Short answer: Low blood sugar (hypoglycemia) is the most common Lyumjev side effect, as with all insulin. In the label's adult trials, nasopharyngitis affected 14.2% to 14.6% in type 1 and 12.5% in type 2 diabetes. On an insulin pump, infusion site reactions affected 19.1% and infusion site pain 15.8%. Severe low blood sugar ranged from 0% to 5.5% across studies. Lyumjev has no boxed warning.
What Lyumjev is approved for: Lyumjev is a rapid-acting mealtime insulin approved to improve blood sugar control in adults and children with diabetes (section 1).
Source
LYUMJEV (insulin lispro-aabc) injection, for subcutaneous or intravenous use, prescribing information and Patient Information. Eli Lilly and Company. DailyMed, version published August 10, 2026. DailyMed setid c5a056e2-b568-4ca6-9ed8-79c010942d00
No. The current Lyumjev label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Lyumjev.
| Adverse reaction | Mealtime LYUMJEV + basal insulin, % (N=451) | Postmeal LYUMJEV + basal insulin, % (N=329) |
|---|---|---|
| Nasopharyngitis | 14.2 | 14.6 |
Reactions at 5% or more and at the same rate or greater than on Humalog. Both columns are Lyumjev, injected at the start of the meal or after it, with basal insulin. Mean exposure was 26 weeks.
| Adverse reaction | Mealtime LYUMJEV + basal insulin, % (N=336) |
|---|---|
| Nasopharyngitis | 12.5 |
| Upper respiratory tract infection | 7.4 |
Mean exposure was 26 weeks.
| Adverse reaction | LYUMJEV by pump, % (N=215) |
|---|---|
| Infusion site reaction | 19.1 |
| Infusion site pain | 15.8 |
| Nasopharyngitis | 6.0 |
Lyumjev U-100 given by insulin pump. Mean exposure was 16 weeks.
| Adverse reaction | Mealtime LYUMJEV + basal insulin, % (N=280) | Postmeal LYUMJEV + basal insulin, % (N=138) |
|---|---|---|
| Nasopharyngitis | 8.2 | 5.1 |
| Upper respiratory tract infection | 5.4 | 1.4 |
Children with type 1 diabetes, mean age 12 years. Mean exposure was 26 weeks.
| Study and group | Severe hypoglycemia, % |
|---|---|
| PRONTO-T1D, type 1 adults, mealtime LYUMJEV + basal insulin (N=451) | 5.5 |
| PRONTO-T1D, type 1 adults, postmeal LYUMJEV + basal insulin (N=329) | 4.6 |
| PRONTO-T2D, type 2 adults, mealtime LYUMJEV + basal insulin (N=336) | 0.9 |
| PRONTO-Pump-2, type 1 adults on a pump, LYUMJEV (N=215) | 1.4 |
| PRONTO-Peds, type 1 children, mealtime LYUMJEV + basal insulin (N=280) | 1.1 |
| PRONTO-Peds, type 1 children, postmeal LYUMJEV + basal insulin (N=298) | 0 |
Severe meant an episode needing another person to give carbohydrate, glucagon or other resuscitative help. The label gives N=298 for the pediatric postmeal arm here.
With injections, injection site reactions occurred in 2.7% of adults (mild in 2.2%, moderate in 0.5%) and 6.2% of children (mild in 5.7%, moderate in 0.5%). The label notes Lyumjev contains treprostinil and sodium citrate as inactive ingredients, which have been linked to site reactions with other products.
With a pump, infusion site reactions were reported in 37.7% of adults (mild 27.9%, moderate 7.9%, severe 1.9%), and 3.3% stopped treatment because of them.
Allergic skin reactions in adults: eczema 0.4%, rash 0.4%, dermatitis 0.3%, hypersensitivity 0.2% and itching 0.2%. In children: rhinitis 0.7%, dermatitis 0.7%, rash 0.5% and hypersensitivity 0.5%.
Lipodystrophy (skin pits or thickening) was reported in 0.2% of adults and children, and peripheral swelling in 0.2% of adults. Average weight gain was 0.6 kg in type 1 and 1.5 kg in type 2 diabetes.
Reported after approval with insulin lispro: localized cutaneous amyloidosis (lumps under the skin) at injection sites. Injecting into those lumps has raised blood sugar, and a sudden switch to normal skin has lowered it.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Who should not use it. Lyumjev is not used during an episode of low blood sugar, or by people allergic to insulin lispro-aabc or any of its ingredients.
Never share a pen or cartridge. Pens and cartridges are never shared, even if the needle is changed, and vial users never share needles or syringes, because of the risk of passing on blood-borne infections.
Changes in insulin regimen. Changing insulin, strength, maker, type, injection site or method can cause high or low blood sugar, so changes are made under close medical supervision with more glucose checks.
Low blood sugar. Hypoglycemia is the most common reaction to insulin. Severe episodes can cause seizures, unconsciousness or death, and can affect driving. Awareness of lows may be reduced with long diabetes, nerve damage, beta-blockers or repeated lows.
Medication mix-ups. Mix-ups between insulins have been reported, so the label is checked before each injection. Lyumjev U-200 is never drawn from the KwikPen into a syringe: syringe markings will not measure it correctly, which can cause an overdose and severe low blood sugar.
Low potassium. All insulins shift potassium into cells and can cause low potassium, which untreated can cause breathing paralysis, heart rhythm problems and death.
Serious allergic reactions. Severe, life-threatening whole-body allergy, including anaphylaxis, can occur; Lyumjev is stopped if it does.
Heart failure with TZDs. Thiazolidinediones (such as pioglitazone) with insulin can cause fluid retention that may lead to or worsen heart failure.
Insulin pump failure. A pump or infusion set malfunction can quickly lead to high blood sugar and ketoacidosis. Pump users are trained to give insulin by injection and keep backup insulin on hand.
From the Patient Information that comes with Lyumjev:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.