A client diagnosed with Parkinson's disease is prescribed carbidopa-levodopa. What is the primary mechanism of action of this medication?

It blocks acetylcholine release in the brain.

It enhances the reuptake of dopamine in the synapses.

It increases the production of dopamine in the brain.

It inhibits the breakdown of serotonin in the brain.

Answer and Explanation

The Correct Answer is C

Parkinson’s disease is a progressive neurodegenerative disorder characterized by the loss of dopamine-producing neurons in the substantia nigra of the brain. This dopamine deficiency leads to motor symptoms such as tremors, rigidity, bradykinesia, and postural instability. Carbidopa-levodopa is the standard pharmacologic treatment used to restore dopamine activity in the central nervous system. It works by increasing dopamine availability in the brain, improving motor function and reducing symptoms.

Rationale:
A. It blocks acetylcholine release in the brain is incorrect because carbidopa-levodopa does not directly inhibit acetylcholine activity. While anticholinergic drugs may be used in Parkinson’s disease to reduce tremors, this medication primarily targets dopamine replacement rather than acetylcholine suppression. Its main mechanism is not based on cholinergic blockade.

B. It enhances the reuptake of dopamine in the synapses is incorrect because carbidopa-levodopa does not work by increasing dopamine reuptake. Dopamine reuptake inhibitors are a different class of medications that prolong dopamine action in the synaptic cleft. Carbidopa-levodopa instead increases the actual synthesis of dopamine in the brain.

C. It increases the production of dopamine in the brain is correct because levodopa is a precursor that crosses the blood-brain barrier and is converted into dopamine in the central nervous system. Carbidopa prevents peripheral breakdown of levodopa, allowing more of it to reach the brain. This results in increased dopamine levels, improving motor control and reducing Parkinsonian symptoms.

D. It inhibits the breakdown of serotonin in the brain is incorrect because carbidopa-levodopa does not affect serotonin metabolism. Serotonin reuptake inhibition or breakdown prevention is associated with antidepressant medications, not antiparkinsonian therapy. The drug’s primary action is specifically related to dopamine synthesis rather than serotonin regulation.

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Free Nursing Study Resources

Correct Answer is A

Explanation

Hemodynamic instability in a postoperative client showing a progressive decline in level of consciousness and urine output can occur as a result of postoperative complications which include fluid volume loss, bleeding, or impaired perfusion leading to decreased cardiac output. Blood pressure trends are critical indicators of circulatory status. A falling blood pressure accompanied by bradycardia, decreased urine output, and altered mental status strongly suggests reduced tissue perfusion and shock-like physiology rather than elevated blood pressure states.

Rationale:

• Hypotension: The client’s blood pressure has dropped significantly from 124/78 mmHg to 88/56 mmHg, indicating decreased vascular perfusion and possible reduced cardiac output. This is supported by worsening mental status, bradycardia, and decreased urine output, which are classic signs of poor systemic perfusion. In postoperative clients, hypotension may result from hypovolemia, bleeding, or distributive causes. The downward trend in vital signs confirms a hypotensive state requiring urgent intervention.

• Hypertension: Hypertension would present with elevated blood pressure readings and is not consistent with the documented trend in this client. Instead of an increase, the client’s blood pressure has progressively decreased to hypotensive levels. Additionally, hypertension would not explain decreased urine output, worsening consciousness, or bradycardia in this context. Therefore, hypertension is not supported by the clinical findings.

A. Encourage client to ambulate independently to the bathroom B. Monitor neurological status closely C. Administer prescribed IV fluids to maintain hydration D. Place the client in Trendelenburg position

Correct Answer is {"A":{"answers":"B"},"B":{"answers":"A"},"C":{"answers":"A"},"D":{"answers":"B"}}

Explanation

This question focuses on prioritizing safe nursing interventions for a client presenting with sudden confusion, weakness, hypotension, and disorientation. These findings suggest impaired cerebral perfusion, possible dehydration, or an acute neurological or systemic event. Nursing care prioritizes safety, close neurological monitoring, and restoring circulating volume. Interventions that increase fall risk or worsen cerebral perfusion are contraindicated.

Rationale:

• Encourage client to ambulate independently to the bathroom: The client is confused, disoriented, and weak, placing them at high risk for falls and injury. Independent ambulation is unsafe because impaired cognition and hypotension reduce balance and coordination. The client requires assistance and fall precautions should remain in place. Therefore, encouraging independent ambulation is contraindicated.

• Monitor neurological status closely: Sudden confusion and disorientation indicate possible acute neurological or systemic compromise. Frequent neurological assessments help detect worsening mental status, stroke progression, or metabolic imbalance. Early identification of changes allows rapid intervention. This is a priority nursing action.

• Administer prescribed IV fluids to maintain hydration: The client’s low blood pressure (96/60 mmHg) and dry skin suggest possible hypovolemia contributing to decreased cerebral perfusion and confusion. IV fluids help restore circulating volume, improve blood pressure, and enhance tissue perfusion. This intervention supports stabilization of hemodynamic status. It is an appropriate and expected treatment.

• Place the client in Trendelenburg position: Trendelenburg positioning is no longer recommended for hypotension because it can reduce lung expansion and increase intracranial pressure. It may also worsen respiratory function and does not reliably improve cerebral perfusion. Safer alternatives include supine positioning with leg elevation if needed. Therefore, this position is contraindicated in this client.

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A client diagnosed with Parkinson's disease is prescribed carbidopa-levodopa. What is the primary mechanism of action of this medication?

Nursing Test Bank

Naxlex Comprehensive Predictor Exams

A nurse is caring for a postoperative client who has shown a gradual decline in level of consciousness and reduced urine output over the past few hours. The client is most likely experiencing: Select answer choice

Correct Answer is A

Explanation

A nurse is assessing a client presenting with sudden onset confusion and weakness in the emergency department. For each planned action, indicate whether it is anticipated or contraindicated in the client’s care.

Correct Answer is {"A":{"answers":"B"},"B":{"answers":"A"},"C":{"answers":"A"},"D":{"answers":"B"}}

Explanation

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