The only drug approved for definitive treatment of babesiosis in the United States is imidocarb dipropionate (Imizol, Schering-Plough).
The recommended dosage is 6.6 mg/kg intramuscularly and repeated in two weeks. Side effects of imidocarb include pain at the
injection site, salivation, lacrimation, gastrointestinal signs and tremors. Pre-treatment with atropine (0.04 mg/kg subcutaneously)
may prevent these cholinergic side effects. Imidocarb is very effective against B. canis but less effective against B. gibsoni.
In many dogs, the degree of parasitemia is markedly reduced within 24 to 48 hours after administration, but three or four
treatments at two-week intervals may be required to clear the parasitemia.
Even then, many dogs apparently develop subclinical infections and remain chronic carriers.
Diminazine aceturate is not available in the United States but can be obtained in other countries. A single injection of 3.5
mg/kg intramuscularly will clear parasitemia and improve clinical signs in dogs with B. canis. A higher dosage (5.0-7.5 mg/kg
intramuscularly, repeated two to three times at two-week intervals) has been recommended for dogs with Babesia gibsoni.
Other drugs that may be effective against babesiosis include clindamycin and metronidazole. Clindamycin has been used to treat
B. microti in people. Metronidazole (25-65 mg/kg daily for 10 days) resulted in clinical improvement in one group of dogs
with B. gibsoni. Supportive care is required in dogs with acute or peracute disease.
A blood transfusion or Oxyglobin is indicated in dogs with severe hemolytic anemia. In one study, 85 percent of Babesia-infected
dogs had a positive direct Coombs' test and 21 percent exhibited autoagglutination. The use of glucocorticoids in these cases
is controversial because immunosuppression may exacerbate the parasitemia.
Use of glucocorticoids is indicated if hemolysis continues to cause severe anemia. Once the parasitemia has cleared, glucocorticoids
can be tapered off fairly quickly in most cases. Other supportive measures include fluid therapy to correct dehydration and
acidosis and management of concurrent diseases, such as ehrlichiosis and Lyme disease.