Insulin Glargine — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Insulin Glargine?
Insulin glargine is a long-acting basal insulin analogue used for the management of type 1 and type 2 diabetes mellitus. This medication is funded by Pharmac for type 1 and type 2 diabetes mellitus.
What is Insulin Glargine Used For?
Insulin glargine (Lantus®, Toujeo®) is used as once-daily basal insulin to provide stable background glucose control in type 1 and type 2 diabetes mellitus.
How Does Insulin Glargine Work?
Insulin glargine forms microprecipitates after subcutaneous injection, creating a depot that releases insulin slowly and predictably over approximately 24 hours. This provides a flat, peakless insulin profile that mimics the physiological low-level basal insulin secretion between meals and overnight.
How to Take Insulin Glargine
Administered by subcutaneous injection once daily (Lantus® 100 units/mL; Toujeo® 300 units/mL). The dose is individualised. Inject into the abdomen, thigh, or upper arm. Rotate injection sites. Do not mix with other insulins in the same syringe. Store unused pens in the refrigerator; opened pens can be kept at room temperature for up to 28 days.
Common Side Effects of Insulin Glargine
- Hypoglycaemia (low blood sugar — most significant; dose titration is key)
- Injection site reactions (lipohypertrophy with repeated use at same site — rotate sites)
- Weight gain (with insulin therapy generally)
- Localised allergic reactions (redness, swelling, itching)
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Severe hypoglycaemia (loss of consciousness, seizures — requires glucagon injection or IV dextrose)
- Severe allergic reaction (anaphylaxis — rare)
- Hypokalaemia (low potassium — insulin shifts potassium into cells)
Drug Interactions
Insulin Glargine may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- All antidiabetic medicines (additive hypoglycaemia risk)
- Beta-blockers (can mask hypoglycaemia symptoms — particularly non-selective beta-blockers)
- ACE inhibitors and ARBs (may enhance insulin sensitivity)
- Corticosteroids and thiazide diuretics (increase blood glucose — may need insulin dose increase)
New Zealand Prescribing Information
Insulin glargine (Lantus® 100 units/mL, 3 mL cartridges and SoloStar® pens; Toujeo® 300 units/mL, SoloStar® pen) is funded by Pharmac. People with type 1 diabetes qualify for free test strips and lancets. CGM (continuous glucose monitoring) devices and insulin pumps may be subsidised under certain criteria. Your diabetes nurse or educator will provide injection technique training.
Frequently Asked Questions
Can I mix insulin glargine with short-acting insulin?
No — insulin glargine must not be mixed with any other insulin in the same syringe. If you use both basal (glargine) and rapid-acting insulin, they are injected separately at different times.
What should I do if my blood sugar is too low?
Treat hypoglycaemia immediately: eat 15 g of fast-acting carbohydrate (e.g., 3–4 glucose tablets, 150 mL of fruit juice, or 3–4 jelly babies). Recheck after 15 minutes. If you lose consciousness, do not give food by mouth — use a glucagon injection kit or call 111.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: