Drugs - Doxycycline (1992)

Product Name: Doxycycline
Commercial Name: Vibramycin
Application: Anti-malarial drug for prophylaxis
Date of Licensure: New indication approved December 1992
Type of Product: : long-acting tetracycline
Company of manufacture: : Pfizer

Reasons for development:: (1) resistance to the effective action of mefloquine (initially effective against all chloroquine-resistant P. falciparum strains) especially noted in Southeast Asia; (2) adverse effects associated with the use of mefloquine. Although doxycycline, which was originally developed as an antibacterial agent, has useful antimalarial properties, the antimalarial mechanism of action of doxycycline is unknown.

Doxycycline-image2

Relevant Military History:advised doxycycline for malaria prophylaxis because of concerns that mefloquine had neurological effects that interfered with piloting skills. Of more than 2,000 personnel treated with doxycycline, only 59 developed malaria.

WRAIR conducted Phase II challenge and clinical trials for doxycycline in Thailand, and obtained FDA approval for use of doxycyline as prophylaxis for both falciparum and vivax malaria.

Although the drug is still used as an antimalarial agent, doxycycline requires daily adminstration and causes phototoxicity, gut discomfort and diarrhea, all of which impact negatively on compliance. Further, the drug cannot be given to pregnant women and children because it can cause tooth discoloration in developing teeth.