GLP-1 Contraindications: Who Should Not Take These Medicines

Every medicine has a list of people it is not for — and with GLP-1 medicines, that list is shorter than the alarmism suggests but more important than the hype admits. This article covers who should not take them, so you understand what the assessment is actually checking.

The hard contraindications

These are situations where the medicines should generally not be used:

• Pregnancy and breastfeeding — and stopping before a planned pregnancy (the medicine should be cleared from the body before conception)
• Personal or family history of medullary thyroid carcinoma (MTC) or MEN2 (a rare genetic syndrome) — the boxed warning
• A previous episode of pancreatitis — usually rules the medicine out
• Known serious hypersensitivity to the medicine or its components (rare, but a documented reason to stop)
• Age under 18 — these medicines are not licensed for adolescents in Singapore

These are not negotiable by “trying a lower dose” — they are structural reasons the treatment does not fit.

The assessment-time cautions

Beyond hard contraindications, the assessment screens for situations that need care rather than refusal:

• Diabetes medication — combining with sulphonylureas or insulin raises the risk of low blood sugar; doses often need adjusting first
• Stomach conditions — severe gastroparesis (slow stomach emptying) or significant digestive disease needs a careful call, since the medicine slows emptying further
• Kidney impairment — mainly relevant during episodes of dehydration or severe vomiting; the doctor needs to know
• Planned surgery — guidance exists on pausing around procedures requiring fasting
• Depression or eating-disorder history — the appetite effects make a full history important

Why this list exists

The boxed warning on thyroid C-cell tumours comes from animal studies — it is a precaution carried into human labelling, and the clinical screening exists because of it. The pancreatitis link is rare but real. None of this makes the medicines “dangerous” in the abstract; it makes them inappropriate for specific people — which is exactly why the prescribing decision belongs to an assessment, not a website.

What the assessment actually does

A proper suitability review covers: your weight and BMI history, medical history (especially thyroid, pancreas, gallbladder, kidney), every medication and supplement, family history, and plans around pregnancy. It is the same assessment that would tell you plainly if no medicine is appropriate — that outcome is as much a success as a prescription.

This screening-first structure is the core of our doctor-led weight management programme: suitability established before any treatment is discussed. The GLP-1 guide explains the class in full if you want the background first.