A nurse is preparing to administer phenytoin 125 mg oral suspension to a client who has epilepsy. Which of the following information should the nurse interpret from the medication label? (Refer to the medication label below.)

A. The label explicitly states that the product must be shaken well especially prior to initial use and before each use. This mechanical agitation is necessary to ensure the uniform distribution of the phenytoin particles within the liquid vehicle. Failure to shake the suspension can lead to inconsistent dosing and subtherapeutic or toxic plasma levels. B. The medication label provides a specific instruction to protect the drug from light to prevent photodegradation. Exposure to ultraviolet or intense visible light can compromise the chemical stability and potency of the anticonvulsant. Storing the medication in a well-lit area would contravene these safety guidelines and potentially render the treatment ineffective for seizure control. C. The manufacturer specifies storage at 20 to 25 degrees Celsius, which corresponds to 68 to 77 degrees Fahrenheit. This range is defined as USP controlled room temperature and is essential for maintaining the physical and chemical integrity of the suspension. Adhering to these thermal parameters prevents the precipitation or degradation of the active pharmaceutical ingredient. D. The label warns that a household teaspoon or tablespoon is not an adequate device for measuring the dose accurately. It recommends the use of a calibrated measuring device to ensure the patient receives the exact prescribed milligram amount. Using household cutlery increases the risk of dosing errors due to the lack of standardized volume measurements.