Does Tirzepatide (MounjaroTM) cause low blood sugar?
What is Tirzepatide?
Tirzepatide is a novel, once-weekly injectable medication that is being studied for the treatment of type 2 diabetes and has been implicated as a good medication for weight loss. The drug, sold under the brand name MounjaroTM, is a glucagon-like peptide-1 (GLP-1) receptor agonist and a glucose-dependent insulinotropic polypeptide (GIP) receptor agonist. These mechanisms of action help to lower blood sugar levels, improve fullness/satiety, and promote weight loss.
Hypoglycemia 101
Like all diabetes medications, tirzepatide can cause side effects. One of the less common, but feared side effects of tirzepatide is hypoglycemia, or low blood sugar. Hypoglycemia occurs when blood sugar levels drop below the normal range (less than 70 mg/dL). Symptoms of hypoglycemia include sweating, shaking, anxiety, dizziness, hunger, confusion, and even loss of consciousness in severe cases. Hypoglycemia can be dangerous, and people with diabetes are advised to take steps to prevent it.
Why does Tirzepatide cause hypoglycemia?
So, why does tirzepatide cause hypoglycemia? One reason is that the drug stimulates insulin secretion, which can cause blood sugar levels to drop. Additionally, tirzepatide slows down the emptying of the stomach, which can delay the absorption of glucose into the bloodstream. This can cause blood sugar levels to drop too low if a person takes tirzepatide with a medication known to cause hypoglycemia, like insulin or sulfonylureas, or if they don’t eat enough.
Hypoglycemia and Tirzepatide in the Literature
In clinical trials, people taking tirzepatide experienced more episodes of hypoglycemia than those taking a placebo.
In the SURPASS-1 clinical trial, tirzepatide was compared to placebo in patients with type 2 diabetes inadequately controlled with diet and exercise (1). Over the course of 40 weeks, over 300 patients taking tirzepatide at three different doses were assessed for events of hypoglycemia <70 mg/dL, clinically significant hypoglycemia <54 mg/dL, and for severe hypoglycemia. They found that patients taking tirzepatide did not experience clinically significant or severe hypoglycemia during the trial. Hypoglycemia <70 mg/dL was only reported in 6% of participants receiving the low dose of tirzepatide (5 mg), and 7% each for the groups receiving medium (10 mg) and high (15 mg) doses, versus 1% in patients taking placebo.
In the SURPASS-4 clinical trial, patients with type 2 diabetes taking tirzepatide were compared to patients taking insulin glargine and assessed for various outcomes, including safety metrics like hypoglycemia (2). They found that the percentage of patients with hypoglycemia of <54 mg/dL was lower with tirzepatide (6-9%, depending on the dose), versus the insulin group (19%). Patients who were not also on a sulfonylurea medication had even fewer events of hypoglycemia, with an incidence of only 1-3% for those on tirzepatide as compared to 16% with insulin.
In these studies, it is clear that there is a risk of hypoglycemia with tirzepatide, but that risk is fairly low and the medication rarely leads to severe hypoglycemia that would warrant emergent medical intervention.
Final Thoughts
In conclusion, tirzepatide is a promising new medication for the treatment of type 2 diabetes, but it does carry the risk of hypoglycemia. By being aware of the potential side effects and taking steps to prevent them, people with diabetes or those using tirzepatide for medication-assisted weight loss can safely and effectively manage their blood sugar levels with tirzepatide.
To minimize the risk of hypoglycemia, patients should closely monitor their blood sugar levels and follow their healthcare provider's instructions for dosing and meal timing. It is also important to educate friends and family members about the signs and symptoms of hypoglycemia and what to do in case of an emergency.
If you would like to learn more about tirzepatide or other GLP-1 medications and their use in diabetes and medication-assisted weight loss, visit us at Mochi Health where we offer a telehealth model with physicians who specialize in Obesity Medicine and have years of experience in prescribing these medications and tailoring regimens for each individual patient. See if you qualify by taking our eligibility quiz here.
Sources:
- Rosenstock J, Wysham C, Frías JP, et al. Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1): a double-blind, randomised, phase 3 trial [published correction appears in Lancet. 2021 Jul 17;398(10296):212]. Lancet. 2021;398(10295):143-155. doi:10.1016/S0140-6736(21)01324-6
- Del Prato S, Kahn SE, Pavo I, et al. Tirzepatide versus insulin glargine in type 2 diabetes and increased cardiovascular risk (SURPASS-4): a randomised, open-label, parallel-group, multicentre, phase 3 trial. Lancet. 2021;398(10313):1811-1824. doi:10.1016/S0140-6736(21)02188-7
