Title

ASSESSMENT OF THE SAFETY OF INTRAVITREAL INJECTION OF METOPROLOL TARTRATE IN RABBITS

Introduction

Intraocular vascular tumors include choroidal hemangiomas, retinal hemangioblastomas, vasoproliferative tumors and very rare lesions, such as cavernous retinal hemangioma and arteriovenous malformations. In recent years, beta-blockers have been shown to be effective for several childhood hemangiomas, including facial and periocular. More recently, intravitreal metoprolol has been used to treat circumscribed choroidal hemangioma. The current study focuses on investigating the safety of intravitreal administration of MT in different doses for the treatment of ocular hemangioma.

Methods

Animals were randomly assigned into 2 groups: group I received 50 µg of MT and group II 100 µg of MT. A volume of 0.05 mL of the drug solution was administered through an intravitreal injection, while the control eyes received an equal volume of saline solution. Safety was assessed by clinical observation, electroretinography (ERG) and histological evaluation.

Results

No evidence of clinical toxicity was observed. ERG waveforms from the MT treated eyes were similar to those recorded from the control eyes, and their retinas had no signs of toxicity by histological evaluation 7 days after intravitreal injection.

Discussion

Intravitreal use of metoprolol at 50 and 100 µg dosages does not cause retina toxicity in rabbits. There was no decrease in amplitude of waves a and b in all luminous stimuli after 7 days of the intravitreal injection, which allows us to infer about the preservation of retinal function and no sign of drug toxicity. In accordance to ERG findings, no toxicity sign was verified by histological analysis in retinas from eyes treated with MT or vehicle. Histological analysis confirmed the integrity of the retina. There was preservation of all retinal layers and no inflammatory cells. Retina sections from study eyes did not differ histologically when compared to healthy control eyes treated with intravitreal saline.

Keywords

metoprolol tartrate, intravitreal injection, electroretinography

Area

CLINICAL CASE

Authors

Mayara Rodrigues Brandão Paiva, Raquel Gregório Arribada, Carolina Nunes Silva, Rodrigo Jorge, Silvia Ligório Fialho, Armando Silva-Cunha