What type of insulin is Actrapid (human soluble insulin)?

Insulin Type: Human Actrapid

Human Actrapid is a short-acting (regular) human insulin that has an onset of action within 30 minutes, peaks at 2-3 hours, and has a duration of action of 5-8 hours. 1

Characteristics of Human Actrapid

Human Actrapid belongs to the category of short-acting insulins, specifically regular human insulin. It differs from:

• Rapid-acting insulin analogs (lispro, aspart, glulisine) which have quicker onset (10-15 minutes) and shorter duration (3-5 hours)
• Intermediate-acting insulins (NPH, lente) which have slower onset and longer duration (12-18 hours)
• Long-acting insulins (glargine, detemir, degludec) which provide basal insulin coverage for 20-42+ hours 2

Pharmacokinetic Profile

Human Actrapid has the following profile:

• Onset: 30 minutes
• Peak effect: 2-3 hours
• Duration: 5-8 hours

This pharmacokinetic profile has important clinical implications:

• Must be administered 30 minutes before meals for optimal postprandial glucose control 3, 4
• Has a more pronounced peak effect compared to newer rapid-acting analogs
• May cause mid-postprandial hypoglycemia if meals are delayed or skipped

Clinical Applications

Human Actrapid is commonly used in:

1. Basal-bolus regimens: As the prandial (mealtime) component
2. Sliding scale regimens: For correction of hyperglycemia
3. Hospital settings: For intravenous administration in DKA or other acute hyperglycemic emergencies
4. Mixed with intermediate-acting insulin: Can be mixed with NPH insulin for twice-daily regimens

Comparison with Newer Insulins

Research has demonstrated that rapid-acting insulin analogs provide better postprandial glucose control compared to Human Actrapid when both are administered immediately before meals 3. However, Human Actrapid given 30 minutes before meals can achieve similar postprandial control as rapid-acting analogs given immediately before meals 4.

Important Considerations

• Timing: Must be administered 30 minutes before meals for optimal effect
• Mixing: Can be mixed with NPH insulin but should be injected within 15 minutes of mixing to prevent loss of potency 5
• Storage: Unopened vials should be refrigerated; opened vials can be kept at room temperature for up to 28 days 2
• Appearance: Should be clear and colorless; do not use if cloudy or contains particles

Potential Pitfalls

1. Timing errors: Administering Human Actrapid immediately before meals (rather than 30 minutes prior) can lead to postprandial hyperglycemia
2. Risk of hypoglycemia: Due to its pronounced peak action, there is a risk of hypoglycemia 2-4 hours after administration
3. Inappropriate mixing: Mixing with long-acting insulin analogs like glargine can reduce effectiveness 2

Human Actrapid remains a clinically useful and cost-effective option for many patients, particularly in resource-limited settings, though newer insulin analogs offer advantages in terms of flexibility and reduced hypoglycemia risk.