Iatrogenic hypervitamnois D

Iatrogenic Hypervitaminosis D – A rare possibly but occasionally may ensue. Empirical prescription of Vitamin D –is that rational?? How many members supplement Vit D (say 60,000 IU per month) empirically for about 2-5  years without an initial assessment of  Vit D level of her for cost reasons??  Ans. The tolerable upper limit, or the maximum daily intake of vitamin D that is unlikely to result in any health risks, has been set at 4,000 IUs per day. (60000 IU Vit D commercial sachet if arbitrarily offered on fortnightly basis then daily dose comes to about  = 4285 IU / per day.  ,Adverse effects have been seen in those taking less than 10,000 IUs per day over an extended period of time. Too much vitamin D can cause abnormally high levels of calcium in the blood. This can affect bones, tissues, and other organs. It can lead to high blood pressure, bone loss, and kidney damage if not treated. dietary allowance of vitamin D for most adults is 600 international units a day (IU). Doctors may prescribe higher doses to treat medical conditions such as vitamin D deficiency, diabetes, and cardiovascular disease, for a short period of time. Daily use of high-dose vitamin D supplements for several months is toxic. Excessive amounts of vitamin D in the body can cause calcium levels in the blood to rise. This can lead to a condition called hypercalcemia (too much calcium in your blood). Symptoms include:

• fatigue
• loss of appetite
• weight loss
• excessive thirst
• excessive urination
• dehydration
• constipation
• irritability, nervousness
• ringing in the ear (tinnitus)
• muscle weakness
• nausea, vomiting
• dizziness
• confusion, disorientation
• high blood pressure
• heart arrhythmias

Long-term complications of untreated hypervitaminosis D include:

• kidney stones
• kidney damage
• kidney failure
• excess bone loss
• calcification (hardening) or arteries and soft tissues

In addition, increased blood calcium can cause abnormal heart rhythms.

  In statements released over the last decade, the Institute of Medicine (IOM)  and the Endocrine Society  have both concluded that acute VDT(Vitamin D Toxicity)  is extremely rare in the literature, that serum 25(OH)D concentrations must exceed 150 ng/ml (375 nmol/l), and that other factors, such as calcium intake, may affect the risk of developing hypercalcemia and VDT(Vitamin D Toxicity). Regardless of additional risk factors for VDT, many studies provided evidence that vitamin D is probably one of the least toxic fat-soluble vitamins, much less toxic than vitamin A

The human body can regulate the quantity of previtamin D (tachy-sterol and lumi-sterol) produced in the skin by ultraviolet-B radiation. A diversified diet typically does not provide large amounts of vitamin D, and the fortification of food products with vitamin D is modest. Vitamin D overdosing is diagnosed by markedly elevated 25(OH)D concentrations (>150 ng/ml) accompanied by severe hypercalcemia and hypercalciuria and by very low or undetectable parathyroid hormone (PTH) activity . Hypercalciuria and hypercalcemia are the first measurable manifestations of Vitamin D Toxicity(VDT-Vitamin D Toxicity))  The   1,25(OH)₂D concentration in patients with VDT may be within the reference range, slightly increased or reduced (less frequently) when an increased level of calcium in serum suppresses PTH activity. 1,25(OH)₂D is down regulated both by the inhibition of 1α-hydroxylase activity and by the enhancement of 24-hydroxylase activity