Intraocular penetration of tamoxifen

OBJECTIVE: To document ocular penetration of oral tamoxifen in patients being administered systemic therapy by measuring intraocular and serum levels of the drug in a series of patients undergoing elective ocular surgery. DESIGN: Nonrandomized, prospective, comparative trial. PARTICIPANTS: Twenty-one eyes of 21 patients undergoing elective ocular surgery (cataract extraction or vitrectomy). Twenty patients were using the antiestrogen, tamoxifen, and one participant was not. Nine patients were excluded in the final analysis because of inadequate sample size. INTERVENTION: Preoperative serum samples and perioperative aqueous samples, vitreous samples, or both were obtained for each patient, and these were analyzed for tamoxifen and its metabolites. Dilated fundus examination was performed before surgery on all patients. MAIN OUTCOME MEASURES: Evidence of tamoxifen, its metabolites, or both in the samples. RESULTS: Tamoxifen was detected in all analyzed serum samples (range, 82.4-290.0 ng/ml.) from patients taking the medication and was found to have penetrated into both vitreous (range, 0.5-7.8 ng/ml) and aqueous (range, 0.5-3.9 ng/ml) cavities. No relationship was found between serum and intraocular levels. CONCLUSIONS: This study shows that tamoxifen penetrates intraocular fluids to varying degrees. The drug levels in aqueous and vitreous do not appear to correlate with serum levels. Evidence of tamoxifen retinopathy or keratopathy was not seen.