Insulin: Complete Notes for Nursing Students | Types, Functions, Complications, and Administration

 Introduction 

In this blog you will get the detailed notes for "Insulin" in which we have covered topics like Definition of insulin, Basic Facts, Synthesis and secretion, Mechanism of Action, Functions of Insulin, Types of Insulin, Insulin Regimens, Sites of insulin injection, Nursing responsibilities in insulin administration, Complications of insulin Therapy, Hypoglycemia-Signs and Nursing Management, Dose calculation, Formulas, quick revision summary.

What is Insulin 

Insulin is a protein Hormone secreted by beta cells of the islets of langerhans in the pancreas. It is the only hormone in the body that lowera blood glucose level - All other hormones (Glycogen, cortisol, epinephrine, growth hormone) raise it . This is why Insulin is called a anabolic / Hypoglycemic Hormone

Basic Facts 

Feature Detail
Chemical nature Polypeptide hormone (protein)
Site of production Beta cells of Islets of Langerhans, Pancreas
Structure 2 polypeptide chains — Chain A (21 amino acids) and Chain B (30 amino acids), joined by disulfide bonds
Precursor Preproinsulin → Proinsulin → Insulin + C-peptide
Normal fasting blood glucose 70–100 mg/dl
Half-life in blood Approx. 5–6 minutes
Discovered by Banting and Best (1921)
Synthesis and Secretion

Insulin is synthesized as Preproinsulin in the rough endoplasmic reticulum of beta cells, converted to proinsulin, Then cleaved in the Golgi apparatus into insulin and C-peptide, which are stored in Secretory granules together in equal amounts.

Trigger for Release 
  • Rise in Blood Glucose (main stimulus ) after a meal
  • Amino acids (especially arginine, Leucine)
  • Certain GI hormones - GIP, GLP-1 (increase effect)
  • Parasympathetic (vagal) stimulation
Mechanism of Action 

Insulin binds to Insulin Receptors (Tyrosine kinase receptors) on the call membrane of target cells (liver, Muscle, Adipose tissue). This  triggers GLUT-4 transporters to move to the cell surface, allowing glucose to enter the cell.

Function Of Insulin 
Metabolism Action of Insulin
Carbohydrate ↑ Glucose uptake into cells, ↑ Glycogenesis (glucose → glycogen), ↑ Glycolysis, ↓ Gluconeogenesis
Fat (Lipid) ↑ Lipogenesis (fat synthesis), ↓ Lipolysis (fat breakdown), ↓ Ketogenesis
Protein ↑ Amino acid uptake, ↑ Protein synthesis, ↓ Protein breakdown
Electrolytes ↑ Potassium (K⁺) entry into cells — this is why IV insulin is used to treat hyperkalemia
Important exam point for 2 mark : Insulin drives potassium into cells along with glucose - used clinically as "insulin" + Glucose " therapy for Hyperkalemia .

Types Of Insulin (Very Important ) 
Insulin preparations are classified based on their onset,  peak, and duration of action.
Type Examples Onset Peak Duration
Rapid-acting Insulin Lispro, Aspart, Glulisine 10–15 min 1–2 hrs 3–5 hrs
Short-acting (Regular) Regular/Soluble Insulin (e.g., Actrapid) 30 min 2–4 hrs 6–8 hrs
Intermediate-acting NPH (Isophane) Insulin 1–2 hrs 4–12 hrs 18–24 hrs
Long-acting Insulin Glargine, Detemir 1–2 hrs No pronounced peak 20–24 hrs
Ultra-long-acting Insulin Degludec 30–90 min Minimal peak Up to 42 hrs
Premixed 70/30 (NPH + Regular), 75/25 30 min Dual peak 10–16 hrs
Mnemonic - "Really Sweet, Never Late" (RSNL) : Rapid -> Short -> NPH (intermediate) -> Long acting -- Remember the order from fastest to slowest onset.

Frequently asked 5 marks : Classify insulin based on duration of action with examples - write the tablr above with onset/peak/duration, this is a favorite RGUHS question.

Insulin Regimens 
  • Single Dose Regimen - One injection of long acting insulin daily
  • Split-mixed regimen - combination of short + intermediate acting, given twice daily (Before breakfast and dinner )
  • Basal-Bolus Regimen - Long acting (basal) once daily+  rapid-acting (bolus) before each meal ; mimics normal physiology best .
  • Continuous Subcutaneous insulin infusion (CSII) - Insulin pump, delivers continuous basal + bonus doses 
Sites of insulin injection 
Insulin is given Subcutaneously (SC) in routine practice ; IV route is used only for regular insulin in emergencies (eg , DKA).



Nursing Responsibilities in Insulin Administration 
  1. Check doctors order verify insulin type, Dose and time three check five rights of medication
  2. Check blood glucose level before administration 
  3. Use insulin syringe (u40/u100) matching the insulin strength - Never mix syringe types.
  4. Is mixing two insulins, draw clear (Regular) before  cloudy and NPH clear before cloudy
  5. Roll (do not shake) cloudy insulin vias gently to mix 
  6. Clean injection site with spirit swab
  7. Inject at 90° angle (or 45° in thin patients) into subcutaneous tissue pinch skin fold 
  8. Do not message the site after injection 
  9. Rotate injection site systematically 
  10. Educate patient about timing of insulin in relation to meals 
  11. Monitor for science of hypoglycemia after administration 
  12. Document time, site, dose and blood glucose reading. 
Storage of Insulin 
  • Unopened vials store in refrigerator (2-8° c ), Do not Freeze vial in current use- Can be kept at room temperature for up to 28 days.
  • Protect from Direct sunlight and heat
  • Clumsing,discloration of frosting before use- discard if present.
Common exam questions 10M :
Discuss the nursing responsibilities of a nurse while administrating insulin to a diabetic patient

Complications of Insulin Therapy:
Complication Cause / Feature
Hypoglycemia Most common; from excess dose, missed meal, or increased activity
Lipohypertrophy Fatty lump from repeated injection at the same site
Lipoatrophy Loss of fat tissue at the injection site (immune reaction)
Somogyi Effect Nighttime hypoglycemia → rebound morning hyperglycemia due to counter-regulatory hormone release
Dawn Phenomenon Early morning rise in blood glucose due to normal surge of growth hormone/cortisol; NOT preceded by hypoglycemia
Insulin Allergy Local redness, itching, rarely anaphylaxis
Weight Gain Due to anabolic effect of insulin
Hypoglycemia science and nursing management

Signs and symptoms 

Adrenergic (Early)
  • Sweating
  • Tremors
  • Tachycardia
  • Palpitation 
  • Hunger
  • Anxiety
  • Irritability 
Neuroglycopenic ( Late )
  • Confusion 
  • Seizures
  • Blurred vision 
  • Blurred speech
  • Unconsciousness
  • Coma
Emergency nursing management of hypoglycemia 

  1. If conscious give 15 to 20 fast acting carbohydrate glucose tablets juice recheck sugar after 15 minute (rule of 15)
  2. If unconscious do not give anything orally : Give IV 25% or 50% Dextrose, or IM/SC Glucagon as per order.
  3. Recheck Blood Glucose, Monitor Vitals, and Notify Physician 
  4. ONCE stable, give a complete carbohydrate + protein snacks to prevent recurrence 


Dose Calculation — Quick Formula
D/H × Q Formula
(Used for insulin as well as other drug calculations)

Formula:
(D ÷ H) × Q = Amount to administer

D = Doctor's prescribed dose
H = Dose on hand
Q = Quantity / Volume on hand
Example:
Doctor orders 10 units of Regular Insulin.
Vial is labelled U-100 (100 units/mL).

Calculation:
(10 ÷ 100) × 1 mL = 0.1 mL
Quick Revision Summary

Point Key Fact
Source Beta cells, Islets of Langerhans, Pancreas
Nature Only hypoglycemic hormone in the body
Fastest insulin Rapid-acting (Lispro, Aspart, Glulisine)
Longest insulin Degludec (up to 42 hrs)
Best absorption site Abdomen
Sick rule Clear before cloudy
Storage 2–8°C in fridge; opened vial usable up to 28 days at room temperature
Treatment for hypoglycemia Oral glucose (conscious) / IV dextrose or Glucagon (unconscious)
Exam Questions (RGUHS Pattern )

  • 2 mark - Define Insulin/ Name the types of insulin / What is Somogyi effect .
  • 5 mark - Classify insulin with example / write nursing management of Hypoglycemia.
  • 10 Mark - Discuss nursing Responsibilities in administration of insulin to a diabetic patient with special reference to complications.
Conclusion:
Insulin is protein hormone secreted by beta cells of the islets of langerhans in pancreas insulin also called anabolic hypoglycemic hormone. Normal blood glucose level is 70-100 mg/dl . Insulin is synthesized as prepro insulin in rough endoplasmic reticulum. Insulin Binds to insulin receptors. Insulin is given Subcutaneously (SC) in routine practice, Common sites are Abdomen, Upperarm, Thigh, Buttocks. INSULIN can be store in 2-8°C do not freeze. Dose calculation Formula always use to administrate. 

Disclaimer : 
The information provided on padhohamesha is for educational and informational purposes only. Medical and nursing content should not replace professional medical advice. Always consult a qualified healthcare professional fro medical concerns.
Stay connected with us on 

❤️ Stay Connected With Us
▶️ YouTube Subscribe Now
✈️ Telegram Join Now

Comments

Post a Comment