A client with Parkinson's disease is prescribed carbidopa-levadopa [Sinemet]. Which of the following side effects does the nurse recognize can occur with this medication?

A) A normal finding:
A normal finding during an edrophonium (Tensilon) test is an improvement in muscle strength for clients with myasthenia gravis (MG). If the client becomes weaker after the dose, it indicates that the test results are not typical and suggest a different issue, not a normal response. This is not a normal finding.

B) A myasthenia gravis crisis due to drug undermedication:
In a myasthenic crisis, the client experiences severe weakness and respiratory difficulty, typically due to insufficient medication (e.g., pyridostigmine). While a myasthenic crisis could cause weakness and respiratory distress, the edrophonium test would typically show improvement in muscle strength if the crisis is due to undermedication. Since the client became weaker after receiving edrophonium, this is not indicative of a myasthenic crisis.

C) An allergic reaction:
An allergic reaction to the edrophonium test would typically result in symptoms such as rash, swelling, or difficulty breathing due to hypersensitivity, but it does not typically cause weakness as the primary response. The worsening of symptoms after the test is more likely related to drug overmedication rather than an allergic reaction.

D) A cholinergic crisis due to drug overmedication:
A cholinergic crisis occurs when there is an overdose of acetylcholinesterase inhibitors (e.g., pyridostigmine or neostigmine), which can lead to excessive acetylcholine at the neuromuscular junction, resulting in muscle weakness and respiratory failure. The edrophonium test helps differentiate between a myasthenic crisis and a cholinergic crisis. If the client becomes weaker after the administration of edrophonium, it suggests a cholinergic crisis due to drug overmedication.

A) Spironolactone:
Spironolactone is a potassium-sparing diuretic commonly used in the treatment of heart failure. Unlike other diuretics, spironolactone works by antagonizing aldosterone, a hormone that promotes sodium and water retention and potassium excretion. By blocking aldosterone's action, spironolactone prevents the kidneys from excreting potassium, thus increasing potassium levels in the blood (hyperkalemia). Additionally, spironolactone can lead to hyponatremia (low sodium levels), as it also causes the kidneys to retain sodium and water, diluting sodium levels in the blood.

B) Furosemide:
Furosemide, a loop diuretic, is typically used in heart failure to remove excess fluid. It works by inhibiting the reabsorption of sodium, chloride, and potassium in the loop of Henle, which increases urine output. While furosemide can cause hypokalemia (low potassium levels) due to the increased excretion of potassium, it does not typically cause hyperkalemia.

C) Hydrochlorothiazide:
Hydrochlorothiazide is a thiazide diuretic, which works by inhibiting sodium and chloride reabsorption in the distal convoluted tubule of the kidney, leading to increased urine production. Thiazide diuretics can cause hypokalemia (low potassium levels) and hyponatremia (low sodium levels) due to the enhanced excretion of both electrolytes.

D) Metolazone:
Metolazone is also a thiazide-like diuretic that works similarly to hydrochlorothiazide. It can cause hypokalemia and hyponatremia, but like hydrochlorothiazide, it does not typically cause hyperkalemia. Metolazone is more potent than hydrochlorothiazide but still does not carry the risk of hyperkalemia like spironolactone does.