Why the risk depends on other medicines
Section 12.1 explains that semaglutide raises insulin and lowers glucagon in a glucose-dependent way: the push is strong when blood sugar is high and weak when it is not. That is why the hypoglycemia warning in section 5.5 is framed around combinations. People using Ozempic® with insulin or an insulin secretagogue such as a sulfonylurea may have a higher risk of low blood sugar, including severe episodes [1].
NIDDK makes the same general point: insulin and medicines that help the pancreas release insulin, such as sulfonylureas and meglitinides, are the diabetes treatments that can cause lows [5].
How the label defines the categories
- Severe: an episode in which the person needed help from someone else [1].
- Documented symptomatic: symptoms of low blood sugar with a measured glucose of 70 mg/dL (3.9 mmol/L) or less [1][3].
- Severe or blood glucose confirmed symptomatic: a severe episode, or symptoms with a measured glucose of 56 mg/dL (3.1 mmol/L) or less [1][3].
The label’s hypoglycemia table
Table 2 reports two 30-week placebo-controlled trials in adults with type 2 diabetes: one with Ozempic® as the only diabetes medicine and one with Ozempic® added to basal insulin, with or without metformin. Each arm had about 130 people [1].
| Trial and category | Placebo | Ozempic® 0.5 mg | Ozempic® 1 mg |
|---|---|---|---|
| Alone: severe | 0% | 0% | 0% |
| Alone: documented symptomatic (≤70 mg/dL) | 0% | 1.6% | 3.8% |
| Alone: severe or confirmed (≤56 mg/dL) | 1.6% | 0% | 0% |
| With basal insulin: severe | 0% | 0% | 1.5% |
| With basal insulin: documented symptomatic (≤70 mg/dL) | 15.2% | 16.7% | 29.8% |
| With basal insulin: severe or confirmed (≤56 mg/dL) | 5.3% | 8.3% | 10.7% |
Reading the table and the sulfonylurea figures
Without other glucose-lowering medicines, lows were uncommon on Ozempic® and no one needed another person’s help; in the stricter category, the only events were in the placebo group. Adding Ozempic® to basal insulin changed the picture: even placebo users on insulin had documented symptomatic lows at 15.2%, the 1 mg group nearly doubled that, and severe episodes appeared only on 1 mg [1]. Canada adds that the insulin dose had been lowered by 20% when Ozempic® was started [3].
With a sulfonylurea, severe episodes occurred in 0.8% on 0.5 mg and 1.2% on 1 mg, documented symptomatic lows in 17.3% and 24.4%, and severe or confirmed lows in 6.5% and 10.4% [1]. Canada gives the comparator groups in those trials as 0.9%, 25% and 14%, so the sulfonylurea itself carried much of the risk [3].
What Europe and Canada add
Europe classes hypoglycaemia as very common with insulin or a sulfonylurea and common with other oral diabetes medicines. When semaglutide 1 mg was added to an SGLT2 inhibitor in SUSTAIN 9, lows by the American Diabetes Association definition occurred in 11.3% against 2.0% on placebo, with severe lows in 0.7% and 0% [2]. Canada reports the same combination with its own categories: documented symptomatic lows in 5.3% and severe or confirmed lows in 2.7%, against none on placebo [3].
In the 40-week trial of 1 mg against 2 mg, 45 of the 49 low blood sugar episodes happened in people also using a sulfonylurea or insulin, and Europe says the 2 mg dose did not increase the overall risk [2]. Canada lists hypoglycemic unconsciousness among reports received after approval [3].
What real-world use shows
A pooled analysis of nine observational SURE studies followed 3,505 adults with type 2 diabetes using weekly semaglutide in routine care for about 30 weeks. Clinically significant (level 2) lows were reported by 1.1% and severe (level 3) lows by 0.1%. Level 2 lows were more frequent in people on insulin who already had small-vessel complications of diabetes [4].
These are observational studies of people already using the medicine and record what they reported, so they describe everyday experience rather than prove what the medicine caused [4].
Signs to know
The Medication Guide lists dizziness or light-headedness, sweating, shakiness or feeling jittery, a fast heartbeat, hunger, headache, weakness, blurred vision, slurred speech, confusion or drowsiness, and anxiety, irritability or mood changes [1]. NIDDK notes that symptoms tend to come on quickly and differ between people, and that lows during sleep can cause nightmares, crying out, sweating through bedclothes and feeling tired or confused on waking [5].
Some of these signs overlap with ordinary Ozempic® side effects such as dizziness or feeling unwell after a meal. That is why a glucose reading, when you have a meter or sensor, matters more than guessing.
Other things that make lows more likely
- Skipping or delaying meals, or eating too little carbohydrate, which can be more likely when appetite is lower [5].
- Fasting for a procedure while still taking glucose-lowering medicines [5].
- More physical activity than usual, which can lower glucose for up to a day afterwards [5].
- Drinking alcohol without enough food, which can also mask early symptoms [5].
- Being ill and unable to eat or keep food down [5].
- Being 65 or older, having had lows before, or having kidney or heart disease [5].
What may help
NIDDK’s general advice for people on insulin or sulfonylureas is to learn how to check your glucose, carry a fast-acting carbohydrate such as glucose tablets or juice, eat something when you drink alcohol, take care around exercise, and work with your diabetes team on a plan for preventing and treating lows. It also describes continuous glucose monitors as an option for people who have frequent lows or do not feel them coming [5].
Canada notes that self-monitoring of blood glucose may become necessary when Ozempic® is started alongside a sulfonylurea or insulin, so that those doses can be adjusted, and that people should take precautions to avoid lows while driving [3]. Section 7.1 of the US label says prescribers should consider reducing the sulfonylurea or insulin dose when Ozempic® begins; any change is for your prescriber to make [1].
Keeping a useful record
If you think you had a low, note the time, your glucose reading if you took one, what and when you last ate, any exercise or alcohol, how you treated it and how long it took to recover. Add the date of your last Ozempic® injection and any change to insulin or other diabetes medicines. A short, dated record helps your diabetes team decide whether a dose needs adjusting.
Ozempic® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| A person with diabetes who becomes less alert, cannot be woken or has a seizure | Emergency services (911) | Emergency | MedlinePlus [6] and NIDDK [5] |
| Symptoms of a low that do not improve after eating a sugary snack | Get a ride to the emergency room; do not drive yourself | Emergency | MedlinePlus [6] |
| A severe low that needed someone else’s help, even if you have recovered | Your diabetes team, the same day | Today | Section 5.5 [1] and NIDDK [5] |
| Repeated lows, lows at night, or lows you do not feel coming | Your prescriber or diabetes team | Today | NIDDK [5] |
| Starting Ozempic® while on insulin or a sulfonylurea, and not yet having a plan for lows | Your prescriber, before the first dose | At your next appointment | Medication Guide [1] |
