ATI RN
Basic pharmacology principles Questions
Question 1 of 5
Pretreatment with propranolol will block which one of the following?
Correct Answer: C
Rationale: Propranolol, a non-selective beta-blocker, blocks norepinephrine-induced bradycardia (C). Norepinephrine's beta-1 stimulation increases heart rate, but high doses trigger reflex bradycardia via baroreceptors; propranolol prevents the beta-mediated component, attenuating this. Methacholine (A), a muscarinic agonist, causes tachycardia reflexively, unaffected by beta-blockade. Nicotine (B) induces hypertension via nicotinic receptors and catecholamine release, partially beta-mediated, but not fully blocked. Phenylephrine (D) causes mydriasis via alpha-1, not beta. Propranolol's beta-adrenergic antagonism is key in managing sympathetic overactivity, though alpha effects persist.
Question 2 of 5
Rectal suppositories intended for adult use usually weigh approximately
Correct Answer: B
Rationale: Rectal suppositories for adults usually weigh approximately 2g (B), a standard size ensuring sufficient drug load (e.g., glycerin for constipation) and comfortable insertion. Options A (1g) and C (3g) are smaller/larger, less common, while D (4g) and original E (5g) are excessive for routine use. This weight balances efficacy, melting time, and patient tolerance, critical in suppository design for systemic (e.g., analgesics) or local effects, with cocoa butter or synthetic bases adjusting to body temperature for release.
Question 3 of 5
Nonionic surface-active agents used as synthetic emulsifiers include
Correct Answer: C
Rationale: Sorbitan esters (spans) (C) are nonionic surfactants used as synthetic emulsifiers, stabilizing emulsions (e.g., creams) by reducing surface tension without ionization. Tragacanth (A) is a natural gum, not synthetic. Sodium lauryl sulphate (B) is anionic, not nonionic. Option D is a placeholder. No original E exists. Spans' lipophilic nature (low HLB) aids oil-in-water emulsions, enhancing drug delivery and stability, widely used in topical and oral pharmaceuticals for their versatility.
Question 4 of 5
The route of drug administration that gives the most rapid onset of the pharmacological effect is
Correct Answer: B
Rationale: Intravenous injection (B) gives the most rapid onset, delivering drug directly into the bloodstream, bypassing absorption (e.g., morphine in seconds). Intramuscular (A) and subcutaneous (original E) are slower due to tissue absorption. Intradermal (C) is slowest, for local effects. Peroral (D) involves GI absorption, delaying onset (e.g., 30-60 min). IV's immediacy suits emergencies, avoiding first-pass metabolism, though it risks rapid toxicity, requiring precise dosing and monitoring.
Question 5 of 5
Creatinine clearance is used as a measurement of
Correct Answer: B
Rationale: Creatinine clearance measures glomerular filtration rate (GFR) (B), estimating kidney filtration capacity (mL/min) via serum/urine creatinine, reflecting renal health (e.g., in drug dosing). Renal excretion rate (A) includes secretion/reabsorption. Active secretion (C) and passive absorption (D) are distinct processes. Drug metabolism (original E) is hepatic. GFR's clinical use adjusts renally excreted drugs (e.g., aminoglycosides), ensuring safety in renal impairment, a cornerstone of pharmacokinetics.