Antihelmenthic Drugs - Chapter 53 review

inhibits microtubule synthesis in nematodes, thus irreversibly impairing glucose uptake.

approved for the treatment of hydatid disease and cysticercosis.

also used for pinworms, Ascariasis, trichuriasis, strongyloidiasis, and hookworms.

**Broad spectrum antihelmenthic

Relatively contraindicated in pregnancy

- When used for 2-3 days it is nearly free of adverse effects

• Long-term treatment is associated with:
• liver toxicity
• agranulocytosis
• and pancytopenia

Dexamethasone, cimetidine, and praziquantel will increase the serum concentration of the active metabolite of Albendazole.

Mechanisms of action

–immobilizes microfilariae and alters their surface structure displacing them from tissues and making them more susceptible to destruction by host defenses.

DOC for filariasis, loiasis, and tropical eosinophilia

• Toxicity
• –headache, dizziness, nausea, and vomiting.

• –Adverse reactions also occur as a result of the release of proteins from dying microfilariae or adult worms.
• (fever, malaise, headache, joint pain)

–use with caution in patients with hypertension or renal disease

It intensifies GABA-mediated neurotransmission in nematodes and causes immobilization.

DOC for strongyloidiasis (threadworm) and onchocerciasis (river blindness)

 - alternative treatment for filariasis.

• Can also be used to control scabies,
• lice, cutaneous larva migrans, and ascariasis.

• Selective toxicity results because in humans, GABA is a neurotransmitter only in the CNS
• and ivermectin does not cross the blood-brain barrier.

In onchocerciasis treatment, the Mazzotti reaction occurs which is due to the killing of microfilariae

Mazzotti reaction - fatigue, dizziness, nausea, and vomiting,  abdominal pain, and rashes.

IVERMECTIN

The drug should not be given to patients with an impaired blood-brain barrier (meningitis and African sleeping sickness).

Avoid using with other drugs that enhance GABA transmission such as benzodiazepines, barbiturates, and valproic acid.

Inhibits microtubule synthesis in nematodes, thereby irreversibly inhibiting glucose uptake.

approved for the treatment of Ascariasis, trichuriasis, hookworm, and pinworms

–Pregnancy

–neutropenia and hepatitis when taken for a long period of time

–Cimetidine will increase mebendazole levels

• Organophosphate compound,
• Inhibits acetylcholinesterase,
• Paralyzes adult worms

Used to treat Schistosoma haematobium

Cholinergic side effects:

intestinal cramping, blurred vision, slow heart beat, muscle weakness, muscle cramps, and muscle pain, convulsions, weak breathing, inability to breath, increased stomach acid and saliva, nausea and vomiting, dizziness, drowsiness, and headache

• Should not be used in pregnancy or after
• exposure to insecticides

Mech of action

– inhibition of oxidative phosphorylation or stimulation of ATPase

Second line treatment for tapeworm infections

– NVD and abdominal discomfort

Alternative to praziquantel for Schistosoma mansoni infections

– dizziness, headache, drowsiness, NVD, abdominal cramps,

pregnancy and HX of seizures

Mechanisms of action

causes paralysis of ascaris by blocking acetylcholine at the myoneural junction

– Ascariasis

–Not used for other helminth infections

• pregnancy,
• patients with impaired renal or hepatic function

• NVD,
• dizziness,
• headache

Antagonistic with pyrantel pamoate

Mechanisms of action

–Increases the cell permeability to calcium in schistosomes; causes strong contractions and paralysis of worm musculature leading to detachment of suckers from the blood vessel walls and to dislodgement

• Schistosomiasis,
• cysticercosis,
• intestinal trematodes,
• and tapeworms

–FLUKES of ALL kinds

Praziquantel

Ocular cysticercosis result from a worm larvae developing in the eye.

If medication (Praziquantel) is taken for a worm in the eye the inflammatory response to the dead worm is worse than leaving the worm alive.

• hypersensitivity to the drug,
• ocular cysticercosis,
• spinal cysticercosis

• dizziness,
• drowsiness,
• headache,
• fever.

• Alcohol increases CNS depression,
• cimetidine increases praziquantel levels

• Stimulates nicotinic receptors present at
• neuromuscular junctions of nematodes

• Contraction of muscles occurs followed by
• a depolarization-induced paralysis.

• broad-spectrum anthelminthic for treating pinworms,
• Ascariasis,
• and Trichostrongylus orientalis.

• headache,
• GI distress,
• and weakness

relatively contraindicated in pregnancy and liver disease

–piperazine antagonizes the effect of pyrantel pamoate.

• strongyloidiasis, cutaneous larva migrans,
• visceral larva migrans, dracunculosis,
• trichinosis, and mixed helminthic infections

–pregnancy

Mechanisms of action

–inhibits helminth-specific mitochondrial fumarate reductase

• dizziness,
• anorexia,
• abdominal pain,
• liver failure,
• and Stevens-Johnson syndrome

Increases serum theophylline concentrations