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Toronto Notes 2019
Antiparasitics
Infectious Diseases ID55
Antiparasitics
Table 35. Antiparasitics
Class and Drugs
ANTIMALARIALS
chloroquine
quinine
mefloquine (Lariam®) primaquine
atovaquone/proguanil (Malarone®)
artemisinin derivatives (artemether, artesunate, etc.) Note: marketed primarily in endemic countries
OTHER ANTI-PROTOZOAL
iodoquinol (Diodoquin®)
metronidazole nitazoxanide
ANTI-HELMINTHICS
praziquantel albendazole
mebendazole (Vermox®) ivermectin
diethylcarbamazine
Coverage
Malaria: treatment of erythrocytic phase of all five species of Plasmodium that infect humans Note: High resistance of P. falciparum and P. vivax in certain geographic areas
Malaria: treatment of all five species of Plasmodium that infect humans, including chloroquine- resistant P. falciparum
Malaria: prophylaxis Malaria: treatment of liver
hypnozoites of P. vivax and
P. ovale; prophylaxis of all Plasmodium spp. Pneumocystis jiroveci (with clindamycin)
Malaria: treatment and prophylaxis of P. falciparum
Malaria: treatment of all Plasmodium spp.
Severe malaria (IV artesunate) Typically used in combination with a longer-acting agent from above
Amoebiasis: E. histolytica, Dientamoeba fragilis, Balantidium coli, Blastocystis hominis
Amoebiasis, T. vaginalis, giardiasis, D. fragilis
Cryptosporidium, giardiasis, cyclosporiasis
Schistosomiasis and other flukes Tapeworms
Intestinal roundworms
Neurocysticercosis Echinococcus Hydatid disease
Intestinal roundworms: pinworm, whipworm, hookworm, roundworm (e.g. Ascaris)
Strongyloidiasis Onchocerciasis Scabies
Wuchereria bancrofti Loa loa
Mechanism of Action
Inhibits parasite heme polymerase
Adverse Effects
CNS: blurred vision, retinopathy, dizziness
Nonspecific GI (rare with prophylaxis)
Cinchonism: ears (tinnitus, vertigo), eyes (visual disturbance), GI (nausea/ vomiting, diarrhea), CNS (headache, fever) Hypoglycemia
CNS/Psych: irritability, nightmares, psychoses, suicide, depression, seizures, headache
Hemolytic anemia in G6PD deficient
GI upset (take with food)
Nausea/vomiting, anorexia, diarrhea, abdominal pain (take with food)
Transient neurologic deficits (nystagmus, balance disturbance) Transient neutropenia (at high doses of oral artesunate) Transient neutropenia (at high doses of oral artesunate)
Delayed hemolysis
GI: nausea/vomiting, diarrhea, abdominal pain CNS: headache, seizures, encephalitis
Nausea/vomiting, diarrhea, abdominal pain, headache
Nausea/vomiting, fever, dizziness
Elevated liver enzymes Alopecia
GI nonspecific Agranulocytosis
Nonspecific GI
Nausea, bloating, diarrhea, myalgias, lightheadedness, headache
Anorexia, nausea/vomiting, headache, drowsiness, encephalitis, retinal hemorrhage Mazzotti reaction if coinfected with onchocerciasis
Contraindications
Hypersensitivity to chloroquine or other 4-aminoquinoline
Retinal or visual field changes due to 4-aminoquinoline
Hypersensitivity to quinine,
may have cross-sensitivity with quinidine
Patients with G6PD
deficiency, tinnitus, optic neuritis, hypoglycemia,
history of blackwater fever or thrombocytopenic purpura due to quinine use
History of seizures, psychosis, severe anxiety or depression
GI nonspecific
G6PD deficiency Concurrent or recent use of quinacrine
Pregnancy
Hypersensitivity to atovaquone or proguanil
Severe renal impairment
Hypersensitivity to artemisinins
Hypersensitivity to any 8-hydroxy-quinoline or iodine Patients with hepatic damage or optic neuropathy
Pregnancy
Hypersensitivity to nitazoxanide
Ocular cysticercosis
Pregnancy
Ocular cysticercosis or intraventricular cysticercosis
Pregnancy, infants
Hypersensitivity to ivermectin Pregnancy
Pregnancy Onchocerciasis
Interferes with mitochondrial function
Inhibits mitochondrial electron transport and dihydrofolate reductase
Binds iron, leading to formation of free radicals that damage parasite proteins
Contact amoebicide that acts in intestinal lumen by uncertain mechanism
See Antibiotics, ID47
Interferes with parasite anaerobic
metabolism
Increases Ca2+ permeability of helminth cell membrane, causing paralysis and detachment
Inhibits glucose uptake into susceptible parasites
Inhibits microtubule formation and glucose uptake
Interferes with polarization
of nerve and muscles cells in susceptible parasites leading to paralysis