Is there a consensus on the minimum intensity of pain on NRS that qualifies itself to deserve the breakthrough pain designation?
Does breakthrough pain have to be at least moderate in intensity?

These questions presented themselves after participating in the third round of a recently completed Delphi study on breakthrough pain.

A recent systematic review by Greenfield et al, characterizing breakthrough pain, brings the following facts about pain intensity into focus,
– most patients rated their pain as at least 7-8/10
– the average pain intensity in other studies was between 4 and 7, reaching a maximal average pain intensity of 8.5 out of 10.
– upon being asked to rate their pain intensity as mild, moderate or severe, the vast majority rated their pain intensity as “severe”.
– descriptors such as “severe” and “excruciating” were used in qualitative studies
– some patients underlined the difficulty in characterizing “severity”.

Other attempts to provide a numerical value to the intensity of BTP, have yielded the following results
– pain severity of more than 7 out of 10 was required for the designation of breakthrough pain.
– there was expert agreement on the need for the pain intensity to be at least 2 points more than the baseline, but no predefined numbers for the baseline have been mentioned.

Adequately controlled baseline pain is assumed to have a severity of 3 or less out of 10 (on NRS). This would imply that intensity of breakthrough pain would be at least 5, which includes moderate pain, but crucially omits episodes of mild pain.

In a study by Mercadente et al, on the prevalence and characterization of breakthrough pain in those receiving low dose opioids (OME less than 60 mg/d), both paracetamol 1000 mg and tramadol 30 mg were used as rescue medications, which suggests that some of these episodes could have been mild. Since medications such as Tramadol, Codeine-paracetamol were used for baseline pain, it may be inferred that these were suited to the situation. Although the authors report the average intensity of background pain as 2.71, they do not mention the average intensity of breakthrough pain or characterize the specific situations where these medications (used for mild to moderate pain in most instances) were found to be useful. The mean OME of 28.3 mg/day leaves the question of equianalgesic conversion unanswered – how was paracetamol dosing taken into consideration?

The learning point from these observation could prove to be something basic, albeit with the potential to impact patient care in a significant manner. While the guideline supported blanket advice to our patients has been on using a particular fraction of the baseline opioid for breakthrough pain, it becomes our responsibility, to ensure that this advice is refined to include a few crucial nuances. There remains a need to ensure that advice for management of mild episodes is provided separately, thus preventing indiscriminate use of opioids. In fact, it might prove to be useful to state implicitly that, if recourse to opioids is to be taken (for use in these mild increase in pain episodes), it is to be reserved when other measures such as step 1 analgesia and non-pharmacological measures have proven to be ineffectual.

The unsaid, but implied dictum that threshold of pain needs to be reconciled with the functional impairment of activities of daily living and psychological impact also needs to be taken into consideration. It is not difficult to foresee that even mild pain episodes might be associated with disproportionate distress in this vulnerable population. At the same time, it is important to understand the counterview that the development of opioid tolerance is a foreseeable, but unavoidable phenomenon in this subset of individuals (definition includes OME more than 60 mg/day for more than 7 days), which might pose specific challenges to the use of mild opioids (less than strong opioids) in this setting. The strength of a single dose (calculated using standard considerations) is expected to fall well below the threshold of that expected to be minimally efficacious for breakthrough pain.

While, these mild pain episodes, might act as a persistent reminder of the advanced stage of disease and need not be ignored, are opioids always suited to this situation?

Or is caution to be advised?

References

Greenfield, K., Schoth, D. E., Hain, R., Bailey, S., Mott, C., Rajapakse, D., Harrop, E., Renton, K., Anderson, A.-K., Carter, B., Johnson, M., & Liossi, C. (2024). A rapid systematic review of breakthrough pain definitions and descriptions. British Journal of Pain, 18(3), 215–226. https://doi.org/10.1177/20494637231208093

Mercadante, S., Maltoni, M., Russo, D., Adile, C., Ferrera, P., Rossi, R., Rosati, M., & Casuccio, A. (2021). The Prevalence and Characteristics of Breakthrough Cancer Pain in Patients Receiving Low Doses of Opioids for Background Pain. Cancers, 13(5), 1058. https://doi.org/10.3390/cancers13051058

U.S. Food and Drug Administration. (2009). DURAGESIC (fentanyl transdermal system) full prescribing information [Package insert]. Janssen Pharmaceutica. https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/019813s044lblnew.pdf

Cite as

Arora, R. D. (2026). Conceptual engineering (CE6): Implications of mild pain intensity on breakthrough pain designation. Zenodo. https://doi.org/10.5281/zenodo.20794483

Disclaimer
Palliative medicine is a relatively young subspecialty whose intellectual and clinical boundaries continue to evolve. In the absence of definitive texts to address contemporary questions, artificial intelligence tools mainly Anthropic (Claude) have been employed to support deeper conceptual exploration, challenge assumptions, and improve clarity of expression. They do not replace critical scholarship, clinical experience, or editorial judgment. Final responsibility for all interpretations, factual accuracy, originality of synthesis, and the quality of the published material rests entirely with the Founder and Editor.