Severe osteomalacia and rickets have been seen in a few patients taking phenytoin
. Rises in phenytoin
levels have also been described in a very small number of patients. Fosphenytoin, a prodrug of phenytoin
, may interact similarly.
importance of this interaction is unknown, but bear it in mind in case of an unexpected response to treatment. Indicators of phenytoin toxicity
include blurred vision, nystagmus, ataxia or drowsiness.