A medical student is involved in a summer research project evaluating the potencies of the α-adrenergic agonists at different receptor sites. Which of the following α-adrenergic agonists would be expected to have the strongest potency at the α-receptor?

Correct Answer: C

Rationale: In this question, the correct answer is C) Norepinephrine. Norepinephrine is expected to have the strongest potency at the α-receptor because it is a direct α-adrenergic agonist, specifically targeting α-adrenergic receptors. Norepinephrine has a higher affinity for α-receptors compared to other options. Acetylcholine (option A) is a neurotransmitter that acts on cholinergic receptors, not adrenergic receptors. Epinephrine (option B) has mixed effects on α and β-adrenergic receptors, so it would not have the strongest potency specifically at the α-receptor. Metanephrine (option D) is a metabolite of epinephrine and does not directly bind to adrenergic receptors. Educationally, understanding the potency of different α-adrenergic agonists is crucial in pharmacology and clinical practice. Knowing which agonist has the strongest potency at specific receptors helps healthcare professionals make informed decisions when selecting medications for patients with various conditions such as hypertension or shock.

Correct Answer: B

Rationale: The correct answer is B) Inhibition of COMT. Rationale: Tolcapone is a catechol-O-methyltransferase (COMT) inhibitor. COMT is an enzyme that breaks down levodopa outside the blood-brain barrier, reducing the amount of levodopa available to cross into the brain and be converted to dopamine. By inhibiting COMT, tolcapone increases the availability of levodopa in the brain, enhancing its therapeutic effects in Parkinson's disease. Explanation of other options: A) Increased norepinephrine synthesis: This is not directly related to the mechanism of action of tolcapone in treating Parkinson's disease. Norepinephrine is not the primary neurotransmitter affected in Parkinson's. C) Inhibition of MAO: Monoamine oxidase (MAO) inhibitors are a different class of drugs used in depression and anxiety disorders, not Parkinson's disease. MAO inhibitors do not have a direct role in increasing dopamine levels in the brain. D) Stimulation of acetylcholine release: While acetylcholine does play a role in Parkinson's disease, the primary focus of treatment is on increasing dopamine levels, not acetylcholine release. Stimulation of acetylcholine release would not be the primary mechanism of action for improving Parkinson's symptoms. Educational context: Understanding the mechanisms of action of drugs used in Parkinson's disease is crucial for nurses and healthcare professionals caring for patients with this condition. By grasping how medications like tolcapone work, healthcare providers can make informed decisions about treatment options and monitor for potential side effects or interactions. This knowledge enhances patient care and safety in managing Parkinson's disease effectively.

Correct Answer: D

Rationale: The correct answer to this question is D) 10g-100 cups. Caffeine is a central nervous system stimulant that can be lethal in high doses. The lethal dose of caffeine for an adult is generally considered to be around 10 grams. Option A) 2g-20 cups and Option B) 4g-40 cups are too low to reach a lethal dose of caffeine. Option C) 8g-80 cups is closer but still below the lethal threshold of 10 grams. In an educational context, it is important to understand the potential dangers of caffeine overdose, especially in vulnerable populations like individuals with suicidal ideations. This question highlights the need for healthcare professionals to be aware of the risks associated with caffeine consumption and to monitor individuals who may be at risk for overdose. It also underscores the importance of providing appropriate mental health support and interventions for individuals in high-risk situations.

Correct Answer: C

Rationale: The correct answer is C) Consider discontinuing her medication. The patient is exhibiting symptoms of tardive dyskinesia, a common side effect of long-term use of antipsychotic medications like fluphenazine. Tardive dyskinesia presents as involuntary movements, such as lip puckering, and is irreversible in some cases. Discontinuing the offending medication is crucial to prevent further worsening of symptoms. Option A is incorrect because adding another neuroleptic can exacerbate the symptoms of tardive dyskinesia and is not recommended. Option B, asking about illicit drug use, is not the immediate priority in this scenario, as the patient's symptoms are likely due to her prescribed medication. Option D, increasing the dose of fluphenazine, is contraindicated as it can worsen the symptoms of tardive dyskinesia. This question highlights the importance of monitoring patients on long-term antipsychotic therapy for the development of tardive dyskinesia. Healthcare providers need to be vigilant in recognizing and managing side effects to ensure the overall well-being of their patients. It also emphasizes the need for regular follow-up and assessment of medication side effects in individuals with chronic mental health conditions.

Correct Answer: B

Rationale: In this scenario, the correct answer is B) β-Adrenergic receptors. Chlorpromazine, a low-potency typical antipsychotic, primarily antagonizes dopamine receptors, leading to side effects like dry mouth, constipation, blurred vision, and fatigue. However, it spares β-adrenergic receptors from antagonism. β-Adrenergic receptors are not directly affected by chlorpromazine's mechanism of action. Option A) α-Adrenergic receptors are not the correct answer because chlorpromazine can antagonize these receptors, leading to side effects like orthostatic hypotension and dizziness. Option C) Dopamine receptors are the primary target of chlorpromazine, not spared. Option D) Histamine receptors are antagonized by chlorpromazine, leading to sedation and weight gain in patients. Educationally, understanding the pharmacological actions of antipsychotic medications like chlorpromazine is crucial for nurses and healthcare professionals when managing patients with schizophrenia. Knowing the receptor profiles affected by these drugs helps in anticipating and managing potential side effects effectively.