Key Feature 3a: In patients with chronic disease: Actively inquire about pain.
Skill: Clinical Reasoning
Key Feature 3b: In patients with chronic disease: Treat appropriately by:
Phase: Treatment, Hypothesis generation
Key Feature 4: In patients with pain, manage it (ex: adjust dosages, change analgesics) proactively through frequent reassessments and monitoring of drug side effects (ex: nausea, constipation, cognitive impairment).
Skill: Clinical Reasoning
Phase: Treatment, Follow-up
The standard general approach to pain control is based on the World Health Organization's Pain Ladder, with the diagram and information below coming from "Palliative medicine: A case-based manual" by Doreen Oneschuk, Neil Hagen, and Neil MacDonald. The "ladder" was designed with cancer pain in mind, but it tends to provide the framework for pain management for people with all sorts of acute and chronic sources of pain. The basic idea is that for mild pain you start with non-opioid medications, with specific choice depending on the type of pain and patient characteristics. It is important to actively inquire not just about the presence of pain, but also about the quality of the pain in patients in order to treat it most effectively. Not illustrated as part of the pain ladder but equally important are also nonpharmacological interventions that can be useful in alleviating pain. As pain increases in severity, the choice of pain medication and/or dose ought to increase accordingly. Adjuvants (medications originally developed for reasons other than to improve pain, but that can also alleviate pain as a secondary effect, depending on the type of pain) can also be very useful when indicated. Poor pain control can have a significant negative impact on quality of life, and we have lots of tools in the box to work to mitigate this source of distress. It is important to continue to reassess patients experiencing pain or receiving therapy for it, to ensure that pain is in fact controlled, as well as to monitor for side and adverse effects.
Nonpharmacological therapies to consider starting, in the context of mild pain and patients who are motivated to try them, or to consider adding on to pharmacological treatments for added pain relief, could include:
Common non-opioid medications for mild pain include acetaminophen and NSAIDs (ex: naproxen, ibuprofen, diclofenac, ketorolac).
For pain that is sufficiently severe and that cannot otherwise be controlled (with non-opioids, adjuncts, and nonpharmacological modalities), treatment with an opioid may be indicated. Opioids exert their analgesic effect mostly by agonising mu opioid receptors in the brain. Commonly prescribed weak opioids include codeine and tramadol, and commonly prescribed strong opioids include morphine, hydromorphone, oxycodone, fentanyl, and methadone.
General principles of opioid initiation and titration include having a regular dosing schedule (initially starting with a short-acting preparation until the baseline pain is controlled) with a prescribed breakthrough dose for pain to be taken as needed for acute exacerbations (generally prescribed to be taken as much as every 1 hour, or in the setting of opioids with a very rapid half life, up to every 30 minutes or so). The degree of pain control as reported by the patient along with the number of needed breakthrough doses in a given 24 hour period indicates whether or not there is a need to adjust the baseline opioid dose. As a general rule of thumb, if greater than 3 breakthrough doses in a 24 hour period are needed, unless this is attributed to being incident pain (aggravated by a specific event such as movement that would not otherwise be present at baseline), then an increase in the baseline opioid dose is warranted. The amount to up-titrate can be calculated by adding up the total quantity of opioid needed in the last 24 hour period (baseline and amount of breakthrough used), calculating the conversion to the new choice of opioid based on number of morphine equivalents, and dividing this quantity so that it is given over the next 24 hour period as the scheduled dose. And then a new quantity of breakthrough pain medication is prescribed, and a rule of thumb for this is dosing it at about 10% of the total daily scheduled amount of opioid to be given over the next 24 hour period.
On the flip side, when patients report good pain control, with minimal to no use of doses required for breakthrough pain, the patient can be gradually weaned down as tolerated.
Side effects of all opioids are generally the same (though they may occur to different degrees depending on the formulation, dose, and patient factors), and they most commonly include transient nausea, transient drowsiness, and constipation that is not transient and that lasts as long as the opioid is being taken. If they are given in a high dose too quickly, they can cause respiratory depression, but when prescribed responsibly in small doses with gradual up-titration, this concern is mitigated. For the nausea, an antiemetic can be prescribed either to be taken routinely or as needed, and for the constipation the patient will likely need to be on a regular dose of laxative medication. See my next post for more detail on these options.
Besides the above side effects that can occur when any opioid is used, there is also the phenomenon of opioid neurotoxicity that can occur. Briefly, this is a situation in which patients can develop altered mental status (ex: delirium, agitation, somnolence), vivid or unpleasant dreams, delusions/hallucinations (usually visual), and increased pain perception (ex: allodynia or hyperalgesia). Myoclonic jerks and seizures can also occur. In the setting of suspected opioid neurotoxicity, rotating to a different opioid is warranted (other options include simply changing the route by which the current opioid is delivered, decreasing the dose of the current opioid and adding an adjuvant, or just treating the toxic symptoms themselves; rotating the opioid is generally the preferred option). This is done by adding up the total number of morphine equivalents a patient has on board in a given 24 hour period, calculating the equivalent dose in the opioid to which the patient is being rotated to, reducing this dose by 25%, and dividing the dose to be scheduled throughout the day as the half-life of the new opioid indicates.
Opioid options include:
Some adjuvants that may be useful in pain management, particularly in the palliative care setting: