Program Review
Given the current concern over the so-called “opioid epidemic” let’s examine the commonly used opioid analgesics. As illustrated in Figure 1, opioids have unlimited efficacy in providing pain relief. As doses are increased greater pain relief is provided, but adverse effects may preclude the use of doses great enough to effectively manage patients experiencing pain of severe intensity. Opioids are identical in their analgesic efficacy at equipotent doses. Morphine 10mg IM and 30mg oral (PO) are regarded as the conventional standard for relief of moderately severe pain. It is a safe dose for reasonably healthy adults (≥ 50kg) and is regarded as the standard reference point when comparing doses of other opioids (see table below). When prescribing opioids, it is prudent to avoid equipotent doses that exceed morphine 30mg PO. DRUG Morphine Codeine Hydrocodone Oxycodone
EQUIPOTENT DOSE (mg) PARENTERAL ORAL 10 30 130 180-200 – 30 – 20
When combined with non-opioids, single doses of opioids rarely (if ever) require a conventional morphine-equivalent when managing postoperative dental pain, but equipotent increments that approach this amount is a reasonable practice. This can be accomplished only by fully appreciating equipotent opioid doses and will be addressed further at the conclusion of this article. The non-opioids provide a ceiling to their analgesic efficacy, and it is important to consider the dose at which this occurs. Acetaminophen (APAP) 1000mg is slightly inferior to ibuprofen 400mg, but both are WEST MICHIGAN DISTRICT DENTAL SOCIETY | WINTER ISSUE 2017
impressive nonetheless. (Higher doses of NSAIDs, e.g., ibuprofen 600800mg, impart a greater antiinflammatory effect and are frequently justified considering that inflammation is a major contributor to dental pain.) Notwithstanding the ceiling to their analgesic efficacy, the actual intensity of this effect is underappreciated. “ NSAIDs are particularly effective when inflammation has caused peripheral and/or central sensitization of pain perception. Thus, postoperative pain or pain arising from inflammation, such as arthritic pain, is controlled well by NSAIDs, whereas pain arising from the hollow viscera usually is not relieved.” 1 Studies have shown repeatedly that 400 mg ibuprofen (or equipotent doses of other NSAIDs) provides pain relief equal to or greater than conventional doses of morphine for musculoskeletal pain. For example, Kleinert et. al.2 conducted an extensive study comparing the efficacy of various doses of the novel analgesic tapentadol using morphine and ibuprofen as comparisons. They found ibuprofen 400 mg superior to both, and reconfirms myriad studies published for decades that document superiority of ibuprofen compared to conventional doses of morphine and meperidine. It is noteworthy that the various NSAIDs are equivalent in their analgesic efficacy. A common misconception is that parenteral ketorolac (Toradol) is superior to other NSAIDs, but studies have confirmed this is simply not the case. For example, Turturro et. al.3 found that ketorolac 60mg IM was comparable to ibuprofen 800mg for traumatic injuries in the emergency department. Ibuprofen is formulated as 200mg, 400mg, 600mg and 800mg tablets, but most other NSAIDs are formulated in only two strengths. Precise equipotency has not been established, but it is reasonable to equate the lower dose of other NSAIDs as approximately equipotent to ibuprofen 400mg and the higher dose equivalent to ibuprofen 800mg. 17