Prescribing Notes
- Prescribe as per NICE NG28 recommendations. See also NICE visual summary for blood glucose lowering therapy in adults with type 2 diabetes.
- Inform patients about the common and serious side effects associated with GLP-1 receptor agonists, see MHRA.
- Stop DPP-4 inhibitor if initiating GLP-1 receptor agonist (the combination is unlikely to provide synergistic effects beyond monotherapy with either agent).
- The formulary covers the use of GLP-1 receptor agonists in type 2 diabetes only. GLP-1 receptor agonists should not be prescribed for managing overweight and obesity until a specialist weight management service (tier 3) has been established. See correspondence for further details.
- To prevent waste, please avoid prescribing large quantities. GLP-1 receptor agonists require refrigeration and are expensive. One month’s supply should be adequate for most patients, refer to SPPG Letter to GPs and CPs GLP1 excessive supplies & Appendix A ready reckoner for further details on appropriate quantities
- Stopping rules with GLP-1 receptor agonists: NICE state only continue GLP‑1 receptor agonist therapy if the person with type 2 diabetes has had a beneficial metabolic response (a reduction of at least 11 mmol/mol [1.0%] in HbA1c and a weight loss of at least 3% of initial body weight in 6 months).
- Gastric emptying may be delayed, therefore the rate and extent of absorption of other oral drugs administered at the same time may be affected.
- Doses of concomitant sulfonylurea may need to be reduced when a GLP-1 receptor agonist is started.
- Upper gastrointestinal side effects such as nausea are common with GLP-1 receptor agonist therapy.
- There are rare reports of acute pancreatitis in patients using these drugs. GLP-1 receptor agonists should be avoided in patients considered to be at high risk of pancreatitis. Patients and their carers should be told how to recognise signs and symptoms of pancreatitis.
- Thyroid adverse events (including increased blood calcitonin, goitre and thyroid neoplasm) have been rarely reported in clinical trials with liraglutide, particularly in patients with pre-existing thyroid disease.
Cautions
- Diabetic ketoacidosis has been reported in patients with type 2 diabetes on a combination of a GLP-1 receptor agonist and insulin who had doses of concomitant insulin rapidly reduced or discontinued. See MHRA for further details.
- There is a potential risk of pulmonary aspiration in patients using GLP-1 or dual GIP/GLP-1 receptor agonists who undergo surgery or procedures with general anaesthesia or deep sedation, see MHRA
- GLP-1 receptor agonists should not be used during pregnancy or just before trying to get pregnant. Contraception should be used while using GLP-1 receptor agonists and, in most cases, for a defined wash-out period before trying to become pregnant. Additionally, those using tirzepatide and oral contraception should add a barrier method of contraception alongside the pill, or switch to a non-oral contraceptive method, for four weeks after starting tirzepatide and for four weeks after any dose increase. See MHRA and FSRH.