Sildenafil: Headache, flushing, dyspepsia; visual disturbances eg, blurred vision, photophobia, chromatopsia, cyanopsia, eye irritation, pain & redness of the eyes. Dizziness, insomnia, anxiety, vertigo, epistaxis, nasal congestion, pyrexia & GI disturbances eg, diarrhea & vomiting; priapism. Panax ginseng: Trouble sleeping.