A patient with Alzheimer's disease is taking an acetylcholinesterase inhibitor specifically approved for that indication, primarily because it is quite lipophilic and so enters the CNS well. Which of the following drugs is the patient most likely receiving?

Correct Answer: A

Rationale: The correct answer is A: Donepezil. Donepezil is a lipophilic acetylcholinesterase inhibitor approved for Alzheimer's disease due to its ability to enter the CNS effectively. It enhances cholinergic transmission by inhibiting the enzyme responsible for acetylcholine breakdown. Edrophonium is a short-acting acetylcholinesterase inhibitor used for diagnostic purposes, not for Alzheimer's treatment. Neostigmine and Pyridostigmine are not lipophilic and are primarily used for myasthenia gravis to enhance muscle strength, not for Alzheimer's disease.

Correct Answer: C

Rationale: Propranolol is a non-selective beta-blocker that slows the heart rate and reduces blood pressure. Heart block refers to a condition where the electrical signals in the heart are delayed or blocked. Propranolol can worsen heart block by further slowing down the heart rate, making it inappropriate for this condition. Therefore, the correct answer is C. A: Propranolol is used to treat hypertension by reducing blood pressure. B: Propranolol is effective in managing anxiety symptoms by blocking the physical manifestations of anxiety, such as rapid heart rate. D: Propranolol is beneficial in treating angina of effort by reducing the workload of the heart and improving blood flow to the heart muscle. In summary, the other choices (A, B, D) are correct uses of propranolol, making C the exception due to its potential to worsen heart block.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Adrenaline causes vasoconstriction leading to increased blood pressure. 2. Prazosin is an alpha-1 adrenergic receptor antagonist. 3. By blocking alpha-1 receptors, prazosin reverses the vasoconstrictive effects of adrenaline. 4. Propranolol (A) is a non-selective beta-blocker and would not directly counteract adrenaline's vasoconstrictive effects. 5. Phenylephrine (B) is a vasoconstrictor itself and would further exacerbate the hypertensive effect of adrenaline. 6. Amphetamine (D) is a sympathomimetic drug that would also enhance the hypertensive effects of adrenaline. Summary: Prazosin (C) is the correct answer as it specifically targets the alpha-1 adrenergic receptors responsible for the hypertensive effects of adrenaline. Propranolol, phenylephrine, and amphetamine would

Correct Answer: C

Rationale: Atropine is used in the treatment of intestinal colic due to its ability to relax smooth muscles, including those in the gastrointestinal tract. It helps relieve spasms and pain associated with intestinal colic. Tachycardia is usually treated with beta-blockers, not atropine. Glaucoma is treated with medications that reduce intraocular pressure, not atropine. Enlarged prostate is typically managed with medications that target prostate enlargement, not atropine. Therefore, the correct choice is C: Intestinal colic.

Correct Answer: C

Rationale: Rationale: C: Prazosin can block Alpha1 receptor only. - Prazosin is a selective Alpha1 blocker, mainly used for hypertension. - By blocking Alpha1 receptors, it reduces vasoconstriction and lowers blood pressure. - Prazosin does not affect Alpha2 receptors, distinguishing it from non-selective Alpha blockers. - Correct as it accurately describes Prazosin's mechanism of action. Incorrect: A: Phentolamine is a non-selective Alpha blocker, affecting both Alpha1 and Alpha2 receptors. B: Alpha2 blockers increase noradrenaline release by inhibiting the negative feedback control. D: Alpha blockers typically decrease blood pressure, but can increase heart rate due to vasodilation.