Trematocides (Praziquantel) and Cestodicides (Niclosamide) – Anthelmintic Drugs

00:00 Let's move on to the trematodes.

00:03 So the trematodicidal agents are -- the prototypical one is praziquantel.

00:09 It increases the membrane permeability to calcium of the organism.

00:14 Which results in a marked contraction of the trematode and then paralysis.

00:19 It's used in trematode and cestode infections.

00:23 And it is the drug of choice in schistocomiasis.

00:28 It's an alternative to albendazole in neurocysticercosis caused by the pork tapeworm.

00:33 And it is contraindicated in ocular cysticercosis.

00:37 So ocular cysticercosis, you must treat with albendazole due to the risk of exacerbating inflammation with praziquantel.

00:45 So here's an example of ocular cysticercosis or pork tapeworm.

00:51 So I'm going to say it again and again.

00:52 For ocular cysticercosis, treat with albendazole. For neurocysticercosis, praziquantel can be used as an alternative, but albendazole is generally preferred.

01:03 In terms of the mechanism of action of praziquantel, it increases the membrane permeability to calcium, causing marked contraction and then paralysis of the parasite.

01:14 Toxicity includes headache, dizziness and drowsiness.

01:20 Let's move on to the cestodes.

01:23 So the cestocidal agents are quite very -- I think I'll talk quickly about niclosamide.

01:30 So niclosamide is interesting because it works differently than the other agents.

01:35 It uncouples the oxidative phosphorylation.

01:39 This cause paralysis of the organisms.

01:42 And it activates ATPases in the tapeworm.

01:45 It is an alternative drug in beef, pork and fish tapeworms, but it is not effective against neurocysticercosis or other tissue cysts caused by the pork tapeworm.

01:55 Now here is an image of cysticercosis. You can see the cysts present in the liver on the CT scan, indicated by the white arrow. The ova and larva are not killed by niclosamide.

02:07 Albendazole is the preferred treatment for the cystic form of the pork tapeworm.