Ketamine Infusion for Refractory Chronic Pain: Who Actually Qualifies
A woman who has tried and failed nearly every standard chronic-pain treatment is being considered for ketamine infusions, a therapy with real reported benefit and no settled protocol for exactly who should get it or how much.
P.N., a 39-year-old woman, developed complex regional pain syndrome in her left foot after a routine ankle fracture repair three years ago — a diagnosis that took nearly a year to reach, during which she says multiple providers told her the pain "should be getting better by now" as the injury itself healed on imaging. She has been through the standard escalation ladder in full: gabapentin, then pregabalin, a lidocaine patch, a course of physical therapy specifically for CRPS desensitization, a sympathetic nerve block that gave her three weeks of partial relief before it wore off, and most recently a bisphosphonate trial that produced no measurable change. She still works part-time as a dental hygienist, cutting her hours nearly in half over the past two years to manage the pain, and describes her current baseline as "constant burning, worse than the break ever was."
Ketamine infusion therapy is the next step her pain specialist is proposing, and the 2018 ASRA/AAPM/ASA consensus guidelines on ketamine for chronic pain — the most authoritative statement on the therapy to date — do support infusion in patients who have genuinely failed standard first-line and second-line treatments, which her chart plainly documents. What the guidelines do not settle is a single protocol: they describe a range of acceptable dosing regimens and infusion durations rather than one fixed formula, and they name psychiatric comorbidity as a factor requiring individualized judgment rather than either automatic exclusion or automatic disregard — a distinction that matters directly for her, since a routine intake screen flagged a PHQ-9 score in the moderate range that has never been formally addressed, buried under three years of a pain workup that never circled back to ask how she was managing emotionally on top of it.
Pain and psychiatry co-consult
She has genuinely failed the standard ladder — first-line, second-line, an interventional block, and a bisphosphonate trial, all documented, all without durable relief. The 2018 ASRA consensus guidelines support ketamine infusion in exactly this picture. Further delay isn't neutral for her; she's already cut her working hours in half over two years, and every month without a therapy that might actually change her trajectory is a real cost, not a safe default.
I'm not arguing against ketamine ever being appropriate for her — I'm flagging that we're about to start a therapy with real dissociative and psychoactive effects on top of a moderate PHQ-9 score that three years of pain workups never circled back to address. If she has an unusually strong reaction, or the infusion doesn't help, we won't know whether that reflects the pain mechanism or an unaddressed mood component the infusion itself may have destabilized.
"She's failed everything else" is true and it's also exactly the situation where untreated depression is most likely to be present and most likely to get missed, precisely because everyone's attention stays on the pain.
You're both reading the same guideline correctly, and it doesn't actually force a choice between "proceed now at standard dose" and "delay until psychiatric workup is finished" — the consensus statement describes a range of acceptable regimens, not one fixed protocol, and it names psychiatric comorbidity as something requiring individualized judgment, not automatic exclusion. A more conservative starting dose, a shorter initial series, and a formal reassessment point built in from the start lets her start now while still respecting what the moderate PHQ-9 score is telling us.
Framing this as choosing between the pain specialist's urgency and the psychiatrist's caution treats the guideline as narrower than it actually is — the range it supports was built for patients whose picture doesn't resolve cleanly into either extreme.
Agreed: a conservative-dose ketamine infusion series, at the lower end of the consensus guideline's dosing range, with concurrent psychiatric follow-up and a formal reassessment checkpoint after the initial shortened series rather than a fixed longer course decided up front. The pharmacologist's reframing — that the guideline's own range supported this without asking either the pain specialist or the psychiatrist to concede their underlying concern — was what both other voices signed onto.
Not agreed: whether her PHQ-9 score, now being formally addressed, should have been caught and addressed years earlier in her pain workup, independent of the ketamine decision. The psychiatrist's view is that this reflects a structural gap in how chronic pain patients get screened; the pain specialist agrees the gap is real but doesn't think it changes anything about today's plan. Both logged the gap as worth raising with the broader pain clinic rather than something either could fix in this one visit.