So long as you are being relatively cautious in your choices, this shouldn't be a big deal. One thing I know that can happen when you combine Opioids with Gabapentinoids is that you can become completely intoxicated from these two substances. The thing that I'm unsure of: are Gabapentinoids going to contribute to a fatal overdose in a meaningful way, hypothetically of course. Like I said OP, take it easy on dosage and understand that some people react quite strongly to Gabapentinoids.
There is not a lot of information in general regarding Gabapentinoids and Opioids aside from the fact that we seem to know pretty well at this point that the former are effective adjuncts to Opioid treatment. They help reduce the overall need for Opioids in a large segment of the population. So, in a roundabout way OP, you could become more intoxicated than you would like, so go slow.
^Above poster, I don't think that the same mechanism will be in effect for somebody who is heavily dependent upon a given Opioid. I believe that Gabapentinoids might help you when you're out of Oxycodone, but I wouldn't expect any kind of earth-shattering effect from combining the two.