It’s that time of the year, when social media is rife with many top 5 and top 10 lists. Let’s revisit some of the most commonly used medications known to increase glucose levels and look at some practical tips on overcoming these.
1. Glucocorticoids
Without a doubt, corticosteroids are at the top of the list when it comes to the potential for increasing blood glucose levels. High-dose glucocorticoid therapy is known to lead to new-onset diabetes (steroid-induced diabetes). Similarly, people with preexisting diabetes may notice significant worsening of glycemic control when they start on glucocorticoid therapy. The extent of glucose elevation depends on their glycemic status prior to initiation on steroids, the dose and duration of glucocorticoid therapy, and comorbid conditions, among other factors.
Management tip: For those with previously well-controlled diabetes or borderline diabetes, glucocorticoid-induced hyperglycemia may be managed by metformin with or without sulfonylurea therapy, especially if corticosteroid treatment is low-dose and for a shorter duration. However, for many individuals with preexisting poorly controlled diabetes or those initiated on high-dose corticosteroids, insulin therapy would perhaps be the treatment of choice. Glucocorticoid therapy generally leads to more pronounced postprandial hyperglycemia compared with fasting hyperglycemia; hence, the use of short-acting insulin therapy or perhaps NPH insulin in the morning might be a better option for many individuals. Dietary modification plays an important role in limiting the extent of postprandial hyperglycemia. Use of continuous glucose monitoring (CGM) devices may also be very helpful for understanding glycemic excursions and how to adjust insulin. In individuals for whom glucocorticoid therapy is tapered down, it is important to adjust the dose of medications with potential to cause hypoglycemia, such as insulin/sulfonylurea therapy, as the degree of hyperglycemia may decrease with decreased dose of the glucocorticoid therapy.
2. Antipsychotic Therapy
Antipsychotic medications can be obesogenic; between 15% and 72% of people who take second-generation antipsychotics experience weight gain of 7% or more. Increases in weight are not the only factor contributing to an elevated risk of developing type 2 diabetes. Antipsychotics are thought to cause downregulation of intracellular insulin signaling, leading to insulin resistance. At the same time, there seems to be a direct effect on the pancreatic beta cells. Antagonism of the dopamine D2, serotonin 5-HT2C, and muscarinic M3 receptors impairs beta-cell response to changes in blood glucose. In addition to the pharmacologic effects, cell culture experiments have shown that antipsychotics increase apoptosis of beta cells. Increased weight and concomitant development of type 2 diabetes is seen particularly in agents that exhibit high muscarinic M3 and histamine H1 receptor blockade. The effect on glucose metabolism is seen the most with agents such as clozapine, olanzapine, and haloperidol and the least with agents such as ziprasidone.
Management tip: Given the ongoing change in the understanding of increases in weight and their association with the risk of developing type 2 diabetes, a metabolically safer approach involves starting with medications that have a lower propensity for weight gain, and the partial agonists/third-generation antipsychotics as a family presently have the best overall data.