On May 12, 2026, the FDA Center for Veterinary Medicine granted conditional approval to Liavium-CA1 (pregabalin chewable tablets) for the management of pain and clinical signs associated with Chiari-like malformation (CM) and syringomyelia (SM) in dogs. It is the first drug specifically approved for this indication — a condition that has historically been managed with off-label human medications, most commonly gabapentin.

For the veterinarians and owners who have been cobbling together pain management protocols for CM/SM dogs, this approval introduces a labeled option. But conditional approval carries specific implications that are worth understanding before prescribing or switching from current protocols.

What is Chiari-like malformation and syringomyelia?

Chiari-like malformation is a congenital condition in which a dog's skull is too small for its brain, causing the cerebellum to herniate through the foramen magnum at the base of the skull. This herniation can obstruct cerebrospinal fluid flow, leading to syringomyelia — fluid-filled cavities (syrinxes) within the spinal cord that expand over time and compress nerve fibers.

The result is neuropathic pain that is often severe and difficult to manage. Affected dogs may cry out when their head, neck, or shoulders are touched. Phantom scratching — scratching at the air or neck without making contact — is a hallmark sign. Some dogs develop gait abnormalities, weakness, or difficulty with bowel movements due to increased intracranial pressure.

Cavalier King Charles Spaniels are the most commonly affected breed, but CM/SM also occurs in other brachycephalic toy breeds including Chihuahuas, French Bulldogs, Pugs, Yorkshire Terriers, Maltese, Pomeranians, Boston Terriers, Papillons, Affenpinschers, and Griffon Bruxellois. The condition is analogous to Chiari malformation type 1 in humans.

What Liavium-CA1 is and how it works

Pregabalin, the active ingredient in Liavium-CA1, is a gabapentinoid that binds to voltage-gated calcium channels in the central nervous system, reducing the release of excitatory neurotransmitters involved in pain signaling. In human medicine, pregabalin is approved for neuropathic pain, epilepsy, fibromyalgia, and generalized anxiety disorder.

In veterinary medicine, gabapentin has been the most commonly used gabapentinoid for neuropathic pain in dogs — but it has never been FDA-approved for CM/SM. Liavium-CA1 is the first product with a specific label indication for this condition.

What the label says

Liavium-CA1 is available as beef-flavored chewable tablets in three strengths: 30 mg, 90 mg (scored), and 180 mg. The labeled dose is 5–10 mg/kg administered orally twice daily with food. Dogs under 3 kg (6.6 pounds) cannot be accurately dosed with the available tablet strengths.

The drug is classified as a Schedule V controlled substance due to pregabalin's potential for abuse and dependence in humans. Veterinary prescriptions must comply with applicable controlled substance regulations.

Liavium-CA1 may be administered concurrently with a non-steroidal anti-inflammatory drug (NSAID), according to the label. This is relevant because multimodal analgesia — combining a gabapentinoid with an NSAID and potentially other agents — is the standard approach to neuropathic pain in dogs with CM/SM.

Dosing considerations

The 5–10 mg/kg twice-daily range means that dose selection within that range depends on the individual dog's response and tolerability. Starting at the lower end and titrating upward is consistent with how pregabalin is used in human neuropathic pain management. Any dose adjustment should be made under veterinary supervision — the label is not a universal dosing instruction, and factors including kidney function, concurrent medications, and the severity of clinical signs all influence the appropriate dose for a specific patient.

Because the tablets come in three fixed strengths (30, 90, and 180 mg), precise dosing for very small dogs may be challenging. The 90 mg tablet is scored, which provides some flexibility, but dogs under 3 kg cannot be accurately dosed with any available combination of these tablets.

Adverse reactions

The FOI Summary reports the following adverse reactions observed during the field study:

• Somnolence
• Increased appetite
• Decreased activity
• Increased water consumption (polydipsia)
• Hypothermia
• Ataxia
• Sedation

Most adverse reactions were mild and did not require discontinuation, but the label notes that individual responses vary. Owners should be counseled that sedation and ataxia may occur, particularly during the initial dosing period, and that dose adjustments should be made only under veterinary supervision.

The drug has not been evaluated in dogs with renal disease. Because pregabalin is primarily excreted unchanged by the kidneys in humans, caution is warranted in dogs with compromised renal function. The FOI Summary does not provide specific guidance for renal-impaired patients beyond noting the lack of evaluation.

Conditional approval: what it means

The FDA's conditional approval pathway is reserved for drugs that address a serious or life-threatening condition, represent an unmet animal health need, or require particularly complex studies to demonstrate full effectiveness. The agency determined that Liavium-CA1 meets these criteria because CM/SM is a serious, painful condition with no previously approved treatment, and designing a pivotal effectiveness study for a chronic neuropathic pain condition in dogs is inherently complex.

Conditional approval means the FDA has determined that Liavium-CA1 is safe and has a "reasonable expectation of effectiveness." It is not the same as full approval. TriviumVet, the sponsor (a subsidiary of PBI Gordon Companies, based in Ireland), has up to five years to generate the additional effectiveness data needed to support a full FDA approval. During this period, the drug can be prescribed and sold commercially.

The company is currently conducting the LUNA Study, the pivotal effectiveness trial that will form the basis of its full approval application. Veterinarians and owners should be aware that if the LUNA Study fails to demonstrate effectiveness to the FDA's standards, the conditional approval could be withdrawn.

How this fits with existing treatment options

Before Liavium-CA1, management of CM/SM in dogs relied on:

• Gabapentin (off-label): the most commonly prescribed gabapentinoid for neuropathic pain in veterinary medicine. While widely used, gabapentin has never been formally evaluated or approved for CM/SM. It has different pharmacokinetics from pregabalin — lower bioavailability, shorter half-life, and more variable absorption.

• NSAIDs: meloxicam, carprofen, robenacoxib, and others, typically used as adjunctive therapy to address inflammatory components of pain.

• Corticosteroids: prednisone or prednisolone, sometimes used for flare management but limited by long-term side effects including polyuria, polydipsia, polyphagia, and immunosuppression.

• Opioids: tramadol is sometimes used, though evidence for its efficacy in canine neuropathic pain is weak, and its serotonin and norepinephrine reuptake inhibition may not address the primary gabapentinoid-responsive pain mechanism.

• Surgical decompression: for cases with severe and progressive clinical signs, surgical decompression of the caudal cranial fossa (foramen magnum decompression) can reduce syrinx size and improve pain control. However, the evidence comparing surgery to medical management is limited, and surgery carries inherent risks including scar tissue formation, continued syrinx progression, and perioperative complications.

A crossover trial by Sanchis-Mora and colleagues in 2019 evaluated pregabalin in eight dogs with CM/SM and found improvements in pain scores when combined with an NSAID. This small study contributed to the evidence base that supported the conditional approval.

Liavium-CA1 does not replace surgical evaluation for severe cases. It does provide the first labeled pharmaceutical tool specifically for this condition, which may improve consistency of care and simplify the conversation between veterinarians and owners about treatment options.

What to ask your veterinarian

If your dog has been diagnosed with or is suspected of having Chiari-like malformation or syringomyelia, the following questions may help guide the conversation with your veterinarian:

• Is my dog a candidate for Liavium-CA1, or does the severity of the condition warrant surgical evaluation first?
• What dose is appropriate for my dog's weight, and which tablet strength will be used?
• Should Liavium-CA1 be combined with an NSAID, and if so, which one?
• What adverse reactions should I watch for, and when should I contact you if they occur?
• How will we assess whether the medication is working? What does a successful response look like?
• Is my dog's kidney function adequate for this medication?
• Are there any controlled substance regulations I should be aware of when filling this prescription?
• What happens if the conditional approval is not converted to full approval — will the medication remain available?

Sources

• FDA CVM. FDA Conditionally Approves Drug to Control Pain and Clinical Signs of Chiari-Like Malformation and Syringomyelia in Dogs. May 12, 2026. https://www.fda.gov/animal-veterinary/cvm-updates/fda-conditionally-approves-drug-control-pain-and-clinical-signs-chiari-malformation-and
• FDA FOI Summary, NADA 141-606. Liavium-CA1 (pregabalin chewable tablets). May 12, 2026. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/18446
• TriviumVet. TriviumVet Receives FDA Conditional Approval for Liavium-CA1. May 2026. https://www.triviumvet.com/blog/triviumvet-receives-fda-conditional-approval-for-liavium-ca1-the-first-drug-approved-to-manage-pain-and-clinical-signs-of-chiari-like-malformation-and-syrin-1779806489882
• dvm360. FDA grants conditional approval to targeted therapy for canine Chiari-like malformation and syringomyelia. 2026. https://www.dvm360.com/view/fda-grants-conditional-approval-to-targeted-therapy-for-canine-chiari-like-malformation-and-syringomyelia
• Sanchis-Mora C, et al. Pregabalin for management of neuropathic pain in dogs with Chiari-like malformation and syringomyelia. https://pmc.ncbi.nlm.nih.gov/articles/PMC11359979/
• Royal Canin Academy. Chiari-like malformation and syringomyelia in dogs. https://academy.royalcanin.com/en/veterinary/chiari-like-malformation-and-syringomyelia