In Europe they are not generally recommended.There is tentative evidence that vasopressin receptor antagonists (vaptans), such as conivaptan, may be slightly more effective than fluid restriction in those with high volume or normal volume hyponatremia. They should not be used in people with low volume. They may also be used in people with chronic hyponatremia due to SIADH that is insufficiently responsive to fluid restriction and/or sodium tablets.Demeclocycline, while sometimes used for SIADH, has significant side effects including potential kidney problems and sun sensitivity. In many people it has no benefit while in others it can result in overcorrection and high blood sodium levels.Daily use of urea by mouth, while not commonly used due to the taste, has tentative evidence in SIADH. However, it is not available in many areas of the world. Precautions
Raising the serum sodium concentration too rapidly may cause osmotic demyelination syndrome. Rapid correction of sodium levels can also lead to central pontine myelinolysis (CPM). It is recommended not to raise the serum sodium by more than 10 mEq/L/day. Epidemiology
Hyponatremia is the most commonly seen water–electrolyte imbalance. The disorder is more frequent in females, the elderly, and in people who are hospitalized. The number of cases of hyponatremia depends largely on the population. In hospital it affects about 15–20% of people; however, only 3–5% of people who are hospitalized have a sodium level less than 130 mmol/L.
Deficient populations
In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency gives rise to hypothyroidism, symptoms of which are extreme fatigue, goiter, mental slowing, depression, weight gain, and low basal body temperatures.Iodine deficiency is the leading cause of preventable mental retardation, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations, but as of March 2006, iodine deficiency remained a serious public health problem in the developing world.Iodine deficiency is also a problem in certain areas of Europe. In Germany it has been estimated to cause a billion dollars in health care costs per year. A modelling analysis suggests universal iodine supplementation for pregnant women in England may save £199 (2013 UK pounds) to the health service per pregnant woman and save £4476 per pregnant woman in societal costs.Iodine deficiency was previously a common disease in Norway, because the content of iodine in the drinking water was low. Before 1950 goiter was a widespread disease caused by iodine deficiency. Up to 80 per cent of the population were affected in inland areas. In the coastal communities, saltwater fish were an important part of the diet, and because of the presence of iodine in seawater, goiter was less common than in the inland districts. From the 1950s, Norwegians started adding iodine to dairy cow feed.