(The oc that embodies the drug, not the drug)
Fun Fact: You shouldn't drink grapefruit juice when taking opioids.
It amplifies the effects and it could increase the risk of overdose. This is called opioid potenation.
I wrote this into Oxy's character by making him allergic to grapefruit and grapefruit products.
He takes allergy meds as needed. Kinda like an Epipen. If he comes into contact with or eats grapefruit he takes the pills asap. He carries them around as sometimes he accidentally eats/comes into contact with grapefruit. Vicodin also has some in case Oxy forgets his medication.
Oxy didn't know about his allergy for a long time, until one day he was in his apartment trying grapefruit. He bit into it and he hated it. And rightly so: he started to take a reaction to it and it wasn't until Vicodin saw him and rushed him to the E.R that he realised he was allergic.
So ye.
He can eat other citrus foods and he likes lemon cake.