A nurse is caring for a client who has a prescription for levothyroxine.

Which of the following laboratory tests should the nurse monitor?

Phenytoin is known to cause gingival hyperplasia, which is characterized by swollen and enlarged gums. This side effect is more common in long-term use and may require dental care and regular oral hygiene practices.

Phenytoin is known to be associated with an increased risk of birth defects in babies born to women taking the medication during pregnancy. It is important for women of childbearing age to discuss the risks and benefits of phenytoin with their healthcare provider and use effective contraception to avoid pregnancy while taking the medication.

Phenytoin can affect liver function, so regular monitoring of liver enzymes and blood levels of the medication is necessary. The frequency of blood work may vary depending on the individual's specific situation, so it is important to follow the healthcare provider's instructions. It is not advisable to skip a dose of phenytoin without consulting a healthcare provider.

Abruptly stopping or missing doses of antiepileptic medications can lead to breakthrough seizures or other complications. Any changes in the medication regimen should be discussed with the healthcare provider.

Headaches are a common side effect of isosorbide dinitrate, especially when initially starting the medication. However, they often improve as the body adjusts to the medication. It is important to reassure the client that the headaches should decrease over time. If the headaches persist or worsen, the client should inform their healthcare provider for further evaluation and possible adjustment of the medication regimen.

The statement about taking the medication on an empty stomach is not relevant to preventing headaches associated with isosorbide dinitrate.

The statement about swallowing the tablet whole does not address the issue of headaches. Chewable isosorbide dinitrate is designed to be chewed or dissolved in the mouth, and swallowing it whole may not provide the intended therapeutic effect.

Discontinuing the medication until the headache goes away is not recommended without consulting the healthcare provider. Abruptly stopping or changing the dose of isosorbide dinitrate can have serious consequences and should only be done under medical supervision.