Antiparasitic drugs Flashcards
Metronidazole - MoA
It inhibits nucleic acid synthesis by disrupting the DNA of microbial cells.
Inhibit pyruvate-ferredoxin oxidoreductase (PFOR)
Metronidazole - Clinical use
Entamoeba histolytica
Giardia intestinalis (Giardia lamblia)
Trichonomas vaginalis
Anaerobic bacteria:
Bacteroides fragilis
Helicobacter pylori
Clostridium difficle
Amebiasis Giardiasis Trichonomiasis Dracunculiasis by Dracunulus medinensis (Guinea worm infection) Balantidiasis Enterocolitis Rosacea (acne rosacea)
Metronidazole and Tinidazole - Contraindications
Contraindicated during first trimester of pregnancy
Metronidazole and Tinidazole - Adverse effects
Metallic taste
Transient leukopenia
Thrombocytopenia
Metronidazole and Tinidazole - Interactions
Increase effect of warfarin.
Ethanol: disulfiram-like reaction
Serum levels affected by drugs inhibiting/inducing CYP3A4.
Tinidazole - Clinical use
Entamoeba histolytica
Giardia intestinalis (Giardia lamblia)
Trichonomas vaginalis
Anaerobic bacteria:
Bacteroides fragilis
Helicobacter pylori
Clostridium difficle
Giardiasis Trichonomiasis Amebiasis Amebic liver abscess Bacterical vaginosis
Iodoquinol, Paromomycin, Diloxanide - Clinical use
Used alone to treat asymptomatic carriers of E. histolytica, but it must be used in combination with a tissue amebicide to treat patients with symptomatic disease, including amebic dysentery and liver abcess
Dientamoeba fragilis (Idoquinolol)
Nitazoxanide - MoA
Noncompetative inhibitor of pyruvate-ferredoxin oxidoreductase
Nitazoxanide - Clinical use
Cryptosporidium parvum
Giardia lamblia
Entamoeba histolytica
Cryptosporidiosis, giardiasis in immunocompetent persons
Ascariasis
Quinine, Chloroquine, Mefloquinine - MoA
Inhibits nucleic acid synthesis/function during erythrocytic schizogony
Chloroquine, Quinine - Clinical use
Chloroquinine
P. falciparum, prevention and treatment
Combination with primaquine to eradicate P. vivax or P. ovale
Quinine: Alternative to artesunate for severe malaria
Chloroquine - Contraindications
Should be used cautiously in pregnant women because fetal damage has been reported
Chloroquine - Adverse effects
Quinine - Adverse effects
Toxic overdose: Retinal damage and blindness
Exacerbation of psoriasis and pruritus
Cinchonizm
Mefloquinine - Clinical use
Prophylaxis and treatment of falciparum malaria, where it is known to be effective
Combination with artesunate is a first-line therapy in parts of Southeast Asia and South America
Mefloquinine - Adverse effects
Severe neuropsychiatric syndrome characterized by hallucinations, anxiety, confusion, seizures and coma
Leukopenia
Thrombocytopenia
Bradycardia and arrythmias
Primaquine - MoA
Form quinones that oxidize and destroy schizont membranes
Primaquine - Clinical use
Exoerythrocytic tissue stage of P. vivax and P. ovale in combination with chloroquine or other drugs
Primaquine - Adverse effects and Contraindications
Hemolytic anemia in G6PD deficiency
G6PD deficiency
Artesunate, Artemether - MoA
Form free radicals that attack heme and proteins in malarial parasites and inhibit erythocytic schizogony
Artesunate - Clinical use
IV is 1st line for severe falciparum malaria (children + adults)
P. vivax
Artemether - Clinical use
P. falciparum malaria
P. vivax
Which drugs has the most rapid action of the current drugs against falciparum?
Artesunate and Artemether
Atovaquone - MoA
Inh synthesis of pyrimidines and nucleic acid synthesis by selective inhibition of mitochondria electron transport in plasmodia
Atovaquone - Clinical use
Prophylaxis and treatment of Chloroquine-resistant falciparum malaria in combination with proguanil
Alone: pneumocystitis jiroveci infections
Atovaquone - Special considerations
Always in combo with proguanil or doxycycline for malaria.
Proguanil - MoA
Inh synthesis of pyrimidines and nucleic acid synthesis by inhibiting dihydrofolate reductase
Proguanil - Clinical use
Prophylaxis and treatment of Chloroquine-resistant falciparum malaria in combination with atovaquone
Pyrimethamine, Sulfadoxine - MoA
Pyrimethamine:
Inh folic acid synthesis in plasmodia by blocking dihydrofolate reductase.
Sulfadoxine:
Inh folic acid synthesis in plasmodia by inhibiting dihydrofolate synthesis
Pyrimethamine, Sulfadoxine - Clinical use
Malaria
Toxoplasmosis (in combination)
Pyrimethamine, Sulfadoxine - Adverse effects
Skin rashes
Megaloblastic anemia and other hematologic reactions
Folate deficiency
Severe hematologic abnormalities
Drugs for toxoplasmosis
Pyrimethamine + sulfadiazine
Spiramycin
Drugs for toxoplasmosis - Clinical use
Pyrimethamine + sulfadiazine: Toxoplasmosis in AIDS Spiramycin: Fetal toxoplasmosis
Which drug is used for pregnant women with toxoplasmosis?
Spiramycin
Drugs for pneumocystic jiroveci infection
Trimethoprim-sulfamethoxazole Atovaquone Pentamidine Dapsone Prednisone
Which drug is preferred for acutely ill patients with pneumocystis jiroveci infections?
Prednisone
Dapsone - Special considerations
In combination with trimethoprim/pyrimethamine
Pyrimethamine + sulfadiazine- Interactions
Lecovorin (folic acid) can be added to reduce hematologic effects.
Pentamidine - Adverse effects
Hematologic toxicity Ventricular tachycardia Edema Pancreatitis Bronchospasm Stevens-Johnsons syndrome
Pentamidine and Suramin - Clinical use
Early African trypanosomiasis (sleeping sickness),
Trypanosoma brucei
Melarsoprol and Eflornithine - Clinical use
Late African trypanosomiasis (sleeping sickness) against CNS manifestations
Nifurtimox - Clinical use
American trypanosomiasis (Chagas disease), Trypanosoma cruzi
Nifurtimox - Special considerations
Often combined with interferon-γ
Miltefosine - MoA
Inhibits enzymes for glycolipid metabolism of the surface of leishmania species
Miltefosine - Clinical use
Cutaneous and visceral leishmaniasis (kala-azar)
Miltefosine - Adverse effect
Reversible hepatic and renal toxicity
Albendazole and mebendazole - Classification
Benzimidazole compounds
Albendazole and mebendazole- MoA
Binds b-tubulin and inhibit its polymerization to form microtubules in the parasites. Makes it impossible for them to obtain glucose
Albendazole and Mebendazole- Clinical use
Both: Intestinal nematode infections: Ascariasis Capillariasis Hookworm (Ancylostoma and Necator) Pinworm (Enterobius vermicularis) Whiphworm (Trichuris trichuria)
Trichinosis (combined with corticosteroid to relieve inflammation)
Albendazole:
Cysticercosis (Pork tapeworm, Taenia solium)
Echinococcosis
Microsporidiosis
Albendazole and mebendazole - Contraindications
Contraindicated during pregnancy
Pyrantel - Classification
Pyrimidine derivative
Pyrantel - MoA and Clinical use
Activates nicotinic ACh receptors in somatic muscles of nematodes. Causes depolarizing neuromuscular blockade.
Hookworm and pinworm infection
Ivermectin - Classification
Broad-spectrum anthelmintic drug
Ivermectin - MoA
Increases Chloride permeability of intervertebrate muscle cells. Cause hyperpolarization of the cell membrane and paralysis of pharyngeal muscles in helminths
Ivermectin - Clinical use
Active against nematodes Strongyloidiasis Onchocerciasis (River blindness) Cutaneous larva migrans (Hookworm) Loa loa (loiasis) Lymphatic filariasis (brugia malayi, Wuchereria bancrofti) Scabies
Diethylcarbamazine (DEC) - Classification
Piperazine derivative
Diethylcarbamazine (DEC) - MoA
Inhibits prostacyclin and prostaglandin E2 and I2 in both host cell and filariae. Blood vessel constriction and aggregation of host granulocytes.
Diethylcarbamazine (DEC) - Clinical use
Elephantiasis (Wuchereria bancrofti, Brugia malayi)
Diethylcarbamazine (DEC) - Adverse effects
Severe hypersensitivity reaction
Praziquantel - Classification
Isoquinoline derivative
Praziquantel - MoA
Increased calcium permeability of the tegument, and cause depolarization
Praziquantel - Clinical use
Schistosomiasis Tissue flukes: Chinese liver fluke (Clonorchis sinesis) Lung fluke (Paragonimus westermani) Tapeworms (cysticerosis).
Triclabendazole - Clinical use
Sheep liver fluke (Flasciola hepatica)
Bithionol - Clinical use
Alternative for sheep liver fluke and lung fluke (Paragonimus westermani)
Oxamniquine - Clinical use
Alternative to praziquantel for Schistosoma mansoni infections
Niclosamide - Clinical use
Alternative to praziquantel for cestode infections
Permethrin - Classification
Synthetic pyrethrin-like compound
Permethrin - MoA
Block sodium currents in neurons of parasites. Paralysis of the organism
Permethrin - Clinical use
Pediculosis (lice)
Scabies (mites)
Spinosad - MoA
Activate nicotinic ACh receptors, causing muscle contraction and paralysis
Spinosad - Clinical use
Head lice (pt over 4 years)