The short answer

Most GLP-1 side effects are uncomfortable, not dangerous — but a handful of symptoms should never be waited out, and after 65 the line between "watch it" and "act now" sits lower. This guide sorts the common symptoms into three buckets: mention it at your next visit, call the office this week or today, and stop and get emergency care. Print it, stick it on the refrigerator, and share it with whoever helps look after you.

One rule above all: when in doubt, call. Your doctor's office would far rather field an unnecessary call than miss a real problem, and 911 exists precisely for the moments you are not sure.

🟢 Mention at your next visit (normal territory)

These are the expected companions of GLP-1 treatment, especially in the first weeks and after dose increases:

  • Mild queasiness, smaller appetite, food aversions — see how to stop nausea
  • Occasional loose stools or constipation
  • Burping, mild heartburn, feeling full quickly
  • Mild fatigue during dose escalation
  • Minor redness or itching at the injection site that fades within days

Track them in a note for your next appointment. Patterns matter more than single bad days.

🟡 Call the doctor's office — this week, or today if worsening

These deserve a phone call, not stoicism:

  • Vomiting or diarrhea lasting more than about 24 hours — in older adults this drains fluid fast, and dehydration can injure your kidneys. Same-day call.
  • No bowel movement for several days with bloating or discomfort — constipation that stops progressing needs attention before it becomes impaction.
  • Dizziness or lightheadedness that keeps recurring — usually fixable causes, covered in dizziness and fall risk, but it needs a medication review.
  • Repeated episodes of pain under the right ribs after fatty meals — the classic gallbladder pattern. Prompt call; urgent if fever joins it.
  • Signs of low blood sugar (shakiness, sweating, confusion) if you also take insulin or a sulfonylurea — treat the low, then call; doses may need adjusting.
  • A new lump in the neck, hoarseness that persists, or trouble swallowing — the FDA label asks patients to report these; they warrant timely evaluation.
  • Any fall, even without apparent injury — a fall is clinical information your doctor needs.

🔴 Stop and get emergency care (911 or the ER)

These are the label's serious warnings. Do not drive yourself if severely unwell.

  • Severe, persistent abdominal pain — especially boring through to the back, with or without vomiting. This is the signature of acute pancreatitis, the most important GLP-1 emergency. The FDA label instructs that the drug be stopped promptly if pancreatitis is suspected. Severe pain that does not pass is an ER visit, full stop.
  • A swollen, hard, painful belly with inability to pass gas or stool, and vomiting — possible ileus (a stalled intestine), added to GLP-1 labeling from post-market reports.
  • Fever with right-upper belly pain, or yellowing of the eyes or skin — an infected gallbladder or blocked bile duct.
  • Signs of severe dehydration: barely urinating, sunken eyes, confusion, a racing heart. Post-market reports include kidney injury severe enough to need dialysis — nearly always downstream of unchecked fluid loss.
  • Severe allergic reaction: swelling of the face, lips, or throat, trouble breathing, widespread hives — 911, immediately.
  • Severe low blood sugar with confusion, inability to swallow safely, or loss of consciousness — bystanders should call 911.
  • Chest pain or pressure — never attribute chest pain to your GLP-1. It is a 911 symptom on its own terms, every time.

The caregiver's corner

If you look after a senior on a GLP-1, the three changes most worth watching are: how much they are drinking, whether eating has quietly fallen to almost nothing, and any new confusion — confusion in an older adult is a "today" symptom no matter the suspected cause. Our full side-effects guide covers the everyday management this triage sheet doesn't.

And a system tip: put the prescriber's office number, the after-hours line, and the pharmacy number on the same refrigerator sheet as this list. Decisions are easier when the numbers are already in front of you. If you don't yet have a prescriber comfortable managing GLP-1s in Medicare patients, our provider directory can help you find one.

Data note

Data as of August 2026, based on current FDA prescribing information for Wegovy, Ozempic, and Zepbound (pancreatitis, gallbladder, ileus, kidney, hypersensitivity, and thyroid warnings). This guide aids recognition — it does not replace medical judgment. When unsure, call your doctor or 911. Not medical advice.