DEAR DR. ROACH: I take 25 mg of quetiapine at night as a sleeping aid, and one of the side effects is an increase in blood sugar. I am curious if that will also show a rise in my A1C blood work as well? — T.F.
ANSWER: Quetiapine (Seroquel), an antipsychotic medication that is often used as a sleep aid due to its side effect of sedation, has at least two ways that it can increase blood sugar. The first is that it directly acts against insulin, causing the body to try to release more insulin. At the same time, it reduces the ability of the body to make insulin. The combination means that in people who don’t have much reserve (such as people with prediabetes or diabetes), this will increase their blood sugar. Secondly, the resistance to insulin helps promotes weight gain, which worsens the resistance to insulin even more.
Any condition that raises blood glucose significantly for a long enough period will increase the A1C. The A1C measures the amount of sugar on hemoglobin molecules in red blood cells. The higher the blood sugar and the longer it stays high, the higher the A1C level.
A dose of 25 mg of quetiapine is relatively small, so it doesn’t usually have these metabolic changes the way that quetiapine used for schizophrenia does — at the usual dose of 400 to 800 mg daily in adults. Still, I do not prescribe quetiapine as a sleep aid, greatly preferring nonmedication treatments such as cognitive-behavioral therapy whenever possible.
