Insulin Therapy Guide
Complete guide to starting and managing insulin therapy for diabetes
Insulin therapy replaces or supplements natural insulin in diabetes management. Types include rapid-acting, long-acting, and premixed. Proper injection technique, timing with meals, and regular blood sugar monitoring are essential. Side effects like hypoglycemia can be managed with proper education.
Understanding Insulin
Insulin is a hormone that helps your body use glucose for energy. When you have diabetes, your body either doesn't make enough insulin (type 1) or doesn't use it effectively (type 2). Insulin therapy replaces or supplements your natural insulin.
Why Insulin May Be Needed
- Type 1 diabetes: Body produces no insulin
- Type 2 diabetes: Oral medications no longer control blood sugar adequately
- Pregnancy: Gestational diabetes requiring insulin
- Hospitalization: Temporary insulin during illness
- Surgery: Better blood sugar control for healing
Types of Insulin
Quick Reference
| Type | Onset | Peak | Duration | Used For |
|---|---|---|---|---|
| Rapid-acting | 15-30 min | 1-2 hrs | 3-5 hrs | Meal coverage |
| Short-acting | 30-60 min | 2-3 hrs | 6-8 hrs | Meal coverage |
| Intermediate | 2-4 hrs | 4-12 hrs | 12-18 hrs | Background |
| Long-acting | 2-4 hrs | Minimal | 24+ hrs | Background |
| Ultra-long | 6 hrs | None | 42+ hrs | Background |
Common Insulins
Rapid-acting:
- Humalog (lispro)
- Novolog (aspart)
- Apidra (glulisine)
Long-acting:
- Lantus (glargine)
- Levemir (detemir)
- Toujeo (glargine U-300)
- Tresiba (degludec)
Premixed:
- 70/30 (70% intermediate, 30% short)
- 75/25 (75% intermediate, 25% rapid)
Injection Technique
Supplies Needed
- Insulin pen or syringe
- Pen needles (if using pen)
- Alcohol swabs
- Sharps container for disposal
Step-by-Step Injection
- Wash hands thoroughly with soap and water
- Check insulin - Clear for rapid/short/long; roll cloudy (NPH) between palms
- Attach needle to pen (if using)
- Prime - Dial 2 units, point up, press until drop appears
- Select site - Rotate injection sites
- Clean site with alcohol swab (optional)
- Pinch skin if needed
- Insert needle at 90° angle (45° for thin skin)
- Push plunger slowly and completely
- Wait 10 seconds before removing needle
- Dispose of needle in sharps container
Injection Sites
Best sites:
- Abdomen (2 inches from navel)
- Back of upper arms
- Outer thighs
- Buttocks
Rotation rules:
- Rotate within the same area for consistent absorption
- Move to a new spot each time
- Avoid scar tissue, moles, or broken skin
Dosing and Timing
Basal-Bolus Regimen
Most common approach for tight control:
Basal (background) insulin:
- Long-acting insulin once or twice daily
- Keeps blood sugar stable between meals
- Usually same dose each day
Bolus (meal) insulin:
- Rapid or short-acting before meals
- Covers carbohydrates eaten
- Corrects high blood sugar
Calculating Meal Doses
Insulin-to-carb ratio (ICR):
- Typically 1 unit per 10-15 grams of carbs
- Your ratio is personalized
Example:
- Meal has 60 grams of carbs
- Your ratio is 1:15
- Dose: 60 ÷ 15 = 4 units
Correction Factor
Also called insulin sensitivity factor (ISF):
- How much 1 unit lowers blood sugar
- Typical range: 1 unit drops BG 30-50 mg/dL
Example:
- BG is 180, target is 120
- Difference: 60 mg/dL
- ISF is 1:30
- Correction: 60 ÷ 30 = 2 units
Managing Side Effects
Hypoglycemia (Low Blood Sugar)
Symptoms:
- Shakiness, sweating
- Rapid heartbeat
- Confusion, dizziness
- Hunger, irritability
Treatment (15-15 Rule):
- Eat 15 grams of fast-acting carbs
- Wait 15 minutes
- Check blood sugar
- Repeat if still below 70 mg/dL
Fast-acting options:
- 4 glucose tablets
- 4 oz juice or regular soda
- 1 tablespoon honey
Injection Site Reactions
- Redness, itching, or lump at injection site
- Usually resolves in days to weeks
- Rotate sites to prevent
- Report persistent reactions to doctor
Weight Management
Strategies to minimize weight gain:
- Count carbohydrates accurately
- Don't treat lows with excessive calories
- Exercise regularly
- Consider GLP-1 agonist if appropriate
Storage and Travel
Home Storage
| State | Location | Temperature | Duration |
|---|---|---|---|
| Unopened | Refrigerator | 36-46°F | Until expiration |
| In use | Room temp | 59-86°F | Per package insert |
Don't:
- Freeze insulin
- Leave in hot car
- Use expired insulin
- Use insulin that looks clumpy or discolored
Travel Tips
- Pack more insulin than needed
- Keep insulin in carry-on (never checked bags)
- Bring prescriptions and documentation
- Use insulated bag with gel pack for hot climates
- Adjust timing for time zone changes (consult your care team)
When to Call Your Doctor
- Frequent low blood sugar
- Blood sugar consistently above target
- Signs of infection at injection sites
- Unexpected weight changes
- Questions about dosing
Starting insulin can feel overwhelming, but it becomes routine with practice. Work closely with your healthcare team, keep learning, and remember that insulin is a powerful tool for managing your diabetes and preventing complications.
Disclaimer: This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider for personalized guidance.