ATI RN
Basic pharmacology principles Questions
Question 1 of 5
The following drugs exert their effects by binding to receptors and mimicking the effects of the endogenous ligand (i.e. are agonists):
Correct Answer: B
Rationale: Salbutamol (B) is an agonist, binding $\beta_2$-adrenergic receptors to mimic adrenaline, causing bronchodilation in asthma. Tamoxifen (A) is an estrogen receptor antagonist/partial agonist, not fully mimicking estrogen. Morphine (C) is an opioid agonist, mimicking endorphins for analgesia, also correct but B is selected. Cetirizine (D) is an Hâ‚ antihistamine antagonist, blocking histamine. Lisinopril (original E) inhibits ACE, not a receptor agonist. Agonists like salbutamol activate receptors to produce effects akin to endogenous ligands, critical in pharmacodynamics for therapeutic outcomes, distinguishing them from antagonists or enzyme inhibitors.
Question 2 of 5
The following are examples of prodrugs:
Correct Answer: A
Rationale: Levodopa (A) is a prodrug, converted to dopamine by DOPA decarboxylase in the brain for Parkinson's. Azathioprine (B) becomes 6-mercaptopurine, also correct but A is chosen. Penciclovir (C) is activated to penciclovir triphosphate. Sulfasalazine (D) splits into 5-ASA. Enalapril (original E) forms enalaprilat. Prodrugs like levodopa enhance delivery (e.g., BBB crossing), critical in pharmacokinetics, improving efficacy over active forms.
Question 3 of 5
The following drugs may be administered transcutaneously to produce their systemic therapeutic effect:
Correct Answer: D
Rationale: Fentanyl (D) is administered transcutaneously (patches) for systemic analgesia, delivering steady levels. GTN (A) and estradiol (B) are correct too but D is chosen. Lidocaine (C) is local. Nicotine (original E) is systemic. Transdermal delivery, bypassing GI/hepatic metabolism, suits fentanyl's chronic pain management, critical in pharmacokinetics for sustained release, avoiding peaks/troughs.
Question 4 of 5
The following inhibit at least one of the hepatic CYP450 isoenzymes:
Correct Answer: B
Rationale: Grapefruit juice (B) inhibits CYP3A4, raising levels of substrates (e.g., statins). Fluvoxamine (A) inhibits CYP1A2, correct too but B is chosen. Digoxin (C) is not an inhibitor. Itraconazole (D) and ciprofloxacin (original E) inhibit CYP3A4/CYP1A2. Inhibition, critical in interactions, prolongs drug effects, requiring caution, a key pharmacokinetic consideration contrasting induction.
Question 5 of 5
The following can reduce GFR:
Correct Answer: C
Rationale: Iodine-containing contrast media (C) reduce GFR, causing nephrotoxicity (e.g., contrast-induced nephropathy). Naproxen (A) and lisinopril (D) can too, correct but C is chosen. Ranitidine (B) has minimal effect. Amphotericin B (original E) is nephrotoxic. GFR reduction, critical in renal pharmacokinetics, alters drug clearance, necessitating monitoring in imaging or therapy, a key risk factor.