Which statement by a client indicates potential phenytoin toxicity?

The statement indicating potential phenytoin toxicity is related to the client feeling unsteady when walking. Phenytoin, an anticonvulsant medication, can lead to several side effects, including ataxia, which is characterized by unsteadiness and coordination issues. This symptom suggests that the drug may be causing central nervous system effects that could indicate a higher-than-therapeutic level of phenytoin in the body.

Phenytoin has a narrow therapeutic index, and signs of toxicity can include neurological symptoms such as dizziness, unsteadiness, lethargy, and confusion. Therefore, a report of feeling unsteady aligns with the potential for phenytoin toxicity and warranting further evaluation.

Other statements, while they may indicate certain side effects or issues, do not directly point to phenytoin toxicity. For example, increased urination at night may be related to other factors, such as fluid intake or certain medical conditions. A metallic taste can occur but is not a definitive sign of toxicity, and puffy, red gums are associated with gingival hyperplasia, a common side effect of long-term phenytoin use, rather than an indication of toxicity.