Intravenous injections are more suitable for oily solutions:

Correct Answer: B

Rationale: The correct answer is B: FALSE. Intravenous injections are not suitable for oily solutions due to the risk of causing pulmonary embolism or other serious complications. Oily solutions can lead to blockages in the blood vessels, posing significant health risks. Other choices are incorrect because intravenous injections should not be used for all oily solutions (Choice C) or none of them (Choice D) due to the potential harm they can cause.

Correct Answer: C

Rationale: The correct answer is C: Bupivacaine. Bupivacaine is used for spinal anesthesia due to its long duration of action and potency. It provides effective anesthesia for surgeries and pain management. Procaine (A) is not commonly used for spinal anesthesia due to its short duration of action. Lidocaine (B) is used more for regional anesthesia and nerve blocks. Dupivacaine (D) is a duplicate choice and not a valid option. In summary, bupivacaine is the preferred choice for spinal anesthesia due to its duration of action and efficacy.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Succinylcholine is a depolarizing agent because it acts as a nicotinic acetylcholine receptor agonist. 2. It causes initial depolarization of the motor end plate leading to muscle fasciculations. 3. By maintaining depolarization, it prevents repolarization and muscle contraction, inducing muscle relaxation. Summary: A. Vecuronium is a non-depolarizing agent that blocks acetylcholine receptors. B. Scopolamine is an anticholinergic drug used for motion sickness. D. Hexamethonium is a ganglionic blocker used for hypertension.

Correct Answer: B

Rationale: The correct answer is B: A decrease in intraocular pressure. Depolarizing blockade, such as with succinylcholine, leads to sustained depolarization of the neuromuscular junction, causing muscle paralysis. This can result in hyperkalemia due to potassium release from muscles, emesis due to stimulation of chemoreceptors, and muscle pain due to fasciculations. Intraocular pressure is not affected by depolarizing blockade. Therefore, a decrease in intraocular pressure is not an effect seen with depolarizing blockade, making choice B the correct answer.

Correct Answer: A

Rationale: Step 1: Identify the key difference between epinephrine and ephedrine - epinephrine is a direct-acting sympathomimetic. Step 2: Ephedrine is a mixed-acting sympathomimetic, acting indirectly by releasing norepinephrine from nerve terminals. Step 3: Therefore, the correct answer is A because ephedrine is not a direct-acting sympathomimetic like epinephrine. Summary: B is incorrect because ephedrine does have oral activity, C is incorrect as ephedrine is not resistant to MAO and has a shorter duration of action, and D is incorrect as ephedrine is less potent than epinephrine.