Correct Answer: C

Rationale: To obtain an accurate gentamicin serum level, the trough should be drawn immediately before administering the medication, and the peak level should be drawn 30 minutes after the dose. This timing allows for the assessment of the lowest and highest drug concentrations in the bloodstream, ensuring therapeutic levels are achieved while minimizing the risk of toxicity. Choice A is correct as it follows this timing protocol. Choices B and D have incorrect timing for peak and trough levels, which would not provide an accurate representation of the drug's concentration in the bloodstream.

Correct Answer: C

Rationale: Digoxin is the correct answer. It is a medication known for its positive inotropic effects, which increase cardiac output, and negative chronotropic effects, which slow the heart rate. These effects are achieved by inhibiting the sodium-potassium ATPase pump in myocardial cells. Therefore, Digoxin is commonly prescribed to manage conditions like heart failure and atrial fibrillation, where enhancing cardiac output and reducing heart rate are beneficial. Choices A, B, and D are incorrect because Heparin is an anticoagulant, Alprazolam is a benzodiazepine used for anxiety disorders, and Levothyroxine is a thyroid hormone replacement drug, none of which have the specified therapeutic effects on cardiac function.

Correct Answer: D

Rationale: Metformin is excreted by the kidneys, and impaired kidney function can lead to an increased risk of lactic acidosis, a serious side effect. Therefore, it is important to monitor kidney function regularly while a client is on Metformin. Hemoglobin A1C is used to monitor long-term glucose control, but kidney function is the priority for monitoring Metformin therapy.

Correct Answer: D

Rationale: The correct answer is D: Decreased incidence of acute manic episodes. Lithium is commonly used to treat bipolar disorder by helping to stabilize mood and reduce the intensity and frequency of manic episodes. This leads to better overall management of the disorder. Choices A, B, and C are incorrect because lithium is not known to reduce the risk of myocardial infarction, GI ulcers, or respiratory distress in patients with bipolar disorder.

Correct Answer: B

Rationale: When educating a client about Digoxin, it is crucial to instruct them to monitor their pulse before taking the medication. Digoxin can lead to bradycardia, so monitoring the pulse is essential to ensure it is not below 60 beats per minute before taking each dose. If the pulse is low, the client should hold the dose and seek guidance from their healthcare provider. Choices A, C, and D are incorrect. Taking Digoxin with food may affect its absorption, Digoxin is not known to increase appetite, and feeling nauseated does not necessarily indicate the need to discontinue the medication.