Use of atypical analgesics by intravenous infusion (IV) for acute pain: evidence base for lidocaine, ketamine and magnesium

Atypical analgesics include antiepileptics and other membrane stabilizers (lidocaine and mexiletine), antidepressants, α-2-noradrenergic agonists, N-methyl-D-aspartate (NMDA) antagonists, corticosteroids and cannabinoids. This review will focus on three drugs commonly infused as co-analgesics. We will review the theoretical mechanisms of action, efficacy and clinical effectiveness of lidocaine, ketamine and magnesium. The evidence base supporting their use has expanded in recent years and is discussed below.