What is known about tadalafil (Cialis) and eye/vision disorders?/nA healthy 43-year-old man taking

Fråga: What is known about tadalafil (Cialis) and eye/vision disorders? A healthy 43-year-old man taking Cialis sporadic in a low dose (1 mg) suffered from a sudden vision disorder on his left eye. He was extensively examined at the eye clinic and he seemed to have developed some kind of disorder of the pigmentepithelium close to macula lutea (yellow spot). The disorder might have been caused by Central serous chorioretinopathy (CSC) but the picture was not really typical for this. There might also have been a detachment of the vitrious body which might have caused a minimal rift close to macula lutea. However, the cause of the disorder was never solved.

Sammanfattning: Tadalafil treatment has been associated with adverse reactions of the eye such as NAION. However, we have found no previous reports of disorder of the pigmentepithelium close to the macula lutea.

Svar: Tadalafil is an inhibitor of phosphodiesterase 5 (PDE5), but is not completely specific for this enzyme. It also has some affinity for PDE6 that is present in the retinal rods and cones, and is inhibited by tadalfil. However, the affinity of tadalfil for PDE5 is 700 times higher than for PDE6 in comparison with sildenafil which affinity is only 10 times higher for PDE5 compared with PDE6. Changes in the color vision is a common dosedependent and reversible adverse drug reaction for sildanafil while this reaction is not listed in the SPC for tadalafil (1,2).

There are several reports in the literature about phosphodiesterase 5 inhibitors and vision disorders. In particular, phosphodiesterase 5 inhibitors have been associated with development of nonarteritic anterior ischemic optic neuropathy (NAION). There are 18 published case-reports of NAION associated with sildenafil exposure and 3 case-reports for tadalafil (1). However, since erectile dysfunction is often a vascular disorder, an increased risk of vascular event in the eye might also be expected among these patients. A review of pooled data from clinical trials for all three phosphodiesterase 5 inhibitors, sildenafil, tadalafil and vardenafil, show no increased risk of NAION or other adverse ocular events (1,5).

There are 4 reports in the literature about Central Serous Chorioretinopathy (CSC) for sildenafil. In one of these cases the association with sildenafil exposure can be considered as probable and for other cases the association is possible. There are no report about CSC and tadalafil exposure (1). According to a case-control study (n=577) there was no association of CSC and treatment of PDE-5 inhibitor (3).

There are no reports in the literature about tadalafil och disorder of the pigmentepithelium close to macula densa or any reports about vitrial detachment.

In the Swedish adverse drug reaction database (SWEDIS) there are 24 reports for tadalafil of which 3 deals with eyesymptoms; (chromatopsia, retinal detachment and blurred vision). The association of chromatopsia and tadalafil was considered as probable while the association between the drug use and the cases of retinal detachment and blurred vision were considered possible (4).

If the vision disorder is considered as an adverse drug reaction to tadalafil we recommend the questioner to send an adverse drug reaction report to the Regional adverse drug reaction monitoring centre.