What the US table shows
Diarrhea is the second row of Table 1 in the US prescribing information, which pools five placebo-controlled glycemic control trials in adults. [1] The step from 1.2 mg to 1.8 mg adds two percentage points, much like nausea. The table counts people who reported diarrhea at least once over months of treatment, not how many days it lasted.
| Group | People in group | Reported diarrhea |
|---|---|---|
| Placebo | 661 | 4% |
| Liraglutide 1.2 mg | 645 | 10% |
| Liraglutide 1.8 mg | 1,024 | 12% |
Rates in other trials and in Europe
The Canadian monograph lists every event reported by at least 1% of people in each trial. [3] Two patterns stand out: the trial without another diabetes medicine had the highest figure, and adding insulin detemir in trial 1842 did not lower it. The European summary gives frequencies by combination instead of by trial. [2]
| Trial and background | Victoza® | Comparison |
|---|---|---|
| LEAD-2, 26 weeks, with metformin [3] | 0.6 mg 9.5%; 1.2 mg 8.3%; 1.8 mg 14.9% | Placebo 4.1%; glimepiride 3.7% |
| LEAD-5, 26 weeks, with metformin and glimepiride [3] | 1.8 mg 10.0% | Placebo 5.3%; insulin glargine 1.3% |
| Trial 1860, 26 weeks, with metformin [3] | 1.2 mg 7.2%; 1.8 mg 11.5% | Sitagliptin 4.6% |
| Trial 1842, 52 weeks, 1.8 mg with metformin [3] | 7.5%; 11.7% with insulin detemir added | No placebo arm |
| LEAD-3, 52 weeks, Victoza® alone [3] | 1.2 mg 15.5%; 1.8 mg 18.7% | Glimepiride 8.9% |
| LEADER, high cardiovascular risk [3] | 1.9% | Placebo 0.7% |
| EU, combined with metformin / with a sulfonylurea [2] | 12.6% / 7.9% | Frequency class: very common |
How long it lasts
None of the three documents gives a typical duration for an episode. The European summary says most episodes of nausea and diarrhea were mild to moderate, appeared in a dose-dependent way and became less frequent and less severe in most patients who kept going. [2] The EU leaflet adds that diarrhea usually goes away over time. [2] The US label says that withdrawals for digestive reactions happened mostly in the first two to three months. [1]
For loose stools that keep coming, MedlinePlus gives a clear marker for adults: contact your provider if diarrhea gets worse or has not improved after 5 days. [6]
Dose and background treatment
A systematic analysis of 32 phase 3 trials of GLP-1 medicines found that diarrhea was dose-dependent, and that long-acting medicines such as liraglutide caused less nausea and vomiting but more diarrhea than short-acting ones. [4] It also compared drugs with liraglutide as a reference. These are pooled published results, useful for patterns but not for predicting one person’s response.
The European data split rates by partner medicine: 12.6% with metformin and 7.9% with a sulfonylurea. [2] In children and teenagers aged 10 and up, the trial behind Victoza®’s paediatric approval reported more digestive side effects with liraglutide than with placebo. [5]
Why fluid loss and tablets matter
The US label’s kidney warning describes acute kidney injury reported after approval, mostly in people who had become dehydrated through nausea, vomiting or diarrhea, and asks prescribers to check kidney function when these reactions occur, especially while the dose is going up. [1] Its postmarketing list includes nausea, vomiting and diarrhea leading to dehydration. [1]
The European summary adds a point that the US label does not make in the same words: a few people on liraglutide had at least one episode of severe diarrhea, and diarrhea may affect the absorption of other medicines taken by mouth. [2] If you rely on a daily tablet whose level matters, tell your pharmacist when you have diarrhea.
Why it might happen
Label-supported: digestive reactions are the main known effects of Victoza®, they are more likely at the start and during dose increases, and the label introduces each step slowly to limit them. [1][2]
Associated in research: the dose relationship and the difference between long- and short-acting GLP-1 medicines come from pooled published trials; how liraglutide speeds up the bowel in some people while slowing the stomach is not explained in these sources. [4]
General medicine: MedlinePlus notes that many medicines can cause diarrhea. [7]
Other causes of loose stools
MedlinePlus names stomach flu as the most common cause of diarrhea, followed by food or water contaminated with bacteria or parasites. [6] Medicines such as some antibiotics and magnesium-containing laxatives can cause it, and so can coeliac disease, inflammatory bowel disease, irritable bowel syndrome, lactose intolerance and C. difficile infection after antibiotics. [6] The European product information says liraglutide is not recommended for people with inflammatory bowel disease, because experience is limited and it causes transient digestive reactions. [2]
What the sources describe
- Fluids first: the Medication Guide asks you to drink fluids to help avoid dehydration, and MedlinePlus says water is best and to drink after each loose stool. [1][7]
- Smaller meals: MedlinePlus suggests several small meals through the day instead of three large ones, plus some salty foods. [7]
- Foods to avoid for now: fried and greasy food, gas-producing vegetables and fruit, caffeine, alcohol and fizzy drinks; cut back on dairy if it makes things worse. [7]
- Kidney disease: MedlinePlus asks people with significant chronic kidney disease to check with their provider before adding high-potassium foods. [7]
- Anti-diarrheal medicines: MedlinePlus says over-the-counter products can be used unless you have a fever or bloody diarrhea; ask your pharmacist whether one suits you and your other medicines. [6]
Victoza® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk A/S.
When to get help
The signs and contact information below come from this article’s sourced guidance.
Emergency
- Confusion, fainting, a racing heart or almost no urine with diarrhea
Contact: Emergency services (911 or local number)
MedlinePlus [8]
Today
- Blood or pus in the stool, or black stools
Contact: Contact your provider right away
MedlinePlus [6]
- Diarrhea with a fever over 38.3 °C (101 °F), or belly pain that stays after a bowel movement
Contact: Contact your provider right away
MedlinePlus [6]
- Less urine, dizziness or a dry mouth during diarrhea
Contact: Your provider, the same day
- Diarrhea that does not go away, or has not improved after 5 days
Contact: Your prescriber
At your next appointment
- Loose stools that come and go after dose increases
Contact: Mention it at your next appointment
US label section 17 [1]