Protozoal

Question 1

Metronidazole MOA?

Answer 1

Toxic radicals –> DNA damage

Question 2

Metronidazole treats? *Remember the mnemonic!

Answer 2

GETGAP: Giardia, Entamoeba, Trichomonas, Gardnerella, Anaerobes (Bacteroides, C. diff), H. Pylori

Question 3

Metabolism/elimination of Metronidazole?

Answer 3

CYPs (glucoronidation); drug levels are increased in hepatic dz. Renal elim

Question 4

ADEs of Metronidazole?

Answer 4

Disulfram w EtOH, teratogen, CI in pts w/ CNS dz, DDI w/ Lithium & Warfarin (increases PT) cuz of CYP2C9 inhibition

Question 5

Atovaquone MOA?

Answer 5

inhibits mitochondrial ETC –> decreased pyramidine synthesis (decreased ATP)

Question 6

Atovaquone treats?

Answer 6

1. Pneumocystis
2. Toxoplasma
3. Entamoeba
4. Malaria (Malarone = atovaquone + proguanil)
   * Proguanil is a folate inhibitor
5. Trichomonas

Question 7

How do you take atovaquone?

Answer 7

With a meal bc it is lipophilic; it is also highly protein bound

Question 8

ADEs of atovaquone?

Answer 8

Not many which is advantageous

Question 9

Iodoquinol MOA?

Answer 9

Unknown; but 90% remains in intestine –> fecal excretion

Question 10

Iodoquinol treats?

Answer 10

Luminal (gut) trophozoites

Question 11

ADEs of Iodoquinol?

Answer 11

1. Optic neuropathy
2. Renal dz
3. Thyroid dz
   * CI in pts w/ iodine intolerance
   * *Discontinue w/ iodine toxicity & diarrhea

Question 12

Paromomycin MOA?

Answer 12

AMG: inhibits initiation complex; requires O2 for uptake

Question 13

Paromomycin treats?

Answer 13

1. Amebiasis
2. Cryptococcus in HIV
3. Giardia (in pregnant women cuz metronidazole is a teratogen)

Question 14

Paromomycin ADEs?

Answer 14

1. Diarrhea

2. Avoid in renal dz

Question 15

Pentamidine MOA?

Answer 15

unknown

Question 16

Pantamidine treats?

Answer 16

1. PCP tx/prophylaxis
2. Visceral Leishmaniasis
3. Trypanosomiasis (hemolytic stage only)

Question 17

How is Pentamidine delivered?

Answer 17

IV or inhalation

Question 18

Where dies Pentamidine accumulate?

Answer 18

Liver –> kidney –> adrenals –> spleen

Question 19

How long does Pentamidine stay in the urine?

Answer 19

6 weeks (but it has a 6 hr half life)

Question 20

ADEs of Pentamidine?

Answer 20

1. HypoTN
2. Hypoglycemia
3. Blood dyscrasias (pancytopenia)
4. Nephrotoxic (inhibits renal DHFR)
5. Cardiotoxicity

Question 21

Melarsoprol MOA?

Answer 21

Metabolized by melarsen oxide –> forms adduct w/ trypanothione –> inhibit trypathione reductase

Question 22

Melarsoprol treats?

Answer 22

Late East African Trypanosomiasis

**Dont use early!!

Question 23

Melarsoprol get in CNS? How is it excreted?

Answer 23

Yes; excreted in feces

Question 24

ADEs of Melarsoprol?

Answer 24

1. Febrile rxn
2. Reactive encephalopathy (give prednisone)
3. Peripheral neuropathy

Question 25

Eflornithine MOA?

Answer 25

Irreversibly inhibits ornithine decarboxylase –> decreased synthesis of polyamines

Question 26

Eflornithine treats?

Answer 26

West African Trypanosomiasis

Question 27

Eflornithine ADEs?

Answer 27

1. Pancytopenia
2. Diarrhea
3. Alopecia

Question 28

Stibogluconate MOA?

Answer 28

Its a prodrug (pentavalent) –> trivalent (toxic)
It alters trypanothione reductase
Alters phagolysosomes
Increases efflux of glutathione/trypanothione from cells

Question 29

Stibogluconate treats?

Answer 29

Leshmainiasis

Question 30

Stibogluconate ADME?

Answer 30

2 phases: slow release from tissue & sequestration of antimony in macrophages

Question 31

Stibogluconate ADEs?

Answer 31

1. Chemical pancreatitis

2. Bone marrow suppression