Phenytoin appears to derive its anticonvulsant action from

Correct Answer: A

Rationale: In this question, the correct answer is A) Selective inhibition of high-frequency neuronal discharges. Phenytoin, an anticonvulsant drug, works by stabilizing the neuronal membranes and inhibiting the spread of seizure activity by selectively blocking sodium channels. Option B) Selective inhibition of the epileptic focus is incorrect because phenytoin does not specifically target the epileptic focus but rather acts on high-frequency neuronal discharges in a more generalized manner. Option C) Selective inhibition of T-type Ca2+ current in brain cells is incorrect because phenytoin primarily targets sodium channels rather than calcium channels. Option D) Selective enhancement of inhibitory transmission in the brain is incorrect because phenytoin's mechanism of action involves reducing excitability rather than enhancing inhibition. Educationally, understanding the mechanism of action of anticonvulsant drugs like phenytoin is crucial for nurses and healthcare professionals to effectively manage and care for patients with seizure disorders. Knowing how these medications work helps in proper administration, monitoring for therapeutic effects, and recognizing and managing potential side effects or adverse reactions.

Correct Answer: B

Rationale: Rationale: The correct answer is B) Minimizes on-off effect. Carbidopa is often used in combination with levodopa in the treatment of Parkinsonism. Carbidopa's primary role is to inhibit the peripheral decarboxylation of levodopa, allowing more levodopa to reach the brain where it can be converted to dopamine. This helps minimize the on-off effect commonly seen with levodopa therapy, where patients experience fluctuations in their symptoms. Option A) Inhibits development of involuntary movements is incorrect because carbidopa does not directly inhibit the development of involuntary movements; rather, it helps improve the effectiveness of levodopa in managing these symptoms. Option C) Inhibits occurrence of behavioral abnormalities is incorrect as carbidopa's main function is not related to the inhibition of behavioral abnormalities in Parkinsonism. Option D) Accentuates nausea and vomiting is incorrect because carbidopa does not directly accentuate nausea and vomiting; in fact, it is often used in combination with levodopa to reduce gastrointestinal side effects associated with levodopa therapy. Understanding the role of carbidopa in combination with levodopa is crucial for healthcare professionals managing patients with Parkinsonism. By preventing the peripheral breakdown of levodopa, carbidopa enhances the therapeutic effects of levodopa while reducing some of its side effects, such as the on-off phenomenon. This knowledge is essential for optimizing treatment outcomes and improving the quality of life for patients with Parkinsonism.

Correct Answer: A

Rationale: In this question, the correct answer is A) Prolactin. Chlorpromazine is a typical antipsychotic medication that belongs to the class of phenothiazines. One of the common side effects of phenothiazines like chlorpromazine is hyperprolactinemia, which is an increased secretion of prolactin. Prolactin is a hormone produced by the pituitary gland that plays a role in lactation and reproductive function. Option B) Gonadotropin is incorrect because chlorpromazine does not directly affect the secretion of gonadotropins, which are hormones that regulate the function of the ovaries and testes. Option C) Corticotropin is incorrect because chlorpromazine does not significantly impact the secretion of adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands to produce cortisol. Option D) Antidiuretic hormone is incorrect because chlorpromazine does not have a direct effect on the secretion of antidiuretic hormone, which regulates water reabsorption in the kidneys. In an educational context, understanding the side effects and mechanisms of action of medications like chlorpromazine is crucial for nurses and healthcare professionals who administer these drugs to patients. It helps in anticipating and managing potential adverse effects and ensuring patient safety. This knowledge also aids in patient education and counseling regarding medication adherence and possible side effects.

Correct Answer: D

Rationale: The correct answer is D) Antidepressant. Explanation of why D is correct: When there is a blockade of noradrenaline and serotonin (5-HT) reuptake in the brain, it leads to increased concentrations of these neurotransmitters in the synaptic cleft. This increase in neurotransmitter levels helps to improve mood regulation, which is the basis of how antidepressants work. By enhancing the transmission of these monoamines, antidepressants help alleviate symptoms of depression and improve overall mood. Explanation of why others are wrong: A) Antipsychotic: Antipsychotic drugs primarily target dopamine receptors in the brain to help manage symptoms of psychosis, such as hallucinations and delusions. They do not primarily work by affecting noradrenaline and serotonin reuptake like antidepressants do. B) Antianxiety: Drugs used to treat anxiety disorders often target gamma-aminobutyric acid (GABA) receptors to help reduce feelings of anxiety and promote relaxation. They do not primarily work by affecting noradrenaline and serotonin reuptake. C) Antiparkinsonian: Antiparkinsonian medications primarily target dopamine pathways in the brain to help manage symptoms of Parkinson's disease, such as tremors and rigidity. They do not primarily work by affecting noradrenaline and serotonin reuptake. Educational context: Understanding the mechanisms of action of different classes of drugs is crucial for healthcare professionals, especially nurses, to effectively administer medications, monitor patient responses, and educate patients about their treatment plans. Knowing how antidepressants work in the brain can help nurses provide comprehensive care to patients with depression, ensuring they receive the appropriate medications and support for their mental health needs.

Correct Answer: A

Rationale: The correct answer is A) Methylphenidate for hyperkinetic children. Methylphenidate is a central nervous system stimulant commonly used to treat attention deficit hyperactivity disorder (ADHD) in children. It works by increasing the levels of certain neurotransmitters in the brain, helping to improve focus, attention, and impulse control in hyperactive children. Option B) Nikethamide is not the drug of choice for hyperkinetic children. Nikethamide is a respiratory stimulant used to treat respiratory depression, not ADHD or hyperactivity. Option C) Caffeine is a stimulant but is not the drug of choice for hyperkinetic children. Caffeine can exacerbate hyperactivity and is not recommended for children with ADHD. Option D) Clonazepam is a benzodiazepine, which is a central nervous system depressant. It is not the drug of choice for hyperkinetic children as it can worsen symptoms of hyperactivity and is not indicated for ADHD. In an educational context, understanding the appropriate pharmacological treatment for hyperkinetic children is crucial for healthcare professionals working with pediatric patients. By knowing the mechanism of action and appropriate use of medications like methylphenidate, nurses and other healthcare providers can effectively manage symptoms and improve outcomes for children with ADHD. It is important to be able to differentiate between various CNS stimulants and depressants to provide safe and effective care for pediatric patients with neurobehavioral disorders.