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. Author manuscript; available in PMC: 2012 Oct 1.
Published in final edited form as: J Am Geriatr Soc. 2011 Sep 13;59(10):1899–1907. doi: 10.1111/j.1532-5415.2011.03586.x

Table 1.

Opioid Classification Scheme and Use of Individual Medications by Study Subjects

Medication Number of prescriptions dispensed* Half-life Immunosuppressive† Morphine equivalent dose‡
n %
Hydrocodone 1,117 34.2% Short No 1.0
Codeine 805 24.6% Short Yes 0.15
Oxycodone (short acting) 670 20.5% Short No 1.5
Propoxyphene 304 9.3% Short Unknown 0.23
Morphine (sustained release) 138 4.2% Long Yes 1.0
Oxycodone (controlled release) 65 2.0% Long No 1.5
Morphine (immediate release) 45 1.4% Short Yes 1.0
Meperidine 44 1.3% Short Unknown 0.1
Hydromorphone 27 0.8% Short No 4.0
Fentanyl (transdermal) 23 0.7% Long Yes 2.4
Tincture of opium 13 0.4% Unknown Unknown 10.0
Tramadol 11 0.3% Short No 0.10
Methadone 3 0.1% Long Yes 3.0
Levorphanol 1 0.0% Long Unknown 11.0
Total 3,266 100%
*

Number of prescriptions dispensed between 5–365 days prior to index date for cases and controls.

†

Based on human and animal studies.11, 15, 16, 26

‡

Conversion factors are based on information from multiple sources and were arrived at by consensus of several investigators in a prior study of opioid medication use.28 For tincture of opium, the conversion factor is based on information from Thomson Micromedex.27 To use conversion factors, multiple the amount of opioid by the conversion factor to get the amount of morphine. E.g. 200 mg of codeine is equivalent to 200 * 0.15 = 30 mg of morphine, and 20 mg of oxycodone is equivalent to 20 * 1.5 = 30 mg of morphine.