Natural opiates and synthetic or semisynthetic opioid drugs are frequently misused for both their euphoric and sedative effects. The drugs differ in their potency and therefore the dose of each that will relieve the same level of acute or chronic pain will differ. Careful opioid selection and management can provide effective pain relief, while helping to decrease the current epidemic of opioid abuse, dependence, addiction, overdose, and death.
Comparing the Potency of Opioids
Morphine, the predominant alkaloid in the opium poppy plant seed, is the most potent natural opiate. The potency of all other opioids is estimated against that of 30 milligrams (mg) of morphine - the estimated morphine milligram equivalent (MME). The MME or potency of an opioid is its dose in mg that provides about the same level of pain relief as 30 mg of morphine taken by mouth.
You can calculate the MME for an opioid by dividing 30 mg by the drug's morphine equivalent conversion factor from a Centers for Disease Control and Prevention (CDC) chart:
- The conversion factor for an oxycodone, such as OxyContin, is 1.5.
- The estimated MME for OxyContin is therefore 20 mg - equivalent to 30 mg of morphine.
Mistakenly taking a high milligram dose of a potent opioid equal to that of a less potent opioid can lead to serious adverse outcomes, including overdose and death.
A Comparison Chart of Commonly Prescribed Opioids
The chart below compares aspects of the most frequently prescribed opioids in decreasing order of potency as calculated from their morphine equivalent conversion factors. Included are the drugs' generic and brand names, and the type and level of pain they are usually prescribed for. To read the chart, the following information is also helpful:
- mg = milligrams
- mcg = micrograms
- Onset of action:
- IR = immediate-release - the opioid dose is released into the blood at once
- ER = extended-release - the opioid is released over a time period
- Usual dosing = how often a dose is taken
- Type of pain treated:
- Acute = short-term pain
- Chronic = long-term, ongoing pain
Pain severity: mild, moderate, moderately severe, severe
List of Opioids in Order of Potency
|Onset of Action||
Type of Pain Treated
12-100 mcg/hour transdermal patches
|hydromorphone hydrochloride||IR||7.5 mg||2-4 mg tablets||4-6 hours|| |
10 -20 mg tablets
|4-6 hours|| |
|Methadone||Methadone hydrochloride||IR||10mg||2.5-10 mg||3-4 hours|| |
|60-80 mg||daily|| |
|Roxicodone||oxycodone hydrochloride||IR||20 mg||5-15 mg tablets||4-6 hours|| |
oxycodone, slow release
|ER||20 mg||10 mg tablets||12 hours|| |
oxycodone plus 325 mg acetaminophen
5-10 mg tablets
|3-6 hours|| |
15-30 mg tablets
|3-4 hours|| |
15 mg tablets
|8-12 hours|| |
hydrocodone bitartrate plus 300 mg acetaminophen
5 -10 mg tablets
|4-6 hours|| |
|Codeine Sulfate||codeine sulfate||IR||200 mg||
15-60 mg tablets
|3-4 hours|| |
|Demerol||meperidine hydrochloride||IR||300 mg||50-150 mg tablets||3-4 hours|| |
25-100 mg tablets
|4-6 hours|| |
Some brands listed here as immediate release, such as Opana, also come in extended release formulations. In addition to tablets, several of the opioids are also available in forms for intravenous, intramuscular, and other routes of administration.
CDC Recommended Opioid Prescribing
The use of an opioid is based on the level of pain, whether the pain is acute or chronic, as well as a person's other individual factors. Doctors rely on various sources of opioid prescribing guidelines to ensure the safe use of opioids, including the most recent, the 2016 CDC Guideline for Prescribing Opioids for Chronic Pain.
In summary, when using opioids for treatment of pain, the CDC recommends doctors should:
- Start with an immediate-release opioid at the lowest effective dose for the level of pain, then proceed from there.
- For acute, short-term pain, treat for a short duration of three days or less and avoid treating more than seven days.
- For chronic, long-term pain, prescribe an extended-release opioid only if an immediate-release option is ineffective.
According to other CDC data, using increasingly higher doses of an opioid does not translate to better pain relief and carries more risks, including overdose.
Potency and Risks
All opioids have similar side effects, as well as the risk of tolerance, abuse, dependence, and the irreversible changes of opioid addiction, based on the dose and the frequency and duration of use. Be aware that if you misuse or abuse opioids, the more potent the drug, the greater the risks of overdose and death.