The treatment of choice is diethylcarbamazine, which eliminates microfilariae and has some activity against adult worms. Treatment is with 8–10 mg/kg/day orally for 21 days; repeat courses may be needed. Mild side effects are common, including fever, pruritus, arthralgias, nausea, diarrhea, and Calabar swellings. These symptoms may be lessened by antihistamines or corticosteroids. Patients with large worm burdens are at greater risk for serious complications of therapy, including kidney injury, shock, encephalitis, coma, and death. Treatment with ivermectin, which is highly active against microfilariae, but not adult worms, entails a higher risk of severe reactions. To attempt to avoid these sequelae, pretreatment with corticosteroids and antihistamines, and escalating dosage of diethylcarbamazine have been used, but this strategy does not prevent encephalitis. The circulating parasite load that indicates particular risk for severe complications with therapy has been estimated at 2500/mL. Strategies to treat patients with high parasite loads include (1) no treatment; (2) apheresis, if available, to remove microfilariae prior to therapy with diethylcarbamazine; or (3) therapy with albendazole, which appears to be well tolerated due to its slow antiparasitic effects, prior to therapy with diethylcarbamazine or ivermectin. Doxycycline is not effective for loiasis.