Intravitreal clindamycin, dexamethasone appears a good alternative to conventional therapy for ocular toxoplasmosis

Treatment of toxoplasmosis retinochoroiditis with intravitreal injection of clindamycin and dexamethasone has shown some promising effects in a few case reports. With good intracellular penetration, clindamycin provides a high intracellular concentration against T. gondii, which is an intracellular parasite.

This prospective study randomized 68 patients with active ocular toxoplasmosis to a combination of intravitreal clindamycin plus dexamethasone or standard treatment with pyrimethamine/sulfadiazine plus prednisolone.  The intravitreal group received one to three injections of 1 mg intravitreal clindamycin and 400 μg dexamethasone, while the standard treatment group received six weeks of treatment with pyrimethamine/sulfadiazine plus prednisolone.

The two treatments were equally effective in terms of lesion size reduction and improvement in visual acuity. However, immunoglobulin M (IgM) positive patients responded better to standard treatment and IgM-negative cases to intravitreal injection. Repeated injection was required in 47.1 percent of cases who did not show sharpening of the retinal lesion. No major injection-related complications were encountered in the clindamycin/dexamethasone group.

The authors conclude that while both approaches appear equally effective, the intravitreal injection may offer patients more convenience, a safer systemic side effects profile, greater availability, and fewer follow-up visits. However, one should be cautious about the possibility of the need for reinjection and their potential complications, as well as the cases with acquired toxoplasmosis that may need systemic therapy. Furthermore, the results of this study cannot be generalized to immunocompromised patients, monocular cases, and eyes with lesions inside the fovea (<500 μm).