Insulin Glargine: A Long-Acting Insulin
Yes, insulin glargine (Lantus) is a long-acting insulin analog that provides basal insulin coverage with a duration of approximately 24 hours. 1
Characteristics of Insulin Glargine
Insulin glargine has several distinctive properties that classify it as a long-acting insulin:
- Duration of Action: Approximately 24 hours 1
- Onset of Action: About 1 hour after injection 1
- Peak Activity: No pronounced peak (relatively flat action profile) 1, 2
- Administration: Typically once daily 1
This pharmacokinetic profile distinguishes insulin glargine from other insulin types:
| Insulin Type | Onset of Action | Peak Action | Duration of Action |
|---|---|---|---|
| Regular Insulin | 15 minutes | 3-4 hours | 6-8 hours |
| Rapid-acting Insulin | 5 minutes | 1-2 hours | 3-4 hours |
| Insulin Glargine | 1 hour | None | 24 hours |
Clinical Advantages
The long-acting, peakless profile of insulin glargine offers several clinical benefits:
- Reduced Hypoglycemia Risk: Moderate-quality evidence shows fewer severe hypoglycemic events in patients treated with glargine (OR, 0.65 [CI, 0.49 to 0.88]) compared to NPH insulin 3
- Consistent Basal Coverage: Provides relatively constant basal insulin levels without pronounced peaks 2
- Flexible Dosing Time: While typically administered at bedtime, it can be given at any consistent time of day 4
Clinical Applications
Insulin glargine is used in both type 1 and type 2 diabetes management:
- Type 1 Diabetes: Used as basal insulin in combination with rapid-acting insulin for mealtime coverage 1
- Type 2 Diabetes: Often the first insulin introduced when oral medications are insufficient, typically as a single daily dose 4
Important Considerations
When using insulin glargine, be aware of these key points:
- Do not mix with other insulins due to its acidic pH 1
- Starting dose is typically 0.1-0.2 units/kg/day or 10 units daily for insulin-naïve patients 1
- Dose adjustments should be made based on fasting glucose levels, increasing by 2-4 units every 3-7 days until target glucose is achieved 1
- Storage: Unopened insulin should be refrigerated; opened vials/pens can be kept at room temperature for up to 28 days 1
Special Situations
For patients with high insulin requirements (>0.5 units/kg/day) with suboptimal control, consider:
- Splitting the dose into twice-daily administration
- Using concentrated formulations (U-300 glargine) 1
- Adding prandial insulin or other injectable therapy
In labile type 1 diabetes, insulin glargine may be more effective when given as two daily injections 4
While the World Health Organization guidelines suggest human insulin as first-line for cost reasons in resource-limited settings 3, insulin glargine's reduced risk of hypoglycemia makes it a valuable option, particularly for patients experiencing frequent severe hypoglycemia with human insulin.