Evidence-based guidelines for drug dosing in intravitreal injections in silicone oil-filled eyes: Pharmacokinetics, safety, and optimal dosage

Abstract

We evaluate the pharmacokinetics, safety, and optimal dosages of intravitreal agents in silicone oil (SO)-filled eyes, addressing challenges in administering such therapies. We assessed the pharmacological properties and safety profiles of intravitreal drugs in SO-filled eyes, deriving conclusions and guidance from available literature and expert consensus. Preclinical data suggest comparable half-lives of anti-vascular endothelial growth factoragents in SO-filled eyes, but clinical evidence is mainly from case reports and small series. Available research prioritizes standard dosages, particularly for bevacizumab (1.25 mg), supported by stronger evidence than aflibercept (2 mg) or ranibizumab (0.5 mg). Intravitreal steroids, especially dexamethasone at 0.7 mg, show efficacy and safety, while evidence for fluocinolone acetonide at 0.19 mg is limited. Intravitreal methotrexate has been reported at the dosage of 250–400 μg, with keratitis as the primary expected side effect. Case reports indicate tolerability of standard dosages of antivirals (foscarnet 1.2–2.4 mg/0.1 mL, ganciclovir 4 mg/0.1 mL) and the antibiotic combination piperacillin/tazobactam (250 μg/0.1 mL).

We offer guidance based on current, but limited, literature. Standard dosage of intravitreal agents should be carefully considered, along with close monitoring for potential side effects, which should be discussed with patients.