Classification of antimalarial drugs.

Clinical classification of antimalarial drugs:

  • True causal prophylactics:
  1. Destroy the sporozoites before their invasion of reticuloendothelial cells.
  2. No such drugs are currently available.
  • Causal prophylactics:
  1. Also called primary tissue schizonticides
  2. These drugs prevent the maturation of or destroy the sporozoites within the infected hepatic cells and thus preventing erythrocytic invasion.
  3. Eg: primaquine, pyrimethamine and proguanil.
  • Suppressives:
  1. Also called schizonticides
  2. Inhibit erythrocytic schizonticides and prevent the rupture of infected erythrocytes.
  3. As rupture is inhibited there is freedom from rigors and pyrexia(clinical cure).
  4. They do not eradicate the infection.
  5. Relapse can occur with the stoppage of suppressive therapy in ovale and vivax species because of hypnozoites.
  6. The suppressive agents include

Rapidly acting:

Quinine

4-aminoquinolines

Mefloquine

Atovaquone

Slow acting:

Proguanil

Pyrimethamine

Tetracycline

Sulphadoxine

  • Radical curatives:
  1. These drugs eradicate both erythrocytic and secondary exoerythrocytic schizogony.
  2. Relapse do not occur
  3. For radical cure of vivax infection , primaquine and proguanil are effective.
  4. Radical cure of falciparum malaria can be achieved with suppressives alone because of absence of secondary exoerythrocytic cycle.
  • Gametocytocidal drugs:
  1. Chloroquine, quinine, artesunate are effective against gametocytes of all species except plasmodium falciparum.
  2. Primaquine is effective against falciparum species gametocytes also.

Chemical classification of antimalarial drugs:

  • Cinchona alkaloids:

Eg: quinine,quinidine

  • Quinoline derivatives:
  1. 4-aminoquinolines:

Eg: chloroquine

Amodiaquine

Pyronaridine

  1. 8-aminoquinolines:

Eg: primaquine

Tafenoquine

Bulaquine

  1. Quinoline methanol

Eg: mefloquine

  • Phenanthrene methanol

Eg: halofantrine

Lumefantrine

  • Antifolates:
  1. Biguanides:

Eg: proguanil

  1. Diaminopyramidines

Eg: pyrimethamine

  1. Sulphonamides:

Eg: sulphadoxine

  • Artemisinin compounds:

Eg: artesunate

Artether

Artemether

  • Antimicrobials:

Eg: doxycycline

Clindamycin

Atovaquone

 

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