TORONTO — Health Canada and Novartis Pharmaceuticals Canada are warning against misuse of a drug patch for an Alzheimer's medication.

They say people have overdosed and even died after using the Exelon Patch in the wrong way.

They are reminding doctors, caregivers and patients that it's important to remove one patch before applying a new one to a different location on the back, upper arm or chest.

And they are stressing that the patches should be used whole, not cut into pieces.

There have been at least 129 reported cases of medication error or misuse worldwide involving the Exelon Patch, including two deaths.

Health Canada says three cases of medication error or misuse of the product have been reported in this country.

Typical symptoms of overdose with this drug include nausea, vomiting, diarrhea, high blood pressure, hallucinations, salivation, sweating, respiratory depression and convulsions.

Someone suffering symptoms of overdose should remove the Exelon Patch and be evaluated by a doctor.