How to Recognize Overdose in Pets from Human Medications

Every year, over 150,000 pets in the U.S. end up in emergency vet clinics because they ate something they shouldn’t have-and most of those cases involve human medications. It’s not just pills left on the nightstand. It’s antidepressants in a purse, ADHD meds in a gym bag, or ibuprofen in a bathroom cabinet. Dogs and cats don’t know the difference between their food and your medicine. And if they swallow it, time becomes the most important factor in saving their life.

What Happens When Pets Ingest Human Medications?

Not all human drugs are equally dangerous to pets, but many are deadly at doses far lower than what’s safe for humans. A single 20mg pill of Adderall can send a 40-pound dog into a life-threatening frenzy. One 37.5mg Effexor capsule can kill a cat. The reason? Pets process these drugs differently. Cats lack key liver enzymes needed to break down acetaminophen. Dogs can’t handle NSAIDs like ibuprofen the way humans do. What’s a harmless dose for you can be a lethal dose for them.

The most common culprits? NSAIDs (ibuprofen, naproxen), antidepressants (Prozac, Effexor), ADHD meds (Adderall, Concerta), and acetaminophen (Tylenol). According to the Pet Poison Helpline, NSAIDs cause nearly 30% of all pet poisoning cases, followed by antidepressants at 17%. And it’s getting worse-cases have risen over 12% in just two years.

Recognizing the Signs: By Medication Type

There’s no single symptom that means “overdose.” It depends on what was swallowed. Here’s what to look for, broken down by the most dangerous drugs.

Antidepressants (SSRIs and SNRIs)

Drugs like Prozac, Lexapro, and especially Effexor are extremely toxic to pets. Dogs and cats don’t just get sleepy-they go into overdrive. Symptoms show up within minutes to 12 hours.

• Fever above 103.5°F
• Shaking, tremors, or muscle rigidity
• Fast heart rate (over 180 bpm in dogs)
• Vocalizing, pacing, or acting confused
• Seizures (if untreated)

Effexor is especially dangerous for cats. Just one capsule can cause liver failure. In one study, cats exposed to Effexor had liver enzyme levels over 1,200 U/L-normal is under 100. That’s a 12-fold spike. And unlike dogs, cats don’t vomit it out easily. They absorb it fast.

ADHD Medications (Adderall, Concerta, Ritalin)

These are stimulants. When a pet ingests them, their body goes into full alarm mode. Symptoms hit fast-within 15 to 60 minutes.

• Heart rate over 220 bpm (normal is 60-140)
• Body temperature above 107°F
• Severe tremors or twitching
• Dilated pupils that don’t react to light
• Aggression or extreme restlessness

Owners often mistake this for an “anxiety attack” or “hysterics.” But the key clue? Hyperthermia + tachycardia + dilated pupils together. That combo is 94% specific to stimulant overdose. If you see all three, don’t wait-get to a vet immediately.

NSAIDs (Ibuprofen, Naproxen)

These are the #1 cause of pet poisonings. People think “it’s just a painkiller,” but even one pill can wreck a dog’s kidneys or stomach.

• Vomiting (92% of cases)
• Black, tarry stools (sign of internal bleeding)
• Lethargy, loss of appetite
• Increased thirst and urination (early kidney warning)
• Eventually, no urine output (kidney failure)

In dogs, toxicity starts around 50mg per kg. A single 200mg ibuprofen tablet can be toxic to a 20-pound dog. Cats? Even 5mg per kg can be fatal. Their kidneys can’t filter these drugs at all.

Acetaminophen (Tylenol)

This is the most species-specific danger. Cats are extremely sensitive. Dogs are less so-but still at risk.

In cats:

• Brown or blue-tinged gums (methemoglobinemia)
• Swelling in face or paws
• Difficulty breathing
• Weakness, collapse

As little as 10mg per kg can be fatal. That’s less than half a 325mg tablet. The brown gums? That’s not normal. It means their blood can’t carry oxygen anymore.

In dogs:

• Vomiting, diarrhea
• Yellowing of skin or eyes (jaundice)
• Lethargy, loss of coordination
• Liver failure (ALT levels above 1,000 U/L)

It takes a lot more to hurt a dog-around 150mg per kg-but a 10-pound dog eating a whole bottle of children’s Tylenol? That’s enough.

What to Do If You Suspect an Overdose

Don’t wait. Don’t Google. Don’t try to make your pet vomit unless a vet tells you to. Time matters more than anything.

Follow this 5-minute checklist:

1. Look for pill fragments, empty bottles, or scattered pills.
2. Take your pet’s temperature rectally. Anything above 103.5°F is a red flag.
3. Check the color of their gums. Brown or blue? That’s acetaminophen.
4. Look at their pupils. Are they wide and unresponsive? That’s stimulants.
5. Ask yourself: When did this happen? Symptoms within 2 hours? That’s urgent.

If you’re unsure, call the Pet Poison Helpline at 1-800-213-6680. They answer in under a minute, 24/7. They’ve handled over 400,000 cases. They know what to ask. And they’ll tell you if it’s an emergency.

Why Most Owners Miss the Signs

Here’s the hard truth: 68% of pet owners don’t recognize early overdose symptoms. They think their dog is “just excited.” Or their cat is “acting weird.”

One owner on Reddit thought her dog’s tremors were “shivering from the cold.” It was Adderall. Another thought her cat’s vocalizing was “just being needy.” It was Effexor. Both pets nearly died.

Why? Because symptoms overlap. Tremors happen with antidepressants, stimulants, and even seizures. Vomiting can be from food poisoning or NSAIDs. The only way to tell is by connecting the dots: What did they eat? When? What symptoms appeared? How fast?

Experts call this the “temporal pattern.” If symptoms start within 30 minutes, it’s likely a stimulant. If they show up after 6 hours, it’s probably NSAIDs or acetaminophen. That timeline tells vets more than any blood test.

How to Prevent This From Happening

Prevention is easier than treatment. Here’s how to keep your pets safe:

• Store all medications in locked cabinets-not on counters or in purses.
• Never leave pills in your pocket, on your nightstand, or in a bag your pet can reach.
• Use child-proof caps even if you don’t have kids. Pets don’t care.
• Never give your pet human medicine without vet approval. Even “natural” supplements can be deadly.
• Keep the Pet Poison Helpline number saved in your phone. Write it on your fridge.

And if you have an older relative living with you who takes meds? Make sure their pills are out of reach. Pets are curious, and seniors often leave bottles on tables or bedside tables.

What Happens at the Vet

If you get there in time, treatment is often successful. In 93% of cases where care starts within 2 hours, pets survive. After 4 hours, the odds drop fast.

Vets will:

• Induce vomiting (if it’s safe and early enough)
• Give activated charcoal to block absorption
• Run blood tests to check liver, kidney, and blood oxygen levels
• Start IV fluids to flush toxins
• Use specific antidotes if available (like N-acetylcysteine for acetaminophen)
• Monitor heart rate, temperature, and neurological status for 24-72 hours

For antidepressant overdoses, they might use sedatives to control seizures. For stimulants, they’ll cool the pet down and slow the heart. For NSAIDs, they’ll protect the stomach and kidneys. Every drug needs a different approach.

What You Can Do Right Now

You don’t need to be a vet to save a pet’s life. You just need to know what to look for.

Take 10 minutes today:

• Check where your meds are stored. Are they truly pet-proof?
• Save the Pet Poison Helpline number (1-800-213-6680) in your phone under “Emergency Contacts.”
• Print out a simple list of symptoms for the top 4 drugs (NSAIDs, antidepressants, stimulants, acetaminophen) and tape it to your fridge.
• Ask your vet if they have a handout on pet medication safety. Most do.

Most pets who survive poisoning do so because their owner acted fast-not because they knew everything. They just knew enough to get help.