What is the effect of being a poor metabolizer of phenytoin in a client?

Being a poor metabolizer of phenytoin means that the client's body processes the drug more slowly than average. Phenytoin is primarily metabolized in the liver, and individuals classified as poor metabolizers have a genetic variation that affects the enzymes responsible for breaking down this medication. As a result, the drug remains in the bloodstream for a longer duration because it is not cleared efficiently. This prolonged presence can lead to higher plasma levels of phenytoin, increasing the risk of side effects and toxicities associated with the medication. Therefore, option C accurately reflects the consequence of being a poor metabolizer of phenytoin, highlighting the need for careful monitoring and potentially adjusted dosing in these patients.