Diabetes and Drug Metabolism: What You Need to Know
"New research highlights how diabetes affects drug metabolism, impacting treatment effectiveness and safety."
Diabetes mellitus (DM), a widespread endocrine disorder characterized by elevated blood glucose levels, affects millions globally. In the Middle East, countries like Jordan and Syria report diabetes prevalence rates of 17.1% and 15.6%, respectively. Beyond its direct impact on blood sugar, diabetes can lead to microvascular and macrovascular damage affecting major organs, including the heart, kidneys, eyes, nerves, and liver.
The liver, a primary site for drug metabolism, is particularly vulnerable in diabetic patients. Uncontrolled diabetes can impair liver function, increasing the risk of liver failure, steatosis, and even cancer. Furthermore, studies suggest that diabetes can alter the liver's capacity to process medications, potentially leading to suboptimal treatment outcomes.
A groundbreaking study investigated how diabetes affects the expression of key drug-metabolizing enzymes in the livers of mice with controlled and uncontrolled insulin-dependent diabetes. The findings shed light on the intricate relationship between diabetes and drug metabolism, offering insights that could improve medication management for individuals with diabetes.
From Discovery to Treatment
In the early 1920s, Banting, Best, Macleod, and Collip identified and purified a pancreatic extract—insulin—as part of the path toward its first use to treat type 1 diabetes. This milestone sits within a longer history of diabetes research, which the Diabetes Research Connection describes as tracing discoveries from ancient times to modern research.
How Does Diabetes Impact Drug Metabolism?
The study revealed significant alterations in the gene expression of cytochrome P450 enzymes (CYP450s), which play a crucial role in drug and arachidonic acid metabolism. These enzymes are essential for breaking down and eliminating drugs from the body. The research compared mice with uncontrolled diabetes (UDM), controlled diabetes (CDM), and a control group to understand these changes.
- Downregulation of CYP450s: Mice with uncontrolled diabetes exhibited a significant downregulation of CYP450 gene expression in the liver. The most affected genes included CYP4A12, CYP1A2, and SLC22A1, with more than a 10-fold reduction.
- Impact of Insulin: Controlled diabetic mice treated with insulin showed higher levels of mRNA compared to UDM mice, though still lower than non-diabetic mice, indicating insulin's role in partially restoring enzyme expression.
- Arachidonic Acid Metabolism: The study also highlighted reduced expression of enzymes involved in arachidonic acid metabolism, which could affect the metabolism of fatty acids and overall liver health.
Metabolism Findings in Mice
In diabetic mice, a study reported that fasting significantly increased hepatic mRNA expression of cyp3a11, cyp2c29, and cyp2d9, while diabetes decreased expression of those drug-metabolizing enzyme genes. Separately, maternal separation markedly reduced mRNA expression of all tested drug-metabolizing CYP450s in the livers of male and female adult mice, without pathological changes. Another mouse study found that a low dose of Calamintha incana extract increased liver cyp3a11 expression by more than tenfold. These findings concern gene expression in mice; they do not establish corresponding effects on drug metabolism in people.
Limits of Models and Treatment
In diabetic mice, five days of insulin therapy did not restore mRNA levels of arachidonic-acid- and drug-metabolizing enzymes to those of controls. A diabetic nonalcoholic steatohepatitis (NASH) mouse model only partially reproduced the human ex vivo CYP alteration pattern, and its authors called for human in vivo studies and more appropriate models. Reviews also identify drawbacks of conventional type 2 diabetes drugs, including severe hypoglycemia, weight gain, reduced therapeutic efficacy linked to improper or ineffective dosing, and altered side effects associated with drug metabolism. Together, these sources highlight limits in interpreting animal findings and challenges associated with existing therapies.
Changes Across Models
The reported direction and size of CYP-related changes vary across the supplied studies and models. In diabetic mice, fasting increased hepatic cyp3a11 expression by 13.7 ± 1.8 folds, while diabetes decreased it by 4.76 ± 1 folds. In high-fat-diet mouse groups, cyp3a11 and cyp3a25 mRNA decreased in liver by more than 2–14-fold and in kidneys by more than twofold; midazolam metabolism also fell by 21-fold in hepatic and fivefold in kidney microsomes. In people with type 2 diabetes, mean metabolic activity was lower for CYP2C19, CYP2B6, and CYP3A by about 46%, 45%, and 38%, respectively, so these results should not be treated as directly interchangeable across species or experimental conditions.
What Does This Mean for People with Diabetes?
The study underscores the importance of understanding how diabetes affects drug metabolism. Healthcare providers need to consider these factors when prescribing medications to diabetic patients. Monitoring drug levels, adjusting dosages, and being vigilant for potential side effects are crucial steps in ensuring optimal treatment outcomes and patient safety. Further research is needed to fully elucidate the clinical implications of these findings and develop personalized medication strategies for individuals with diabetes.
Precision Medicine and Sulfonylureas
A 2020 review set out to develop a practice-based expert group opinion on precision medicine in diabetes management, with a specific focus on sulfonylureas (SUs). Its stated scope also includes diabetes etiology, presentation, and complications. The source describes an expert-opinion objective rather than reporting a specific clinical recommendation or outcome, so it supports framing precision medicine as a topic for expert discussion, not a settled conclusion about SU treatment.
Inflammation and Systemic Disease
A systematic review reports that available in vitro and animal studies indicate inflammation can affect cytochrome P450 activity through complex transcriptional and post-transcriptional mechanisms. The effects depend on the CYP isoform and the inflammation mediators involved. A separate 2026 article frames type 2 diabetes as a systemic disease involving networks of neural, endocrine, and immune signaling, rather than only hyperglycemia. These sources point to broader biological context, but the supplied material does not establish a specific causal link between diabetes-related inflammation and altered drug metabolism.