A client with type 2 diabetes mellitus is prescribed metformin, a biguanide antidiabetic agent. The nurse should instruct the client to monitor for which adverse effect of this medication?

Disequilibrium syndrome is a neurological complication of hemodialysis that occurs when the rate of solute removal from the blood exceeds the rate of solute removal from the brain, creating an osmotic gradient that causes fluid to shift into the brain cells, resulting in cerebral edema. Symptoms of disequilibrium syndrome include headache, nausea, vomiting, restlessness, confusion, and seizures. It usually occurs during or shortly after the first few dialysis sessions or when there is a large decrease in blood urea nitrogen (BUN) levels.

Incorrect options:

A) Hyperkalemia - This is an incorrect option, as hyperkalemia is a common complication of CKD that occurs when the kidneys are unable to excrete excess potassium. Hemodialysis helps to lower potassium levels by removing it from the blood. However, hyperkalemia may occur between dialysis sessions if the client consumes foods high in potassium or takes medications that increase potassium levels, such as angiotensin-converting enzyme (ACE) inhibitors or potassium-sparing diuretics.

B) Hypertension - This is an incorrect option, as hypertension is a common complication of CKD that occurs when the kidneys are unable to regulate fluid and sodium balance. Hemodialysis helps to lower blood pressure by removing excess fluid and sodium from the blood. However, hypertension may occur between dialysis sessions if the client consumes foods high in sodium or fluid or takes medications that increase blood pressure, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids.

C) Hypocalcemia - This is an incorrect option, as hypocalcemia is a common complication of CKD that occurs when the kidneys are unable to activate vitamin D and promote calcium absorption from the gut. Hemodialysis helps to correct hypocalcemia by adding calcium to the dialysate solution. However, hypocalcemia may occur between dialysis sessions if the client consumes foods low in calcium or takes medications that lower calcium levels, such as phosphate binders or bisphosphonates.

Lactic acidosis is a rare but potentially fatal complication of metformin therapy, especially in clients with renal impairment, liver disease, heart failure, or alcohol abuse. It occurs when metformin accumulates in the body and causes an increase in lactate production and a decrease in lactate clearance, leading to metabolic acidosis. Symptoms of lactic acidosis include nausea, vomiting, abdominal pain, hyperventilation, muscle weakness, and confusion.

Incorrect options:

A) Hypoglycemia - This is an incorrect option, as metformin does not cause hypoglycemia by itself. However, hypoglycemia may occur if metformin is combined with other antidiabetic agents that lower blood glucose levels, such as sulfonylureas or insulin.

C) Pancreatitis - This is an incorrect option, as metformin does not cause pancreatitis. However, pancreatitis may occur as a complication of diabetes mellitus or as an adverse effect of other antidiabetic agents, such as glucagon-like peptide-1 (GLP-1) agonists or dipeptidyl peptidase-4 (DPP-4) inhibitors.

D) Hepatotoxicity - This is an incorrect option, as metformin does not cause hepatotoxicity. However, hepatotoxicity may occur as a complication of diabetes mellitus or as an adverse effect of other antidiabetic agents, such as thiazolidinediones or alpha-glucosidase inhibitors.