Abstract
To provide information on the effects of phosphodiesterase type 5 (PDE5) inhibitors on choroidal vessels and central serous chorioretinopathy (CSC) and possible implications for development of exudative age-related macular degeneration (AMD). Two independent investigators conducted a qualitative review of PubMed to identify studies on the choroidal effect of PDE5 inhibitors in June 2019. The search used key words that included PDE5 inhibitors, sildenafil, tadalafil, vardenafil, choroid, choroidal flow, choroidal vessels, choroidal thickness, CSC, AMD or a combination. Only studies which assessed choroidal findings were included. Many ocular diseases are related to changes in choroidal thickness and perfusion. Patients with AMD, who have decreased choroidal perfusion, may manifest more severely diminished choroidal ability to deliver oxygen and other metabolites to the retina, leading to growth of neovascular tissue. As a result of this engorgement of the choroidal vasculature, some patients may have leakage across the retinal pigment epithelium (RPE) and accumulation of subretinal fluid, resulting in CSC. Transient visual symptoms, i.e., changes in color perception and increased light sensitivity, are well-known adverse effects, but there have been rare reports of vision-threatening ocular complications in users of PDE5 inhibitors, such as nonarteritic anterior ischemic optic neuropathy and cilioretinal artery occlusion. The choroid is a vascular tissue analogous in many respects to the corpus cavernosum, and PDE5 inhibitors may increase the choroidal thickness and perfusion. While it is intuitively obvious that thickness of the choroid alone does not guarantee better choriocapillaris oxygenation, it is a reasonable step towards ameliorating ischemia. These drugs have numerous physiologic effects on the choroid related to blood flow, such as clinical consequences in CSC and AMD.
Highlights
Sildenafil (Viagra, Pfizer Pharmaceuticals, Secaucus, NJ, USA), tadalafil (Cialis, Eli Lilly Medical, Indianapolis, IN, USA), vardenafil (Levitra, Bayer Pharmaceuticals, Whippany, NJ, USA), and avanafil (Stendra, Vivus, Inc., Campbell, CA, USA) are used widely to treat pulmonary arterial hypertension and are currently the first-line da Cruz et al Int J Retin Vitr (2020) 6:38The ocular adverse reactions of this drug class are often mild and related to color and brightness perception in 3–11% of men taking sildenafil 25–100 mg [27], 0.3–2% of those taking vardenafil [54, 59], and 0.1% of tadalafil users [16]
The current report reviews published studies that examined the effects of phosphodiesterase type 5 (PDE5) inhibitors on the choroidal vessels, central serous chorioretinopathy (CSC), and their possible implications for exudative age-related macular degeneration (AMD), diseases that are associated with changes in choroidal thickness and perfusion
Pharmacology of PDE5 inhibitors PDE5 inhibition increases the level of cyclic guanosine monophosphate (cGMP), an intracellular messenger affecting vasodilation by relaxation of smooth muscle in the arterioles
Summary
Sildenafil (Viagra, Pfizer Pharmaceuticals, Secaucus, NJ, USA), tadalafil (Cialis, Eli Lilly Medical, Indianapolis, IN, USA), vardenafil (Levitra, Bayer Pharmaceuticals, Whippany, NJ, USA), and avanafil (Stendra, Vivus, Inc., Campbell, CA, USA) are used widely to treat pulmonary arterial hypertension and are currently the first-line da Cruz et al Int J Retin Vitr (2020) 6:38The ocular adverse reactions of this drug class are often mild and related to color and brightness perception in 3–11% of men taking sildenafil 25–100 mg [27], 0.3–2% of those taking vardenafil [54, 59], and 0.1% of tadalafil users [16]. The current report reviews published studies that examined the effects of PDE5 inhibitors on the choroidal vessels, CSC, and their possible implications for exudative AMD, diseases that are associated with changes in choroidal thickness and perfusion. Other studies have reported that PDE5 inhibitors significantly increase choroidal blood flow (CBF) [53, 61, 84, 96, 105].
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