Registration Exam for Practical Nursing (REx-PN) Practice Test

The most important aspect to communicate to a client starting phenytoin is that regular blood level monitoring is essential for safety. Phenytoin is an anticonvulsant medication used primarily to manage seizures, and it has a narrow therapeutic index, meaning that the range between an effective dose and a harmful dose is quite small.

Regular monitoring of serum phenytoin levels is necessary to ensure that the drug remains within this therapeutic range. Levels that are too low may lead to uncontrolled seizures, while levels that are too high can cause toxicity, resulting in adverse effects such as drowsiness, nausea, or even more severe complications like ataxia or encephalopathy. This consideration is critical to safe medication management and effective seizure control.

Furthermore, while it is also important to consider how phenytoin is taken (with or without food) and be aware of potential drug interactions, the foundational knowledge of the need for consistent monitoring addresses the significant risks associated with fluctuations in drug levels.