By Dr. Michelle Frye, DVM · Published 2026-05-01
TL;DR. Trazodone is a serotonin-modulating sedative used in dogs and cats for situational anxiety, post-op rest, and the existential horror that is a car ride. Onset 30–90 minutes. Effect lasts 6–10 hours. Trial-dose at home before the storm/vet visit/in-laws. Not a painkiller.
The Dog Who Has Decided Today Is a Disaster
You knew the storm was coming. The dog also knew. Dogs always know. By 4 p.m. she was already pacing, by 6 she was wedged behind the toilet, and by midnight she was attempting to chew through your bedroom door because thunder is, in her view, the end of the world. You thought about closing the windows. You thought about a Thundershirt. You thought, briefly and unkindly, about renting a hotel room for yourself.
This is the situation trazodone was made for. It will not stop the thunderstorm. It will not stop her opinions about thunderstorms. What it will do is take the edge off enough that the door is still attached at 6 a.m.
What Trazodone Actually Does
Trazodone is a serotonin antagonist and reuptake inhibitor (SARI) borrowed from human medicine. In dogs and cats it acts as a fast-onset, short-duration sedative and anxiolytic.
- Onset: 30–90 minutes after an oral dose.
- Duration: 6–10 hours.
- Typical dog dose: 3–7 mg/kg for situational anxiety; some patients tolerate higher.
- Typical cat dose: 50–100 mg per cat, given 90 minutes before the event.
- Half-life: short. Daily build-up is minimal; this is a dose-as-needed drug for most patients.
Trazodone does not provide pain relief. It is regularly combined with an NSAID and/or gabapentin during post-op crate rest because keeping a TPLO patient from re-injuring her surgical knee is otherwise a sport.
Things People Are Wrong About
Myth 1: "It will make her a zombie." The right dose makes a dog calm, not unconscious. If your dog is staggering or slack-jawed, the dose is too high — trial it at home before the actual stressful event.
Myth 2: "It builds up in the system." Half-life is short. Most patients get the same effect on day 30 as on day 1. This is not benzodiazepine-style accumulation.
Myth 3: "My dog can take Xanax instead, it's the same." Different drug class, different mechanism. Benzodiazepines (alprazolam, diazepam) cause paradoxical excitation in some dogs and disinhibit aggression in some. Trazodone is generally a cleaner sedative.
Myth 4: "Cats can't have it." They can, and many of mine do, especially the carrier-haters. The dose is different and the math matters.
When NOT to Use Trazodone
Avoid in pets already on serotonergic drugs (fluoxetine, sertraline, tramadol, certain MAOIs) without veterinary supervision — serotonin syndrome is rare but real. Reduce the dose in pets with significant liver or heart disease. Stop and call your vet if your pet becomes more agitated rather than calmer; about 1–2% of dogs paradoxically wind up. Not a substitute for a behavior plan in pets with chronic anxiety.
What I Tell Owners After 30 Years
Trazodone is one of the great quality-of-life drugs in small-animal practice. It has saved countless veterinary appointments from being traumatic, countless post-op recoveries from re-injury, and countless owner-pet relationships from the slow erosion of fireworks night. Trial the dose at home a week before you need it. Know what "too sedated" looks like for your individual dog. And accept that your cat will still hate the carrier — she'll just hate it from a slightly more reposed place.
Frequently Asked Questions
How long does trazodone take to work in dogs?
Trazodone reaches peak effect 60–90 minutes after an oral dose, with onset of calming around 30 minutes. For pre-event use (vet visits, storms), give 90 minutes ahead.
How much trazodone can I give my dog?
Typical situational dosing is 3–7 mg/kg by mouth, with some patients dosed higher under veterinary direction. Always start with the lowest dose your veterinarian prescribes and trial it at home first.
Can cats take trazodone?
Yes. The typical cat dose is 50–100 mg per cat given 90 minutes before a vet visit, car ride, or stressful event. Cats tolerate it well in most cases.
How long does trazodone last?
The sedative effect typically lasts 6–10 hours in dogs and cats. A second dose may be appropriate for prolonged events under veterinary direction.
Is trazodone safe long-term?
Daily long-term use is reasonable for chronically anxious patients under veterinary supervision, with periodic bloodwork. Most patients use it situationally.
Can I give trazodone with gabapentin?
Yes, and it is a common combination — the two work through different mechanisms and pair safely. Many pre-vet-visit "chill protocols" combine the two.
What are the side effects of trazodone in dogs?
Common side effects are sedation, mild GI upset, and occasional disinhibition (a paradoxical increase in excitement). Rare side effects include ataxia and serotonin syndrome when combined with other serotonergic drugs.
Where can I buy trazodone for my dog?
Trazodone is prescription-only. Smarty Vets verifies your prescription and ships from a licensed pharmacy.
This article is for educational purposes and is not a substitute for veterinary advice. Always consult your veterinarian before starting, stopping, or changing any medication for your pet.