The numbers depend on what is counted
The US label gives a single adult figure for reactions such as rash and redness. [1] The EU summary reports all injection-site adverse events and, separately, those that may be immune-related. [3] Canada counts every site event that happened during treatment, including bruising and pain, whether or not the medicine caused it. [4] The same trials therefore yield 0.5%, 0.7%, 1.7% or 1.9%.
| Document, population and pool | Trulicity® | Comparison |
|---|---|---|
| US label, adults, placebo-controlled studies [1] | 0.5% | Placebo 0.0% |
| US label, children 10 and older [1] | 0.75 mg: 3.9% (2); 1.5 mg: 3.8% (2) | Placebo 2.0% (1) |
| EU SmPC, adults, all site adverse events [3] | 1.9%; possibly immune-related 0.7% (“uncommon”) | — |
| EU SmPC, paediatric study [3] | “Common”; all mild to moderate | Placebo 2% |
| Canada, placebo-controlled trials [4] | 38 people (1.7%); 2 stopped treatment | Placebo 6 (0.9%) |
| Canada, studies up to 104 weeks [4] | 1.9%; immune-type 0.5% (0.75 mg) and 0.7% (1.5 mg); 1 stopped | — |
Bruising, pain and redness in the Canadian detail
Canada is the only document that names the individual events. In its placebo-controlled trials, a bruise at the injection site was the most frequent entry in both groups, 17 people on Trulicity® (0.8%) and 3 on placebo (0.4%). Pain (6 people, 0.3%) and redness (4 people, 0.2%) were reported only on Trulicity®. [4] In studies of up to 104 weeks, bruising again led, at 0.9% on 0.75 mg and 0.6% on 1.5 mg. [4]
Those counts are small, and very few people stopped treatment because of a site reaction. [4] The US label does not describe how long reactions lasted. [1]
Children and teenagers
In the US label, the safety profile in young people aged 10 and over matched adults with one exception: injection-site reactions, which section 8.4 says were more frequent than in adults. [1] Behind the percentages are five young people in total, two in each Trulicity® group and one on placebo, so a single case shifts the figure by about two points. [1] Europe adds that every paediatric event was mild to moderate. [3]
Antibodies against dulaglutide appeared in 4% of young people on Trulicity® during the first 26 weeks, and the US label says their effect in children is unknown because so few developed them. [1] Europe reports 4.0% on dulaglutide against 2.1% on placebo. [3] Health Canada has not authorised Trulicity® for anyone under 18. [4]
Where antibodies come in
Across the adult trials, 64 of 3,907 people on Trulicity® (1.6%) developed antibodies to dulaglutide, and the US label found no clinically significant effect on safety or effectiveness. [1] The Canadian monograph adds one link: immune-type site reactions occurred in 2 of those 64 people (3.1%) against 18 of 3,843 without antibodies (0.5%). [4] Both Europe and Canada note that no one with antibodies had a body-wide allergic reaction. [3][4]
What studies across the drug class show
A 2026 meta-analysis pooled 14 randomised trials with 4,861 participants and 396 site reactions, and found a risk ratio of 3.55 (95% CI 2.35 to 5.36) for GLP-1 medicines against comparators. [5] In the same paper, an analysis of US voluntary reports flagged injection-site bleeding as disproportionately reported for dulaglutide, a pattern that fits Canada’s finding that bruising was the leading local event. [4][5] Voluntary reports show what people report more often, not how frequently it happens or whether the medicine caused it.
A 2020 narrative review of 30 phase 3 trials of once-weekly GLP-1 medicines, dulaglutide included, judged the risk of site reactions generally low. [6] The two findings are compatible: a reaction can be several times more likely than with a comparator and still affect only a few people in a hundred.
Local, infected or allergic?
- Local: a little redness, a small bruise or some soreness confined to the spot. MedlinePlus expects some soreness after an injection under the skin. [7] Europe describes the possibly immune-related reactions as usually mild. [3]
- Infected: redness that keeps spreading, warmth, swelling, red streaks or fever. MedlinePlus lists these as signs of infection to report, and cellulitis can grow quickly within a day. [7][8]
- Allergic: hives or itching away from the injection site, a swollen face, lips, tongue or throat, difficulty breathing or swallowing, a very fast heartbeat or fainting. The guide asks you to stop Trulicity® and get medical help right away. [2] Trulicity® should not be used after a serious allergic reaction to dulaglutide or any ingredient. [1]
- Ingredient note: the pens contain polysorbate 80, which Europe says may cause allergic reactions, so known allergies are worth mentioning before starting. [3]
Injection technique in the official documents
- Places: the abdomen, thigh or upper arm, always under the skin and never into a muscle or vein. [1][2] The EU and Canadian pen instructions keep the upper arm for injections given by someone else. [3][4]
- Rotation: change the spot every week; you may stay in the same body area as long as you pick a different site within it. [1][3]
- With insulin: two separate injections, never mixed; the same body area is acceptable, but not right next to each other. [1][2]
- Before injecting: the solution should be clear and colourless, and a pen with particles or discolouration should not be used. [1] MedlinePlus adds that the chosen spot should be free of redness, swelling, scarring and bruising. [7]
- Training: the US label asks prescribers to show patients and caregivers how to inject before the first dose. [1]
Soothing a sore spot
None of the Trulicity® documents recommends ice, creams or other treatments for a local reaction, so there is no product-specific advice to follow. [1][3][4] The one comfort step they mention is Canada’s: let the pen warm to room temperature before injecting, never by microwave or hot water. [4] The US label allows a pen to stay at room temperature, up to 30°C (86°F), for a total of 14 days if needed. [1]
For itchy welts, MedlinePlus suggests avoiding hot baths and tight clothing, and says a provider may suggest an antihistamine; ask a pharmacist before using one. [9] MedlinePlus’s dulaglutide entry treats hives, rash or itching as a reason to stop and contact your doctor, so do not assume a spreading itch is only local. [10]
Trulicity® is a registered trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Swelling of the face, lips, tongue or throat, wheezing, trouble breathing or swallowing, or fainting | Stop Trulicity® and call emergency services (911 / 112) | Emergency | Medication Guide [2]; MedlinePlus [11] |
| Hives, rash or itching that spreads beyond the injection site | Stop Trulicity® and contact your doctor right away | Emergency | Medication Guide [2]; MedlinePlus [10] |
| Redness that keeps spreading, warmth, red streaks or fever after an injection | Your prescriber or primary care, the same day | Today | MedlinePlus [7][8] |
| A reaction that returns after most doses or does not fade before the next one | Your prescriber, to review technique and possible causes | At your next appointment | Canadian monograph [4]; Medication Guide [2] |
| A child or teenager on Trulicity® with repeated site reactions | The prescribing team | At your next appointment | US label 8.4 [1] |
