Assertion: viagra's effect | /r/HasProperty | headache
Facets:
value: in clinical trials
type: LOCATION
Source sentences:
text: In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, indigestion, nasal congestion, and impaired vision, including photophobia and blurred vision.
text: The side effects of Levitra include: headache
text: In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, indigestion, nasal congestion, and impaired vision, including photophobia and blurred vision.