Overdose of vitamin D (cholecalciferol) exposes children to the risk of hypercalcaemia, the main manifestations of which are vomiting, refusal to breast feed, dehydration, urinary stone formation and calcium deposition in the kidneys.

A French poison control centre analysed 1255 calls received between January 2017 and April 2020, concerning proprietary medicines (Zyma D° and Adrigyl°) based on vitamin D alone and designed for use in infants. More than half of the cases involved self-administration by the child. Most often, the child had taken the bottle and drunk the solution, or had given it to a younger child to drink. The dose of vitamin D ingested ranged from a few drops to an entire 10 ml bottle.

Vitamin D was administered or splashed into an eye on 235 occasions, in 15 cases by the child itself. In 70 cases, eye exposure to vitamin D was accidental, resulting from mishandling during oral administration. 66 cases of overdose were linked to a defect in the bottle, e.g. a defective dropper with fluid coming out as a "spurt" rather than the limited flow expected, detachment of the dropper nozzle, etc.

Around one hundred cases of overdose were linked to communication failure between adults leading to administration of duplicate doses, to carelessness, to prescription errors, or to failure to properly understand a prescription. In 20 cases, vitamin D was administered orally in place of products supplied in bottles with a similar appearance.

Vitamin D supplementation is warranted for prevention of rickets. Regular large supplements of vitamin D should be avoided in children less than 12 months old. It is important to ensure that parents have properly understood the dose to administer, how to administer it, and what precautions to take with the dropper bottles, which, like other drugs, should always be stored out of reach of children.

©Prescrire 1 January 2022

Source: "Vitamin D in dropper bottles for infants and children: accidental overdoses and eye exposure" Prescrire International 2022; 31 (233): 20. Subscribers only.

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