Diethylcarbamazine immobilizes microfilariae by an unknown mechanism, increasing their susceptibility to host defense mechanisms.
Diethylcarbamazine is the drug of choice for several filarial infections including those caused by Wucheria bancrofti and Brugia malayi and for eye worm disease (loa loa). The drug undergoes renal elimination, and its half-life is increased significantly by urinary alkalinization.
Adverse effects include headache, malaise, weakness, and anorexia. Reactions to proteins released by dying filariae include fever, rashes, ocular damage, joint and muscle pain, and lymphangitis. In onchocerciasis, the reactions are more intense and include most of the symptoms described as well as hypotension, pyrexia, respiratory distress, and prostration.