Vitamin D overdose
Vitamin D is the unified name for a whole group of fat-soluble biologically active substances formed under the influence of ultraviolet radiation in animal and plant tissues. Some of the vitamins of this group are synthesized in the cells of the human body, some come exclusively from the outside.
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D vitamins include:
- vitamin D 2 - ergocalciferol;
- vitamin D 3 - cholecalciferol;
- vitamin D 4 - dihydroergocalciferol;
- vitamin D 5 - sitocalciferol;
- vitamin D 6 - stigma-calciferol.
Currently, the term "Vitamin D" denotes two forms - D 2 and D 3, colorless, odorless crystals, resistant to high temperatures. The activity of vitamin D preparations is expressed in international units (ME): 1 ME contains 0.000025 mg (0.025 μg) of chemically pure vitamin D.
Food sources of vitamin are some types of algae, fatty fish, fish oil. To a lesser extent - butter, cheese and other fatty dairy products, egg yolk, caviar, forest (not grown in artificial conditions) mushrooms, yeast.
Vitamin D is a unique biologically active substance that combines the functions of a vitamin and a hormone, in the capacity of which it influences intestinal cells, stimulating the production of a carrier protein necessary for calcium transport, as well as kidney and muscle, where it enhances the reabsorption of Ca 2+. The main task of vitamin D is to ensure the absorption of calcium and phosphorus from the small intestine into the systemic circulation. The absorption of these microelements in the intestine (maximum in the duodenum 12) is carried out due to active transport against the electrochemical gradient, this transition through cell membranes becomes possible only with the help of a calcium-binding protein dependent on vitamin D.
Other functions of vitamin D:
- stimulates cell proliferation and development (often used externally in dermatology to reduce skin manifestations of diseases);
- participates in the synthesis of monocytes;
- inhibits the growth of cancer cells, which makes it effective in the prevention and treatment of certain types of tumors, including malignant blood diseases;
- affects the level of insulin, thereby also the level of glucose in the blood;
- provides adequate neuromuscular interaction.
How Much Vitamin D is Needed for Overdose?
The therapeutic dose of the vitamin is 100-4000 IU, depending on the age and functional state of the body. Exceeding the specified threshold provokes symptoms of an overdose, the so-called D-vitamin intoxication.
Some researchers point to a much higher dose of the vitamin as toxic - about 1 million IU per day.
Signs of overdose
Vitamin D overdose can be both acute and chronic.
Acute overdose develops, as a rule, in children of the first six months of life when taking unjustifiably high doses of vitamin D preparations for 2-3 weeks, or in individuals with individual hypersensitivity to the substance. Acute vitamin intoxication is characterized by violent symptoms, and signs of dehydration come to the fore:
- a sharp decrease in appetite up to its complete absence;
- drowsiness, lethargy;
- excruciating thirst;
- dry skin and mucous membranes;
- increased blood pressure;
- decrease in heart rate;
- nausea, frequent vomiting;
- increased urination;
- unstable stools: diarrhea, alternating with constipation;
- the appearance of clonic-tonic cramps, muscle rigidity is possible;
- short-term loss of consciousness.
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Chronic intoxication develops for a long time (6 months or more) with regular intake of vitamin doses that slightly exceed the therapeutic dose. Her symptoms:
- irritability;
- increased fatigue;
- sleep disorders;
- muscle and bone pain, cramps, muscle twitching;
- weight loss;
- dyspeptic disorders (decreased appetite, nausea, vomiting, stool disorders);
- enlargement of the liver and spleen;
- dull aching pain in the lumbar region, increased urination, edema (mainly on the face) - signs of kidney damage;
- decreased immunity, manifested by susceptibility to colds and other infectious and inflammatory diseases.
As a result of chronic overdose, there is a toxic effect of vitamin D on cell membranes, metabolic disorders with an increase in the content of Ca 2+ ions in the blood and urine, acidification of the internal media of the body, deposition of calcium salts in organs and tissues.
First aid for overdose
With a single oral intake of an ultra-high dose of vitamin D, it is necessary:
- Rinse the stomach (drink 1-1.5 liters of water or a weak solution of potassium permanganate and induce a vomiting reflex).
- Take a saline laxative (magnesium sulfate).
- Take an adsorbent (Enterosgel, Polysorb, Polyphepan according to the scheme or activated carbon at the rate of 1 tablet per 10 kg of body weight).
With the development of symptoms of intoxication against the background of systematic intake, it is necessary to immediately discontinue the drug and consult a doctor.
Antidote
There are no specific antidotes for vitamin D.
According to some reports, it is advisable to take antioxidant drugs, for example, vitamin E (tocopherol), which prevent the damaging effect of vitamin D.
When is medical attention required?
Medical assistance is needed if:
- a child, pregnant woman or elderly person is injured;
- indomitable vomiting or diarrhea;
- neurological symptoms (convulsions, intense headache);
- symptoms of dehydration (sharp thirst, dry skin and mucous membranes, a decrease in the amount of urine discharge, a change in its concentration, a decrease in blood pressure, tachycardia);
- traces of blood appeared in the vomit or feces;
- the victim has limited contact or is unconscious.
The victim, depending on the severity of the condition, receives outpatient treatment or is hospitalized in a specialized department of the hospital, where further pharmacotherapy of D-vitamin intoxication is carried out:
- a therapeutic diet that restricts foods containing calcium and vitamin D;
- parenteral administration of an isotonic solution of 0.9% sodium chloride and 5% glucose in order to restore lost fluid and reduce symptoms of intoxication;
- introduction of 4% sodium bicarbonate solution to eliminate acidosis;
- forced diuresis;
- oxygen therapy;
- vitamins of group A and B, ascorbic and pantothenic acid for leveling the side effects of vitamin D;
- antibiotic therapy (penicillins, cephalosporins) to prevent the addition of a secondary bacterial infection;
- glucocorticosteroids (Prednisolone) in a short course to normalize intracellular processes;
- therapy of concomitant complications (for the correction of cardiovascular disorders, cardiac glycosides, adrenergic blockers, metabolites are used; drugs of the nitrofuran series and derivatives of nalidixic acid for the treatment of renal pathology; neuroprotectors for neurological symptoms, etc.).
Possible consequences
Vitamin D overdose can cause the following complications:
- renal failure;
- accession of a secondary infection;
- deposition of calcium crystals in the kidneys with the subsequent development of renal failure;
- toxic hepatitis;
- toxic damage to the myocardium;
- vascular calcification, early atherosclerosis;
- damage to the thyroid and parathyroid glands.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
