Antiparasitic Drugs Flashcards
What is a broad spectrum drug against Round Worms?
Mebendazole - low systemic
What is a common mechanism between Mebendazole and Albendazole?
They both disrupt microtubules and immobilize the parasite.
What drug is typically used for systemic round worm infections and Echinococcus?
Albendazole - metabolite is active and distributes throughout body.
What drug is used for strongyloides and hook worms larvae?
Thiabendazole
What drug is used as an alternative for broad spectrum round worm infections?
Thiabendazole
What round worm drug is most rapidly absorbed and which has the least absorption?
Rapidly Absorbed - Thiabendazole
Poorly Absorbed - Mebendazole and Pyrantel Pamoate
What drug is primarily used to treat pin worms and hook worms?
Pyrantel Pamoate
How does Pyrantel Pamoate work on the round worms?
depolarizing neuromuscular blocker causing paralysis of the worms.
What is the drug of choice for schistosoma fluke infections?
Praziquantel - some activity against other trematodes
What drug is used as a broad spectrum against cestodes (tapeworms)?
Praziquantel
What is the best treatment for taenia solium (pork tape worm from undercooked meat)?
Praziquantel - additionally kills the eggs and larvae together stopping the infection
What drug is used to treat neurocysticerosis (once the larvae migrate into the brain)?
Albendazole (Remember - drug metabolite is well distributed throughout body)
What drug is used if the patient is a wussie and can’t tolerate other medications for cestrodes?
Paromomycin Sulfate
How do antimalarial drugs typically work?
They do not kill the sporozoites, but prevent the spread within the body and the immune system kills them.
–Prevents progression of symptoms–
When an individual is in the endemic zone of malaria what is the target of the preventative drug?
RBC from of the disease of all species
After leaving the endemic zone, what should the targets of the therapy be?
Hepatocyte Form - for 14 days after leaving endemic zone of P. Vivax and Ovale.
In regards to disease process, how are P. Malariae and Falciparum similar?
They only have hepatic form at the beginning of the infection the stay in the RBC form.
How do you have to treat P. Vivax and P. Ovale differently compared to the other forms of malaria?
They can have latent hepatic infection that can reside lifelong, so treatment must target both RBC and Hepatic forms.
How does Chloroquine selectively target infected RBCs?
The drug is a weak base that can diffuse, but in the an infected RBC there is an acidic vacoule that charges the drug now allowing it to escape, essentially concentrating in the infection.
What drug would you take while you are in Africa to prevent malaria?
Chloroquine
What is the mechanism of Chloroquine?
Prevents heme polymerase, causing a build up of free radicals effectively killing the parasite.
(Resistance is increasing year by year)
What two forms of malaria can Chloroquine treat?
P. Falciparum
P. Malariae
–Unable to kill the hepatic infections of the other two–
What is a side effect of prolonged use of Chloroquine?
Visual impairment
What drug can be used to treat/prevent malaria if it is resistant to Chloroquine?
Mefloquine
What are the side effects of Mefloquine and who should not take it?
Causes CNS effects - anxiety, depression, paranoia, vertigo, etc.
Individuals with psychiatric disorders or siezures should not take it can make symptoms worse. (Even if taking psychiatric drugs)
What is the two drug combination that treats/prevents RBC malaria and works synergistically?
Atovaquone + Proguanil
- -more specifically can treat Chloroquine resistant P. Falciparum
- Better tolerated, but more expensive
How does each drug of Atovaquone and Proguanil work?
Atovaquone - inhibits mitocondrial transport preventing pyrimidine synthesis
Proguanil - inhibits dihydrofolate reductase, blocking pyrimidine synthesis
What drug can be used for fast action in acute malaria infections?
Quinine - similar mechanism of Chloroquine
What drug can be used as a second line for chloroquine resistant P. Falciparum?
Quinine.
What are common side effects of Quinine?
Cinchonism - causes all the following symptoms.
Headache, visual distrubances, dizziness, and tinnitis.
What drug can be used for broad spectrum bacteria coverage and can treat malaria?
Doxycyline
What are the three ways Doxycyline can treat malaria?
- decreases protein synthesis
- depresses dihydroorate dehydrogenase synthesis
- inhibits prymidine synthesis
When is it most common to use Doxycycline for malaria?
Multi-drug resistant P. Falciparum or prevent of Chloroquine-resistant strains.
What anti-malarial drug can be used to treat hepatocyte latent infection of P. Vivax and P. Ovale?
Primaquine
What drug would you give a patient who had returned from an endemic zone for 14 days?
Primaquine - to kill of any P. Vivax and Ovale that remained or were able to penetrate to the liver.
Who should not take Primaquine due to adverse reaction and hemalytic anemia?
Individuals with G6PDH deficiencies.
What drugs would you use for an asymptomatic entamoeba histolytica?
Iodoquinol or Paromomycin Sulfate - targets the lumen of the bowel, does not penetrate tissues
What drug would be used for symptomatic infection that can penetrate the tissues of the bowel?
Metronidazole
Should also used Iodoquinol or Paromomycin
What are unique effects of Paromomycin Sulfate and Iodoquinol?
Iodoquinol - should not be used for people with iodine allergies
Paromomycin Sulfate - does not absorb, minimal systemic side effects, tolerated well
What drug can be used for both Trichomonas and Giardia Lamblia?
Metronidazole
What drug is commonly used for Giardia Lamblia and Cryptosporidum?
Nitazoxanide (not first choice for Giardia)
What drug is used to treat Toxoplasma and treat/prevent pneumocystitis jiroveci?
Atovaquone
What are common treatment options for pneumocystisis jiroveci?
- TMP/SMX
- Clindamycin + Primaquine
- Atovaquone
- Dapsone
