The antiparkinsonian drug which acts by inhibiting the degradation of dopamine in the brain is

Correct Answer: C

Rationale: In this question, the correct answer is C) Selegiline. Selegiline is a selective and irreversible inhibitor of monoamine oxidase B (MAO-B) enzyme. MAO-B is responsible for the breakdown of dopamine in the brain. By inhibiting this enzyme, selegiline increases dopamine levels in the brain, which helps in managing symptoms of Parkinson's disease. Option A) Carbidopa is incorrect because it doesn't directly inhibit the degradation of dopamine. Carbidopa is often used in combination with levodopa to prevent its peripheral conversion to dopamine and enhance its central effects. Option B) Amantadine is incorrect because it mainly works by increasing dopamine release from nerve endings and also has NMDA receptor antagonist properties. It does not inhibit dopamine degradation. Option D) Bromocriptine is incorrect because it is a dopamine agonist that directly stimulates dopamine receptors in the brain, rather than inhibiting dopamine degradation. Understanding how different antiparkinsonian drugs work is crucial for healthcare professionals to make informed decisions when treating patients with Parkinson's disease. Knowing the mechanisms of action of these drugs helps in tailoring treatment plans to individual patient needs and optimizing therapeutic outcomes.

Correct Answer: A

Rationale: In pharmacology, understanding the actions and effects of CNS drugs like lithium is crucial for safe and effective patient care. The correct answer, A) "It has a sedative action in normal individuals," is not correct. Lithium is not a sedative; instead, it is a mood stabilizer commonly used to treat bipolar disorder. Option B) "It controls mania but takes 1-2 weeks to produce the effect" is correct. Lithium does indeed have a delayed onset of action, typically taking 1-2 weeks to see the full therapeutic effects in managing manic episodes. Option C) "It has a prophylactic effect in recurrent unipolar depression" is incorrect. Lithium is not typically used as a first-line treatment for unipolar depression but is more commonly indicated for bipolar disorder. Option D) "It can be combined with tricyclic antidepressants for refractory cases of major depression" is incorrect. Lithium is not commonly combined with tricyclic antidepressants due to the risk of serotonin syndrome and other potential adverse effects. In an educational context, understanding the correct use and effects of lithium is essential for healthcare providers to make informed decisions about treatment options for patients with mood disorders. This question highlights the need for precise knowledge of drug actions to ensure safe and effective pharmacological interventions.

Correct Answer: B

Rationale: Pyritinol (pyrithioxine) is classified as a cerebroactive drug (Option B) because it is known for its effects on brain function and cognitive enhancement. Pyritinol is used to improve brain metabolism, increase neurotransmitter levels, and enhance cognitive function. It is not primarily used as an analeptic drug (Option A), which is a central nervous system stimulant. It is also not an antiepileptic drug (Option C) as it is not typically prescribed to control or prevent seizures. Additionally, pyritinol is not classified as an antidepressant drug (Option D) since it is not commonly prescribed for the treatment of depression. From an educational perspective, understanding the classification of drugs like pyritinol is crucial for healthcare professionals, particularly those working in pharmacology or neurology. Knowing the specific effects and uses of cerebroactive drugs helps healthcare providers make informed decisions when prescribing medications to patients with cognitive impairments or neurological conditions. This knowledge also aids in preventing medication errors and ensuring optimal patient outcomes.

Correct Answer: C

Rationale: In a patient with atrial fibrillation, digoxin typically leads to an increase in atrial fibrillation frequency but a decrease in ventricular rate. This is because digoxin primarily acts on the atrioventricular node, slowing down conduction through this node and thus decreasing the ventricular rate. Option A, restoration of normal sinus rhythm, is incorrect because digoxin does not directly convert atrial fibrillation to normal sinus rhythm. This would typically require other antiarrhythmic medications or procedures. Option B, conversion of atrial fibrillation to atrial flutter, is also incorrect as digoxin does not specifically convert one atrial arrhythmia to another. Option D, decrease in atrial fibrillation frequency but increase in ventricular rate, is incorrect as digoxin does not typically increase the ventricular rate. Educationally, understanding the effects of digoxin in atrial fibrillation is crucial for healthcare professionals managing patients with this condition. Knowing the specific actions of digoxin helps in making informed decisions about treatment strategies and potential outcomes. It also highlights the importance of individualized therapy based on the patient's clinical presentation and response to medications.

Correct Answer: D

Rationale: In the context of pharmacology and the treatment of hypertension, the correct answer is D) Congestive heart failure. Furosemide, a loop diuretic, is preferred over hydrochlorothiazide, a thiazide diuretic, when hypertension is accompanied by congestive heart failure due to its potent diuretic effect and ability to reduce fluid overload in patients with heart failure. A) Asthma is not a specific indication for choosing furosemide over hydrochlorothiazide in hypertension management. Loop diuretics like furosemide may exacerbate asthma symptoms in some individuals. B) Hyperuricemia is not a primary consideration when choosing between furosemide and hydrochlorothiazide for hypertension treatment. Thiazide diuretics like hydrochlorothiazide are actually preferred in patients with hyperuricemia as they can lower uric acid levels. C) Diabetes is not a determining factor in choosing between furosemide and hydrochlorothiazide for hypertension. Thiazide diuretics are commonly used in patients with diabetes as they can help control blood pressure and have a positive impact on glucose metabolism. Educationally, understanding the rationale behind selecting specific medications for hypertension based on comorbid conditions is crucial for healthcare professionals to optimize patient care. It is important to consider the underlying conditions and individual patient characteristics when making treatment decisions to achieve the best outcomes and minimize potential complications.