Neuropathic Pain is a term referred to “pain arising as a direct consequence of a lesion affecting the somatosensory system”. As a first line option, oral medications are mostly used, as they are easily available, relatively safe, and do not need much resources. They include antidepressants in the form of tricyclics, newer selective reuptake inhibitors of serotonin and norepinephrine, gabapentin, pregabalin etc. Although neuropathic pain conditions do share some common clinical features, they are quite diverse when considered individually according to their etiology and pathogenesis. Hence not all patients and not all types of neuropathic pain respond to such oral therapy
Complex Regional Pain Syndrome Type 1 (CRPS-1) responds poorly to standard pain treatment. We evaluated if the N-methyl-D-aspartate receptor antagonist S(+)-ketamine improves pain in CRPS-1 patients. Sixty CRPS-1 patients (48 females) with severe pain participated in a double-blind randomized placebo-controlled parallel-group trial. Patients were given a 4.2-day intravenous infusion of low-dose ketamine (n = 30) or placebo (n = 30) using an individualized stepwise tailoring of dosage based on effect (pain relief) and side effects (nausea/vomiting/psychomimetic effects).
Ketamine has demonstrated usefulness as an analgesic to treat nonresponsive neuropathic pain; however, it is not widely administered to outpatients due to fear of such side effects as hallucinations and other cognitive disturbances. This retrospective chart review is the first research to study the safety and efficacy of prolonged low-dose, continuous intravenous (IV) or subcutaneous ketamine infusions in noncancer outpatients.