The most common Byetta side effects are gastrointestinal. In the trials, nausea affected 44% of people on Byetta against 18% on placebo, and vomiting 13% against 4%. The gap between the two columns is the part the drug is responsible for. Serious but uncommon risks include pancreatitis and gallbladder disease.
Side-effect probability vs placebo
Percent of Byetta trial participants reporting each side effect at any time during the trial, vs the placebo arm.
Primary sources: Byetta FDA label, Table 3 (added to metformin and/or a sulfonylurea, vs placebo) · FDA prescribing information (DailyMed)
- Nausea44% vs 18%
- Vomiting13% vs 4%
- Diarrhea13% vs 6%
- Feeling jittery9% vs 4%
- Dizziness9% vs 6%
- Headache9% vs 6%
Individual experience varies. Most GI side effects resolve over weeks 4–12 as the body adjusts.
Detailed safety information
Important safety information for Byetta
Summarized from the FDA-approved prescribing information. Always review the full label and discuss with your prescriber.
Contraindications (2)
Risk factors:Hypersensitivity to active ingredientPregnancyPersonal/family MTC historyMEN 2 syndrome
- Prior serious hypersensitivity reaction to exenatide or any ingredient
- History of drug-induced immune-mediated thrombocytopenia from exenatide products
Common side effects
- Nausea
- Vomiting
- Diarrhea
- Feeling jittery
- Dizziness
- Headache
Serious side effects (6)
Risk factors:Pancreatitis historyGallbladder diseaseKidney impairmentDiabetic retinopathyConcurrent insulin / sulfonylurea
- Acute pancreatitis
- Acute gallbladder disease
- Acute kidney injury
- Hypoglycemia (with sulfonylureas)
- Severe hypersensitivity / anaphylaxis
- Drug-induced thrombocytopenia
Information is educational and not a substitute for the full prescribing label or clinical judgment. Read our full medical disclaimer.
Byetta side effects vs placebo, from the trials
Rates from the Byetta FDA label, Table 3 (added to metformin and/or a sulfonylurea, vs placebo). People on placebo reported several of these too, so the difference between the columns is the part attributable to the drug.
| Side effect | On Byetta | On placebo | Difference |
|---|---|---|---|
| Nausea | 44% | 18% | +26 pts |
| Vomiting | 13% | 4% | +9 pts |
| Diarrhea | 13% | 6% | +7 pts |
| Feeling jittery | 9% | 4% | +5 pts |
| Dizziness | 9% | 6% | +3 pts |
| Headache | 9% | 6% | +3 pts |
Percentages are trial-population rates, not a prediction for any one person. Rates differ by dose and by how fast the dose was raised. Check the Medication Guide dispensed with your own prescription, and tell your prescriber about anything that does not settle.
Managing the common ones
Nausea affected 44% of people on Byetta in the trials, against 18% on placebo. Stomach side effects are usually worst early in treatment and ease over the following weeks for most people. Smaller, lower-fat meals, stopping at the first sign of fullness and steady fluids help; vomiting or diarrhea that does not settle can dehydrate you enough to injure the kidneys, so tell your prescriber. The GLP-1 side effects guide covers each symptom in more depth.
Serious side effects — when to get care now
- Severe stomach pain that does not go away, sometimes spreading to the back — possible pancreatitis. Stop Byetta and get care.
- Pain in the upper right abdomen, fever, or yellowing skin or eyes — possible gallbladder disease.
- Vomiting or diarrhea you cannot keep up with, or passing little urine — dehydration can injure the kidneys.
- Swelling of the face, lips or throat, hives, or trouble breathing — a severe allergic reaction.
- Shakiness, sweating, confusion or a racing heartbeat if you also take insulin or a sulfonylurea — low blood sugar.
- Unusual bleeding or bruising — exenatide can cause a drug-induced drop in platelets.
FAQ about Byetta side effects
When do Byetta side effects start?
Stomach side effects are most common when treatment starts and after each dose increase, and for most people they lessen over the following weeks. Tell your prescriber if they persist or get worse.
Does Byetta have a boxed warning?
No. The Byetta label has no boxed warning. Its warnings cover acute pancreatitis, acute gallbladder disease, acute kidney injury, hypoglycemia (with sulfonylureas), severe hypersensitivity / anaphylaxis, drug-induced thrombocytopenia.
Editorial summary based on FDA prescribing information. Not a substitute for the full label or your prescriber's judgment. Full medical disclaimer.