How Do Medications Raise Blood Glucose Levels?

By Health & Medical Last updated Saturday, April/06/2024

Considerations

Many medications, including barbiturates, decongestants, diuretics, oral contraceptives and particularly steroids, can raise blood glucose levels. Most do not have a significant effect, however, particularly if a person is taking insulin. An individual with diabetes or pre-diabetes who begins taking any medication known to raise blood sugar should test blood glucose three to four times a day if not already doing so. The reasons for the rise in blood glucose levels vary for different medications, but the problem appears to center primarily around hormonal effects.

The medications most likely to raise blood glucose levels are corticosteroids. Physicians usually prescribe steroids to reduce inflammation and swelling. Steroids raise blood sugar similarly to the way stress hormones do, and some naturally occurring steroids act as hormones, such as the primary stress hormone cortisol. Steroids cause the liver to manufacture extra glucose, and they block the hormone insulin's activity in removing glucose from the blood and into body cells.

Some cholesterol-lowering medications, such as rosuvastatin calcium, or Crestor; atorvastatin calcium, or Lipitor; and simvastatin, or Zocor, can raise blood glucose levels. A study of more than 17,000 people published in the New England Journal of Medicine in 2008 found a higher incidence of diabetes in those taking Crestor. Another study, published in the Journal of the American Medical Association in 2002, found that Zocor raised fasting insulin levels without lowering fasting glucose. This may indicate a decrease in insulin sensitivity as well. Even large amounts of niacin, or vitamin B3, which is sometimes used to lower cholesterol, can raise blood glucose levels.

Some oral contraceptives can raise blood glucose levels. Although research is inconclusive, a study published in the American Journal of Obstetrics and Gynecology indicated these contraceptives act on the anterior pituitary gland and affect hormone secretion.

Blood glucose levels can be increased in people taking thiazide diuretics, typically prescribed to control high blood pressure. A 2006 issue of the Archives of Internal Medicine studied three groups of people, one on a thiazide diuretic, one on a calcium channel blocker and another on an ace inhibitor. Significantly more people taking thiazide developed diabetes than the other two groups. Thiazides appear to decrease insulin secretion and possibly reduce insulin sensitivity.