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Solensia™ for Cats & Librela™ for Dogs: Side Effects & How Lion’s Mane Mushroom Could Help

Solensia™ for Cats & Librela™ for Dogs: Side Effects & How Lion’s Mane Mushroom Could Help cover
Written by Dr. Rob Silver DVM, MS - Updated: June 11, 2024

Librela™ and Solensia™ are new pharmaceuticals for osteoarthritis (OA) in dogs and cats, respectively (1,2). These drugs use monoclonal antibodies (MAB) as their mechanism of action to bind up a specific molecule involved in the pain associated with arthritis in dogs and cats.

The original research that was part of gaining FDA approval of Solensia™ and Librela™ for dogs, had pretty good rates of success in reducing pain with minimal side effects. The medication is also very convenient in that only 1 injection monthly is needed to achieve relief from the pain of osteoarthritis.

Unfortunately, as is often the case with FDA-approved drugs, the true test of the drug’s effectiveness and side effects comes when the drug becomes widely used through its availability in the marketplace. This has proven true for both Librela™ and Solensia™, where some serious side effects have been noted by several pet parents and veterinarians.

This article will help pet parents understand some of the possible risks associated with these pharmaceuticals. Further, it will suggest how a natural intervention of Lion’s Mane mushroom supplementation could be used to reverse some of the serious side effects if they occur.

dog with owner at the vet
Serious concerns arise among pet parents about MAB drug side effects. From ataxia to seizures and hypersensitivity reactions, the impact is alarming.

How Solensia™ and Librela™ Work

Researchers created monoclonal antibodies through genetic manipulation of yeast that are specific for the molecule involved with osteoarthritic pain. The molecule that Solensia™ and Librela™ acts upon is called nerve growth factor (NGF). When NGF binds to a specific membrane receptor, pain, and impaired mobility result. The antibodies in the Solensia™ and Librela™ injections prevent nerve growth factor from binding to the receptor responsible for OA pain, therefore preventing that pain from occurring.

The monoclonal antibodies have been hailed as a breakthrough in the treatment of arthritis in dogs and cats, and a similar product has been created for people with OA. The good thing about this form of medication is that it does not pose a risk of toxicity to the liver, kidney, or heart as our current arthritis medications have that potential. Therefore these medications have the potential to help pets in pain and restore some of their mobility without the typical risk to the liver, kidney, or heart.

Common Side Effects of Solensia™ and Librela™ for Dogs and Cats

Pet parents have been observing that some pets who are on these MAB drugs have very serious and concerning side effects. Some dogs are experiencing neurologic problems, like being unsteady on their feet (ataxia). Other dogs have experienced seizures following the Librela™ injection. Still others have developed hypersensitivity-like reactions (anaphylaxis, pruritus, facial swelling).

Other side effects that can potentially arise from the use of these two MAB drugs for arthritis in dogs and cats are (3):

  • Lethargy
  • Drooling
  • Shaking
  • Behavior changes
  • Hiding
  • Urinary incontinence
  • Inappetence
  • Increased or decreased thirst
  • Hind-end weakness
  • Inability to walk
  • New or worsened seizures
  • Organ damage

There is no published, peer-reviewed paper describing these side effects in dogs. There is one published, peer-reviewed paper detailing reported side effects observed with the use of Solensia™ in cats (4). This MAB for cats was launched several years before the launching of Librela™. This is why we have this adverse event paper for cats. Hopefully, a publication regarding the side effects in dogs will be published soon.

The side effects, specifically found in the 5 cats included in this feline medicine paper, were limited to dermatological lesions that were described as:

  • Moderate to severe pruritus (scratching) resulting in self-trauma to the neck and/or head
  • Superficial dermatitis
  • Alopecia (hair loss)
  • Ulcerations of the skin secondary to self-trauma
  • No reactions at the injection site
  • Eczema
dog examination with veterinarian
Understanding the impact of Nerve Growth Factor (NGF) on our pets' nervous and immune systems sheds light on observed adverse reactions. From increased nerve sensitivity to seizures and inflammation, the effects are concerning.

Adverse reactions have been observed in humans using MAB injections for osteoarthritis. People complain of hyperesthesia (increased nerve sensitivity); and paraesthesia (feels like pins and needles, skin crawling, numbness, or itching). Also, a burning sensation has been described by people taking the MAB injections. If these kinds of side effects are what some cats are also feeling following the Solensia™ injections, you can understand why they would be scratching themselves sore.

Why do some of these side effects occur?

Nerve growth factor (NGF) is a very important chemical messenger in mammals, including people, and our beloved dogs and cats. NGF works in part on sensory nerves, which “sense” the pain. It has an influence, not just on the nervous system, but also on the immune system. In the nervous system, the effects of NGF influence the survival of nerves and the growth of nerves. This may be why one of the side effects noted from Librela™ are seizures and weakness.

NGF is involved in the inflammatory process and can play a role in reducing inflammation. Certain nerves that produce the neurotransmitter acetylcholine depend on NGF for survival and maintenance. This may be another reason why certain adverse symptoms have been observed with Librela™. If there is a sudden loss of NGF due to it being bound up by the antibodies of Librela™, there may be a dramatic increase in inflammation due to the loss of this neurotransmitter. This effect may also influence movement difficulty, weakness, and seizures.

How Lion’s Mane Mushroom Could Help Address the Side Effects of Solensia™ and Librela™ for Dogs and Cats

Lion’s mane mushroom contains terpenes and other molecules that stimulate the production of NGF. In particular, it stimulates the production of a specific NGF found in the central nervous system called brain-derived NGF or bNGF. The possibility exists that using lion’s mane mushroom supplementation for dogs concurrently with the use of Librela™, or in the event of an adverse side effect, might reduce the development of side effects or allow the dog (or cat) to overcome those side effects.

Real Mushrooms Lion's Mane Powder
Could Lion's Mane mushroom hold the key to mitigating adverse reactions to drugs like Librela™ and Solensia™ in pets? While still in experimental phases, its potential influence on NGF levels offers hope for managing side effects.

This theory has not been tested in an objective study, but does seem like a potential antidote to these adverse reactions to both Librela™ and Solensia™. In consultation with plant pharmacologist Kevin Spelman, Ph.D., who has co-authored a peer-reviewed paper on the pharmacology of lion’s mane, he expressed that using lion’s mane with its influence on NGF levels has the potential to be helpful (5). Dr. Spelman said that pet parents who want to give lion’s mane mushroom extract to their dog or cat would likely need to give relatively high doses. Also, it could take up to 4 weeks (or possibly more) to achieve any benefits. It is important to understand that at this point, the use of lion’s mane mushroom to help with the side effects of Librela™ or Solensia™ is still in the experimental phase.

Concluding Remarks

Monoclonal antibodies are a new pharmaceutical technology to address different problems, such as cancer, atopy, and now, arthritis. Although the technology promises a less toxic medication in terms of adverse effects on the kidneys and liver, a whole new set of problems now exist with this newly emerged category of drug.

MAB drugs are quite specific for certain protein molecules associated with a disease condition. But, because these molecules are also involved in other bodily processes, their loss due to the monoclonal antibodies binding them up, may cause unexpected adverse effects in other systems, as we have seen with both Librela and Solensia.

Due to the effect of Librela™ and Solensia™ on reducing the serum and tissue levels of NGF, there is a lot of interest in the NGF-stimulating properties of lion’s mane mushroom for addressing this problem. In all likelihood, if lion’s mane supplementation were able to help, it would take fairly significant amounts used over a fairly prolonged period, possibly on the order of 1-3 months.

Pet parents need to learn that there are possible adverse side effects of these two new MABs for osteoarthritis to make an informed decision regarding the use of an MAB for their furry friend.

Facebook Groups dedicated to Librela™ and its adverse effects:

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  1. Corral, MJ, Moyaert H, Fernandes, T., et al. A prospective, randomized, blinded, placebo-controlled multisite clinical study of bedinvetmab, a canine monoclonal antibody targeting nerve growth factor, in dogs with osteoarthritis. Veterinary Anesthesia and Analgesia, 2021, 48, 943-955.
  2. Gruen, ME, Myers, JAE, et al. Frunevetmab, a felinized anti-nerve growth factor monoclonal antibody, for the treatment of pain from osteoarthritis in cats. Journal of Veterinary Internal Medicine 2021;35(6):2752-2762.
  3. Bassingthwaighte E.  Librela (Beransa) – Wonder drug or disaster in the making?  Dogs Naturally.  October 31, 2023.  Accessed on February 15, 2024 at
  4. Storrer, A, Mackie, J, Gunew, MN, Aslan, J. Cutaneous lesions and clinical outcomes in 5 cats after Frunevetmab injections; 2023 J. Feline Med and Surgery; doi:10.1177/1098612X231198416
  5. Spelman, K., Sutherland, E., and Bagade A. Neurological Activity of Lion’s Mane (Hericium erinaceus); J Restorative Med (2017)6:19-26.

Dr. Robert Silver graduated in 1982 from Colorado State’s College of Veterinary Medicine. He established one of the first integrative vet clinics in the USA in Boulder, CO in 1993. Since then, Dr. Silver has become a nationally recognized expert in veterinary herbal and nutraceutical medicines, medicinal mushrooms, veterinary CBD and cannabis therapeutics. He has adjunct faculty positions at Lincoln Memorial University, College of Veterinary Medicine, and Chi University, a College of Traditional Chinese Veterinary Medicine. Learn more about Dr. Silver.

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