Medication Summary
Anthelmintic drugs act locally to rid the GI tract of worms or systemically to rid the body of the helminth forms that invade organs and tissues. Much of the success of development of these medications is dedicated to the efforts of veterinarians because many cestodes have animal hosts.
Anthelmintics
Class Summary
Parasite biochemical pathways are sufficiently different from the human host, which allows for selective interference by chemotherapeutic agents in relatively small doses.
Albendazole (Albenza)
Decreases ATP production in worm, causing energy depletion, immobilization, and finally death. To avoid inflammatory response in CNS, patient also must be started on anticonvulsants and high-dose glucocorticoids. DOC for some of the potentially fatal cestode infections, namely cysticercosis (for T solium) and hydatid cyst disease (from Echinococcus).
Patients with cysticercotic encephalitis develop intracranial hypertension with antihelmintic use and, thus, require a ventricular shunt prior to drug therapy.
Paromomycin (Humatin)
Alternative therapy for patients infected with Diphyllobothrium species, Hymenolepis species, T solium, and T saginata. Since action is mainly in adult worms, does not reach ova. Patients with T solium infections remain at risk of cysticercosis.
Praziquantel (Biltricide)
Acylated isoquinoline that increases cell membrane permeability in susceptible worms, resulting in a loss of intracellular calcium, massive contractions, and paralysis of their musculature. In addition, produces vacuolization and disintegration of the schistosome tegument. This is followed by attachment of phagocytes to the parasite and death. Tablets should be swallowed whole with some liquid during meals. Keeping tablet in the mouth may reveal a bitter taste that can produce nausea or vomiting.
Effective against cestodes (except Echinococcus species) and trematodes, but not nematodes. DOC in the treatment of hymenolepiasis.
In cysticercosis, this medication has the potential to provoke an inflammatory response in the CNS. Thus, the patient must also be started on high-dose glucocorticoids.
Patients with cysticercotic encephalitis develop intracranial hypertension with antihelmintic use and, thus, require a ventricular shunt prior to drug therapy.
Niclosamide (Niclocide)
A chlorinated salicylanilide. DOC; inhibits mitochondrial oxidative phosphorylation and glucose uptake in parasite. Cure rate of about 90% for Taenia species and a little less than 90% for Diphyllobothrium species.
Mebendazole (Vermox)
Causes worm death by selectively and irreversibly blocking uptake of glucose and other nutrients in susceptible adult intestine where helminths dwell.
Anticonvulsants
Class Summary
These agents are used to manage symptoms in patients being treated for neurocysticercosis.
Diazepam (Valium)
Depresses all levels of CNS, including limbic and reticular formation, possibly by increasing activity of GABA, which is a major inhibitory neurotransmitter.
Individualize dosage and increase it cautiously to avoid adverse effects.
Glucocorticoids
Class Summary
These agents have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, they modify the body's immune response to diverse stimuli.
Prednisone (Deltasone, Sterapred, Orasone)
Useful in treatment of inflammatory and allergic reactions. By reversing increased capillary permeability and suppressing PMN activity, may decrease inflammation.
If a safer alternative therapy is available, do not administer glucocorticoids.
Methylprednisolone (Solu-Medrol, Depo-Medrol, Medrol)
Decreases inflammation by suppressing migration of PMNs and reversing increased capillary permeability.
Vitamins
Class Summary
These agents are essential for normal DNA synthesis. Indicated for use in patients with megaloblastic anemia due to deficiency in vitamin B-12.
Cyanocobalamin (Cobex, Berubigen, Crystamine)
Deoxyadenosylcobalamin and hydroxocobalamin are active forms of vitamin B-12 in humans. Vitamin B-12 synthesized by microbes but not humans or plants.
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Adult tapeworm of Dipylidium caninum. Image courtesy of the Centers for Disease Control and Prevention (CDC).
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Ultrasonographic appearance of echinococcal cysts (Gharbi type I, World Health Organization [WHO] standardized classification CE1).
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Diagram of the Echinococcus life cycle. Image courtesy of the Centers for Disease Control and Prevention.
Tables
Cestode |
Primary Host |
Intermediate Host |
T solium |
Humans |
Pigs, humans, dogs, cats, sheep |
T saginata |
Humans |
Cattle |
Diphyllobothrium |
Humans |
Fish |
Hymenolepis |
Humans |
Hymenolepis nana: None; Hymenolepis diminuta: Rodents |
D caninum |
Humans, dogs, cats |
Fleas on dogs/cats |
Echinococcus |
Dogs |
Humans, sheep, cattle, goats, horses, camel |
Spirometra |
Humans |
|
T multiceps |
|
Hares, rabbits, squirrels, humans (rarely) |
