Not all Generic Metformin is The Same!

I've been taking Metformin ER for more than 3 years. When I got them at Stop & Shop's pharmacy, they always gave me big puffy white pills from one of two manufacturers. I noticed one brand seemed to cause a bit of digestive uproar the first day or two I tried it, but didn't notice anything significant in how they affected my blood sugar.

Well this past month I filled my prescription at Walgreens and they gave me a dark pink, dense pill from a manufacturer named Teva. They looked so different from the pills I'd been taking, that I went and looked them up online to make sure that they were, in fact, metformin ER. Based on the numbers on the pills, they checked out as being Metformin ER.

Within two days of starting the new pills, I started seeing dramatically lower blood sugar numbers. Suddenly I was in in the 80s after meals even when I didn't use any insulin (after a low carb breakfast and lunch). I cut back on my insulin at dinner to 2 units max and started seeing 80s and low 90s by 9 PM and fasting blood sugars from 80-89 the next morning every day even with hefty portions of carb at dinner.

When I called the pharmacy the pharmacist insisted that all the generic drugs had to perform the same to be approved, but when I went in, in person, another pharmacist told me that he had another patient who found one brand of regular metformin worked much better for him, too, though the pharmacist didn't say which brand.

To test out whether it wasn't something else causing the drop in my blood sugars, I cut back on the metformin, dropping back to one pill. Immediately my blood sugars went back up about 20 mg/dl. So it looks like it is because of the pink Metformin ER.

I take all 1500 mg at once, around 10:00 in the morning because if I take them at night I find it makes me have to wake up more to pee. My guess is that this particular generic formulation releases the medication more quickly so I'm getting more metformin in my system at once.

OTOH, I didn't see better numbers last year when I was prescribed 2500 mg of Met ER (an overdose, it turns out). That would make me wonder why a higher dose would have that effect. But I was taking that high dose back before I started insulin when my system was really burnt out from trying to normalize blood sugars with not enough insulin being secreted. After almost a year of supplementing with insulin daily perhaps my beta cells have perked up some.

Whatever it is, I'm asking for this stuff next month, too! If you've tried this pink stuff (750 mg Metformin ER) and experienced anything similar, let me hear from you. I'm intrigued!