Parents and caregivers should ensure the vitamin dropper is marked so that the units of measure are clear and easy to understand. ((Romeo Ranoco/Reuters))

Parents should only use the dropper that comes with liquid vitamin D supplements for infants, Health Canada says.

The department's alert follows a U.S. Food and Drug Administration advisory warning that some supplements come with droppers that hold more than the recommended 400 international units of vitamin D, which may result in parents or caregivers accidentally giving an excess dose to an infant under one year old.

Health Canada is reminding parents and caregivers to:

  • Only use the dropper that comes with the vitamin D supplement purchased because it is made specifically for that product. Do not use a dropper from another product or a spoon.
  • Ensure the dropper is marked so that the units of measure are clear and easy to understand. Also check that the units of measure correspond to those cited in the instructions. If you have questions about the proper dose, talk to a health-care professional before giving the supplement to the infant.
  • As with any health product, follow the manufacturer instructions carefully. Keep the vitamin D supplement with its original package so you and other caregivers can follow the instructions.
  • Infant formula contains vitamin D. If an infant is being fully or partly fed with infant formula, check with your pediatrician or other health-care professional before giving the child vitamin D supplements.

Health Canada said it has not received any reports suggesting dosing errors associated with the use of liquid vitamin D products in infants.

Vitamin D promotes calcium absorption in the gut and plays a key role in the development of strong bones. Deficiency can lead to bone problems such as rickets.

But excessive amounts may cause harmful health effects such as nausea and vomiting, loss of appetite, excessive thirst, frequent urination, constipation, abdominal pain, muscle weakness, muscle and joint aches, confusion, and fatigue, as well as more serious consequences like kidney damage, the FDA said.

Health Canada continues to recommend that all breastfed, healthy term infants aged 12 months and under receive a daily vitamin D supplement of 400 international units, the equivalent of 10 micrograms.