Anxious, reactive pets need serious help. Research-based behavior modifications are essential in nearly every case but a prefrontal cortex that’s overwhelmed by excitatory neurotransmitters just can’t learn healthy behaviors. It’s our job to make that possible. Pharmaceuticals are generally necessary for severe disorders but neutraceuticals, herbs, or supplements can be effective in some cases.

Clients should be made aware that manufacturers of prescription medications are required to provide substantial research in order to gain FDA approval. It is not necessary for makers of supplements to provide evidence to substantiate their efficacy.

Tryptophan is an essential amino acid involved in the production of niacin, serotonin and melatonin. There have been some positive results in humans with behavior disorders associated with low serotonin but no significant research in pets. Some human studies have shown that diets low in tryptophan may contribute to anger, depression, and aggression while an increase in dietary tryptophan may promote feelings of well-being. Incorrect dosing can be dangerous in pets. Royal Canin Calm Diets (canine and feline) are supplemented with safe amounts of tryptophan.

5-HTP (5-hydroxytryptophan) is a tryptophan metabolite that is decarboxylated by the liver to form serotonin (5-HT). Supplementation can increase serum serotonin resulting in reduced anxiety. 5-HTP supplements may lead to diarrhea and heart problems while only slightly increasing brain serotonin.
Starting dose: Dogs: 1-2 mg/kg sid. Some veterinary behaviorists have gone as high as 5 mg/kg sid. Results vary by individual. Be careful with dosing.

SAMe (s-adenosyl methionine) is an endogenous molecule found in virtually all physical systems. Its antidepressant effects are a result of increased serotonin turnover and increases in dopamine and norepinephrine. There are no contraindications for SAMe in dogs but it can contribute to serotonin syndrome. SAMe can cause GI side effects, insomnia, and anxiety. Administer on an empty stomach 1 hour prior to feeding or at least 2 hours after. Dogs: 18 – 20 mg/kg sid. Cats: 200 mg/cat sid.

St. John’s Wort (hypericum perforatum) inhibits the reuptake of glutamate, GABA, serotonin, dopamine, and norepinephrine. It is primarily used to treat depression in humans. Some studies show similar efficacy to SSRIs and TCAs with a comparable rate of side effects. Drug interactions occur when St. Johns Wort is used with antidepressants, cyclosporine, digoxin, and many others. There are many formulations. Dosing is not standardized.

Serotonin syndrome is a potentially severe consequence if a supplement’s dose is excessive or if it’s added to serotonergic drugs like SSRIs, TCAs, trazodone, tramadol, buspirone, or the supplement St. John’s Wort. Discuss signs of serotonin syndrome with clients when considering serotonergic supplements.

Melatonin is a dopamine inhibiting, free radical scavenger important for regulating circadian rhythms. Melatonin may potentiate the effects of benzodiazepines. Side effects are rare in dogs. It can be used for phobias, separation anxiety, and sleep cycle disorders of cats and geriatric dogs. Dosing: Dogs: 3 – 6 mg/dog sid –bid or 0.1 mg/kg tid; Cats: 3 – 12 mg/cat sid –bid.

Anxitane (l-theanine) is an amino acid found in green tea, which is thought to increase GABA, serotonin, and dopamine in the brain. There is some weak scientific data supporting its use in dogs and cats for mild anxiety. Along with flower essences l-theanine is also found in the supplement Solliquin.

Zylkene (alpha casozepine) is a hydrolyzed milk protein with gabaergic, benzodiazepine-like activity. Helpful for mild-moderate fears and anxieties, Zylkene can be given during the first 30 days of SSRI or TCA use until the primary anxiolytic becomes effective. Zylkene capsules contain maltodextrin, which has a glycemic index 3 times that of table sugar. Treating diabetics with Zylkene is known to destabilize their management.

Adaptil (available as a plug-in diffuser, spray, and collar) is a structural analogue of a canine appeasing maternal pheromone. Adaptil is used for travel anxiety, fears, phobias, and separation anxiety. It can help puppies transition to new homes.

Feliway Classic (available as a plug-in diffuser and spray) is a synthetic analogue of a feline facial pheromone, intended to reduce stress and promote facial marking in place of urine marking. Feliway Classic may also help established cats relax when a new cat is introduced into a household.

Feliway Multi Cat (available as a plug-in diffuser) is a synthetic analog of a pheromone produced by lactating queens. Feliway Multi Cat is intended to decrease tension and conflict in multiple cat households.

Pheromones should not be considered effective as a sole treatment except in minor cases.

I hope this information is helpful to you, your clients, and their pets.

All the best,
Jeff Nichol, D.V.M.
Residency trained by the American College of Veterinary Behaviorists
Veterinary Emergency and Specialty Centers in Albuquerque and Santa Fe

I invite you to peruse and use any of the information from this and past nmvetlist missives. You will find the entire archive on the For Veterinarians page of my website,