Central Retinal Vein Occlusion in 2 Patients Using Antipsychotic Drugs

Potential drug-drug interactions with mitogen-activated protein kinase (MEK) inhibitors used to treat melanoma

INTRODUCTION

The management of patients with BRAF-mutated advanced melanoma who are undergoing targeted therapy with MEK inhibitors can be complicated by the co-administration of multiple medications, which can give rise to drug-drug interactions of clinical significance.

COVERED AREAS

Our review presents a comprehensive analysis of the pharmacokinetic and pharmacodynamic interactions of the three approved for advanced melanoma MEK inhibitor drugs - binimetinib, cobimetinib, and trametinib. MEDLINE (PubMed) was utilized for the literature search, comprising clinical studies, observational studies, and preclinical research. The review discusses the impact of these interactions on efficacy and safety of the treatments and differentiates between interactions supported by pharmacokinetic or pharmacodynamic mechanisms, those encountered in clinical practice, and those observed in preclinical studies.

EXPERT OPINION

Physicians should be aware about potential benefits, but also increased toxicity caused by drug interactions between MEK inhibitors and other drugs in the management of patients with metastatic melanoma.

Clinical Features of Central Retinal Vein Occlusion in Young Patients

Retinal vein occlusion (RVO) is the second most common retinal vascular disease. Central RVO (CRVO), in which obstruction occurs posterior to the lamina cribrosa due to various causes, manifests with extensive venous tortuosity, dilatation of blood vessels in the four quadrants, and retinal hemorrhage. The presence of macular edema decreases visual acuity in patients with CRVO, especially in elderly patients with hypertension, hyperlipidemia, and diabetes. In the last decade, treatment modalities for CRVO have improved, with anti-vascular endothelial growth factor agents being widely used as treatment. However, there are cases of refractory or recurrent macular edema. Moreover, CRVO also occurs in young patients. This article reviews previous studies and case reports and summarizes the differences in etiological factors, clinical manifestations, treatment, and prognosis between young and elderly patients. Due to the low incidence of CRVO in young patients, clinical data from these age groups are limited. Hence, further studies are warranted to explore the differences between age groups to improve individualization of treatment of young patients.

Central retinal vein occlusion in a patient using the antipsychotic drug olanzapine: a case report

Background

We report our findings in a patient who developed central retinal vein occlusion (CRVO) and was a chronic user of olanzapine, an antipsychotic medication.

Case presentation

A 50-year-old Caucasian man, non-smoker, was referred to our clinic with the chief complaint of floater appearance in his left eye for the past 3 days. His past medical history indicated that he had been taking antipsychotic drugs (olanzapine) for about 3 years, with no other systemic disease or risk factors for CRVO.

In the examination, his best-corrected visual acuity (BCVA) was 0.7 in the left eye. The fundus showed signs of nonischemic CRVO with subhyaloid hemorrhage and intraretinal hemorrhage in the posterior pole and superior and inferior retina, without macular edema, confirmed by optical coherence tomography (OCT).

We ruled out other probable differential diagnoses and risk factors which lead to CRVO through a complete physical exam and blood analysis (complete blood count, glucose, urea, creatinine, lipid profile, erythrocyte sedimentation rate, C-reactive protein, prothrombin time, partial thromboplastin time, Bleeding time (BT), fibrinogen level, proteins, antiphospholipid antibodies, homocysteine blood level, antithrombin III, protein C and S, factor V Leiden, prothrombin mutation, angiotensin-converting enzyme level, other autoantibodies, and human leukocyte antigen [HLA]-B51). Finally, we confirmed the probable side effect of olanzapine in CRVO, which has not been previously reported. A possible pro-thrombogenic mechanism of olanzapine at the molecular level is an affinity for 5-HT_2Aserotonin receptors. Blocking these receptors results in increased platelet aggregation and increased blood coagulability.

Conclusions

These results indicate that CRVO can be a complication of chronic use of antipsychotic medications such as olanzapine, as shown for the first time in our case report. Clinicians should question patients who develop a sudden CRVO whether they are using antipsychotic medications such as olanzapine.

Quetiapine associated Central Serous Chorioretinopathy: Implicit role of serotonin and dopamine pathways

A 30-year-old insomniac, an off-label user of quetiapine, presented with blurring of central vision, eventually diagnosed as central serous chorioretinopathy. A potential association was suspected based on the drug's actions on the autonomic nervous system. He showed improvement on drug withdrawal; then he unwittingly resumed quetiapine and had a recurrence. Possible underlying mechanisms that include alteration in choroidal perfusion through serotonin and dopamine receptors are discussed. Although retinal vein occlusions and pigment epithelial detachment have been described with quetiapine, to the author's knowledge, this is the first case report of quetiapine-associated central serous chorioretinopathy.