Correct Answer: C

Rationale: Liver failure impairs metabolism, leading to increased medication concentrations. To prevent adverse effects, lower dosages are required when liver function is compromised.

Correct Answer: D

Rationale: Metformin's primary pharmacological action is to decrease hepatic glucose production. By reducing hepatic glucose production, metformin helps to lower blood sugar levels and improve insulin sensitivity in the liver.

Correct Answer: B

Rationale: When a client is receiving Gentamicin, the nurse should monitor serum creatinine levels to assess for nephrotoxicity. Gentamicin is known to potentially cause nephrotoxicity, leading to impaired kidney function. Monitoring serum creatinine levels helps in early detection of any kidney damage or dysfunction.

Correct Answer: C

Rationale: Lithium is typically administered orally to ensure proper absorption and distribution in the body. It is important to follow the prescribed route of administration to achieve the desired therapeutic effect and avoid potential adverse effects.

Correct Answer: B

Rationale: The correct answer is B. Visual disturbances, such as blurred vision or seeing halos, can be a sign of digoxin toxicity. It is crucial for the client to report any changes in vision to their healthcare provider promptly to prevent serious complications.