Why is this dangerous?
ACE inhibitors (enalapril, lisinopril, ramipril), beta blockers (atenolol, metoprolol, propranolol) and calcium channel blockers (amlodipine, diltiazem, verapamil) all lower heart rate or blood pressure. In a pet with a fraction of a human body weight, a therapeutic human dose becomes an overdose that causes shock.
Some of these tablets are also xylitol-containing chewables, adding a second, fast-acting poison.
Why speed matters
Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.
Signs to watch for
- Weakness, collapse, fainting after standing
- Very slow heart rate, weak pulse
- Pale gums, cold limbs
- Wobbliness, disorientation, vomiting
- Difficulty breathing and shock in severe cases
What to do right now
- Go to an emergency vet now — blood pressure support and IV fluids may be needed within minutes to hours.
- Bring the pill bottle so the vet knows the drug class and strength.
- Carry the pet rather than letting it walk, and keep it warm.
- Do not give food or water if the pet is drowsy or collapsing.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.
The step-by-step response, from the first minute to the vet visit, is in our Blood Pressure & Heart Medicines emergency guide.