How quick is dog's allergic reaction after giving medication

[spamgirl]

I gave my dog Tramadol for the first time this morning, but I have to go out in 2 hours. He's been allergic to other things in the past (olive oil, plants we've brought into the house), so I'm worried he might have an allergic reaction. If he was to, would it be within two hours?

[Traci]

Doubtful he would react to tramadol (other than potential slight sedation) and of course, never give more than the prescribed dose.

All pain meds are generally quick-acting, that is, within a couple hours - tramadol is one of the more mild meds.