In dogs with chronic spinal cord injury, does 4-aminopyridine vs placebo improve gait scores? — POSSIBLE

In dogs with chronic spinal cord injury, does 4-aminopyridine vs placebo improve gait scores?

Shelf #452 · gate-verified and displayed under the developer's blinded-trial rule

POSSIBLE: One blinded, placebo-controlled cross-over trial answers this question in chronically non-ambulatory dogs. In Lim 2014 (PMID: 25551385), 19 dogs were enrolled and 13 completed the protocol; on 4-aminopyridine (4-AP) the supported stepping score rose from 17.39% to 37.24% and the open field gait score (OFS) rose from 3.63 to 4.73 (stepping P < 0.0001 and OFS P = 0.005 for the treatment effect, as reported), but unsupported stepping stayed at or close to zero in 16 dogs — only 3 dogs progressed to independent unsupported stepping. Design class (a): randomised + blinded established by this carded record answering the shelf's own comparison and population — dogs were randomized to one of two treatment groups by the North Carolina State University College of Veterinary Medicine pharmacy (using random.org), investigators and owners were blinded to treatment group, and, from the full text (PMC4281252), video clips were identified with randomly generated numbers so that the two scorers (J-HL and NJO) were blinded to treatment period when scoring gait. Tier C adjudication: Tier C is NOT engaged — the primary claims are gait scores, not a mortality, fetal-loss or survival-primary benefit claim; two dogs were euthanized for unrelated health problems, which is not an efficacy claim, so the Tier C guess of No stands. Near-misses NOT carded: PMID: 30235970 (Lewis 2019 — a predictor analysis of response to a single 4-AP administration in 34 dogs, 15/33 responders, with no placebo or control group; it does not test 4-AP vs placebo); PMID: 1870134 (Blight 1991 — a phase I clinical trial of 4-AP in 39 chronically paraplegic/paraparetic dogs with no placebo or comparator group); PMID: 34438900 (Martins 2021 — a multimodal neurorehabilitation case series of 16 dogs in which 4-AP was only one component, with no control group); PMID: 33195591 (a review of emerging therapies for acute intervertebral disc herniation, no new primary data). No narrowing was needed, with one disclosure on the face: the carded trial co-tested a t-butyl carbamate derivative of 4-AP in the same cross-over, and the card reports the 4-AP figures specifically; its population was dogs left chronically non-ambulatory by an acute spinal cord injury. Searches run (PubMed, this session): '4-aminopyridine dogs spinal cord injury chronic' — count 5; '4-aminopyridine dogs gait spinal' — count 2; 'fampridine dogs spinal cord injury' — count 8; '4-aminopyridine placebo dogs spinal cord' — count 1; 'aminopyridine chronically paralyzed dogs placebo controlled' — count 1. Drafted Nov 10, 2026 (VetMed build, topic #452); figures from the records fetched and verified at drafting.

Lim 2014: 4-aminopyridine improved supported stepping (17.39% to 37.24%) and open field gait score (3.63 to 4.73) vs control periods in chronically non-ambulatory dogs, but most dogs still could not step unsupported

Blinded, placebo-controlled trial (record's own title wording; cross-over design; PubMed publication type: Randomized Controlled Trial)

Who: Dogs: 19 dogs that had suffered an acute spinal cord injury that left them chronically paralyzed (chronically non-ambulatory), entered into a blinded, placebo-controlled cross-over trial conducted in two-week treatment blocks: placebo first, followed by random assignment to 4-aminopyridine (4-AP) or its t-butyl carbamate derivative (t-butyl), a washout, then the opposite medication, followed by placebo. Dogs were randomized to one of two treatment groups by the North Carolina State University College of Veterinary Medicine pharmacy (using random.org); investigators and owners were blinded to treatment group. Thirteen of 19 dogs completed the protocol.

Result: Dogs showed significant improvement in supported stepping score (from 17.39 to 37.24% with 4-AP; 16.85 to 29.18% with t-butyl; P < 0.0001) and open field gait score (OFS; from 3.63 to 4.73 with 4-AP; 3.78 to 4.45 with t-butyl; P = 0.005). For 4-AP specifically, the full-text outcome table gives control-period vs 4-AP means (SD): OFS 3.63 (2.10) vs 4.73 (1.42) on a 0-13 scale, and supported stepping score 17.39 (13.57) vs 37.24 (20.94). No significant difference was found between 4-AP and t-butyl. Response was individually variable: in the full text, 5 dogs showed no change in supported stepping while the remaining 14 improved, and when unsupported on the treadmill 16 dogs were still unable to generate any weight-bearing steps with either treatment, while 3 dogs improved to independent stepping (2 responded to both drugs and 1 to 4-AP alone). No adverse effects were reported with t-butyl, but gastrointestinal upset and seizures were observed in two dogs with 4-AP.

Watch out: Small and incomplete: 19 dogs enrolled, only 13 completed (2 euthanized for unrelated health problems, 2 removed for possible adverse effects on 4-AP, 2 unable to complete for unrelated reasons). The demonstrated gain is in supported stepping and a 1.1-point mean OFS gain — most dogs remained unable to step unsupported — and 4-AP carried seizures in one dog and severe gastrointestinal upset in another. The trial co-tested the t-butyl derivative, so the treatment-effect P values are reported for the potassium-channel-antagonist comparison as a whole in the abstract, with drug-specific means in the full-text table.

Lim JH, Muguet-Chanoit AC, Smith DT, Laber E, Olby NJ. Potassium channel antagonists 4-aminopyridine and the T-butyl carbamate derivative of 4-aminopyridine improve hind limb function in chronically non-ambulatory dogs; a blinded, placebo-controlled trial. PLoS One. 2014;9(12):e116139. PMID: 25551385. Registry ID: none in the record. MeSH: 4-Aminopyridine/adverse effects, analogs & derivatives, therapeutic use* · Animals · Demyelinating Diseases/drug therapy · Dogs · Double-Blind Method · Female · Gait/drug effects · Hindlimb/physiopathology · Lameness, Animal/drug therapy* · Male · Paralysis/drug therapy* · Placebos/therapeutic use · Potassium Channel Blockers/therapeutic use* · Spinal Cord Injuries/drug therapy* · Treatment Outcome · Walking/physiology

Synthesis: a single small randomised, blinded cross-over trial shows 4-AP improves supported gait scores, not unsupported walking for most dogs

Synthesis

Who: Synthesis of the card above: Lim 2014, the single trial on this shelf — a blinded, placebo-controlled cross-over trial in 19 chronically non-ambulatory dogs after acute spinal cord injury (13 completed), randomised by the university pharmacy with investigators, owners and video scorers blinded to treatment.

Result: On 4-AP, supported stepping score rose from 17.39% to 37.24% and open field gait score from 3.63 to 4.73 (treatment effect P < 0.0001 and P = 0.005 respectively, as reported), a real but modest gait-score gain. The limit is equally clear: unsupported stepping remained at or near zero in 16 of 19 dogs, only 3 dogs reached independent stepping, and response ranged from no change (5 dogs, supported stepping) to large gains. That mix — a rigorous design, a significant supported-gait effect, a small sample with dropouts, and no restoration of unsupported walking for most dogs — is why the stamp is POSSIBLE rather than LIKELY. No mortality or survival benefit is claimed, so the pack is not Tier C.

Watch out: This shelf has no second trial and no parallel-group placebo trial: the evidence is one cross-over study in severely affected, chronically non-ambulatory dogs, and it does not speak to dogs that are still ambulatory or to acute-phase spinal cord injury (the acute methylprednisolone question is homed separately on shelf #450).

Synthesis of Lim JH et al. PMID: 25551385. Registry ID as on the individual card.

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