Indicate the sedative-hypnotic agent which has the highest abuse potential:

Correct Answer: B

Rationale: Step 1: Diazepam is a benzodiazepine known for its high abuse potential due to its sedative and hypnotic effects. Step 2: Benzodiazepines like diazepam can lead to physical and psychological dependence. Step 3: Buspirone is a non-benzodiazepine anxiolytic with low abuse potential. Step 4: Phenobarbital is a barbiturate with significant abuse potential but generally less than benzodiazepines. Step 5: Zolpidem is a non-benzodiazepine sedative-hypnotic with lower abuse potential compared to benzodiazepines like diazepam.

Correct Answer: D

Rationale: The correct answer is D: Sodium phosphate. Osmotic laxatives like sodium phosphate work by drawing water into the colon to soften the stool and stimulate bowel movements. Docusate sodium (A) is a stool softener, not an osmotic laxative. Bisacodyl (B) is a stimulant laxative that works by increasing muscle contractions in the intestines. Phenolphthalein (C) was previously used as a laxative but has been banned due to safety concerns.

Correct Answer: A

Rationale: Step 1: Digitalis increases vagal tone by enhancing parasympathetic activity. Step 2: This results in a decrease in heart rate and improved contractility. Step 3: Therefore, choice A is correct as it accurately states that digitalis increases vagal tone. Summary: Choices B, C, and D are incorrect because digitalis does increase vagal tone, which is a specific action of the medication.

Correct Answer: D

Rationale: The correct answer is D, "All of the above," because all three choices are nitrates used for the prevention of angina attacks. Nitroglycerin, in both ointment and oral sustained-release forms, works by dilating blood vessels to improve blood flow to the heart, reducing angina symptoms. Isosorbide mononitrate is another nitrate used for the same purpose. Therefore, all three options are effective in preventing angina attacks. Options A, B, and C are incorrect because each drug listed is individually used for angina prevention, making the correct answer D, as it includes all the effective drugs for this purpose.

Correct Answer: D

Rationale: The correct answer is D: Angiotensinamide. This is because angiotensinamide is a hormone produced endogenously by the body that acts as a potent vasoconstrictor. It plays a crucial role in regulating blood pressure by constricting blood vessels. Rationale: 1. Angiotensinamide is a naturally occurring hormone in the body. 2. It acts specifically as a vasoconstrictor, narrowing blood vessels. 3. This physiological function of angiotensinamide helps regulate blood pressure. 4. In contrast, choices A, B, and C are exogenous substances with pharmacological vasoconstrictive effects, not endogenously produced hormones like angiotensinamide. Summary: A, B, and C are incorrect because they are synthetic substances with vasoconstrictive properties, whereas angiotensinamide is the correct answer as it is an endogenous vasoconstrictor hormone in the body.