A nurse is reviewing the medication list for a client who has a new diagnosis of type 2 diabetes mellitus. The nurse should recognize which of the following medications can cause glucose intolerance?

Choice A reason: Vaginal cultures are not necessary for oral contraceptive therapy. They are used to diagnose infections such as bacterial vaginosis, yeast infection, or sexually transmitted diseases.

Choice B reason: Complete blood count is not essential for oral contraceptive therapy. It is used to measure the number and types of blood cells, such as red blood cells, white blood cells, and platelets.

Choice C reason: Serum potassium level is the most important laboratory test for oral contraceptive therapy. This is because some oral contraceptives can increase the risk of hyperkalemia, which is a high level of potassium in the blood. Hyperkalemia can cause serious complications such as cardiac arrhythmias, muscle weakness, and paralysis.

Choice D reason: Pregnancy test is not a laboratory test, but a urine test. It is important to rule out pregnancy before starting oral contraceptive therapy, but it is not the most important test for the nurse to assess.

Choice A reason: This is incorrect because reporting symptoms that last longer than 2 days is not specific to guaifenesin. This is a general instruction for any patient with a sinus infection, regardless of the medication they are taking.

Choice B reason: This is incorrect because reporting clear-colored sputum to the prescriber is not necessary. Clear-colored sputum indicates that the infection is improving and the mucus is thinning. This is a desired effect of guaifenesin, not a problem that needs to be reported.

Choice C reason: This is incorrect because guaifenesin does not have sedating effects. Guaifenesin is an expectorant that helps to break up and expel mucus from the respiratory tract. It does not cause drowsiness or impair the ability to drive or operate machinery.

Choice D reason: This is correct because increasing fluid intake is an important instruction for a patient taking guaifenesin. Fluids help to hydrate the body and thin the mucus, making it easier to cough up and clear the sinuses. Fluids also help to prevent dehydration and dryness of the mucous membranes.