Mastiff almost gave owners a broken heart for Valentine’s Day

With Valentine’s Day nearing, veterinary professionals and clients are sharing the love with each other, significant others, friends, family, and, of course, their pets. One dog from Musquodoboit Harbour, Nova Scotia, Canada, decided that this Valentine’s Day, he would treat himself to his owner’s blood pressure medication.

According to Alexandra Jackson, Sully, a 185-lb mastiff, had never shown interest in her medication before. However, after going out to dinner one night, Jackson was heading to bed early when she noticed a strange white powder all over her bed. She then realized Sully had ripped open the bag her unopened blood pressure medication was in and chewed the bottle open.¹

“I collected all of the uneaten pills, and there were 30 missing—a month’s supply. I think the bag must have looked like a snack to him,” she said to Pet Poison Helpline in an organizational release.¹

Despite Sully’s size, Jackson knew right away that the amount he ingested could be dangerous and needed medical attention. Her husband called the local hospital, Maritime Veterinary Emergency and Specialty Centre in Dartmouth, to give them a heads-up that they would be bringing Sully in for treatment, and the hospital called Pet Poison Helpline to start developing a treatment plan right away.

“Sully ingested a medication used in animals and humans for hypertension and arrhythmias [irregular heartbeat] called amlodipine, and the amount he ingested was a life-threatening dose for his size,” said Renee Schmid, DVM, DABT, DABVT, a senior veterinary toxicologist and director of veterinary medicine at Pet Poison Helpline.¹

“When taken in too great a quantity, amlodipine can result in cardiovascular depression such as a low heart rate and blood pressure, hypocalcemia [low levels of calcium in the blood], a metabolic abnormality called acidosis, and hypokalemia [low levels of potassium in the blood]. In rare cases, it can cause pulmonary edema [fluid in the lungs]. Unfortunately, death can occur due to the severe effects of an amlodipine overdose,” she continued.

By the time Sully and his family arrived at the hospital, with help from Pet Poison Helpline, the team had already begun developing a treatment plan for Sully. Since Jackson had called in advance, the hospital staff immediately began working on Sully when they arrived, even though Sully had not yet shown symptoms. His original treatment included an antiemetic, blood work, medical-grade activated charcoal, intravenous (IV) fluids, and aggressive monitoring of his blood pressure, heart rate, and other vitals.¹ While at the hospital, Sully developed dangerously low blood pressure, and it was recommended that the team give him additional medications, including IV lipid emulsion and calcium, to counter the negative effects of amlodipine.

Despite being touch-and-go in responding to therapy, Sully made a full recovery and, after a day or 2, became himself again.

“Sully’s family, Pet Poison Helpline, and Maritime Veterinary were all lifesavers. Working together, [they] gave Sully the greatest chance for survival,” Schmid said. “There is a high likelihood Sully would not be here today without the contributions of everyone involved.” After 3 days in the hospital, Sully was able to return home.

Each pet featured in Pet Poison Helpline’s “Toxin Tails” has been successfully treated for the poisoning and made a full recovery.

References

1. Heart medication almost kills lovable mastiff. Pet Poison Helpline. Accessed February 11, 2026. https://www.petpoisonhelpline.com/toxintails/heart-medication-almost-kills-lovable-mastiff/
2. Calcium channel blockers. Pet Poison Helpline. Accessed February 11, 2026. https://www.petpoisonhelpline.com/poison/calcium-channel-blockers/