Nutrition Interventions for Children with Special Health Care Needs

Chapter 5 - Medication-Nutrient Interactions
Vitamin D
Long-term use of anticonvulsants has been associated with vitamin D deficiency,
resulting in rickets or osteomalacia (1). The effects of anticonvulsant therapy on
vitamin D status are multiplied by the following factors (1,4):
• multiple medication regimens
• inactivity
• little exposure to sunlight
• dark skin
• poor dietary intake of vitamin D
The anticonvulsants most frequently implicated in vitamin D deficiency are phenytoin
(Dilantin), phenobarbital, and carbamazepine (Tegretol). Primidone (Mysoline) and
valproic acid (Depakene/Depakote) have also been shown to be associated with
vitamin D deficiency and decreased bone mineral density (1,3,4).
Recent research on vitamin D has shown that optimal levels are much higher than
previously thought (>30ng/mL versus >20 ng/mL). Vitamin D deficiency has been
found to be widespread in the normal population, especially for those living at
greater than 45 degrees latitude (north or south) (5,6). It is imperative that vitamin
D levels are evaluated and deficiencies treated at time of initiation of anticonvulsant
therapy, and regularly thereafter. Children on anticonvulsant therapy who have
normal vitamin D levels should be given a prophylactic dose of up to 2000 IU
vitamin D daily. Those with documented deficiencies will need pharmacologic doses
prescribed by their physicians (7).
Folic Acid
Longterm use of anticonvulsants has also been strongly associated with folic acid
deficiency and possibly with deficiencies of other B vitamins and vitamin C. Folic acid
deficiency has been observed with phenytoin alone and in combination with other
medications; the strongest effects have been observed with multiple medication
regimens. There is some indication that folic acid supplementation may result in
more frequent seizures. However, supplementation with Dietary Reference Intake
(DRI) levels of folic acid and close monitoring of seizure activity is appropriate to
prevent folic acid deficiency (1). Folic acid deficiency is associated with hyperhomocysteinemia
which in turn increases risk for heart disease. Supplementation with folic
acid has been shown to both replete folic acid levels and decrease homocysteinema
levels in individuals on anticonvulsants (8,9).
60 Nutrition Interventions for Children With Special Health Care Needs