Cefuroxime:

Correct Answer: A

Rationale: Cefuroxime has activity against streptococci (A), making it effective against Streptococcus pneumoniae and other streptococcal infections, such as respiratory tract infections. As a second-generation cephalosporin, it also covers many Gram-negative organisms (B is incorrect), including Haemophilus influenzae and some Enterobacteriaceae, though not as broadly as third-generation agents. Plasma concentration monitoring (C) isn't routine for cefuroxime, unlike aminoglycosides, as its toxicity profile (e.g., renal or allergic reactions) doesn't necessitate it. It is principally renally eliminated (D), with a half-life of about 1-2 hours, requiring dose adjustment in renal impairment. Its cross-sensitivity with benzylpenicillin (original E) is about 5-10%, relevant for penicillin-allergic patients. Cefuroxime's balanced Gram-positive and Gram-negative coverage makes it versatile in hospital settings, particularly for surgical prophylaxis and pneumonia.

Correct Answer: A

Rationale: Nystatin paired with oral Candida infections (A) is correct, as it's a topical polyene antifungal used for thrush, binding ergosterol to disrupt fungal membranes, with minimal systemic absorption. Voriconazole with invasive aspergillosis (B) is accurate, a first-line triazole for Aspergillus infections. Flucytosine with tinea pedis (C) is incorrect; it's used systemically for cryptococcosis or candidiasis, not dermatophytes (terbinafine is preferred). Clotrimazole with intertrigo (D), a Candida-related skin infection, is correct. Miconazole with cold sores (original E) is wrong; antivirals like aciclovir are used. Nystatin's non-absorbable nature makes it ideal for mucosal candidiasis, avoiding systemic side effects, though it's ineffective against deeper infections requiring agents like amphotericin.

Correct Answer: D

Rationale: Oseltamivir (D) is used in the prophylaxis and treatment of influenza, a neuraminidase inhibitor reducing viral spread by preventing release from infected cells, effective against influenza A and B. Amantadine (A) was used for influenza A prophylaxis/treatment, but resistance limits its role today. Palivizumab (B) prevents RSV, not influenza. Entecavir (C) treats hepatitis B, unrelated to influenza. Zanamivir (original E) also treats influenza, but D is selected. Oseltamivir's oral administration and efficacy within 48 hours of symptoms make it a primary choice in seasonal flu and pandemics, shortening illness duration and reducing complications.

Correct Answer: C

Rationale: Psychosis paired with mefloquine (C) is correct, a known neuropsychiatric side effect (e.g., hallucinations, anxiety), limiting its use in those with psychiatric history. Acneiform eruption with chloroquine (A) is rare; retinopathy is more typical. Stevens-Johnson syndrome with quinine (B) is incorrect; it's linked to hypersensitivity but not a hallmark. QTc prolongation with proguanil (D) is wrong; quinine causes this. Hemolytic anemia with primaquine (original E) is accurate in G6PD deficiency. Mefloquine's schizonticidal action is effective for prophylaxis and treatment, but its CNS toxicity, including rare seizures, necessitates careful patient selection and counseling.

Correct Answer: C

Rationale: Daunorubicin paired with cardiomyopathy (C) is correct, an anthracycline causing dose-dependent cardiotoxicity via oxidative stress and topoisomerase inhibition, common in leukemia treatment, mitigated by dexrazoxane. Etoposide (A) causes myelosuppression, not neuropathy (vincristine does). Paclitaxel (B) causes alopecia, a hallmark taxane effect. Irinotecan (D) causes diarrhea, due to cholinergic and mucosal damage. 6-Mercaptopurine with pulmonary fibrosis (original E) is incorrect; myelosuppression is typical. Daunorubicin's efficacy in acute leukemias is balanced by lifetime dose limits to protect cardiac function, monitored via echocardiography.