Anti-Parasitic drug →↑↓

Question 1

Route and SIgns and Symptoms and form of Protozoal infection : Amebiasis

Answer 1

Fecal-oral route
some cysts open in the ileum to release amebae which produce trophozites

Severe Signs and Symptoms
Abdominal tenderness
Bloody stools
Fever
Vomiting

Two forms

Cystic form
→inactive
→resistant to drugs heat cold anddrying
→can survive outside the body for long periods

Active form (trophozoites
→Invade into body tissue
→Penetrate into blood vessel→→forming abscess in other ograns
→cause erosions and ulcerations in the intestinal wall with resultant diarrhoea

Question 2

Drug for Amebiasis classified to their site of actions

Answer 2

Intestinal ambeicide
Iodoquinol

Tissue or extraintestinal amebicide
Chloroquine

For both intestinal and extraintestinal amebiasis
Metronidazole

no prophylaxis drugs for amebasis

Question 3

Effect of Amebicides Iodoquinol

Answer 3

Active against active amebae (trophozoites) in the intestinal lumen

An iodine compound

Often given in combination with tissue amebicide

exact mechanism of action of iodoquinol is unknown

Question 4

Effect and Moa of Amebicides : Chloroquine

Answer 4

Effective in tissue amebiasis (hepatic amebiasis)
Treatment combined with intestinal amebicide

MoA
digestion of rbc by parasites which in high quantities release free heme→ Free heme is toxic to cells →formation of heme polymerase (acted on by chloroquine) →inhibit formation of non-toxic hemozoin

Question 5

Effect. MoA and contraindication Amebicides : Metronidazole

Answer 5

Acts on intestinal and extraintestinal sites of infection

Metronidazole reduced by reacting with reduced ferredoxin and produces toxic products to cells
→take up into amoeba DNA and form unstable molecules

MoA
damaging protozoa’s DNA
inhibits protozoa’s DNA synthesis

Contraindication
pregnancy
blood disorders
alcohol should be avoided

Question 6

Helminthiasis infections

Answer 6

Parasitic worms

may penetrate body tissues or produce larvae that migrate to the blood, lymph channels, lungs, liver,
and other body tissues

Question 7

Symptoms of having worms

Answer 7

Nausea

Weakness

Diarrhoea

Abdominal Pain

Hunger or loss of appetite

Fatigue

Weight loss

Vitamin and mineral deficiencies

Question 8

MoA and adverse effect of Anthelmintics

Mebendazole

Answer 8

MoA
inhibit the worm’s ability to absorb glucose→ stop production of ATP
Helminths die slowly, expelled from GI track dup to 3 days

Adverse effects
GI disturbances

Elevated liver enzymes

in rare cases associated with low white blood cell count, low platelet count and hair loss in high dose

Question 9

MoA and Adverse effect of Anthelmintics Pyrantel (praiquantel)

Answer 9

Act as a depolarizing neuromuscular blocker
→Phase I activation of nicotinic receptors in worms
→→resulting in persistent depolarization
→Phase II sensitization of nicotinic receptors, membrane can only be repolarized but not depolarized
→→→paralyzing the worm

Result of causing to worm to lose its grip on the intestinal wall and be passed out of the system by natural process

Adverse side effect:
GI disturbance
headache

Question 10

MoA and Adverse effect Anthelmintics: Ivermectin

Answer 10

In muscle and nerve cells of the parasitic worm

Binds to Glutamate-gated chloride ion

Increase the permeability of the cell membrane to chloride ions

results in hyperpolarization of the cell leading to paralysis and death of the parsite

Adverse effect
GI disturbance, headache

Question 11

Transmission and symptoms of Malaria

Answer 11

Only be anopheles mosquitoes
usually affect travelers or immigrants from malarious areas

Symptoms
cycles of chills and fever
nausea fatigue

Question 12

Entry of malaria in body

Answer 12

Exo-erythrocytic (hepatic) stage
→ Liver cell entry
→ →liver cell rupture, merozoite release
→ → →RBC penetration

Erythrocytic stage
Asexual production
Development into gametocytes

Symptoms at erythrocytic stage
fever chill

Question 13

Effec, Moa and Antimalarial agents Chloroquine

Answer 13

effective against erythrocytic forms

not effetive against tissue exoerythrocytic form. Do not prevent recurrence

can be used for prophylaxis, it is given before, during and after travel or residence in endemic areas

Chloroquine-resistant strains has developed in many areas

Question 14

Antimalarial agent for chloroquine resistance strains

Answer 14

Melfoquine
Halofantrine
inhibits heme polymerase
→ →inhibit Hemozoin formation

Question 15

Artemisinin

Answer 15

have presence of endoperoxide bridge
→→interacts with heme in parasite
→→→heme iron cleaves this endoperoxide bridge
→→→→there is the generation of highly reactive free radicals which damage parasite membrane by covalently binding to membrane proteins

Kill erythrocytic forms

Question 16

Effect and MoA of Antimalarial agent : Primaquine

Answer 16

Effective against exo-throcytic or tissue forms

Primaquine is not effective on erythrocytic form

radical cure= eradicating the tissue forms of the plasmodium

used for prophylaxis after the patient has returned from a malarious area

given concurrent with chloroquine

MoA may be acting by generating reactive oxygen species

Question 17

Effect and Moa of Antimalarial agents : Pyrimethamine Proguanil

Answer 17

Inhibition of folic acid formation, a essential nutrient required by the parasite

Selective inhibitor of dihydrofolate reductase of the plasmodium
Kill erythrocytic forms mainly but has some activity on exo-erythrocytic form

Question 18

Effect and MoA of antimalarial agents : Atovaquone

Answer 18

inhibits mitochondrial function

→interfere ATP production
→effective against exo-erythrocytic and erythrocytic forms