Pharmacology Exam I

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Anti-malarial agents are important for travelers to
- South America
- Africa
- Asia
Types of Malaria
- single cell invasion and multiplication
- dormant hepatic stage
Single liver cell invation and multiplication
- falciparum
- malariae
Dormant hepatic stage
- vivax
- ovale
goal for treatment of falciparum and malaria

eradicate erythrocytic stage
goal for treatment of vivax and ovale

eradicate erythrocytic and hepatic stages
A single sporozoite infecting a liver cell can produce____ merozites within 6 days of infection

30-40K
agents that target stages of malaria
- blood schizonticidal agent
- tissue schizonticidal agent
- gametocidal agent
Classes of antimalarial agents
- 4-aminoquinoline
- quinoline
- 8-aminoquinoline
- folate antagonists
- artemisinins
- antagonistic combinations
4-aminoquinolines
- chloroquine
- drug of choice
- schizonticide and gametocide
- 3-5 day half life
Chloroquine is not effective against

falciparum
Chloroquine clinical use

prophylaxis 500mg weekly
must be used to cure dormant liver forms vivax and ovale

primaquine
chlorpquine mechanism of action

causes heme toxicity to parasite
Adverse effects with chloroquine
- pruritus
- hemolysis with G6PD deficiency
Chloroquine contraindications
- psoriasis
- visual field abnormalities
- caution in liver disorders
- cations (antidiarrheals) interfere with absorption
safe for use during pregnancy

chloroquine
Amodiaquine
- similar to chloroquine but limited use due to toxicity
- used for falciparam that is resistant to chloroquine
Toxicities with amodiaquine
- agranulocytosis
- hepatotoxicity
- aplastic anemia
Quinoline class
- quinine
- quinidine
- mefloquine
quinine and quinidine used for
- protection against erythrocitic stage
- not active against hepatic parasites
- not gametocidal (falciparum)
Quinine and quinidine are not generally used for prophylaxis due to
- toxicity
- cardiac dysrhythmias and hypotension
- tinnitus
- chinchonism
Contraindications of quinine and quinidine
- mefloquine
- digoxin
- warfarin
Mefloquine
- potent blood schizonticide
- used for chloroquine resistant parasites
prophylactic dose of mefloquine given

weekly
mefloquine usually recommended for

travelers
Mefloquine contraindicated with
- seizures
- psychosies
- arrhythmias
- children under 5kg
8-aminoquinoline class
- primaquine
- atovaquone
only agent effective agiainst hepatic stage of vivax and ovale

primaquine
Atovaquone
- recommened for chloroquine resistance
- disrupts mitochondrial electron transport
Atovaquone active against

falciparum but not vivax and ovale
Atovaquone bioavailability increased with

fatty food
Atovaquone + rifampin or tetracycline

decrease plasma concentrations by 50%
Folate metabolism antagonists
- Pyrimethamine
- Proguanil
- erythrocytic stage
Sulfonamides and sulfones
- active against erythrocytic stage
- not used alone
Fansidar
- sulfadoxine and pyrimethamine
- for toxoplasmosis
- no longer for malaria due to resistance
Fansidar is contraindicated in
- 3rd trimester of pregnancy
- lactating mothers
Fansidar and sulfonamides act on

pteridine synthetase
pyrimethamine or proguanil act on

dihydrofolate reductase
Antibiotics used as co-therapy in malaria
- doxycycline
- clindamycin
- azithromycin
Artemisinin
- chinese herbal
- no prophylaxis
- irreversible neurotoxicity
- avoid in pregnancy
Artesunate
- artemisinin derivative
- available through CDC
- free radical production
- active against multi drug resistant malaria
Drugs used for travelers
- mefloquine
- doxycycline
- chloroquine
- hydroxychloroquine
- malarone
Prophylaxis dosing

2 weeks before travel and up to 1 month after return

Author

Rx2013

61333

Card Set

Pharmacology Exam I

Description

Anti-malarial agents

Updated

2011-01-22T21:55:25Z

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