The Lisinopril is probably already in the dogs system if he ate your blood pressure medicine while you were away and he then went on a rampage. Vomiting may not help. Immediately see a vet if you think your dog ate a lot of tablets while you were away. A Lisinopril overdose can cause dizziness sleepiness or lethargy as well as a rapid heartbeat
An overdose of Lisinopril can cause dangerously low blood pressure and your dog might need intravenous fluids to maintain blood pressure. Your sweet dog may find this unpleasant and costly but chances are you will be able to recover without enduring any harm.
You should speak to your vet if your pet has diabetes is on a low-salt diet or is taking other medications even if he only swallowed one tablet and seems to be doing well. Additionally if your dog has kidney failure you should immediately contact your veterinarian if he eats any blood pressure pills.