💊 GLP-1 Receptor Agonists
Drug Class & Overview
GLP-1 Receptor Agonists (incretin mimetics) are injectable antihyperglycaemic agents used in Type 2 Diabetes Mellitus, often as an add-on therapy, particularly in patients who are overweight or obese and have not achieved glycaemic targets with other oral agents.
Mechanism of Action
GLP-1 receptor agonists mimic the action of natural glucagon-like peptide-1 (GLP-1). They enhance glucose-dependent insulin secretion, suppress glucagon secretion, slow gastric emptying, and promote satiety, leading to weight loss.
Key Indications
GLP-1 receptor agonists are indicated for Type 2 Diabetes Mellitus, usually as a second or third-line agent in combination with metformin, a sulfonylurea, or basal insulin. They are particularly beneficial in overweight or obese patients due to their weight-reducing effects and cardiovascular benefits.
Contraindications
Contraindications include Type 1 Diabetes Mellitus, diabetic ketoacidosis, and severe gastrointestinal disease (e.g., gastroparesis) due to their effect on gastric emptying. Caution is advised in patients with a history of pancreatitis or severe renal impairment. They are not recommended in pregnancy or breastfeeding.
Adverse Effects
Common adverse effects include gastrointestinal disturbances such as nausea, vomiting, diarrhoea, and constipation, which are often transient. Hypoglycaemia risk is low when used as monotherapy but increases in combination with sulfonylureas or insulin. Rare but serious adverse effects include pancreatitis and gallbladder disease.
Monitoring
Renal function should be monitored periodically, as some GLP-1 RAs require dose adjustment in renal impairment. HbA1c is monitored every 3-6 months. Patients should be advised to report symptoms suggestive of pancreatitis or gallbladder issues. Weight should also be monitored.
Prescribing Safety (OSCE)
When prescribing GLP-1 RAs, ensure the patient is suitable for an injectable medication and can self-administer. Counsel on common GI side effects and the importance of hydration. Advise on symptoms of pancreatitis and gallbladder disease. Check for renal impairment and adjust dose if necessary.
MLA High-Yield Notes
GLP-1 RAs are effective for glycaemic control, promote weight loss, and some have demonstrated cardiovascular benefits. They are injectable, which can be a barrier for some patients. Remember the common GI side effects and the rare but serious risk of pancreatitis. Examples include exenatide, liraglutide, and semaglutide.
Common SBA Themes
SBAs often focus on their injectable route of administration, mechanism of action (incretin mimetic), and their benefits beyond glycaemic control, such as weight loss and cardiovascular protection. Questions may also test the common GI side effects and the rare risk of pancreatitis.
References
- BNF (British National Formulary)
- NICE Guideline NG28: Type 2 diabetes in adults: management
- MHRA Drug Safety Update: GLP-1 receptor agonists and risk of pancreatitis