Hmmm, I used to run and take vicodin or 5mg Percocet quite frequently (very moderate doses: 20mg vikes; 15 mg percs).* A runner's high is my favorite potentiator and I think it works the best at potentiating my favorite part of the high: the energy and euphoria. So it's especially synergystic with oxy which is so energetic.
Anyway, perhaps your 60mg is gone by now. But having had lot of experience with mixing opiate highs with runner's highs, I think you'd be best off taking the 60 right before your run (especially since it's only 3km). That way the oxy will have started kicking in and will synergize with your runner's high. I've had good results with that.
Or, take the 60mgs right at the end of your run so that its onset coincides with the slight diminishment of the runner's high. 3km is such a short run that I don't think taking it in the middle of the run will really make that much difference. I don't even take water with me when I run 3k so it just seems like a lot of extra hassle to bring water and pill(s) and dose half-way in.
* (little warning) Combining pain meds and running was part of the reason I ignored my injury and ended up with a rather severe back injury. To be honest, far worse damage was caused by the bad doctors insisting that I couldn't possibly have anything strucutrally wrong with my back because "you look so young and heathy" (I can't tell you how many times I've heard that in my life), and expensive but hideous health insurance that wouldn't pay for an MRI. And I did already have structural damage from a previous severe injury when they were telling me this.
But, just a word of warning so that you don't fuck yourself over by ignoring certain types of pain/injuries that will really ruin your ability to enjoy the exercise you love so much. If you have an extreme personality and always overdo shit, pay careful attention to your body. I was running 30-5 miles a week when this was all going down and that's 10 times more stupid than what you're doing.
