, and has been in charge of over 2,000 deliveries, striving always to achieve a normal delivery rather than operative.

Source: Read Full Article