Antiparasitic Drugs: Master Medicinal Chemistry for MPharm Students

Question 1

Which mechanism of action is NOT utilized by antiparasitic drugs?

Accepted Answer

Stimulating the host's immune response

Answer

Inhibiting parasite DNA synthesis

Answer

Disrupting parasite energy metabolism

Answer

Altering parasite cell membrane permeability

Question 2

Describe the mechanisms by which parasites develop resistance to antiparasitic drugs, providing specific examples for each mechanism.

Accepted Answer

Mutations in the drug target, such as altered binding sites or decreased affinity for the drug, can render the drug ineffective. For instance, mutations in the dihydrofolate reductase enzyme of Plasmodium falciparum confer resistance to antifolates.

Accepted Answer

Alterations in drug transport can affect the uptake or efflux of drugs, reducing their intracellular concentration. For example, overexpression of the P-glycoprotein efflux pump in Trypanosoma brucei leads to resistance to various antitrypanosomal drugs.

Accepted Answer

Overexpression of drug efflux pumps can actively expel drugs from the parasite, reducing their intracellular concentration. An example is the overexpression of the multidrug resistance 1 (MDR1) efflux pump in Leishmania species, which confers resistance to multiple antileishmanial drugs.

Answer

Only mutations in the drug target can lead to drug resistance.

Question 3

Select the primary mechanism of action by which benzimidazoles exert their antiparasitic effects:

Accepted Answer

Inhibition of tubulin polymerization, leading to disruption of microtubule function

Answer

Disintegration of mitochondrial function, impairing cellular energy production

Answer

Interference with DNA synthesis, hindering parasite replication

Answer

Inhibition of protein translation, preventing parasite protein synthesis

Question 4

Identify the class of antiparasitic medications primarily used for the treatment of malaria caused by Plasmodium species:

Accepted Answer

Artemisinins

Answer

Quinolones

Answer

Nitroimidazoles

Answer

Sulfonamides

Question 5

Which mechanism of action is primarily responsible for the antiparasitic activity of avermectins?

Accepted Answer

Inhibition of voltage-gated sodium channels, leading to paralysis of parasites

Answer

Depolarization of neuronal membranes, causing disruption of parasite neurotransmission

Answer

Interruption of mitochondrial electron transport, impairing parasite energy production

Answer

Inhibition of DNA synthesis, preventing parasite replication

Question 6

Which class of antiparasitic drugs is commonly used to treat trypanosomiasis?

Accepted Answer

Nitroimidazoles

Answer

Benzimidazoles

Answer

Artemisinins

Answer

Quinolones

Question 7

Which of the following is an essential pharmacokinetic characteristic of antiparasitic drugs intended for systemic infections?

Accepted Answer

Extensive distribution throughout the body, reaching target parasites in various tissues

Answer

High protein binding, ensuring prolonged drug retention in the body

Answer

Rapid elimination from the body, minimizing the risk of accumulation

Answer

Targeted delivery to specific organs, maximizing drug concentration at the site of infection

Question 8

Which major class of antiparasitic drugs is effective against both roundworms (nematodes) and tapeworms (cestodes)?

Accepted Answer

Benzimidazoles

Answer

Avermectins

Answer

Nitroimidazoles

Answer

Artemisinins

Question 9

Why are combination therapies used to treat parasitic infections? Provide examples of effective combinations.

Accepted Answer

To overcome drug resistance and enhance treatment efficacy

Answer

To reduce treatment costs

Answer

To improve patient adherence to treatment regimens

Question 10

The mechanism of action of metronidazole against protozoal parasites involves:

Accepted Answer

Generation of free radicals

Answer

Inhibition of DNA synthesis

Answer

Disruption of microtubule assembly

Answer

Inhibition of protein synthesis

Question 11

The first-line treatment for uncomplicated malaria caused by Plasmodium falciparum as recommended by the World Health Organization is:

Accepted Answer

Artemether-lumefantrine

Answer

Chloroquine

Answer

Mefloquine

Answer

Malarone

Question 12

Which of the following antiparasitic drugs primarily targets the parasite's energy metabolism?

Accepted Answer

Benznidazole

Answer

Ivermectin

Answer

Albendazole

Answer

Praziquantel

Question 13

Malaria, a parasitic infection, is caused by:

Accepted Answer

Protozoan parasites

Answer

Helminth parasites

Answer

Fungal parasites

Answer

Bacterial parasites

Question 14

Which parasitic infection is primarily transmitted through contaminated water?

Accepted Answer

Cryptosporidiosis

Answer

Malaria

Answer

African trypanosomiasis

Answer

Leishmaniasis

Question 15

Which of the following is not a class of antiparasitic drugs?

Accepted Answer

Antibiotics

Answer

Antimalarials

Answer

Antiprotozoals

Answer

Anthelmintics

Question 16

The mechanism of action of artemisinin and its derivatives involves:

Accepted Answer

Formation of free radicals

Answer

Disruption of membrane integrity

Answer

Inhibition of protein synthesis

Answer

Intercalation into DNA

Question 17

The drug of choice for treating giardiasis is:

Accepted Answer

Metronidazole

Answer

Praziquantel

Answer

Artemisinin

Answer

Albendazole

Question 18

The recommended dose of praziquantel for treating schistosomiasis is:

Accepted Answer

20 mg/kg single dose

Answer

30 mg/kg once daily for 5 days

Answer

40 mg/kg once daily for 7 days

Answer

10 mg/kg once daily for 3 days

Question 19

Which of the following drugs is used to treat cutaneous leishmaniasis?

Accepted Answer

Miltefosine

Answer

Ivermectin

Answer

Artemisinin

Answer

Fluconazole

Question 20

The treatment of choice for cryptosporidiosis in immunocompromised patients is:

Accepted Answer

Nitazoxanide

Answer

Metronidazole

Answer

Albendazole

Answer

Praziquantel

Question 21

Which of the following is NOT a common mechanism of action for antiparasitic drugs?

Accepted Answer

Stimulation of the host's immune system

Answer

Inhibition of nucleic acid synthesis in the parasite

Answer

Interference with parasite cell division

Answer

Disruption of parasite metabolic pathways

Question 22

Which class of antiparasitic drugs primarily targets the parasite's microtubules, disrupting their assembly and function?

Accepted Answer

Benzimidazoles

Answer

Nitroimidazoles

Answer

Quinolones

Answer

Macrolides

Question 23

Which of the following drugs is commonly used to treat African trypanosomiasis (sleeping sickness)?

Accepted Answer

Pentamidine

Answer

Metronidazole

Answer

Chloroquine

Answer

Ivermectin

Question 24

Which of the following side effects is most commonly associated with the use of metronidazole?

Accepted Answer

Nausea and vomiting

Answer

Dizziness

Answer

Skin rash

Answer

Hepatotoxicity (liver damage)