Parasitic tx

Question 1

Metronidazole is drug of choice for what?

Answer 1

Giardiasis
Severe amebiasis
Trichomoniasis
Pseudomembranous colitis
Anaerobic bacteria

Question 2

Adverse rxn for metronidazole

Answer 2

metallic taste
HA/nausea
peripheral neuropathy

Question 3

Drug intxns with metrinidazole

Answer 3

alcohol (induces disulframic state)
disulfram
inducers of hepatic enzymes

Question 4

tx for:
cryptosporidiosis (aids pts)
Leishmanias

Answer 4

Paromomycin
(an AG)
- [ ]ed in parasite in gut
- inhibits protein synth 
(bind to A site on ribosome)

Question 5

Tx for toxoplasmosis

Answer 5

Pyrimethamine + sulfadiazine

Pyrimethamine + clindamycin

• selectively targets parasitic enzymes

Question 6

Diff targets of sulfonamide and TPM or pyrimethamine

Answer 6

TPM or pyrimethamine: inhibits DHFR

Sulfonamide: inhibits DHP synthase

Question 7

Tx for pentamidine

Answer 7

1. P. carinii pneumonia
2. West african Trypanosomiasis
3. Visceral Leishmanias

• accumulates in tissues

Question 8

Adverse rxn of pentamidine

Answer 8

1. Histamine release (rxn to dying organism)
2. Hypotension
3. Hypoglycemia
4. Elevated AST/ALT
5. Impaired renal fxn

Question 9

Benzimadazoles inhibit _____

Answer 9

microtubule formation by bind to beta-tubulin and prevent formation of alpha/beta dimers

Question 10

Which has better absorption, albendazole or mebendazole? Where is each excreted? WHich to avoid in pregnancy?

Answer 10

albendazole

• better absorption
• excreted in urine

*note that mebendazole is excreted in bile

avoid both in pregnancy

Question 11

Tx for cysticercosis

pork tapeworm - taenia solium

Answer 11

albendazole
- has systemic absorption and is distributed into tissues
(unlike mebendazole where >95% is bound to plasma protein)

Question 12

pyrantel pamoate

• MOA
• therapeutic use
• where does it [ ]?

Answer 12

ACh Receptor Agonist!
- so dont use piparazine (ACh R antag)

ascariasis (roundworm)
Enterobiasis (pinworm)
Hookworm infxn

• [ ]s in parasite

Question 13

Mechanism of praziquantel

Answer 13

Ca2+ ionophore
- salt on preztle!
- induces paralysis in cestodes and trematodes –>
detachment, excretion

Question 14

Therapeutic use of praziquantel

Answer 14

Cestodes (tapeworm)

Trematode (flukes)

Question 15

What do you absolutely avoid when giving praziquantel?

Answer 15

Avoid if neurocystercicosis is present! or else . . .

• meningismus
• seizures
• CSF pleocytosis

Question 16

Drug of choice for Plasmodium species

- where does it [ ]?

Answer 16

Chloroquine
(anticancer drug targeting autophagy)

[ ]s in food vacoules

Question 17

Adverse rxn of chloroquine

Answer 17

If given via IV form, can have risk of very high dose

1. Cardiovascular fx
   - hypotension
   - cardiac arrythmia
   - cardiac arrest
2. CNS dysfxn
   - confusion
   - convulsion
   - coma

Question 18

Quinine is used when?

Answer 18

tx for erythrocytic stages of chloroquine resistant and multidrug resistant (MDR) P. falciparum malaria

Question 19

Adverse rxns of quinine

Answer 19

1. Chinchonism*
   - visual, auditory, GI
2. stimulates pancreatic beta cells
   - hyperinsulinemia
   - hypoglycemia
3. Hypotension

Question 20

When is mefloquine (quinine analog) used?

Answer 20

MDR P. faciparum

but quinine better

Question 21

Proguanil/Atovaquone use

Answer 21

MDR malaria

Toxoplasma gondii

Question 22

Malarone use

Answer 22

DHFR inhibitor

- but main fxn: somehow increases efficacy of atovaquone to collapse proton gradient

Question 23

Only drug useful for latent forms of P. vivax and P. ovale

Answer 23

primaquine

Question 24

When treating malaria, which drug to use:
Not MDR:
- Prophylaxis
- Treatment
MDR:
- Prophylaxis
- Tx

Answer 24

Not MDR:

• Prophylaxis: chloroquine phosphate (oral)
• Treatment: Chloroquin phosphate

MDR:
- Prophylaxis: 
atovaquone/proguanil or doxy
- Tx:
Quinine +
TCN or Pyrimethamine - Sulfadoxine + clindamycine

Question 25

What do you have to make sure pts do not have if you are using primaquine?

Answer 25

G6PD def:

hemolytic anemia can be severe