Correct Answer: A

Rationale: The best immediate action by the nurse in this situation is to place the client on a cardiac monitor immediately. A serum potassium level of 6.5 mmol/L indicates hyperkalemia, which can lead to life-threatening dysrhythmias. Monitoring the cardiac status is crucial to detect any potential arrhythmias promptly. Teaching the client to limit high-potassium foods (Choice B) may be important for long-term management, but it is not the priority at this moment. Continuing to monitor intake and output (Choice C) is important for assessing renal function but does not address the immediate risk of dysrhythmias. Asking to have the laboratory redraw the blood specimen (Choice D) is unnecessary since the current results indicate a critical situation that requires immediate action.

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.

Correct Answer: C

Rationale: The correct answer is 16 mcg/mL (Choice C). The therapeutic serum phenytoin range is typically 10 to 20 mcg/mL. A level below this range may lead to continued seizure activity, indicating subtherapeutic levels. Choices A, B, and D are below the therapeutic range and would not be considered therapeutic for a client with a seizure disorder on phenytoin therapy.

Correct Answer: C

Rationale: An abrupt increase in pain following a percutaneous kidney biopsy may indicate internal hemorrhage. Assessing the client's pulse rate and blood pressure is crucial as changes in vital signs can be indicative of hemorrhage. This assessment is essential in determining the client's hemodynamic status and the need for immediate intervention. Repositioning the client, administering pain medication, or checking urine color are not the priority actions in this situation and may delay necessary interventions for potential hemorrhage.

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.