On September 28th, 2018 – Health Canada issued an information update regarding labeling changes in the product monograph for fluorometholone acetate (FlarexTM) eye drops. Systemic corticosteroid adverse reactions such as Cushingoid symptoms or adrenal suppression may occur after intensive or long-term, continuous fluorometholone use in persons treated with CYP3A4 inhibitors including ritonavir (NorvirTM, KaletraTM ) or cobicistat (in PrezcobixTM, StribildTM, GenvoyaTM), which are used as antiretroviral ‘boosters’ in the treatment of HIV.
The product monographs for other potent ophthalmic corticosteroids, including difluprednate (DurezolTM) and dexamethasone (MaxidexTM, MaxitrolTM, TobradexTM) include similar drug interaction warnings with ritonavir and cobicistat.
The combination of potent corticosteroid eye drops with ritonavir or cobicistat should be avoided unless the benefit outweighs the increased risk, in which case patients should be monitored for systemic corticosteroid adverse reactions.
For more information: Click here to view the Health Canada advisory
The drug interaction between ritonavir or cobicistat and other corticosteroid products such as inhalers, nasal sprays, and intra-articular injections is well documented.
For more information about how to manage or monitor the drug interaction between ritonavir or cobicistat and ophthalmic/ inhaled/ injectable corticosteroids, Click here to download the BC-CfE Pharmacovigilance Safety Alert Bulletin (June 2010) on this topic.