Dynamics of breakthrough pain vs. pharmacokinetics of oral morphine: implications for management.

Dynamics of breakthrough pain vs. pharmacokinetics of oral morphine: implications for managementBreakthrough pain is a transient exacerbation of pain that occurs either spontaneously, or in relation to a specific predictable or unpredictable trigger, despite relatively stable and adequately controlled background pain. The onset of breakthrough pain is typically fast and the duration is usually relatively short, but despite the self-limiting nature of each breakthrough pain, the repeated episodes can have a significant impact on patients' quality of life. Effective management is therefore imperative and often involves the use of supplemental doses of medication known as 'rescue medication'. The ideal rescue medication should be efficacious, have a rapid onset of action, a relatively short duration of effect and minimal adverse effects. Normal-release oral opioids have been the mainstay approach for patients who are receiving around the clock opioid regimen, but the onset and duration of action of oral opioids such as morphine may not be suitable for treating many breakthrough pains.