Antiparasitic Agents — MCQs
Treatment of Neurocysticercosis includes all of the following except -
Mass Drug Administration is NOT routinely used as the primary strategy for:
Treatment for filariasis is
Which of the following drugs has gametocidal action against all species of Plasmodium?
Emtricitabine is a/an:
Which of the following topical agents boosts cell-mediated immunity in burns?
Which of the following is the most hepatotoxic inhalational anesthetic agent?
What is the first line of management in malignant hyperthermia?
Which of the following increases uric acid excretion?
Which of the following inhalation anesthetic agents is hepatotoxic?
Antiparasitic Agents Indian Medical PG Practice Questions and MCQs
Question 1: Treatment of Neurocysticercosis includes all of the following except -
- A. Praziquantel
- B. Niclosamide (Correct Answer)
- C. Albendazole
- D. Corticosteroids
Explanation: ***Niclosamide***- **Niclosamide** is an oral anthelmintic primarily used to treat **intestinal tapeworm infections** by inhibiting **oxidative phosphorylation** in the parasites.- It has **poor systemic absorption** and therefore is **not effective** against **neurocysticercosis**, which involves cysts in the brain parenchyma requiring drugs with good CNS penetration.*Praziquantel*- **Praziquantel** is an orally administered anthelmintic that increases the **calcium permeability** of the parasite's cell membrane, leading to paralysis and death.- It is used in the treatment of **neurocysticercosis**, particularly for **viable parenchymal cysts** and as an alternative to albendazole [2].*Albendazole*- **Albendazole** is a broad-spectrum anthelmintic that works by inhibiting **tubulin polymerization**, causing disruption of **parasite metabolism** and glucose uptake.- It is considered the **first-line treatment** for **parenchymal neurocysticercosis** due to its excellent penetration into the central nervous system and proven efficacy.*Corticosteroids*- **Corticosteroids** (such as **dexamethasone** or **prednisolone**) are used as **adjunct therapy** in neurocysticercosis management.- They help reduce **inflammation and edema** associated with parasite death, preventing complications like seizures and increased intracranial pressure during anthelmintic treatment [1].
Question 2: Mass Drug Administration is NOT routinely used as the primary strategy for:
- A. Vitamin A Deficiency
- B. Scabies (Correct Answer)
- C. Lymphatic Filariasis
- D. Worm infestation
Explanation: ***Scabies*** - While **mass drug administration with oral ivermectin** has shown effectiveness in specific endemic outbreak settings, MDA is generally **not the primary recommended strategy** for routine scabies control in most public health contexts. - Scabies control typically prioritizes **case finding, contact tracing, simultaneous household treatment, and environmental decontamination**—which are more complex to implement than standard MDA programs. - Unlike the other conditions listed, scabies lacks well-established **routine MDA programs** at the scale of national public health initiatives, making it the least suitable option for MDA among these choices. *Vitamin A Deficiency* - **Vitamin A supplementation** through MDA is a **highly effective and widely implemented** WHO-recommended strategy to combat Vitamin A deficiency in at-risk populations, particularly children under 5 years. - Regular mass supplementation helps prevent **xerophthalmia** and reduces morbidity and mortality from infectious diseases. - This is a cornerstone of routine public health programs globally. *Lymphatic Filariasis* - **Lymphatic filariasis** is a classic example where MDA with anti-filarial drugs like **diethylcarbamazine (DEC), albendazole,** or **ivermectin** is the cornerstone strategy for interrupting transmission. - MDA is the **primary WHO-recommended approach** to achieve elimination of lymphatic filariasis, with established national programs in endemic countries. *Worm infestation* - **Mass deworming programs** using drugs like **albendazole** or **mebendazole** represent highly effective and well-established forms of MDA for controlling **soil-transmitted helminth infections**. - These routine programs significantly reduce disease burden in school-aged children, improving nutritional status, growth, and learning outcomes.
Question 3: Treatment for filariasis is
- A. Chloroquine
- B. Praziquantel
- C. Tetracycline
- D. Diethyl Carbamazine (Correct Answer)
Explanation: ***Diethyl Carbamazine*** - **Diethyl Carbamazine (DEC)** is the drug of choice for treating lymphatic filariasis, acting against both microfilariae and adult worms. - It works by paralyzing the microfilariae and making them more susceptible to destruction by the host's immune system. *Chloroquin* - **Chloroquine** is an antimalarial drug used to treat malaria, a protozoal infection transmitted by mosquitoes, not filariasis. - Its primary mechanism involves interfering with the parasite's ability to detoxify heme. *Praziquantel* - **Praziquantel** is an anthelmintic agent primarily used to treat infections caused by **schistosomes** and **other flukes** and **tapeworms**. - It works by increasing the permeability of the worm's cell membranes to calcium, leading to paralysis and expulsion. *Tetracycline* - **Tetracycline** is a broad-spectrum antibiotic used to treat bacterial infections; it is not effective against **parasitic worms** like filaria. - It inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
Question 4: Which of the following drugs has gametocidal action against all species of Plasmodium?
- A. Primaquine (Correct Answer)
- B. Quinine
- C. Chloroquine
- D. None of the options
Explanation: ***Primaquine*** - **Primaquine** is a **8-aminoquinoline** that is effective against the **gametocytes** of all *Plasmodium* species, including *P. falciparum*. - Its gametocidal action is crucial for **blocking transmission** of malaria, as gametocytes are the parasite forms ingested by mosquitoes. *Quinine* - **Quinine** is a **blood schizonticide** primarily used for treating acute, uncomplicated malaria, especially due to **chloroquine-resistant *P. falciparum***. - While it has some activity against *P. vivax* and *P. malariae* gametocytes, its action against mature *P. falciparum* gametocytes is limited. *Chloroquine* - **Chloroquine** is a highly effective **blood schizonticide** for **sensitive *P. falciparum***, *P. vivax*, *P. ovale*, and *P. malariae*. - It rapidly clears asexual parasites but has no effect on **mature *P. falciparum* gametocytes** and therefore does not prevent transmission of this species. *None of the options* - This option is incorrect because **Primaquine** possesses the described broad-spectrum gametocidal activity.
Question 5: Emtricitabine is a/an:
- A. Alkylating agent
- B. Mitotic inhibitor
- C. Nucleoside reverse transcriptase inhibitor (NRTI) (Correct Answer)
- D. None of the options
Explanation: ***Nucleoside reverse transcriptase inhibitor (NRTI)*** - **Emtricitabine** is a synthetic nucleoside analog that inhibits the activity of HIV-1 **reverse transcriptase**, an enzyme essential for viral replication. - It works by being phosphorylated to its active triphosphate form, which then competes with natural deoxycytidine triphosphate for incorporation into the viral DNA, leading to **chain termination**. *Alkylating agent* - **Alkylating agents** are a class of antineoplastic drugs that work by adding an alkyl group to DNA, forming a covalent bond that interferes with DNA replication and transcription. - They are primarily used in **cancer chemotherapy**, not as antiviral agents for HIV. *Mitotic inhibitor* - **Mitotic inhibitors** are drugs that interfere with cell division (mitosis) by targeting microtubules, either inhibiting their polymerization or depolymerization. - These agents are also used in **cancer treatment** to prevent rapidly dividing cells from completing mitosis. *None of the options* - This option is incorrect because **emtricitabine** clearly belongs to the class of **nucleoside reverse transcriptase inhibitors**.
Question 6: Which of the following topical agents boosts cell-mediated immunity in burns?
- A. Cerium nitrate (Correct Answer)
- B. Povidone iodine
- C. Mafenide acetate
- D. Silver nitrate
Explanation: Cerium nitrate - **Cerium nitrate** is notable for its ability to **stabilize complement activation** and reduce inflammatory responses in burn wounds. [1] - By modulating the immune response, it helps to **restore cell-mediated immunity**, which is often compromised in severe burns. Povidone iodine - **Povidone iodine** is a broad-spectrum **antiseptic** used for disinfection due to its strong oxidative properties against bacteria, viruses, and fungi. - It does not specifically boost **cell-mediated immunity** but rather exerts its effect through direct antimicrobial action. Mafenide acetate - **Mafenide acetate** is a potent **antibacterial agent** used topically for burns, particularly effective against Gram-negative bacteria like *Pseudomonas aeruginosa*. - Its primary function is to **penetrate eschar** and prevent infection; it does not directly enhance cell-mediated immunity. Silver nitrate - **Silver nitrate** is an antiseptic that precipitates proteins and is used to prevent bacterial growth in burn wounds. [2] - While effective in controlling infection, it does **not have immunomodulatory properties** that boost cell-mediated immunity.
Question 7: Which of the following is the most hepatotoxic inhalational anesthetic agent?
- A. Halothane (Correct Answer)
- B. Sevoflurane
- C. Desflurane
- D. Enflurane
Explanation: ***Halothane*** - **Halothane hepatitis** is a rare but potentially fatal complication characterized by severe liver damage, especially after repeated exposure. - The mechanism involves the formation of **trifluoroacetylated liver proteins** acting as neoantigens, triggering an immune-mediated hepatotoxic reaction. *Sevoflurane* - **Sevoflurane** is generally considered to have a very low risk of hepatotoxicity. - It is known for its **rapid tissue uptake and elimination**, and its metabolism does not produce significant hepatotoxic intermediates. *Desflurane* - **Desflurane** is also considered to have a very low risk of hepatotoxicity, similar to sevoflurane. - It undergoes **minimal hepatic metabolism**, with most of the drug being eliminated unchanged through pulmonary excretion. *Enflurane* - While enflurane has been associated with a slightly higher incidence of hepatic dysfunction compared to newer agents, it is **less hepatotoxic than halothane** and primarily linked to renal toxicity. - Its metabolism produces **fluoride ions**, which were a concern for renal toxicity, rather than severe immune-mediated hepatitis.
Question 8: What is the first line of management in malignant hyperthermia?
- A. Institute cooling
- B. IV dantrolene 2.5 mg/kg
- C. Administer bicarbonate
- D. Discontinue triggering agent (Correct Answer)
Explanation: ***Discontinue triggering agent*** - The immediate and most crucial first step is to **discontinue** all **halogenated inhalational anesthetics** and **succinylcholine**, as these are the agents that trigger malignant hyperthermia. - Failure to remove the triggering agents will lead to continued progression of the hypermetabolic state, making other interventions less effective. *Institute cooling* - While **cooling measures** are essential for managing the **hyperthermia** and are implemented early, they are secondary to discontinuing the causative agent. - Cooling alone will not cease the underlying muscle hypermetabolism and calcium release without removing the triggering substance. *IV dantrolene 2.5 mg/kg* - **Dantrolene** is the specific antidote for malignant hyperthermia, directly interfering with calcium release from the sarcoplasmic reticulum, and should be administered as soon as possible after suspicion. - However, the very first step is to stop the continuous exposure to the triggering agents that are causing the condition. *Administer bicarbonate* - **Bicarbonate** is used to manage the **metabolic acidosis** that develops in malignant hyperthermia due to excessive CO2 production and lactic acid. - This is a supportive measure addressing a consequence of the condition, not the primary intervention to halt the hypermetabolic crisis itself.
Question 9: Which of the following increases uric acid excretion?
- A. Probenecid (Correct Answer)
- B. Allopurinol
- C. Aspirin
- D. Colchicine
Explanation: **Probenecid** - **Probenecid** is a **uricosuric agent** that increases renal excretion of uric acid by inhibiting its reabsorption in the proximal tubule. - It is used in the treatment of **chronic gout** to lower serum uric acid levels. *Allopurinol* - **Allopurinol** works by inhibiting **xanthine oxidase**, an enzyme responsible for uric acid synthesis, thereby reducing its production. - It does not increase uric acid excretion but rather decreases its formation, making it suitable for **overproducers** of uric acid. *Aspirin* - **Low-dose aspirin** can actually *decrease* uric acid excretion by interfering with tubular secretion of uric acid. - **High-dose aspirin** has a uricosuric effect, but it is not typically used for gout due to side effects and more effective alternatives. *Colchicine* - **Colchicine** is an **anti-inflammatory agent** used to treat acute gout flares by inhibiting neutrophil chemotaxis and activation. - It does **not affect uric acid synthesis or excretion** directly, but rather mitigates the inflammatory response to uric acid crystals.
Question 10: Which of the following inhalation anesthetic agents is hepatotoxic?
- A. Halothane (Correct Answer)
- B. Sevoflurane
- C. Isoflurane
- D. Desflurane
Explanation: ***Halothane*** - **Halothane** is known for its potential to cause **halothane hepatitis**, a severe and sometimes fatal form of liver damage. - This toxicity is typically due to the formation of reactive metabolites during its metabolism, which can lead to immune-mediated liver injury. *Sevoflurane* - **Sevoflurane** is generally considered to have a very low risk of hepatotoxicity. - While it can produce a small amount of inorganic fluoride, which was a concern with older halogenated anesthetics, its metabolic profile makes it much safer for the liver compared to halothane. *Isoflurane* - **Isoflurane** is metabolized to a very small extent (less than 0.2%), significantly reducing the risk of generating toxic metabolites that could harm the liver. - It is commonly used in clinical practice due to its favorable safety profile, including minimal hepatotoxicity. *Desflurane* - **Desflurane** has an even lower metabolism rate than Isoflurane, making it one of the safest inhaled anesthetics in terms of liver toxicity. - Its rapid onset and offset properties, coupled with its minimal metabolism, contribute to its low potential for hepatotoxic effects.
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