CSC is a condition characterized by the accumulation of subretinal fluid at the posterior pole of the fundus, causing single or multiple areas of serous retinal detachment [1
]. Although the exact mechanism of CSC is not understood, it is thought to be associated with type A personality and elevated glucocorticoid levels. Other factors associated with CSC include the usage of systemic steroid, antibiotics, and antihistaminic medications, pregnancy, use of alcohol and tobacco, autoimmune diseases, and untreated hypertension [1
]. When our patient was admitted to our clinic due to a complaint of blurred vision, none of the conditions mentioned above which are thought to initiate the CSC could be detected in our patient. The only positive sign to be associated with the CSC in his history was that the patient had received the third dose of tadalafil last night.
However, in literature, there are some reported studies [8
] supporting the idea of PDE-5 inhibitors are safe drugs with no visual disturbance. Cordell et al. [8
] investigated whether the daily use of tadalafil (n=85) or sildenafil citrate (n=77) for 6 months led to any changes in the retinal function or not. They found out that the daily administration over a prolonged time of tadalafil or sildenafil did not lead to any abnormalities in electroretinographic variables or visual functions and anatomic assessments of retina.
French and Margo 9 did not determine any association between the usage of PDE-5 inhibitor and CSC, in their post-marketing surveillance series which had 577 men with newly diagnosed CSC. However post-marketing studies have some limitations. For instance, they cannot assure if the patients have taken the drug regularly. Even if they have, the studies still cannot provide any posology, or information on other medical conditions.
Damar et al. [10
] assessed the short-term effects of the recommended starting dose of sildenafil citrate on visual functions and CSC development in 43 patients who used the drug at the dosage of 50 mg, 2-3 times per week for a month. It was concluded that the therapeutic dose of sildenafil citrate therapy did not cause CSC or any other visual disorder. We thought that this study did not contain sufficient numbers of patients to achieve a certain result.
Although, among the urologist there is no consensus on the dosage of tadalafil, individual dose adjustment is usually recommended. The prospectus information of tadalafil as follows: the recommended initial dose of tadalafil for use as needed is 10 mg, and it may be increased to 20 mg or decreased to 5 mg, based on individual efficacy and tolerability. The recommended initial dose of tadalafil for once daily use is 2.5 mg and it may be increased to 5 mg, based on individual efficacy and tolerability. Tadalafil 5 mg once daily or 20 mg two times per week has been proposed by his urologist to our patient. Since tadalafil has the longest half-life (approximately 18 hours) among the PDE-5 inhibitors, use of 20 mg dose of tadalafil on alternate days is generally not recommended [11
Our patient’s complaints immediately began after receiving the third dose of tadalafil 20 mg on the fifth day and his symptoms and pathological fundus findings resolved completely six weeks after stopping the drug intake. There was not a history of medication containing corticosteroid.
It is well-known that CSC generally affects middle-aged men. It is the same age group with the patient who use PDE-5 inhibitors. It is thought that the PDE-5 inhibitors also partly have an inhibitory effect on PDE-6 enzyme which is located in the retinal photoreceptors and acts photo transduction cascade . Another aspect is that they cause a decrease in the retinal and choroidal blood flow, which is also believed to occur in the pathogenesis of CSC . In the fact that the eyes with CSC have thicker subfoveal choroidal thickness compared to fellow eyes and healthy eyes of age matched normal patients, supports this opinion [12
]. Enhanced depth imaging OCT (EDI-OCT) is an extremely useful device that shows the difference of the choroidal thickness in retinal pathologies such as CSC [12
The power of our case report and its superior aspect compared with the other case reports were thanks to the findings of the patients’s ophthalmic examination carried out two weeks earlier and the incidentally captured images of Stratus OCT (SD-OCT is not available in our clinic, so we took the patient’s follow-up macular images with SD-OCT in another eye clinic) were completely normal and changing objective refraction errors throughout the disorder were well-documented. However, if EDI-OCT could be used in follow-up examinations it could be better.
In the fact that our patient didn’t have any of the known risk factors of CSC, and his detail ophthalmologic examination two weeks before tadalafil intake was entirely normal, and he received the third dose of tadalafil 20 mg last night, and the symptoms, and findings of CSC resolved spontaneously immediately after ceasing the drug intake, tadalafil seems to be most likely caused CSC.
In conclusion, urologists should advise the patients who receive a PDE-5 inhibitor, not to use more than the recommended dose as in our case and when the patient happen to experience negative visual symptoms, the drug intake must be ceased and they should seek a medical help.