Several opioid medications are stronger than Percocet, which contains oxycodone (typically 5 to 10 mg per tablet) combined with acetaminophen. Hydromorphone, oxymorphone, fentanyl, and methadone all deliver more pain relief per milligram than the oxycodone in Percocet. How much stronger depends on the specific drug, the dose, and how it enters the body.
Understanding relative potency matters because moving to a stronger opioid is not simply a matter of “more is better.” Higher potency brings a sharper increase in overdose risk, and doctors weigh that tradeoff carefully before making a change.
How Opioid Strength Is Measured
Doctors compare opioids using a standard called oral morphine milligram equivalents (MME). Every opioid gets a conversion factor that expresses how much pain relief it provides relative to the same amount of oral morphine. A higher conversion factor means fewer milligrams are needed to achieve the same effect. Oxycodone, the active opioid in Percocet, has a conversion factor of 1.5. That means each milligram of oxycodone equals about 1.5 mg of morphine. A standard 10 mg Percocet tablet, then, is roughly equivalent to 15 mg of oral morphine.
Hydromorphone
Oral hydromorphone (sold under the brand name Dilaudid) has a conversion factor of 5, making it about 3.3 times stronger milligram-for-milligram than oxycodone. It is roughly five times more potent than hydrocodone. In its intravenous form, the gap widens dramatically, with a conversion factor of 18. Hydromorphone is commonly prescribed when patients need stronger relief than oxycodone provides or when they can’t tolerate other opioids well.
Oxymorphone
Oxymorphone has an oral conversion factor of 3, putting it at twice the potency of oxycodone per milligram. The initial conversion ratio used when switching from oxycodone to oxymorphone is roughly 2:1, meaning 20 mg of oxycodone would translate to about 10 mg of oxymorphone. Its oral bioavailability is only about 10 to 11%, similar to morphine, because the liver breaks down most of the drug before it reaches the bloodstream. Despite that low absorption rate, what does get through is potent enough to make oxymorphone a meaningful step up from Percocet.
Fentanyl
Fentanyl is in a different league. Intravenous fentanyl has a conversion factor of 300 per microgram (not milligram), making it roughly 50 to 100 times more potent than oral morphine depending on the route. Even the transdermal patch, which delivers fentanyl slowly through the skin, carries a conversion factor of 100 per microgram per hour. Because fentanyl is measured in micrograms rather than milligrams, the margin between a therapeutic dose and a dangerous one is extremely narrow.
Fentanyl patches are typically reserved for patients who already take opioids daily and need around-the-clock relief. They release the drug steadily over 48 to 72 hours, which is a fundamentally different approach than Percocet’s every-six-hour dosing. Rapid-onset fentanyl products (lozenges, nasal sprays, buccal films) are used almost exclusively for breakthrough cancer pain in patients already on a baseline opioid regimen.
Methadone
Methadone is uniquely complicated. Its relative strength changes depending on how much opioid a person is already taking. At low doses (under 30 MME per day), the morphine-to-methadone ratio is about 2:1, making it only modestly stronger than morphine. But at higher doses, methadone becomes disproportionately more powerful. At 100 to 299 MME per day, the ratio shifts to 8:1. At 500 to 999 MME per day, it reaches 15:1. At doses above 1,000 MME per day, the ratio is 20:1.
This nonlinear behavior makes methadone one of the trickiest opioids to dose safely. When switching a patient to methadone, doctors typically reduce the calculated equivalent dose by 75 to 90% to avoid overdose. Methadone also has an unusually long and variable half-life, meaning it builds up in the body over days. That accumulation can catch people off guard.
Extended-Release Oxycodone
OxyContin contains the same active ingredient as Percocet (oxycodone) but without the acetaminophen, and it is formulated for extended release. It is dosed every 12 hours rather than every 6 hours and comes in higher per-tablet strengths. OxyContin is not stronger per milligram of oxycodone, but it delivers more total drug over a longer period, which provides steadier pain control. Standard Percocet tablets contain 2.5 to 10 mg of oxycodone alongside 325 mg of acetaminophen. The acetaminophen ceiling (which protects the liver) effectively caps how much Percocet you can take in a day, limiting the maximum oxycodone dose. Extended-release oxycodone removes that cap.
Why Stronger Does Not Always Mean Better
The CDC’s 2022 prescribing guideline flags 50 MME per day as a threshold where additional precautions should kick in. Above that level, overdose risk climbs while the additional pain relief for most patients starts to flatten out. Patients taking 50 MME per day or more are advised to keep naloxone (an overdose-reversal medication) at home, and their household members should know how to use it.
These thresholds are guideposts, not hard rules. Some patients genuinely need doses above 50 MME. But the CDC data makes clear that the relationship between dose and pain relief is not a straight line: doubling the dose does not double the relief, yet it can significantly increase the chance of respiratory depression.
When Doctors Add Medications Instead
Rather than jumping to a more potent opioid, doctors sometimes add a second medication that works through a different mechanism. For nerve-related pain in particular, combining a lower-dose opioid with a nerve-pain drug like gabapentin often produces better relief than simply increasing the opioid alone. In studies of patients with diabetic neuropathy and postherpetic neuralgia, this combination achieved better pain control at lower doses of each drug than either one used on its own.
This approach matters because it can reduce the total opioid load a person needs. For pain that has a neuropathic component (burning, tingling, shooting sensations), a stronger opioid may not target the problem as effectively as a combination strategy. The type of pain, not just the intensity, shapes which medication makes sense.
Quick Potency Comparison
- Oral oxycodone (Percocet): 1.5x morphine, the baseline for this comparison
- Oral oxymorphone: 3x morphine, roughly twice as strong as oxycodone
- Oral hydromorphone (Dilaudid): 5x morphine, about 3.3 times stronger than oxycodone
- Methadone: variable, from 2x to 20x morphine depending on total daily dose
- Fentanyl (transdermal patch): roughly 50 to 100x morphine depending on route
Each step up this ladder narrows the gap between a dose that controls pain and a dose that suppresses breathing. That is why these transitions are made cautiously, with close follow-up, and typically only after lower-potency options have been fully explored.