Toxoplasma gondii & Neospora caninum

Clindamycin

• Dogs: 10–20 mg/kg PO, IM, IV q12h for 4 weeks^1-5

• Cats: 10–12.5 mg/kg PO, IM, IV q12h for 4 weeks^1-5

As a broad-spectrum lincosamide antibiotic with parasiticidal activity against protozoal organisms, clindamycin is the current drug of choice for both Toxoplasma gondii and Neospora caninum infections.

Pyrimethamine + Sulfonamide

Pyrimethamine

Dogs, Cats: 1 mg/kg PO q24h for 4 weeks³

Sulfonamide Options

Dogs, Cats: Sulfadimethoxine at 20–30 mg/kg PO q24h for 4 weeks³

Although it reportedly is not as effective as clindamycin, the combination of pyrimethamine and a sulfonamide (ie, sulfadimethoxine, sulfadiazine) is synergistic.

Trimethoprim–Sulfonamide

Dogs, Cats: All formulations at 15 mg/kg PO q12h for 4 weeks^2,3

Trimethoprim–sulfonamide (ie, sulfadiazine, sulfamethoxazole) is a potentiated sulfonamide antibiotic that inhibits some protozoal organisms, including T gondii and N caninum.

Image 1. Toxoplasma gondii

Image 2. Neospora caninum infection

Azithromycin

Cats: 10 mg/kg PO q24h for 4 weeks^6,7

Azithromycin is a macrolide antibiotic that has been used to treat toxoplasmosis in a small number of cats. While clindamycin is the treatment of choice, azithromycin may be used if adverse effects associated with clindamycin treatment develop.

Monensin

Cats: 0.02% w/w concentration in dry food⁸

Monensin is an anticoccidial drug that may be effective in suppressing T gondii oocyst shedding if given within 1–2 days after infection.^8,9

Toltrazuril

Cats: 5–10 mg/kg PO q24h for 2 days³

The mechanism of action is unknown, but toltrazuril may inhibit protozoal enzyme systems. It may reduce oocyst shedding after infection or reshedding and may be beneficial in treating T gondii-positive cats owned by pregnant women, reducing the risk for fetal malformation.³

w/w = weight by weight