Assertion: viagra's use | /r/HasProperty | advised
Facets:
Source sentences:
text: As neither drug prevents sexually transmitted diseases, use of a condom for protection is advised.
text: Concomitant use with alpha-blockers Caution is advised when sildenafil is administered to patients taking an alpha-blocker, as the co-administration may lead to symptomatic hypotension in a few susceptible individuals (see section 4.5).