Oxycodone and hydrocodone are both prescription opioid painkillers that work on the same receptors in your brain and spinal cord, and for most people, they provide very similar levels of pain relief. The key difference is potency: oxycodone is about 1.5 times stronger milligram for milligram. That distinction shapes how they’re prescribed, but in practice, when doses are adjusted to account for that gap, the two drugs perform remarkably alike.
How They Compare in Strength
The standard way to compare opioids is by converting them to an equivalent dose of morphine. Hydrocodone has a 1:1 ratio with oral morphine, meaning 1 mg of hydrocodone equals roughly 1 mg of morphine. Oxycodone’s conversion factor is 1.5, so 1 mg of oxycodone equals about 1.5 mg of morphine. In practical terms, a 10 mg hydrocodone tablet delivers roughly the same pain relief as a 6 to 7 mg dose of oxycodone.
Both drugs bind to the same mu-opioid receptors, which are the receptors responsible for pain relief, sedation, euphoria, and the slowed gut motility that causes constipation. Lab studies measuring receptor binding affinity place oxycodone and hydrocodone in the same middle tier, alongside morphine, methadone, and fentanyl’s close relatives. Neither drug is dramatically different from the other at the receptor level.
Pain Relief in Head-to-Head Studies
A well-known trial published in JAMA compared single doses of oxycodone with acetaminophen, hydrocodone with acetaminophen, codeine with acetaminophen, and plain ibuprofen with acetaminophen in emergency department patients with acute arm or leg pain. At two hours, pain scores dropped by 4.4 points in the oxycodone group and 3.5 points in the hydrocodone group on a 0-to-10 scale. That 0.9-point difference fell below the threshold of 1.3 points that researchers consider clinically meaningful, meaning patients couldn’t feel a real-world difference between the two.
The study also found that ibuprofen with acetaminophen performed just as well as any of the opioid combinations, which is worth knowing if you’re weighing your options for short-term pain.
How Your Body Processes Each Drug
Both medications kick in quickly. Hydrocodone starts working within 10 to 30 minutes and peaks at about 30 to 60 minutes. Oxycodone’s onset is around 15 minutes, with peak effects arriving between 1 and 2 hours. For most people, this difference is barely noticeable.
Where the two drugs diverge more meaningfully is in how your liver breaks them down. Oxycodone relies on two major liver enzyme pathways. When one of those pathways is blocked, whether by another medication or by your individual genetics, the other can usually pick up the slack. But when both pathways are inhibited at once, oxycodone levels in the blood can nearly triple, which raises the risk of oversedation and breathing problems. This is one reason your prescriber needs a full list of your current medications before writing an oxycodone prescription. Hydrocodone is also processed in the liver, and dose reductions may be necessary for people with significant liver or kidney disease. The same is true for oxycodone.
Addiction and Abuse Risk
Both drugs carry a real risk of dependence and misuse. A controlled study in experienced opioid users found that oxycodone and hydrocodone produced virtually identical profiles of euphoria, “liking,” and other reward-related effects. The researchers concluded that the abuse liability of these two opioids does not differ substantially. Oxycodone was roughly equipotent to, or slightly more potent than, hydrocodone in producing those rewarding effects, which tracks with its higher milligram-for-milligram strength.
Both are now classified as Schedule II controlled substances by the DEA, the most restrictive category for drugs with accepted medical use. Hydrocodone was actually reclassified from Schedule III to Schedule II in 2014, reflecting growing concern about its misuse. Before that change, hydrocodone combination products were easier to prescribe and refill, which contributed to their widespread use.
Common Brand Names and Formulations
Neither drug is typically prescribed alone in its immediate-release form. Hydrocodone is most commonly combined with acetaminophen and sold under brand names like Vicodin, Norco, and Lortab. It also comes combined with ibuprofen (Vicoprofen) and in cough suppressant formulations like Tussionex. Oxycodone paired with acetaminophen is sold as Percocet. On its own, oxycodone is available as OxyContin, which is an extended-release tablet designed for around-the-clock pain management rather than as-needed use.
The acetaminophen in combination products adds a ceiling to how much you can safely take in a day, since exceeding 3,000 to 4,000 mg of acetaminophen risks serious liver damage. If you’re taking any other medications containing acetaminophen, including over-the-counter cold medicines, you need to account for the total.
Which One Gets Prescribed and Why
In practice, the choice between these two drugs often comes down to a prescriber’s preference, your insurance formulary, and your medical history rather than a clear clinical advantage of one over the other. Hydrocodone combination products have historically been the most widely prescribed opioid in the United States. Oxycodone prescribing has grown rapidly as well, with U.S. production increasing nearly sixfold between 1998 and 2008.
Your doctor may lean toward one or the other based on how your body handles medications. If you have liver problems, both drugs require caution and possible dose adjustments. If you’re taking medications that interact with specific liver enzymes, that could tip the decision. Some people also respond better to one opioid than another in terms of side effects like nausea, constipation, or drowsiness, and switching between the two is common when one isn’t well tolerated.
The side effect profiles are nearly identical because both drugs activate the same receptors: constipation, nausea, drowsiness, dizziness, and at higher doses, dangerously slowed breathing. Neither drug is meaningfully “safer” than the other.