I didn't know Viagra was illegal.
What, you pop it like candy? LOL
If you don't have a prescription for it, it's illegal.
The government knows what's best.
IIRC, it is not good to try to get through customs with a prescription drug that you don't have a prescription for. It isn't that Viagra is illegal.
They don't actually say that the Viagra was illegal, more so that the Viagra was found among the illegal drugs. Of course, Viagra is a prescription drug so possession without a prescription would be illegal.
More importantly, why would he need Viagra? He isn't married.