Desmopressin for bed-wetting linked to convulsions in children

Australian authorities have issued a warning regarding a drug sometimes used to treat primary nocturnal enuresis (bed-wetting) in children.

According to the Therapeutic Goods Administration (TGA) it has received 68 reports of adverse reactions in relation to the drug Desmopressin, which is used as a nasal spray to limit urination in children.

The drug sold under the brand names Minirin or Octostim, also comes in oral tablet form and the TGA says there have been 17 reports of convulsions and 10 of hyponatremia (dangerously low levels of salt in the blood) following the use of the nasal spray, and seven children under 13 years of age were affected.

The TGA says the side-effects were mostly seen with the nasal spray formula, however the drug will not be removed from shelves but doctors have been warned to prescribe the product only when a bed-wetting alarm device has failed to work.

The TGA says excessive fluid intake should be avoided during treatment with Desmopressin as, if this occurs quickly it can result in a shift of water intracellularly and cerebral oedema; this causes symptoms such as nausea and vomiting, difficulty concentrating, confusion, lethargy, agitation, headache and seizures.

The TGA says an ongoing need for the products should be reviewed periodically in patients taking desmopressin in the long-term.

TGA guidelines concerning the drug were revised in 2007 after the Food and Drug Administration in the U.S. received 61 reports of serious adverse events, including two deaths, and removed it from sale - the nasal spray was implicated in 36 of the cases, with 25 involving children, however as many of those affected were also taking other medications, establishing a definite causal link was difficult.

The drug desmopressin works by limiting the amount of water that is eliminated in the urine and is the synthetic version of the natural antidiuretic hormone (ADH) arginine vasopressin - it mimics the effects of ADH and prevents excessive loss of water.

It is used to prevent excessive thirst, urination and dehydration caused by injury, surgery and certain medical conditions including a form of diabetes and certain blood disorders.

For further information see http://www.tga.gov.au/adr/aadrb/aadr0808.htm.