44-Antiparasitic Drugs

Question 1

What are endoparasites and where do they live?

Answer 1

Worms (tapeworm, pinworm etc) and they live in a host

Question 2

What are ectoparasites and where do they live?

Answer 2

Lice, mites, scabies and they live on the host

Question 3

What are the reasons for the increase in prevalence of both endo and ectoparasites in the US?

Answer 3

Immigration
Travelers
AIDS

Question 4

Name some of the lumen and tissue dwelling protozoans?

Answer 4

Amebiasis, Balantidiasis, Cryptosporidiosis, Giardiasis and trichomoniasis

Question 5

What might be the first line drug to use against lumen and tissue dwelling protozoans

Answer 5

Metronidazole (Amebiasis, Giardiasis, Trichomoniasis, Enterocolitis by C-dif, Rosacea)

Question 6

Name some of the properties of metronidazole?

Answer 6

It is orally well absorbed and distributed
It crosses the BBB
Extensively metabolized
Can be given IV
Active vs protozoa as well as H.pylori, B. Fragilis and C-dif and other anaerobic bugs

Question 7

What do you want to caution the patient when putting them on Flagyl?

Answer 7

To avoid alcohol consumption while on this drug because it causes abdominal cramps, N/V/D, Headache and flushing.

Question 8

What are some ADR’s of metronidazole?

Answer 8

• GI discomfort, N/V/D, metalic taste, leukopenia, thrombocytopenia
• Increases anticoagulant effects of coumadin (it kills the anaerobes in the stomach that synthesize Vit K)
• Disulfiram reactions with ETOH
• Photosensitivity

Question 9

What other drug causes you to have a metallic taste? hint its macrolide.

Answer 9

Clarithromycin-used for pharyngitis/tonsilitis etc

Question 10

If a patient is resistant to metronidazole, what other drug can you hit them with?

Answer 10

Tinidazole-used for metronidazole resistant trichomonas

Question 11

What are some properties of Tinidazole?

Answer 11

• it is also indicated for giardiasis, intestinal amebiasis, amebic liver abscess, B.frag, H.pylori
• higher cure rate in a shorter amount of time than flagyl
• Metabolized by CYTP450

Question 12

What are some ADR’s of Tinidazole?

Answer 12

Anorexia, N/V/D, bitter taste in mouth and contraindicated in the first trimester.

Question 13

What does the intestinal protozoa Cryptosporidiosis cause?

Answer 13

Chronic diarrhea in immunocompromised patients. it is also found in up to 50% of AIDS patients

Question 14

What is the recommended treatment for Cryptosporidiosis?

Answer 14

Nitazoxanide-its a broad spectrum and approved for crypto and giardiasis in immunocompetant patients

Question 15

What is the most common Infectious dz in the world

Answer 15

Malaria

Question 16

How is malaria spread?

Answer 16

Mosquito bite

Question 17

Describe Malaria’s mechanism of infection?

Answer 17

Mosquito bite transmits plasmodium sporozites in the blood which invade the liver, replicates into merozoites and then released into the blood stream infecting RBC

Question 18

What are some drugs that can be used to treat malaria?

Answer 18

Primaquine, Chloroquine, Quinine, Mefloquine, Atovaquone and proguanil

Question 19

What are the properties of primaquine?

Answer 19

Used to treat the persistent phase of malaria, eradicates the tissue plasmodia, prevents re-emergence from the liver and relapse.

Question 20

What is an important ADR of primaquine?

Answer 20

In patients with G6PD deficiency, primaquine can accumulate in RBC and cause hemolytic anemia

Question 21

Chloroquine used to be the DOC for malaria until the 80s, what happened?

Answer 21

There was resistance due to the arrival of HIV

Question 22

What are the ADR’s of chloroquine?

Answer 22

GI distress, N/V/D, high doses can cause retinal and fetal damage

Question 23

What do you know about Quinine?

Answer 23

It was the DOC prior to WWII, then chloroquine was introduced. Due to chloroquine resistance, quinine is now being used again and its good for leg cramps.

Question 24

What anti malaria drug is used as a prophylaxis treatment for chloroquine resistance malaria?

Answer 24

Mefloroquine

Question 25

What are there properties of mefloroquine?

Answer 25

It can be given orally and undergoes hepatic metabolism. It also has a half life of 14 days so its good for travelers (so too is Malarone)

Question 26

What are some ADRs of Mefloroquine?

Answer 26

It can cause severe neuropsychiatric syndrome associated with Hallucinations, anxiety, confusion and seizures.

Question 27

What combo anti-malaria drug is given to treat chloroquine resistant malaria?

Answer 27

Atovaguone (mepron) and Proguanil (HIV pts). This combo also stimulates appetite.

Question 28

________ is a common infection in immunocompetent patients but are rarely symptomatic?

Answer 28

Toxoplasmosis

Question 29

What serious complications can Toxo present in immunocompromised or congenitally infected neonates?

Answer 29

Ocular infections and encephalitis is the most common CNA dz in AIDS pts.

Question 30

What do you treat Toxo with?

Answer 30

Pyrimethamine and Sulfadiazine, Bactrim, Dapsone

Question 31

What medication may be given to Toxo patients taking as an adjunct therapy to prevent toxicities?

Answer 31

Folinic acid (leucovorin)

Question 32

What causes pneumonia in premature and malnourished infants as well as immunocompromised patients.

Answer 32

PCP Pneumonia

Question 33

What is the DOC for PCP PNA?

Answer 33

Bactrim- 1 DS tablet TID for 21 days. Steroid can be added to reduce lung swelling.

Question 34

What other medication helps to treat PCP PNA in HIV patients who have sulfa allergy?

Answer 34

Pentamidine. Given IV for treatment and inhaled for prophylaxis. Given once every 21days

Question 35

If a patient is too sick to receive chemotherapy, do you still give them a prophylaxis for PCP?

Answer 35

Yes, otherwise they will be twice as vulnerable for further opportunistic infections.

Question 36

How does helminth infections spread?

Answer 36

Spread by food, water, feces, unwashed hands, formites. Some can be via bug bites.

Question 37

What are parasitic worms that live in the hosts intestine causing malnourishment and anemia called?

Answer 37

Helminths

Question 38

What will be the definitive Dx for tapeworm?

Answer 38

Stool sample

Question 39

True of false, are helminths fat soluble?

Answer 39

True, that's why they can stay in the body for long

Question 40

What oral meds are used to treat nematode infections?

Answer 40

Albendazole and Mebendazole. They inhibit metabolism in the parasites and exhibit selective toxicity.

Question 41

What aids in the absorption of Albendazole?

Answer 41

When taken with a high fat meal

Question 42

Where is the greatest parasitic resistance to drugs?

Answer 42

Livestock, not yet a problem with humans

Question 43

What are some ADRs of Albendazole?

Answer 43

N/V/D, delirium and hallucinations. | High doses used to treat tapeworm can cause hepatitis or hematologic toxicity. also Teratogenic

Question 44

What parasitic drug is dose yearly and also effective in river blindness?

Answer 44

Ivermectin

Question 45

What are ADRs of Ivermectin?

Answer 45

N/V/D, vertigo and sedation

Question 46

What is the most common helminth infection in the US?

Answer 46

Pinworm

Question 47

How does pinworm spread?

Answer 47

family members (bed linens), daycares. treat with albendazole/mebendazole

Question 48

What is the DOC for ectoparasites (lice, mites scabies)

Answer 48

Permethrin (apply on hair for 10mins and then rinse

Question 49

What must you tell the patient to use along with the permethrin medication?

Answer 49

Tell them to buy a comb and brush off the nits

Question 50

What is Lindane?

Answer 50

It is another ectoparasitic drug. Comes as a Topical lotion for scabies and shampoo for lice

Question 51

How much of Lindane should you dispense?

Answer 51

No more than 2 ounces and don't leave on hair for >4mins, it causes brain damage (seizures and myelosuppression)