Correct Answer: D

Rationale: The correct answer is D. The desired action of oral contraceptives can be reduced when taken with tetracyclines like doxycycline. Therefore, patients on oral contraceptives should be advised to use a backup contraception method while taking doxycycline. Choice A is incorrect because nausea and vomiting are common adverse effects of doxycycline. Choice B is incorrect because doxycycline is not known for causing teratogenic effects. Choice C is incorrect because dairy products can interfere with the absorption of doxycycline, so they should be avoided when taking this medication.

Correct Answer: A

Rationale: When a patient on TMP-SMX presents with a petechial rash, it can be indicative of a severe adverse reaction such as thrombocytopenia or a hypersensitivity reaction. The appropriate action for the nurse to take in this situation is to hold the dose of TMP-SMX and notify the healthcare provider immediately. This is crucial to prevent further administration of a medication that may be causing a serious adverse effect. Requesting a blood glucose level (Choice B) is not relevant in this scenario as the patient's presentation is suggestive of a skin-related issue rather than a glucose-related problem. Similarly, requesting a BUN and creatinine level (Choice C) would not address the immediate concern of a petechial rash and its association with TMP-SMX. Requesting an order for diphenhydramine (Choice D) may help manage itching or mild allergic reactions but is not the priority when a petechial rash is observed, as it may indicate a more severe reaction requiring immediate intervention.

Correct Answer: B

Rationale: The correct answer is B: To decrease bacterial resistance. Trimethoprim-sulfamethoxazole (TMP-SMX) is a combination drug used to prevent bacterial resistance to sulfonamides. It works by targeting different steps in the bacterial metabolic pathway, making it harder for bacteria to develop resistance. Choice A is incorrect because the combination does not broaden the antibacterial spectrum; instead, it enhances effectiveness against specific bacteria. Choice C is incorrect as taste improvement is not the primary reason for combining these drugs. Choice D is incorrect because while combination therapy can sometimes help minimize toxic effects, the primary purpose in this case is to address bacterial resistance.

Correct Answer: D

Rationale: The correct answer is D: 'Complaints of feeling sweaty.' Scopolamine, an anticholinergic medication, commonly causes the side effect of decreased sweating, not increased urine output or pupil constriction. While dry mouth is a possible side effect, it is less likely than the altered sweating pattern. Therefore, the nurse should monitor the client for complaints of feeling sweaty due to the potential side effect of decreased sweating associated with scopolamine.

Correct Answer: C

Rationale: When a patient has a history of rash from penicillin, it indicates a potential allergic reaction to penicillin and other related drugs, such as amoxicillin. It is crucial to avoid administering penicillins to such patients unless there is no alternative. The nurse's best action in this situation is to contact the provider to discuss using a different antibiotic from a different class. This approach helps prevent potential severe allergic reactions. While epinephrine and antihistamines are used to manage allergic reactions, administering amoxicillin despite the known allergy is not advisable and could lead to serious consequences. Requesting a beta-lactamase-resistant drug does not address the issue of potential allergic reactions in this scenario.