What are considered the ‘Big Three’ properties of an ideal drug? (Select all that apply)

Choice A reason: Antidotes counteract specific toxins or drugs (e.g., naloxone for opioids). Antihistamines don’t neutralize allergens but block histamine receptors to reduce allergic symptoms like itching or sneezing. They target H1 or H2 receptors, not a toxin, making this choice incorrect for describing antihistamine mechanism of action.

Choice B reason: Antihistamines are antagonists, binding to histamine receptors (H1 or H2) without activating them, preventing histamine from triggering allergic responses like vasodilation or bronchoconstriction. This competitive inhibition reduces symptoms such as itching, sneezing, or gastric acid secretion, making this the correct choice for their pharmacological action.

Choice C reason: Agonists activate receptors to produce a response. Antihistamines block histamine receptors, not activate them, preventing allergic effects. Acting as agonists would mimic histamine, worsening symptoms like swelling or itching, which is opposite to their therapeutic role, making this choice incorrect.

Choice D reason: Activators is a vague term not used in pharmacology to describe drug action. Antihistamines specifically act as receptor antagonists, not general activators. They inhibit histamine effects without stimulating other pathways, making this choice inaccurate for explaining the mechanism of antihistamines in allergy management.

Choice A reason: Inhaled glucocorticoids, like budesonide, reduce airway inflammation over time but don’t act quickly enough to abort acute asthma attacks. Short-acting beta-agonists (e.g., albuterol) are used for acute relief, as glucocorticoids lack immediate bronchodilatory effects, making this choice incorrect for chronic asthma management.

Choice B reason: Using inhaled glucocorticoids only in emergencies is ineffective for chronic asthma. These drugs prevent inflammation and exacerbations through consistent use, not acute intervention. Emergency use is reserved for rescue inhalers like albuterol, making this choice inappropriate for long-term asthma control.

Choice C reason: Inhaled glucocorticoids require daily use to maintain anti-inflammatory effects, reducing airway hyperresponsiveness and preventing asthma exacerbations. Consistent dosing ensures steady suppression of chronic inflammation, improving lung function and reducing symptoms, making this the correct choice for managing chronic asthma effectively.

Choice D reason: A 2-week on/off schedule disrupts the consistent anti-inflammatory action of inhaled glucocorticoids needed for chronic asthma control. Intermittent use reduces efficacy, allowing inflammation to rebound, increasing exacerbation risk. Daily use is standard to maintain therapeutic benefits, making this choice incorrect.