Medical Pharmacology - Antiparasitic Drugs (Test V)

Created by Polo423 

Upgrade to
remove ads

What are the three targets for antiparasitic chemotherapy?

1) Enzymes/processes found only in the parasite

2) Enzymes/processes found in both the host and parasite but indispensable only in the parasite

3) Common biochemical functions found in both parasite and host, but with different pharmacological properties

Metronidazole

Mechanism:
Spectrum:
Resistance:

Mechanism
- activated by PFOR (is NOT found in host cells)
- reactive intermediates disrupt protein and DNA
structure and function (an electron "sink")

Spectrum
- Trichomoniasis (*treat sexual partner too!),
Giardiasis, Amebiasis

Resistance
- rare
- due to DEC PFOR activity

What is the drug of choice for the treatment of Giardia lambia, Entamoeba histolytica, and Trichomonas vaginalis?

Metronidazole

Which drugs are the primary choice for the treatment of asymptomatic carriers of E. histolytica?

Iodoquinol and Paromomycin

Iodoquinol

Mechanism:
Spectrum:
Resistance:

Mechanism
- eliminates trophozoite and cyst forms of E.
histolytica from the LUMEN (not in tissue)

Spectrum
- asymptomatic/mild amebiasis (20 day regimen)

Resistance
- none

Paromomycin

Mechanism:
Spectrum:
Resistance:

Mechanism
- inhibits protein synthesis
- eliminates trophozoite and cyst forms of E.
histolytica from the LUMEN (not in tissue)

Spectrum
- asymptomatic/mild amebiasis

Resistance
- none

Nitazoxanide

Mechanism:
Spectrum:
Resistance:

Mechanism
- interference with PFOR

Spectrum
- Cryptosporidium parvum and Giardia lamblia
(OPPORTUNISTIC)

Resistance
- none

Pyrimethamine-Sulfadiazine AND
Trimethoprim-Sulfamethoxazole

Mechanism:
Resistance:

Mechanism
- inhibit pteroic acid formation via
dihydroptheroate synthase
(sulfamethoxazole/sulfadiazine)
- inhibit DHFR (Trimethoptrim/Pyrimethamine)

Resistance
- widely reported
- due to amino acid substitutions (point
mutations)

What is the drug of choice for Cryptosporidium parvum infection in the HIV/AIDS population?

Paromomycin and Nitazoxanide

What is the drug of choice for the treatment of Pneumocystis jirovecii?

Trimethoprim-Sulfamethoxazole

What is the drug of choice for the treatment of Toxoplasma gondii (Toxoplasmosis)?

Pyrimethamine-Sulfadiazine

True or False

Pyrimethamine-Sufadiazine can treat both active and dormant tissue cysts during Toxoplasmosis

False (CANNOT destroy dormant tissue cysts)

Chloroquine

Mechanism:
Spectrum:
Resistance:

Mechanism
- eliminates asexual erythrocytic stages of ALL
Plasmodium stages
- interferes w/ parasite's ability to detoxify

Spectrum
- effective against ALL species of Plasmodium in
the asexual erythtocytic stages

Resistance
- rapid, widespread resistance
- due to INC efflux

Quinine

Mechanism:
Spectrum:
Resistance:

Mechanism
- interferes with transcription and replication
- targets the intraerythrocytic forms

Spectrum
- effective against ALL species of Plasmodium in
the asexual erythtocytic stages

Resistance
- beginning to emerge in Asia

**not used often due to TOXICITY

Which anti-malarial drug can lead to CINCHONISM (tinnitus, hearing loss, headache, N/V, and visual disturbances)?

Quinine

**also causes HYPOGLYCEMIA

Which anti-malarial drug drug of choice that is active against the LIVER (hypnozoite) forms of P. vivax and P. ovale?

Primaquine

Mefloquine

Mechanism:
Spectrum:
Resistance:

Mechanism
- targets the intraerythrocytic forms

Spectrum
- effective against ALL species of Plasmodium in
the asexual erythtocytic stages

Resistance
- none

Primaquine

Mechanism:
Spectrum:
Resistance:
Toxicity:

Mechanism
- interferes with ETC and pyrimidine synthesis

Spectrum
- treats dormant LIVER (hypnozoite) forms of P.
vivax and P. ovale

Resistance
- some have emerged (require repeated therapy
and INC dosage)

Toxicity
- hemolysis w/ G6PD deficiency (SCREEN!!)

Malarone

Mechanism:
Spectrum:
Resistance:

Mechanism
- inhibits DHFR

Spectrum
- highly efficacious in the treatment of P.
FALCIPARUM (as well as prophylaxis)

Resistance
- none

What is the drug of choice for the treatment of P. falciparum?

Malarone

Doxycycline

Mechanism:
Spectrum:
Resistance:

Mechanism
- inhibit protein synthesis and cell growth

Spectrum
- effective against all species of Plasmodium
(treatment and prophylaxis)

Resistance
- none

Benzimidazoles (Albendazole, Mebendazole, Thiabendazole)

Mechanism:
Spectrum:
Resistance:

Mechanism
- inhibits assembly of microtubules and disrupts
mitosis via binding to beta-tubulin

Spectrum
- Albendazole/Mebendazole = drugs of choice of
Ascariasis, Hookworm, Pinworm, and
Whipworm
- Thiabendazole = second line drug for
Strongyloidiasis, and topical for Cutaneous
Larval Migrans

Resistance
- occurs in veterinary medicine only

Ivermectin

Mechanism:
Spectrum:
Resistance:

Mechanism
- causes INC Cl permeability and muscle
paralysis
- mainly works on embryogenesis

Spectrum
- Strongyloidiasis, and other tissue dwelling
helminths

Resistance
- none

Pyrantel Pamoate

Mechanism:
Spectrum:
Resistance:

Mechanism
- produces depolarizing neuromuscular blockade
via cholinergic nicotinic receptor activation

Spectrum
- drug of choice for PINWORM
- **treat the ENTIRE househole

Resistance
- only in veterinary medicine

Praziquantel

Mechanism:
Spectrum:
Resistance:

Mechanism
- INC Ca permeability & cause depolarization

Spectrum
- drug of choice for nearly all TAPEWORM and
FLUKE infections

Resistance
- resistant Schistosomes are emerging

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set