What is characteristic of the intramuscular route of drug administration?

Correct Answer: B

Rationale: The correct answer is B: Oily solutions can be injected. In the intramuscular route of drug administration, oily solutions can be injected due to the higher vascularity of muscle tissues, allowing for slower absorption and prolonged drug release. Oily solutions facilitate the absorption of lipid-soluble drugs. This route is suitable for drugs that require sustained release or have poor water solubility. Choices A and C are incorrect because not only water solutions but also oily and other types of solutions can be injected intramuscularly. Choice D is incorrect as intramuscular administration generally results in faster onset of action compared to oral administration.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Dibucaine, Lidocaine, and Mepivacaine are all local anesthetics commonly used for infiltrative and regional anesthesia. These agents work by blocking sodium channels, preventing the generation and propagation of action potentials in nerves. They are effective for producing anesthesia in a localized area, making them suitable for procedures like dental work, minor surgeries, and nerve blocks. Each of these local anesthetics has a slightly different onset, duration, and potency, allowing for flexibility in choosing the most appropriate agent based on the specific clinical situation. Therefore, choosing all of the above options is correct as they are all suitable choices for infiltrative and regional anesthesia.

Correct Answer: B

Rationale: The correct answer is B: Hexamethonium. Ganglion-blocking drugs act by blocking nicotinic receptors in autonomic ganglia, leading to decreased sympathetic and parasympathetic responses. Hexamethonium is a ganglion-blocking drug that specifically acts on ganglionic nicotinic receptors. - A: Homatropine is a muscarinic antagonist used to dilate the pupil. - C: Rapacuronium is a non-depolarizing neuromuscular blocking agent. - D: Edrophonium is an acetylcholinesterase inhibitor used for the diagnosis of myasthenia gravis.

Correct Answer: D

Rationale: The correct answer is D: Succinylcholine. Succinylcholine can cause cardiac arrhythmias by inducing hyperkalemia, especially in patients with certain conditions like burns, denervation injuries, or spinal cord injuries. This hyperkalemia can lead to dangerous arrhythmias such as ventricular tachycardia or fibrillation. Vecuronium (A), Tubocurarine (B), and Rapacuronium (C) are not known to cause cardiac arrhythmias as they do not have the same mechanism of action as Succinylcholine.

Correct Answer: B

Rationale: The correct answer is B: Bronchodilation. Ephedrine is a sympathomimetic amine that acts on alpha and beta adrenergic receptors. It primarily stimulates beta-2 adrenergic receptors in the lungs, leading to bronchodilation. This action helps in the treatment of asthma and other respiratory conditions. Miosis (choice A) is constriction of the pupil, which is not a known effect of ephedrine. Hypotension (choice C) is low blood pressure, but ephedrine is more likely to cause hypertension due to its vasoconstrictive effects. Bradycardia (choice D) is a slow heart rate, but ephedrine usually causes tachycardia due to its stimulatory effects on the heart.