PH8.1-11 | Antimicrobial and Chemotherapy Pharmacology — Graded Quiz

A 62-year-old man with hospital-acquired pneumonia is started on once-daily amikacin. The pharmacist recommends extended-interval dosing (single large daily dose rather than divided doses three times daily). Which pharmacokinetic/pharmacodynamic parameter BEST justifies this dosing strategy?

A 28-year-old HIV-positive man (CD4 count 180/µL) is diagnosed with pulmonary TB (smear positive). He is already on TDF+3TC+DTG for 3 months with an undetectable viral load. What is the MOST important drug interaction concern when starting HRZE?

A 30-year-old woman on Month 4 of MB MDT for leprosy presents with sudden appearance of 5 new erythematous tender nodules on her face and arms (different sites from existing lesions), fever 38.5°C, and bilateral ankle oedema. Existing lesions are unchanged. What is the MOST likely diagnosis and appropriate management?

A 22-year-old student presents with 5 days of bloody diarrhoea and lower abdominal cramps. Stool examination shows Entamoeba histolytica trophozoites containing ingested red blood cells. He is started on metronidazole 750mg three times daily for 10 days. What is the MOST important next step after completing metronidazole?

A 19-year-old immunocompetent patient with cryptococcal meningitis is started on conventional (deoxycholate) amphotericin B. On day 3, his serum creatinine rises from 0.9 to 2.4 mg/dL, potassium falls to 2.8 mEq/L, and he develops rigors during infusion. Which intervention is MOST appropriate?

A medical student is studying anticancer drug pharmacology. She correctly states: 'Vinca alkaloids arrest cell division in M-phase, while antimetabolites are most active in S-phase.' Her examiner asks: 'Which drug class kills cancer cells in ANY phase of the cell cycle, including G0 (resting phase)?'

A 65-year-old man develops fever (39°C), productive cough, and consolidation in the right lower lobe on chest X-ray 5 days after elective hip replacement surgery. He is on ceftriaxone post-operatively. His blood cultures are sent. The microbiologist advises empiric escalation. Which SINGLE change is MOST consistent with rational antibiotic stewardship?

A 68-year-old diabetic woman presents with a 3-day history of painful vesicular rash over the left T6-T8 dermatomes. She is started on aciclovir. Which statement BEST explains why aciclovir is selective for herpes-infected cells?

A 19-year-old sexually active woman presents with 7 days of purulent urethral/cervical discharge. Gram stain shows intracellular Gram-negative diplococci. NAAT confirms Neisseria gonorrhoeae. She is allergic to penicillin. According to Indian NACO guidelines for syndromic STD management, which treatment is MOST appropriate?

A 25-year-old man with newly diagnosed generalised tonic-clonic seizures has an MRI brain showing multiple calcified lesions and one 2cm viable cystic lesion in the right parietal lobe with perilesional oedema. He is diagnosed with active neurocysticercosis (NCC). Which treatment combination is MOST appropriate?

A 45-year-old man with aggressive non-Hodgkin lymphoma is receiving high-dose methotrexate (5g/m²) as part of his chemotherapy protocol. Eighteen hours after the infusion, he develops severe oral mucositis and his urine output decreases. His serum methotrexate level is markedly elevated. Which intervention is CRITICAL to prevent life-threatening toxicity?

A laboratory reports that a fluoroquinolone antibiotic has a minimum inhibitory concentration (MIC) of 0.5 µg/mL for Escherichia coli. In a patient receiving the drug, the peak plasma concentration (Cmax) is 8 µg/mL and the 24-hour area under the concentration-time curve (AUC24) is 60 µg·h/mL. What is the AUC24/MIC ratio, and does it meet the pharmacodynamic target for fluoroquinolones?