PURPOSE: Sildenafil citrate (Viagra(R)) acts as a relatively specific inhibitor of the type 5 phosphodiesterase isoenzyme (PDE5) in the corpus cavernosum. But, it also has a mild inhibitory effect on PDE6 in the retinal photoreceptor. Therefore, we studied the ocular side effects of sildenafil. METHODS: We tested the visual acuity, intraocular pressure, color vision, visual evoked potential (VEP), electroretinogram (ERG), anterior segment and fundus appearance. All tests were done before and after medication of 50 mg and 100 mg sildenafil, respectively. RESULTS: There was no significant effect of sildenafil on visual acuity, intraocular pressure, color vision, VEP, anterior segment and fundus appearance. ERG changes after 50 mg sildenafil were not significant. The a-wave amplitude of the maximal combined response after 100 mg sildenafil showed significant changes (p=0.021). The b-wave amplitude of the maximal combined response after 100 mg sildenafil showed changes with borderline significance (p=0.059). CONCLUSIONS: In considering the fact that even single dose of 100 mg sildenafil showed changes on ERG, it seems that retinal function in patients receiving sildenafil for a longer period, especially in patients with underlying vascular abnormalities should be monitored by clinical and electrophysiologic tests.
Citric Acid ; Color Vision ; Eating* ; Evoked Potentials, Visual ; Humans ; Intraocular Pressure ; Photoreceptor Cells, Vertebrate ; Retinaldehyde ; Visual Acuity ; Sildenafil Citrate

BACKGROUND: Abdominal pain is a common complaint seen at emergency centers. Various diseases can cause abdomin al pain making it difficult to make a correct diagnosis. In the elderly, however, the consequences of an incorrect or delayed diagnosis can be more critical. We investigated the accuracy of initial diagnoses in the emergency center and analyzed the associations among medical factors including age. METHODS: We compared the ICD 10 codes of initial diagnoses to the codes of final diagnoses, defined the 'degree of agreement' using a 5 point scale, and classified patients into 'high degree of agreement' or 'low degree of agreement' groups. According to the severity of illness, we classified patients as 'admission' or 'out patient follow up'. According to their illness, we classified them as 'surgical' or 'medical'. According to age, we classified them as 'elderly' or 'adult'. Finally, we analyzed the statistical significance of each association. RESULTS: Overall, admitted patients and surgical diagnoses had higher degrees of agreement. 'Elderly' patients had no significant difference in 'degree of agreement' from 'adult' patients. CONCLUSION: Among patients presenting with acute abdominal pain to the emergency center, the degree of agreement between initial diagnosis and final diagnosis is dependent on the diagnostic characteristics of the disease, and not on the age of the patients. Further studies on the diagnostic accuracy of individual diseases are needed. Additional diagnosis associated variables, for example comorbidity and prognosis, needs to be studied regarding relationship to diagnostic accuracy.
Abdominal Pain ; Aged ; Comorbidity ; Delayed Diagnosis ; Emergencies ; Humans ; Prognosis