What happens when you take grapefruit with oxycodone?
Oxycodone is a semi-synthetic mu-opioid agonist sold as immediate-release tablets, oral solution, and combination products with acetaminophen (Percocet) or aspirin (Percodan), as well as the extended-release formulation OxyContin. After oral dosing, oxycodone is metabolized by two main pathways: CYP3A4 produces the inactive metabolite noroxycodone (the major route, about 45 percent of clearance), while CYP2D6 produces the highly potent metabolite oxymorphone (a smaller fraction). A small portion is also conjugated.
Grapefruit juice contains furanocoumarins (bergamottin and 6,7-dihydroxybergamottin) that irreversibly inhibit intestinal CYP3A4. With the major metabolism pathway suppressed, more oxycodone survives first-pass metabolism, less is shunted to inactive noroxycodone, and the relative contribution of the CYP2D6 pathway to oxymorphone (a more potent metabolite) rises.
In a randomized crossover study of 12 healthy volunteers, 200 mL of grapefruit juice taken three times daily for five days before a 10 mg oral oxycodone dose raised oxycodone AUC by 1.7-fold, peak concentration by 1.5-fold, and elimination half-life by 1.2-fold compared to water. Noroxycodone and noroxymorphone metabolite ratios fell by 44 and 45 percent, respectively, while the AUC of the potent metabolite oxymorphone increased. Self-reported performance was impaired.
Why is this important?
Opioid overdose deaths are dominated by respiratory depression, in which sedation deepens to the point that breathing slows or stops. The danger zone is determined by how much active opioid reaches the brain. A 70 percent increase in oxycodone exposure with a parallel rise in oxymorphone activity moves a person closer to that zone, especially if other depressants are on board.
Patients on oxycodone are often also taking benzodiazepines (alprazolam, lorazepam, diazepam), sleep aids (zolpidem, zopiclone), muscle relaxants (cyclobenzaprine, carisoprodol), gabapentinoids (gabapentin, pregabalin), other opioids, or alcohol. Each of these compounds the sedation and respiratory depression risk of an oxycodone exposure increase. The FDA has issued multiple boxed warnings about opioid-benzodiazepine combinations precisely because of this stacking risk.
The interaction is also relevant for patients with chronic pain who self-medicate breakthrough pain by adding extra doses; an extra dose taken on a day when grapefruit has already inhibited CYP3A4 produces a much larger and longer exposure than the patient expects.
What should you do?
Avoid grapefruit, grapefruit juice, pomelo, and Seville oranges while taking oxycodone. Sweet oranges, mandarins, clementines, lemons, and limes are safe.
Do not drink alcohol with oxycodone, full stop. Alcohol plus an opioid is the most common combination implicated in opioid-related deaths, and grapefruit juice on top of either makes the situation worse.
If you have accidentally consumed grapefruit, take the next oxycodone dose at the lowest effective amount, and have a sober companion with you. Watch for unusual sleepiness, slowed or shallow breathing, snoring during the day, pinpoint pupils, confusion, or unresponsiveness. If any of these appear, call emergency services and use naloxone (Narcan, available without prescription in most US states) if you have it.
People on chronic oxycodone or oxycodone extended-release should make grapefruit avoidance a permanent dietary habit, not something they remember just on dosing days, because the enzyme effect persists for up to 72 hours.
Which specific products are affected?
The interaction affects all oral oxycodone formulations: oxycodone IR tablets and oral solution, Roxicodone, OxyContin extended-release tablets, OxyIR, and combination products like Percocet (oxycodone + acetaminophen), Percodan (oxycodone + aspirin), and Endocet. Buccal and transmucosal formulations also pass through CYP3A4 metabolism.
Other opioids vary in their grapefruit sensitivity. Hydrocodone is largely metabolized by CYP2D6, with a smaller CYP3A4 component; the effect of grapefruit is therefore smaller. Fentanyl, methadone, and tramadol are CYP3A4 substrates and can show meaningful grapefruit interactions. Morphine, hydromorphone, and codeine are conjugated or use other pathways and are largely unaffected by grapefruit.
The bottom line
Grapefruit juice inhibits intestinal CYP3A4 and raises oxycodone exposure by roughly 70 percent, while also shifting metabolism toward the potent metabolite oxymorphone. This can deepen sedation and respiratory depression, especially when oxycodone is combined with benzodiazepines, alcohol, or other depressants. Avoid grapefruit while on oxycodone and seek emergency care if breathing becomes slow or shallow after accidental exposure.