Practice Questions Flashcards
Adepoju
Classify antimalarial agents, stating two examples in each class.
- Naturally occurring antimalarial agents e.g. quinine, cinchonine, artemisinin and its derivatives
- 8-aminoquinolines e.g. primaquine
- 4-aminoquinoline e.g. chloroquine and mefloquine
- Sulphonamides e.g. sulphadoxine
- Phenanthrene methanol e.g. halofantrine, lumefantrine
- Naphthoquinones e.g. atovaquone
- 9-amino acridines e.g. mepacrine and pyronaridine
- Dihydrofolate reductase inhibitors e.g. trimethoprim, proguanil, chlorproguanil, pyrimethamine
- Antibiotics e.g. Doxycycline, Azithromycin
Give 3 examples of ACTs with brand name examples.
i. Artemether-Lumefantrine (Coartem®)
ii. Artesunate-Amodiaquine (Camoquin-Plus®)
iii. Dihydroartemisinin-Piperaquine (Eurartesim®)
Explain the mode of action of the artemisinin and its derivatives as antimalarial agent.
Artemisinin and its derivatives contain a peroxide bridge that is crucial for their antimalarial activity. Inside the malaria parasite (Plasmodium species), the degradation of haemoglobin by the parasite in its digestive vacuole releases heme (iron-protoporphyrin IX) or ferrous iron (Fe²⁺). The interaction between the peroxide bridge and the iron results in the cleavage of the peroxide bond.
The cleavage of the peroxide bond generates reactive oxygen species (ROS) and carbon-centred radicals. These highly reactive radicals cause extensive damage
Concomitant administration of ACTs like Armatem with Vitamin C should be avoided, explain.
Artemisinin and its derivatives rely on the generation of reactive oxygen species (ROS) for their antimalarial activity. Vitamin C is a potent antioxidant, which means it can neutralise ROS. By reducing ROS levels, Vitamin C might decrease the effectiveness of artemisinin in killing malaria parasites.
Furthermore, Artemisinin’s activation involves its interaction with iron to produce free radicals. Vitamin C can reduce ferric iron (Fe³⁺) to ferrous iron (Fe²⁺), potentially affecting the availability of the necessary iron species for artemisinin activation.
What is amoebiasis?
Amebiasis is an infection caused by the amoeba Entamoeba histolytica.
Classify amoebicides with examples.
- Antibiotics – tetracyclines, paromomycin, erythromycin, fumagillin
- Quinoline derivatives – chloroquine
- 8-hydroxyquinoline derivatives - e.g. chiniofon, diiodohydroxyquine
- Nitroheterocyclic compounds - e.g. metronidazole, tinidazole, niridazole
- Haloacetamides - e.g. diloxanide furoate
- Pentavalent arsenicals e.g. carbarsone, acetarsone
What are luminal and tissue amoebicides?
Luminal amebicides: these are drugs that act primarily in the intestinal lumen, where the non-invasive cysts and trophozoites of E. histolytica reside. They are used to eradicate the parasite from the intestine and are particularly effective against the cyst form. Examples include Paromomycin and Iodoquinol.
Tissue amebicides: these are drugs that act in tissues where the invasive forms of E. histolytica (trophozoites) have penetrated, such as the intestinal wall, liver, and other extraintestinal sites. They are used to treat invasive amoebiasis, including amoebic dysentery and liver abscesses. Examples include Metronidazole and Tinidazole.
Give 3 examples of luminal amoebicides with trade names, generic names and structures of examples available in the market in Nigeria.
i. Diloxanide furoate (Amicline®)
ii. Paromomycin
iii. Iodoquinol
Give 3 examples of tissue amoebicides with trade names, generic names and structures of examples available in the market in Nigeria.
i. Metronidazole (Flagyl®)
ii. Secnidazole (Secwid®)
iii. Tinidazole (BRAWN Tinidazole tablets)
What is trypanosomiasis? What are the causative agents?
Trypanosomiasis is a disease caused by parasitic protozoans known as trypanosomes.
Trypanosoma brucei gambiense
Trypanosoma brucei rhodesiense
Classify trypanocidal agents.
- Urea derivatives e.g. Suramin
- Organic arsenicals e.g tryparsamide, melarsoprol
- Quinoline derivatives e.g. quinapyramine
- Phenanthridium derivative e.g. dimidium bromide
- Diamidines e.g. pentamidine
- Nitrofurans e.g. nifurtimox
- Amino acid derivatives e.g. eflornithine
What is schistosomiasis? Causative agents
Schistosomiasis also known as bilharziasis, is a parasitic disease caused by trematodes (blood flukes) of the genus Schistosoma
Schistosoma haematobium
Schistosoma mansoni
Schistosoma japonicum
Give the classes of schistosomicidal agents with relevant examples.
- Antimonials - e.g. Antimony sodium gluconate, Antimony potassium tartrate, Antimony sodium dimercato succinate
- Thioxanthones – e.g lucanthone
- Nitrothiazoles – e.g. Niridazole
- Others are: praziquantel, metrifonate and oxamniquine
Write briefly on onchocerciasis.
Onchocerciasis, commonly known as river blindness, is a parasitic disease caused by the worm Onchocerca volvulus. It is transmitted through the bites of infected black flies (Simulium species). The disease primarily affects communities near fast-flowing rivers in tropical regions
Initial symptoms include intense itching and skin nodules. Over time, the infection can lead to skin depigmentation, vision impairment, and blindness.
Life cycle and treatment of trypanosomiasis and schistosomiasis.
