The nurse is reviewing the laboratory results of a serum medication level assay for a client seen in the health care clinic who has been taking phenytoin for the control of seizures. the nurse determines that a subtherapeutic level of phenytoin is present and that additional medication is required if which level is found?

The answer to the question above is 1.3 mcg/mL. This is the level found which would make the nurse decide to have a required additional medication. Phenytoin is a common anti-seizure medication. Usually, the serum level of phenytoin is often checked in order to ensure effectiveness and safe levels. It is determined that the therapeutic level of phenytoin for adults is 10.0-20.0 mcg/mL.