A client is admitted with bipolar disorder and lithium carbonate is prescribed. Before administering the daily dose, the practical nurse (PN) plans to monitor the client’s serum lithium levels. Which physiologic action necessitates frequent monitoring of serum lithium levels?

Choice A reason: Polyethylene glycol, a bowel prep for colonoscopy, requires rapid drinking at specified intervals to ensure effective colon cleansing. This osmotic laxative draws water into the bowel, promoting evacuation. Consistent, rapid intake ensures complete bowel clearance, critical for clear visualization during the procedure.

Choice B reason: Diluting polyethylene glycol with fruit juice is incorrect, as it may alter the solution’s osmotic balance, reducing efficacy. The preparation must remain undiluted to draw sufficient water into the colon for cleansing, making this instruction inappropriate for achieving a clear colonoscopy.

Choice C reason: Drinking polyethylene glycol with a meal is incorrect, as food can interfere with bowel cleansing. The solution is taken on an empty stomach, typically the day before the exam, to ensure the colon is clear, making this instruction counterproductive to the prep’s purpose.

Choice D reason: Watery diarrhea is the expected outcome of polyethylene glycol, not an adverse effect requiring reporting. It indicates effective bowel cleansing for colonoscopy. Instructing to report this normal response is unnecessary and may cause confusion, as diarrhea is the goal of the preparation.

Choice A reason: Peak and trough levels are relevant for drugs like antibiotics, not meloxicam, a nonsteroidal anti-inflammatory drug (NSAID). Meloxicam’s efficacy is assessed clinically, not via blood levels, as it reduces inflammation and pain, making this choice irrelevant for costochondritis management.

Choice B reason: Reassessing pain 30 minutes after meloxicam administration evaluates its effectiveness, as this NSAID inhibits cyclooxygenase, reducing prostaglandin-mediated inflammation and pain in costochondritis. Timely reassessment ensures adequate pain relief, guiding further interventions for breathing discomfort, making this the appropriate intervention.

Choice C reason: Involuntary lip and tongue movements are associated with antipsychotics, not meloxicam. This NSAID does not cause neurological side effects like tardive dyskinesia. Monitoring for this is irrelevant, as meloxicam’s primary concerns are gastrointestinal or renal, not movement disorders.

Choice D reason: Strict intake and output monitoring is unnecessary for meloxicam, which primarily affects inflammation, not fluid balance. While long-term use may impact kidneys, pain reassessment is more immediate for costochondritis, making this choice less relevant than evaluating therapeutic pain relief.