Table 1.

Characteristics of intravenous ketamine studies in patients with complex regional pain syndrome (primary analyses only)

Study and Year	Study Design	Sample Size	Setting	Drug	Infusion Rate	Treatment Duration, d	Duration of Pain Relief	Percent Responders	Definition of Responder	Medications to Control Side Effects
Correll et al, 75 2004	Retrospective chart review	33	Inpatient	Racemic ketamine	10–50 mg/h	4.7	9.44 mo (mean duration of being pain free)	54	“Pain free” for ≥3 mo	Not reported
Goebel et al, 76 2015	Open-label single-arm study	5	Inpatient	Racemic ketamine	0.15–0.9 mg/kg/h	5	6.7 wk (mean duration of “meaningful” pain relief)	20	“Meaningful” relief at 3 mo	Not reported
Goldberg et al, 77 2010	Open-label single-arm study	16	Inpatient	Racemic ketamine	10–40 mg/h	5	—	60	“Meaningful pain relief” at 3 mo	Midazolam 2–4 mg intravenous (IV) q4h for restlessness, dysphoria, or hallucination, transdermal clonidine 0.1 mg/day
Kiefer et al, 51 2008	Open-label single-arm study	20	Inpatient (intensive care)	Racemic ketamine	3–7 mg/kg/h	5	—	65	"Full remission" at 3 mo	Midazolam 0.15–0.4 mg/kg/h IV, clonidine 0.2–0.85 μg/kg/h IV
Mangnus et al, 56 2021	Retrospective chart review	48	Inpatient	S(+)-ketamine	3–14 mg/h	7	—	48	Reduction of ≥2 points on the 0–10 Numeric Rating Scale pain scale at first follow-up (median 4 wk)	None (ketamine dose was reduced until side effects abated)
Schwartzman et al, 18 2009	Randomized placebo-controlled trial	26	Out patient	Racemic ketamine	0.175–0.35 mg/kg/h	10	Up to 12 mo (significant decrease compared with placebo)	—	—	Midazolam 2 mg IV before and after infusion, clonidine 0.1 mg PO before infusion
Sigtermans et al, 19 2009	Randomized placebo-controlled trial	60	Inpatient	S(+)-ketamine	0.072–0.432 mg/kg/h	4.2	11 wk (significant decrease compared with placebo)	—	—	None (ketamine dose was reduced until side effects abated)