A nurse is providing education to a client with chronic asthma who has been prescribed the anti-leukotriene modifier montelukast. The nurse evaluates the client's understanding of the medication's purpose. Which statement by the client indicates understanding of the medication?

A. Antibiotic therapy reduces normal vaginal bacterial flora, resulting in a superinfection.: Broad-spectrum antibiotics destroy beneficial bacteria such as Lactobacillus that help maintain the acidic environment of the vagina. This disruption allows Candida albicans, a fungus normally present in small amounts, to overgrow and cause vaginal candidiasis.

B. The infection spreading from the patient's lungs to the new site of infection.: Upper respiratory infections are typically viral or bacterial and do not spread to the vagina. Vaginal candidiasis results from local fungal overgrowth, not from systemic infection migration.

C. Unprotected sex during antibiotic treatment.: Vaginal yeast infections are not sexually transmitted infections. Although sexual activity can sometimes worsen irritation, the underlying cause here is the alteration of normal vaginal flora due to antibiotic use.

D. An allergic reaction to the antibiotics.: Allergic reactions to antibiotics usually present as rash, itching, or anaphylaxis rather than fungal overgrowth. The vaginal symptoms in this case are due to an imbalance in normal microorganisms, not a hypersensitivity reaction.

A. An Antihistamine medication like fexofenadine.: Antihistamines are most effective for allergic symptoms such as sneezing, runny nose, and watery eyes. They can thicken secretions, making mucus more difficult to expel, which is not helpful for a client already producing thick sputum.

B. An Antitussive medication like dextromethorphan.: Antitussives suppress the cough reflex, which could prevent the clearance of mucus from the airways. In a client with productive coughing, this may lead to mucus retention and increase the risk of secondary infection.

C. A Decongestant medication like pseudoephedrine.: Decongestants primarily reduce nasal swelling and sinus pressure by vasoconstriction. They do not thin mucus or assist in mobilizing secretions from the lower airways, making them less effective for thick sputum production.

D. An Expectorant medication like guaifenesin.: Guaifenesin helps thin and loosen mucus in the airways, promoting more effective coughing and clearance of secretions. This facilitates airway patency and improves breathing comfort, making it the most appropriate for thick yellow mucus.