ATI RN
Chapter 26 principles of pharmacology Questions
Question 1 of 5
Cross Match each of the following adverse effect to the corresponding drug: Diarrhea & alopecia
Correct Answer: A
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
Question 2 of 5
The following drugs are effective in staphylococcal infections:
Correct Answer: D
Rationale: Flucloxacillin (D) is the correct answer as it's highly effective against staphylococcal infections, particularly those caused by Staphylococcus aureus, including beta-lactamase-producing strains. Its stability against these enzymes makes it a first-line choice for skin, soft tissue, and bone infections. Ampicillin (A) is less effective against staphylococci due to its susceptibility to beta-lactamases, targeting mainly Gram-negative bacteria. Co-amoxiclav (B), combining amoxicillin with clavulanic acid, is effective against resistant staphylococci, broadening coverage to anaerobes and other pathogens. Fusidic acid (C) is also effective, often used topically or in combination for systemic staphylococcal infections like osteomyelitis. Metronidazole (original E) targets anaerobes, not staphylococci. Flucloxacillin's narrow-spectrum activity and resistance to beta-lactamases make it ideal for MSSA (methicillin-sensitive S. aureus), balancing efficacy with reduced resistance development.
Question 3 of 5
Metronidazole is used to treat:
Correct Answer: A
Rationale: Metronidazole is used to treat trichomonal infections (A), caused by Trichomonas vaginalis, as a first-line therapy due to its efficacy against anaerobic protozoa, disrupting DNA synthesis. It's also effective in amoebic dysentery (B) from Entamoeba histolytica, targeting liver abscesses and intestinal disease. It treats giardiasis (C), caused by Giardia lamblia, with high cure rates. It's used in gas gangrene (original E), caused by Clostridium perfringens, often with surgery, but not tetanus (D), where antitoxin and penicillin are standard. Metronidazole's selective toxicity to anaerobes and protozoa, sparing aerobic bacteria, stems from its activation in low-oxygen environments, making it invaluable in mixed infections, though its metallic taste and disulfiram-like reaction with alcohol are notable side effects.
Question 4 of 5
Amphotericin:
Correct Answer: B
Rationale: Amphotericin is effective in systemic Candida spp. infections (B), such as candidemia or invasive candidiasis, due to its broad-spectrum antifungal activity, binding ergosterol in fungal membranes to cause cell death. It's also effective in local Candida infections (A), like oral thrush, but systemic use is more critical. It's nephrotoxic (C), damaging renal tubules, often dose-limiting, requiring hydration and monitoring. It causes hypokalemia (D), from distal tubule effects, necessitating potassium supplementation. It's effective in cryptococcosis (original E is incorrect), notably meningitis. Amphotericin's efficacy in severe fungal infections is unmatched, but its toxicity profile, mitigated by lipid formulations, demands careful administration, balancing therapeutic benefit with renal and electrolyte disturbances.
Question 5 of 5
Ribavirin:
Correct Answer: C
Rationale: Ribavirin must be taken up into cells and phosphorylated to be effective (C), converting to its triphosphate form to inhibit viral RNA synthesis, critical for its antiviral action. It's not indicated in CMV retinitis (A); ganciclovir or foscarnet are used. It inhibits viral RNA methyltransferase (B), part of its broad mechanism against RNA viruses. It's given via aerosol for RSV bronchiolitis (D), especially in infants. It's combined with interferon alfa for hepatitis C (original E). Ribavirin's efficacy in hepatitis C and severe RSV stems from its interference with viral replication and mRNA capping, though anemia is a significant side effect requiring monitoring.