The efficacy and safety of intravenous lidocaine for analgesia in the older adult: a literature review.

Opioids remain the mainstay of analgesia for the treatment of moderate to severe acute pain. Even in the young, the use of opioids can be associated with an increased incidence of post-operative complications such as respiratory depression, vomiting, pruritus, excessive sedation, slowing of gastrointestinal function, and urinary retention. The need to manage acute pain in the older patient is becoming more common as the population ages, and increasingly older patients are undergoing more major surgery. Medical conditions are more common in older people and can result in the requirement of systemic analgesia for fractures, malignancy, nociceptive or neuropathic pain and peripheral vascular disease. Effective pain control can be difficult in older patients as there is a higher incidence of coexistent diseases, polypharmacy and age-related changes in physiology, pharmacodynamics and pharmacokinetics. Consequently, due to the fear of respiratory depression in older people, this leads to inadequate doses of opioid being given for the treatment of their pain. Lidocaine has analgesic, anti-hyperalgesic and anti-inflammatory properties and is metabolized by the liver which is limited by perfusion, and heart failure or drugs can alter this, affecting its clearance. Therefore, there are concerns regarding safety in older patients as plasma concentrations have both intersubject and intrasubject variability. The aim of this literature review is to assess the efficacy and safety of intravenous lidocaine as an adjuvant in pain management for the older patient. In total, 12 studies fulfilled the criteria. Lidocaine infusions were found to reduce pain scores and be opioid sparing in abdominal and urological surgery, in patients with opioid-refractory malignancy pain, neuropathic pain and critical limb ischaemia. Patients with malignancy were more likely to develop adverse effects, but no patients required treatment for lidocaine toxicity.