RESUMO
INTRODUCTION: An elevated intraocular pressure (IOP) remains the main risk factor for progression of glaucoma upon which we can efficiently act. Pharmacological strategies to reduce IOP are directed towards the reduction of aqueous humour (AH) production and/or the increase in AH drainage through the uveoscleral pathway. However, there are no drugs currently available as first-line treatment to increase AH outflow primarily via the conventional route. Ocular nitric oxide (NO) production takes place in AH outflow pathways and in the ciliary muscle, modulating the cellular response to elevated IOP. METHODS: This review describes the mechanism of action of endogenous NO and NO-donating compounds that are under research. It includes information regarding pre-clinical and clinical studies previously conducted with these compounds, discussing their role and therapeutic potential in the pharmacological treatment of ocular hypertension in glaucoma. RESULTS: The topical ocular administration of NO-donating compounds significantly lowered IOP and maintained it in animal models of glaucoma and subjects with ocular hypertension. CONCLUSIONS: The mechanism of action of these compounds is novel and scientific evidence that shows promising results. However, there is a need for more comprehensive studies to assess long-term safety and tolerability in order to properly evaluate their use in chronic therapies.