Effects of low‐dose intranasal (S)‐ketamine in patients with neuropathic pain

Abstract

Intranasal administration of low dose (S)-ketamine rapidly induces adequate plasma concentrations of (S)-ketamine and subsequently of its metabolite (S)-norketamine. The time course of analgesia correlated with plasma concentrations.

Intranasal ketamine for the treatment of patients with acute pain in the emergency department

“…Intranasal delivery of pain medication is an attractive, convenient, efficient, cheap and rapid form of pain control in the ED where time, manpower, space and proper monitoring to all patients with pain are not feasible, especially in the setting where IV initiation or opioid administration exists. Researchers [11,12] have reported that the nose-brain pathway leads to a rapid delivery of some nasal medications across the olfactory mucosa to the cerebral spinal fluid and the brain, bypassing the first pass metabolism and the blood brain barrier.…”

“…Current evidence suggests that IN ketamine is an effective safe and well tolerated method of analgesia in burn dressing [13] and pediatric laceration repair, [14] in control of post-operative pain [2] and neuropathic pain, [12] and in prehospital setting [15] and the ED. [5][6][7] In 1996 Kulbe et al [13] published a case report confi rming that intranasal ketamine spray can be effective for acute pain control during burn dressing changes, suggesting this was an area that deserved further investigation.…”

“…Carr et al [16] found that doses of up to 50 mg of IN ketamine were effective in many patients with uncontrollable pain (mean pain score reductions of about 23 mm on a 100 mm VAS), and detectable blood level was noted after 2 minutes, which peaked at 30 minutes. Another study [12] investigated the pharmacokinetics of low doses of intranasal ketamine as well as its impact on pain control and the resulting side effects which demonstrated a measurable impact on pain control within 15 minutes and peaked at 60 minutes, lasting several hours. Christensen et al [2] investigated intranasal ketamine for treating post-operative pain following wisdom tooth removal and found that meaningful pain relief was achieved by 14 minutes in 70% of patients receiving a 50 mg dose of IN ketamine.…”

The Use of Ketamine in Neuropathic Pain

“…There are at least 9 randomized, double-blind trials demonstrating the efficacy of ketamine in NP [66][67][68][69][70][71][72][73][74][75]. In patients with post-nerve injury NP, ketamine administered IV has shown significant reduction in pain and allodynia as compared to placebo [66-70, 73, 74] as well as compared to morphine [73].…”

“…Intranasal use of the more potent enatiomer (S) ketamine at doses of 0.2 and 0.4 mg/kg was studied in 16 patients with NP and showed a significant reduction in NP that was dose-dependent, lasting 2-3 h with maximum pain reduction of 30-40 % at 50 min after application [72]. The two randomized, double-blind, placebo-controlled studies on topical administration of ketamine did not show efficacy in the treatment of peripheral NP with no effect from ketamine 1 % topical cream applied three times daily for 3 weeks in 92 patients with peripheral NP [76] or when ketamine 5 % topical cream was applied for 1 month in 17 patients with diabetic peripheral neuropathy [75].…”