Characteristics of cocaine abstinent syndrome include all of the following phases EXCEPT:

Correct Answer: C

Rationale: The correct answer is C because psychosis with visual and auditory hallucinations is not a common characteristic of cocaine abstinent syndrome. A: Feeling of depression, irritability, confusion, insomnia in the initial days is common due to withdrawal symptoms. B: Depression, apathy, excessive appetite, and the wish to sleep in the subsequent days are typical withdrawal symptoms. D: A new attack of depression, anxiety, irritability, dullness, and intense thirst for cocaine after initial improvement is consistent with the stages of cocaine abstinent syndrome.

Correct Answer: B

Rationale: The correct answer is B: Folic acid. Folic acid is not a drug used for iron deficiency anemia; it is a B-vitamin essential for normal cellular function but not directly related to iron supplementation. Ferrous sulfate, ferrous gluconate, and ferrous fumarate are all iron salts commonly used to treat iron deficiency anemia by replenishing the body's iron stores. Folic acid, on the other hand, is primarily used to prevent neural tube defects in pregnancy and to treat certain types of anemia not related to iron deficiency.

Correct Answer: C

Rationale: Amrinone inhibits breakdown of cAMP by inhibiting phosphodiesterase enzyme in vascular smooth muscle. This leads to increased cAMP levels, causing vasodilation. Digoxin, dobutamine, and dopamine have no direct effect on cAMP breakdown in vascular smooth muscle. Digoxin increases intracellular calcium, dobutamine is a beta-adrenergic agonist, and dopamine acts on dopamine receptors.

Correct Answer: C

Rationale: Step 1: Beta-adrenoceptor-blocking drugs primarily work by blocking the beta-adrenergic receptors in the body. Step 2: By blocking these receptors, these drugs decrease heart rate, blood pressure, and contractility of the heart muscle. Step 3: These hemodynamic effects lead to decreased myocardial oxygen requirements at rest and during exercise, providing beneficial effects. Step 4: Choice C is correct as it accurately describes the main mechanism and beneficial effects of beta-adrenoceptor-blocking drugs. Step 5: Choices A, B, and D are incorrect as they do not accurately describe the primary mechanism or effects of beta-adrenoceptor-blocking drugs.

Correct Answer: D

Rationale: The correct answer is D because all the listed drug groups influence cerebral blood flow. Ca-channel blockers dilate blood vessels, enhancing cerebral perfusion. GABA derivatives can modulate blood flow by affecting neurotransmission. Vinca minor derivatives like vincamine can improve cerebral circulation. Therefore, all choices have a direct impact on cerebral flow, making D the correct answer.