Reinstituting the Bolus – New Reasoning for an Existing Technique

Abstract

Improved intrathecal (IT) pump technology is increasing the accuracy of IT opioid bolus dosing and promising advances in pain therapy. Opioid bolus dosing can be used with a minimal continuous infusion or it can function as the sole therapy. Bolus-only dosing is characterized by minimal use of opioid (often less than 1 mg of IT morphine). It achieves adequate pain control while reducing tolerance and possibly opioid-induced hyperalgesia. It may prevent receptor saturation, and provide a “washing out” of the opioid receptor that prevents the observed dose escalation resulting from continuous infusions. With new bolus dosing possibilities, IT pumps can be used earlier in the treatment algorithm instead of being a latestage treatment for patients who responded poorly to conservative treatments. We hypothesize that morphine bolus-only IT dosing will have comparable adverse effect rates, and possibly increased safety as compared to the more conservative continuous delivery method. We further predict that bolus-only delivery will provide better therapy satisfaction, improved functional scores, lower 24 hour opioid dose, and less dose escalation. Key words: Intrathecal morphine, patient-controlled analgesia, microdosing, decreased tolerance, bolus only - no continuous dosing

Investigation of Human Intrathecal Solute Transport Dynamics Using a Novel in vitro Cerebrospinal Fluid System Analog

“…To our knowledge, multiple flushes and flush timing has not been non-clinically or clinically investigated. However, repeated bolus injections have been shown to have a therapeutic effect in context of intrathecal pain and spasticity therapeutics: improved functional scores, lower 24-h opioid dose, and less dose escalation (McRoberts et al, 2017 ). Additionally, multiple bolus doses showed reduced potential for intrathecal fibrosis in dogs when compared to continuous infusion, though this may be accounted for by a drug specific effect and may not hold true for all drugs (Hildebrand et al, 2019 ).…”