Can atenolol (beta blocker) cause hyperglycemia (high blood sugar)?

Atenolol and Hyperglycemia: Metabolic Effects and Clinical Implications

Yes, atenolol can cause hyperglycemia and is associated with an increased risk of developing type 2 diabetes. This effect is supported by multiple clinical guidelines and research studies.

Mechanism and Evidence for Hyperglycemic Effects

• Beta-blockers, including atenolol, have been shown to increase the risk of new-onset diabetes by approximately 22% compared to non-diuretic antihypertensive agents 1
• Atenolol specifically has been identified as having a higher risk for causing new-onset type 2 diabetes, particularly in elderly patients and with longer duration of treatment 1
• The risk appears to be dose-dependent, with higher plasma atenolol exposure being associated with greater increases in fasting plasma glucose levels 2
• Metabolomic studies have identified β-alanine as a potential biomarker for atenolol-induced hyperglycemia, suggesting specific metabolic pathways may be involved 3

Metabolic Impact of Atenolol

• Atenolol decreases insulin sensitivity, with studies showing reduced glucose uptake from 5.6 to 4.9 mg/kg/min during treatment 4
• It causes small but significant increases in fasting plasma insulin and blood glucose concentrations 4
• First and second-generation beta-blockers like atenolol are associated with unfavorable changes in blood lipid profiles, including:
  • Increased very low-density lipoprotein (VLDL) and triglyceride concentrations
  • Decreased high-density lipoprotein (HDL) cholesterol levels 1, 4

Clinical Significance and Comparison with Other Agents

• In the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT), atenolol-based therapy was inferior to amlodipine-based therapy in patients with diabetes, with higher rates of cardiovascular events and stroke 1
• Comparative studies show that carvedilol (a vasodilating beta-blocker) has more favorable metabolic effects than atenolol in diabetic patients with hypertension 5
• The European Society of Hypertension (ESH) and European Society of Cardiology (ESC) guidelines acknowledge the diabetogenic effect of beta-blockers like atenolol and recommend caution 1

Special Considerations

• Atenolol may mask symptoms of hypoglycemia (particularly tachycardia) in patients with diabetes, which is especially concerning for those with type 1 diabetes or insulin-treated type 2 diabetes 1, 6
• While atenolol can blunt hypoglycemia-induced QTc interval lengthening (which may be protective against arrhythmias), this same mechanism masks important warning signs of low blood sugar 6
• The hyperglycemic effect appears to be more pronounced in certain populations:
  • Elderly patients 1
  • Women may be more susceptible to atenolol-induced changes in fasting glucose 2
  • Patients with higher BMI 1

Clinical Recommendations

• For hypertensive patients with or at risk for diabetes, consider alternative antihypertensive agents such as ACE inhibitors, angiotensin receptor blockers, or calcium channel blockers, which have more favorable metabolic profiles 1
• If beta-blocker therapy is necessary in patients with diabetes or metabolic syndrome, newer vasodilating beta-blockers (like carvedilol) may be preferable to atenolol 5
• Monitor blood glucose levels regularly in patients taking atenolol, particularly during the initial months of therapy 1
• Be aware that atenolol may mask hypoglycemic symptoms in diabetic patients, requiring additional vigilance and patient education 1

The evidence clearly indicates that atenolol has diabetogenic effects that should be considered when selecting antihypertensive therapy, especially for patients with existing metabolic abnormalities or risk factors for diabetes.