Myocardial infaction
Sickle cell vasoocclusive crisis
Ischemic optic neuropathy, retinal hemorrhage
Hearing loss
Priapism
Headache
Insomnia
Visual disturbance
Erythema, flushing
Indigestion
Epistaxis, nasal congestion, rhinorrhea
Sildenafil
Acebutolol
Amlodipine
Bosentan
Hydralazine
Epoprostenol 
Tropicamide
Timolol