Which statement by a client taking phenytoin (Dilantin) indicates an understanding of the medication instructions?

The statement indicating an understanding of medication instructions for phenytoin is that using a soft toothbrush to brush teeth is the appropriate choice. Phenytoin is known to cause gum hyperplasia, which can lead to inflammation and irritation of the gums. Using a soft toothbrush helps to minimize trauma to the gum tissue and reduces the risk of further irritation or injury, promoting better oral hygiene and care.

Maintaining good dental hygiene is particularly important for patients on phenytoin to prevent complications such as gum disease, which can result from the medication's side effects. Therefore, this statement reflects a good understanding of safe practices while taking phenytoin.

The other statements present misunderstandings or concerns regarding proper medication administration and potential side effects. For instance, breaking capsules can interfere with the drug's efficacy, and forgetting a dose typically requires specific actions rather than skipping that dose, while sore throat is not typically a normal effect and should be evaluated.