The nurse caring for a patient with a productive cough would anticipate an order for the following medication:

Choice A reason: This is incorrect. Distributing the doses evenly throughout the day may increase the risk of daytime sedation and impair the client's ability to perform daily activities. Diphenhydramine is a sedating antihistamine that causes drowsiness and reduces alertness.

Choice B reason: This is correct. Taking most of the daily dose at bedtime may minimize daytime sedation and help the client sleep better at night. Diphenhydramine is often used as a short-term treatment for insomnia.

Choice C reason: This is incorrect. Taking the medication with meals does not affect the sedative effect of diphenhydramine. It may only reduce the risk of stomach upset, which is not a common side effect of diphenhydramine.

Choice D reason: This is incorrect. Gradually decreasing the dose once tolerance to the effect is reached may not be advisable, as it may reduce the effectiveness of the medication for relieving pruritus. Diphenhydramine is an antihistamine that blocks the action of histamine, a chemical that causes itching and inflammation in allergic reactions.

Choice A reason: Dextromethorphan (Robitussin) is not the correct medication for a patient with a productive cough. Dextromethorphan is a cough suppressant that works by acting on the brain to reduce the cough reflex. Dextromethorphan is used for a dry, nonproductive cough that is caused by irritation or inflammation. Dextromethorphan is not effective for a productive cough that produces mucus, and it may even be harmful by preventing the clearance of secretions from the lungs.

Choice B reason: Fluticasone (Flonase) is not the correct medication for a patient with a productive cough. Fluticasone is a corticosteroid that works by reducing inflammation and swelling in the nasal passages. Fluticasone is used for allergic rhinitis, which is a condition that causes sneezing, itching, and runny nose due to an allergic reaction. Fluticasone is not effective for a productive cough that produces mucus, and it may even worsen it by suppressing the immune system and increasing the risk of infection.

Choice C reason: Pseudoephedrine (Sudafed) is not the correct medication for a patient with a productive cough. Pseudoephedrine is a decongestant that works by constricting the blood vessels in the nasal passages and sinuses. Pseudoephedrine is used for nasal congestion, which is a condition that causes stuffy nose and difficulty breathing due to swelling of the mucous membranes. Pseudoephedrine is not effective for a productive cough that produces mucus, and it may even cause side effects such as increased blood pressure, insomnia, and anxiety.

Choice D reason: Guaifenesin (Mucinex) is the correct medication for a patient with a productive cough. Guaifenesin is an expectorant that works by thinning and loosening the mucus in the chest and throat. Guaifenesin is used for a productive cough that produces mucus, as it helps the cough to be more effective and clear the airways. Guaifenesin is generally safe and well tolerated, but it may cause some minor side effects such as nausea, vomiting, and headache.