Antimicrobials Practice Questions

Q: A patient from a North-Eastern state was diagnosed to have an infection with P. Falciparum malaria. What is the most appropriate treatment for this patient?

Artemether plus lumefantrine. ***Artemether plus lumefantrine*** - Artemether-lumefantrine is the recommended first-line treatment for **uncomplicated P. falciparum malaria** in regions with known **chloroquine resistance**, such as North-Eastern India. - This combination therapy, an **Artemisinin-based Combination Therapy (ACT)**, is highly effective due to its rapid parasiticidal action and synergy. *Chloroquine* - Chloroquine resistance in **P. falciparum malaria** is widespread, particularly in many parts of India, including the North East. - Using chloroquine alone would likely lead to **treatment failure** and worsening of the patient's condition. *Mefloquine* - Mefloquine is an alternative treatment option, but it has significant drawbacks including **neuropsychiatric side effects** (e.g., anxiety, depression, hallucinations) and a long half-life. - It is often reserved for specific situations or as a second-line agent when ACTs are not available or contraindicated. *Sulfadoxine plus pyrimethamine* - **Sulfadoxine-pyrimethamine (SP)** is an older antimalarial drug combination that is not recommended as first-line treatment for **uncomplicated P. falciparum malaria** due to widespread **parasite resistance**. - While it was formerly used for prophylaxis and intermittent presumptive treatment, its efficacy against P. falciparum has significantly declined. *Quinine plus doxycycline* - **Quinine plus doxycycline** is an effective alternative for treating **P. falciparum malaria**, particularly in **severe cases** or when ACTs are contraindicated or unavailable. - However, it is **not the first-line treatment** for uncomplicated malaria due to longer treatment duration (7 days), more frequent dosing, and potential side effects (cinchonism, GI disturbances). - Requires adherence to a multi-day regimen, making ACTs more practical for uncomplicated cases.

Q: Which of the following chelating agents is indicated in iron overdose?

Desferrioxamine. ***Desferrioxamine*** - **Desferrioxamine** is a **chelate** formed by the bacterium *Streptomyces pilosus* that has a high affinity for **iron**. - It is currently the most commonly used chelating agent for **acute iron overdose** and **chronic iron overload** conditions like hemochromatosis or transfusional hemosiderosis. *BAL* - **BAL (dimercaprol)** is a chelating agent primarily used for poisoning with **arsenic**, **mercury**, and **gold**. - It works by forming stable cyclic compounds with these metals, facilitating their excretion. *Calcium Edetate* - **Calcium edetate (Calcium-EDTA)** is primarily used for **lead poisoning**. - It works by forming a stable, water-soluble complex with lead, which is then excreted by the kidneys. *DTPA* - **Diethylenetriamine pentaacetate (DTPA)** is a chelating agent primarily used for poisoning with **plutonium** and other **radioactive metals**. - It is not indicated for iron overdose. *Penicillamine* - **Penicillamine** is a chelating agent primarily used for **copper** overload (Wilson's disease) and can also be used for **lead** and **mercury** poisoning. - It is not effective for iron chelation in overdose situations.

Question 1

A 19-year-old woman is brought to the emergency department after ingesting an unknown substance at a party. On examination she is agitated, diaphoretic, and tachycardic (HR 138 bpm). Her pupils are 7 mm and reactive. Temperature is 39.8°C. She has hyperreflexia and bilateral ankle clonus. Which of the following agents is most likely responsible for this clinical picture?

Accepted Answer

3,4-Methylenedioxymethamphetamine acting via monoamine transporter reversal

Answer

Phencyclidine acting via NMDA receptor antagonism and dopamine reuptake inhibition

Answer

Gamma-hydroxybutyrate acting via GABA-B receptor agonism and GHB receptor activation

Answer

Lysergic acid diethylamide acting via partial agonism at serotonin 5-HT2A receptors

Answer

Ketamine acting via dissociative NMDA antagonism and sympathomimetic stimulation

Question 2

A tourist with a travel history to India presents with complaints of abdominal pain and multiple episodes of watery diarrhea. He reports having food at a local restaurant the previous night. Which of the following antidiarrheal agents is used in this condition?

Accepted Answer

Rifaximin

Answer

Bismuth subsalicylate

Answer

Octreotide

Answer

Loperamide

Answer

Ciprofloxacin

Question 3

A patient from a North-Eastern state was diagnosed to have an infection with P. Falciparum malaria. What is the most appropriate treatment for this patient?

Accepted Answer

Artemether plus lumefantrine

Answer

Chloroquine

Answer

Mefloquine

Answer

Sulfadoxine plus pyrimethamine

Answer

Quinine plus doxycycline

Question 4

Which of the following chelating agents is indicated in iron overdose?

Accepted Answer

Desferrioxamine

Answer

BAL

Answer

Calcium Edetate

Answer

DTPA

Answer

Penicillamine

Question 5

An 18-year-old boy from Rajasthan weighing 50 kg is diagnosed with mixed P . vivax and P . falciparum malaria. What is the appropriate treatment regimen on day 2?

Accepted Answer

Artesunate 50 mg (4 tablets) + Sulfadoxine/ pyrimethamine ( 750/37.5 mg ) (2 tablets) + Primaquine 2.5 mg ( 6 tablets)

Answer

Artesunate 50 mg (4 tablets) + Primaquine 2.5 mg ( 6 tablets)

Answer

Artesunate 50 mg (4 tablets) + Primaquine 7.5 mg (6 tablets)

Answer

Artesunate 50 mg (4 tablets) + Sulfadoxine/ pyrimethamine ( 750/37.5 mg ) (2 tablets) + Primaquine 7.5 mg ( 6 tablets)

Answer

Artesunate 50 mg (4 tablets) only

Antimicrobials — MCQs

Antimicrobials — MCQs

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