Weather can take a toll on mail-order drugs

Question: I read your column concerning pharmaceutical drugs left in a cold mailbox in the winter. A few years ago, I measured summer temperatures in our mailbox with an accurate electronic thermometer.

I was concerned that my drugs might be damaged by the very high temperatures here in Tempe, Arizona. The mail is delivered in the afternoon, when the sun hits the mailbox.

I am attaching an Excel file of what I found. The temperature of the mailbox was significantly higher than the air temperature. The average daily mailbox temperature between August and October was 121 F. Clearly, those high temperatures would be expected to have some effect on many drugs.

Since doing that project, I stopped having my drugs sent by mail, and now use an in-store pharmacy. Neither the drug companies nor the Food and Drug Administration seemed to provide helpful information when I asked them about this problem.

Answer: Your spreadsheet is fascinating. On some days, the temperature in your mailbox reached 130 to 140 F. That is way outside the acceptable storage range, even for a short period of time. Guidelines for medications generally call for storage at room temperature (68 to 77 F). During shipping, temporary fluctuations are allowed between 59 and 86 F; even on the coolest days of your two-month project, your mailbox hit at least 95 F.

Some medications could deteriorate rapidly under such conditions, including certain drugs for asthma, diabetes, thyroid and anxiety. Mail-order pharmacies and the FDA need to address this weakness in our drug delivery system.

Question: I went on metformin when my HbA1c went up to 6.2. After three months on this drug, it dropped to 5.9.

I was nauseated and had stomach cramps at first. A few days later I started having bad diarrhea and then heartburn. My latest symptom is feeling like my bladder is full, and when I go to empty it, there is only a drop of urine. I’ll go back soon to have my kidneys and my HbA1c checked.

I want to get off this medication to start feeling like myself again. Is there any way to do that?

Answer: HbA1c is a way of measuring average blood sugar levels over a couple of months. Your levels represented prediabetes.

Metformin is the most commonly prescribed drug to treat Type 2 diabetes. Doctors also may prescribe it to prevent high blood glucose levels from turning into diabetes.

Some people cannot tolerate the side effects of this medication. Common adverse reactions include heartburn, gas, diarrhea, nausea and stomachache. Kidney function should be monitored, as metformin can be dangerous for people with compromised kidneys.

You can learn more about metformin and a range of nondrug approaches to keeping your blood sugar under control in our “Guide to Diabetes Management.” You should discuss your plans with your doctor. Anyone who would like a copy, please send $3 in check or money order with a long (No. 10), stamped (71 cents), selfaddressed envelope to: Graedons’ People’s Pharmacy, No. DM-11, P.O. Box 52027, Durham, NC 27717-2027. It also can be downloaded for $2 from our website: www.peoplespharmacy.com.

Joe Graedon has a master's in pharmacology and Dr. Teresa Graedon a doctorate in medical anthropology. Visit peoplespharmacy.com.