Which of the following muscular relaxants causes hypotension and bronchospasm?

Correct Answer: C

Rationale: In pharmacology across the lifespan, understanding the effects of muscle relaxants is crucial for safe patient care. In this question, the correct answer is C) Tubocurarine. Tubocurarine is a non-depolarizing neuromuscular blocking agent that can cause hypotension and bronchospasm as adverse effects. It competes with acetylcholine at the motor end plate, leading to muscle paralysis. The hypotension results from histamine release and blockade of autonomic ganglia, while bronchospasm can occur due to histamine release and vagal stimulation. A) Vecuronium is a non-depolarizing muscle relaxant but is less likely to cause hypotension and bronchospasm compared to Tubocurarine. B) Succinylcholine is a depolarizing muscle relaxant that can cause fasciculations, hyperkalemia, and malignant hyperthermia but not hypotension and bronchospasm. D) Rapacuronium is associated with bronchospasm and was withdrawn from the market due to safety concerns, but it is not specifically known for causing hypotension. Educationally, this question highlights the importance of knowing the side effect profiles of different muscle relaxants to anticipate and manage potential complications during anesthesia and critical care scenarios, emphasizing patient safety and individualized treatment plans.

Correct Answer: C

Rationale: In pharmacology, understanding the specificity of adrenomimetic agents is crucial for safe and effective patient care. In this scenario, the correct answer is C) Isoproterenol. Isoproterenol is a non-selective adrenomimetic agent that activates both beta₁ and beta₂ adrenoreceptors. Activation of beta₁ receptors leads to increased heart rate and contractility, while activation of beta₂ receptors causes bronchodilation and vasodilation. Option A) Dobutamine is a selective beta₁ adrenomimetic agent commonly used to increase cardiac output in conditions like heart failure. Option B) Salbutamol is a selective beta₂ adrenomimetic agent used for bronchodilation in conditions like asthma. Option D) Phenylephrine is an alpha adrenomimetic agent that causes vasoconstriction by acting on alpha adrenergic receptors. Educationally, understanding the selectivity of adrenomimetic agents is vital for prescribing the right medication based on the desired physiological effects. It also highlights the importance of considering receptor specificity when treating patients of different age groups, as pharmacological responses may vary across the lifespan due to age-related changes in receptor sensitivity and distribution.

Correct Answer: C

Rationale: In pharmacology, especially when considering ophthalmic medications, it is crucial to understand the specific properties of each adrenomimetic drug. In this case, the correct answer is C) Clonidine, which cannot be used as an ophthalmic dropping. Clonidine is an alpha-2 adrenergic agonist, primarily used for systemic conditions like hypertension, ADHD, and certain pain syndromes. It is not suitable for ophthalmic use due to its mechanism of action and potential side effects on the eye. On the other hand, options A, B, and D (Epinephrine, Phenylephrine, and Norepinephrine) are commonly used adrenomimetics in ophthalmology. Epinephrine and Phenylephrine are alpha-1 adrenergic agonists that can cause pupil dilation (mydriasis) and are used during eye exams or surgeries. Norepinephrine, although less commonly used in ophthalmology, can also exert adrenergic effects on the eye. Understanding the variations in adrenomimetic drugs and their specific applications is crucial for healthcare professionals, especially when considering the route of administration and potential side effects. This knowledge ensures safe and effective pharmacological interventions tailored to the needs of individual patients.

Correct Answer: D

Rationale: Isoproterenol is a nonselective beta receptor agonist, making option D the correct choice. Isoproterenol stimulates both beta₁ and beta₂ adrenergic receptors in the body. This pharmacological action results in effects such as increased heart rate, bronchodilation, and vasodilation. Option A, stating that isoproterenol is both an alpha- and beta-receptor agonist, is incorrect because isoproterenol primarily acts on beta receptors rather than alpha receptors. Option B, suggesting that isoproterenol is a beta₁-selective agonist, is inaccurate as isoproterenol affects both beta₁ and beta₂ receptors. Option C, indicating that isoproterenol is a beta₂-selective agonist, is also incorrect because isoproterenol stimulates both beta₁ and beta₂ receptors, not just beta₂ receptors. Educationally, understanding the pharmacological properties of isoproterenol is crucial for healthcare professionals, especially in scenarios requiring the use of beta receptor agonists. This knowledge helps in selecting appropriate medications for specific clinical conditions and in managing patient care effectively.

Correct Answer: B

Rationale: The correct answer is B) Xylometazoline. Xylometazoline is an alpha₂-selective agonist, making it the appropriate topical decongestant agent for this question. As an alpha₂-selective agonist, xylometazoline acts specifically on alpha-2 adrenergic receptors, leading to vasoconstriction and reduced nasal congestion without significant systemic effects like increased blood pressure or heart rate. Now, let's discuss why the other options are incorrect: A) Phenylephrine is an alpha₁-selective agonist, not an alpha₂-selective agonist. C) Ephedrine is a mixed-acting sympathomimetic amine with effects on both alpha and beta receptors, not specific to alpha₂ receptors. D) Epinephrine is a non-selective adrenergic agonist, affecting both alpha and beta receptors, and is not alpha₂-selective like xylometazoline. In an educational context, understanding the selectivity of decongestant agents is crucial for pharmacology students and healthcare professionals. Knowing the specific receptor targets of these medications helps in selecting the most appropriate treatment based on desired effects and potential side effects. This knowledge is essential for safe and effective patient care across the lifespan.