Saxenda® (liraglutide) and low blood sugar

The figures, group by group

The trials measured low blood sugar in different ways. Adults with type 2 diabetes and the teenagers had glucose meters; adults without diabetes did not, so their figures rely on symptoms people mentioned. ^[1] The thresholds also differ, so rows are not directly comparable.

Adults with type 2 diabetes

The main trial in diabetes, SCALE Diabetes, enrolled 846 adults taking up to three oral diabetes medicines. ^[4] In the sulfonylurea subgroup, the protocol halved the sulfonylurea dose at the start, and readings below 54 mg/dL were still more than twice as common on Saxenda® as on placebo. ^[1] The label asks for blood sugar to be checked before starting Saxenda® and during treatment, and notes that reducing the sulfonylurea or insulin dose may lower the risk. ^[1]

A separate trial, SCALE Insulin, studied 396 adults on basal insulin. Weight loss was greater with liraglutide 3 mg, insulin doses were lower, and more low blood sugar events occurred on placebo than on liraglutide. ^[5] The US label reports severe episodes in 1.5% against 1% and no meaningful difference in readings below 54 mg/dL. ^[1] The EU summary gives documented symptomatic events of 47.2% on liraglutide and 51.8% on placebo in that trial. ^[2]

The documents differ on insulin. The EU summary says Saxenda® must not replace insulin and warns that diabetic ketoacidosis has followed rapid reduction of insulin. ^[2] The Canadian monograph says Saxenda® and insulin should not be used together. ^[3]

Teenagers and adults without diabetes

None of the teenagers in the trial had diabetes, but they were given meters. With them, 15.2% on Saxenda® recorded symptomatic readings below 70 mg/dL, against 4.0% on placebo; two teens on Saxenda® (1.6%) had readings below 54 mg/dL, and none had a severe episode. ^[1] During the trial, the dose was not increased if a teen had a low reading in the week before. ^[1] The 2020 trial report found the liraglutide group lost more weight than placebo over 56 weeks. ^[6]

In adults without diabetes, nobody had a meter or a diary. Unconfirmed symptoms were reported by 1.6% on Saxenda® and 1.1% on placebo, no episode needed another person’s help, and the EU summary says most were mild. ^[1][2] The EU classes hypoglycaemia as common in this group on the basis of these self-reported symptoms. ^[2]

Antibodies to liraglutide developed in 2.8% of tested adults, and the label says they may be associated with more reports of low blood sugar; these events were usually mild. ^[1]

Why liraglutide alone rarely drives sugar too low

Liraglutide stimulates insulin release and reduces glucagon in a glucose-dependent way: the effect weakens as blood sugar falls. ^[1] In a study of 49 adults with obesity but no diabetes, liraglutide 3 mg lowered fasting glucose by about 0.5 to 0.6 mmol/L and reduced the after-meal glucagon response by about 30%. ^[7] Insulin and medicines that make the pancreas release insulin, such as sulfonylureas, are the ones the label and MedlinePlus link with low blood sugar, which is why the combination carries most of the risk. ^[1][9]

Eating much less can add to the problem. MedlinePlus lists not eating enough carbohydrates, being sick and unable to keep food down, more activity than usual, and alcohol without food among causes of low blood sugar in people on diabetes medicines. ^[9] Nausea and vomiting are the most common Saxenda® side effects. ^[1]

Low blood sugar without diabetes has other causes too, including alcohol, some heart medicines and antibiotics, hormone deficiencies, severe kidney or liver disease and some types of weight-loss surgery. ^[8]

Warning signs and treatment basics

The Medication Guide lists dizziness or light-headedness, blurred vision, anxiety, irritability or mood changes, sweating, slurred speech, hunger, confusion or drowsiness, shakiness, weakness, headache, a fast heartbeat and feeling jittery. ^[1] MedlinePlus adds that symptoms come on quickly, and that some people have none until blood sugar is very low. ^[8][9]

MedlinePlus describes treatment for people with diabetes as a juice or other sugary drink, food or glucose tablets, with glucagon for severe episodes, and says your provider should teach you how to treat yourself. ^[8][9] It suggests carrying a fast-acting carbohydrate if you take insulin or other glucose-lowering medicines. ^[9] The Saxenda® Medication Guide likewise asks you to talk with your provider about how to recognise and treat low blood sugar. ^[1]

The Canadian leaflet notes that low or high blood sugar can affect concentration and reaction time, and that you should not drive if you feel dizzy. ^[3]

Saxenda® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.