I think the problem is that each of us can react differently to the same amount of a drug, including the delivery method. The extended release is made to release the medicine slowly into the body.

Drugs.com: "Do not crush, chew, or break an extended-release tablet (Glucophage XR). Swallow the pill whole. It is specially made to release medicine slowly in the body. Breaking the pill would cause too much of the drug to be released at one time."

Metformin is the generic name.

I have the same problem with aspirin, but I can tolerate the coated variety.

I would talk to my local pharmacist about whether you might tolerate the extended release better. Then talk to my doctor about switching to the extended release. You often won't know what the effect will be until you try the new method or drug. But you can protect yourself as best as possible by talking to those two sources first.

If you suffer side effects, make sure you let the doctor know about them, they need to know. They may want to stop, lower the dosage, or try something else.