Oxycodone and hydrocodone are both narcotic analgesics indicated for the relief of moderate-to-severe cancer-related or acute pain. Studies have shown no differences in their pain-relieving properties; however, the incidence of constipation may be higher with hydrocodone.
Hydrocodone is not widely available outside of the U.S., so has limited use internationally. Oxycodone appears to have a higher abuse liability potential compared with hydrocodone. Hydrocodone is also effective as a cough suppressant.
Both are available in abuse-deterrent forms.
See also: Drugs.com Compare Tool - Oxycodone vs Hydrocodone
Long answer
Are there any studies that compare oxycodone to hydrocodone?
For cancer-related pain, a number of different studies have concluded that both oxycodone and hydrocodone have similar effectiveness at relieving pain.1,2,3,4
For acute severe pain, such as that following a fracture, no difference in effectiveness at relieving pain was noted between oxycodone 5mg and hydrocodone 5mg (both were given in combination with acetaminophen).5 The incidence of side effects such as nausea, vomiting, itching, or drowsiness were similar; however, constipation was more likely to be experienced by people taking hydrocodone patients (21% of hydrocodone patients reported constipation in one study compared with no oxycodone patients).5
When used for chronic non-cancer-related pain, trials DO NOT support the use of opioids over other forms of pain relief. A meta-analysis (detailed review) of 46 studies showed no significant difference in pain relief between opioids and other pharmacological (such as NSAIDs) or non-pharmacological treatments (such as psychotherapy or physiotherapy). The analysis did not support the use of opioids (including oxycodone and hydrocodone) as the sole or preferential form of treatment for chronic non-cancer-related pain. In fact, the authors declared a combination approach the most beneficial way to manage chronic pain; for example, psychotherapy + physiotherapy + acetaminophen or ibuprofen. If anything, this analysis highlights the widespread misconceptions that opioids are the most effective treatment for any sort of pain - they are not. And when used for chronic, non-cancer-related pain, risks such as addiction and withdrawal symptoms associated with their use far outweigh any benefits.6
What is the equivalent dose of oxycodone to hydrocodone?
There does appear to be some controversy over the potency on a mg for mg basis between hydrocodone and oxycodone; however, the Marco study5 detailed above found 5mg oxycodone to be just as effective as 5mg of hydrocodone.
Which drug is more likely to be abused?
Oxycodone was found to be more likely to be abused than oral morphine and hydrocodone in a review of nine good quality clinical studies.7
Opioid abuse remains a major challenge in countries such as the U.S., Mexico and Canada. Reported abuse rates in North America are almost five times the global average (3.7% vs 0.7% in the rest of the world). More than 16,000 deaths occur each year involving overdoses of opioid drugs primarily containing oxycodone, hydrocodone, or methadone, out numbering those involving heroin and cocaine combined.8
Over 99% of the global consumption of hydrocodone occurs in the U.S.; mainly because hydrocodone is not widely available or used internationally. Although more widely distributed, Oxycodone use far outweighs any other country, at 84% of global availability.8
Formulations
Because opioids usually work better in combination with other analgesics, both oxycodone and hydrocodone are available formulated with other ingredients such as acetaminophen or ibuprofen.
Oxycodone is available in an immediate and controlled-release forms, and in combination with acetaminophen, aspirin, and ibuprofen. A naloxone combination product was available but this has recently been discontinued. Oxycontin, the controlled-release form, was reformulated by the manufacturer in 2010 in an attempt to curb epidemic levels of abuse.1,9,10
Hydrocodone intended for pain relief is available as abuse-deterrent controlled-release capsules (Hysingla ER, Zohydro ER) and in combination with acetaminophen or ibuprofen.2,10
Are there any differences in the way oxycodone and hydrocodone work in the body?
Structurally, oxycodone (molecular formula C18H21NO4) and hydrocodone (molecular formula C18H21NO3) are very similar, the difference in their structure comes down to one extra oxygen atom on Oxycodone.11,12
Oxycodone is semi-synthetic and is synthesized from thebaine (an opium alkaloid) and will only relieve pain, not cough.1,12
Hydrocodone is also semi-synthetic but derived from codeine, and while more potent than codeine, still retains cough suppressant properties. It is more commonly found in combination with other nonopioid analgesics (for example acetaminophen), although abuse-deterrent formulations of just hydrocodone are available.2,11