Prescribing Guides
Insulin Prescribing Guide for Indian Clinical Practice
Comprehensive insulin prescribing guide for Indian clinicians covering types, initiation, titration, storage in Indian conditions and NEET PG pharmacology.
MedNext Editorial Team | 2026-08-01 | 10 min read
Insulin Prescribing Guide for Indian Clinical Practice
Comprehensive insulin prescribing guide for Indian clinicians covering types, initiation, titration, storage in Indian conditions and NEET PG pharmacology.
Insulin is the cornerstone of type 1 diabetes management and an essential treatment for type 2 diabetes when oral therapies fail. India is one of the world's largest insulin markets, with significant biosimilar manufacturing. This guide covers insulin types, initiation, titration, and practical prescribing considerations for the Indian context.
Clinical Pharmacology Overview
Insulin is a peptide hormone that binds to the insulin receptor (a receptor tyrosine kinase) on target cells, promoting glucose uptake, glycogen synthesis, lipogenesis, and protein synthesis while inhibiting gluconeogenesis, glycogenolysis, lipolysis, and proteolysis. Exogenous insulin replaces or supplements endogenous secretion.
Key pharmacokinetic categories:
Rapid-acting (lispro, aspart, glulisine): onset 10-20 min, peak 1-2 hours, duration 3-5 hours.
Short-acting (Regular/Soluble): onset 30-60 min, peak 2-4 hours, duration 6-8 hours.
Intermediate-acting (NPH/Isophane): onset 1-2 hours, peak 4-8 hours, duration 12-16 hours.
Long-acting (glargine, detemir): onset 1-2 hours, minimal peak, duration 20-24 hours.
Ultra-long-acting (degludec): onset 1-2 hours, no peak, duration more than 42 hours.
Premixed: combinations like 30/70 (30% Regular + 70% NPH) or analogue premixes.
Indian Brand Names
- Biocon: Insugen (Regular, NPH, premix), Basalog (glargine biosimilar)
- Novo Nordisk: Actrapid (Regular), Mixtard (premix), NovoRapid (aspart), Tresiba (degludec)
- Sanofi: Lantus (glargine), Apidra (glulisine), Toujeo (glargine U-300)
- Eli Lilly: Huminsulin (Regular, NPH), Humalog (lispro), Basaglar (glargine)
- Wockhardt: Wosulin (Regular, NPH, premix)
Approved Indications in Indian Clinical Practice
- Type 1 diabetes mellitus (always requires insulin)
- Type 2 diabetes mellitus (when oral agents fail or are contraindicated)
- Gestational diabetes mellitus (when dietary measures are inadequate)
- Diabetic ketoacidosis (DKA) and hyperglycaemic hyperosmolar state (HHS)
- Perioperative glycaemic management
- Critical illness (insulin infusion for tight glucose control)
- Severe hyperglycaemia at presentation (glucose above 300 mg/dL or HbA1c above 10%)
Dosing in Adults
Type 1 DM: total daily dose 0.4-1.0 units/kg/day. Typically divided as 40-50% basal + 50-60% bolus (basal-bolus regimen).
Type 2 DM (basal insulin initiation): start 10 units or 0.1-0.2 units/kg at bedtime. Titrate by 2-4 units every 3-7 days to fasting glucose target (under 130 mg/dL per ADA, or as per clinician's target).
Premixed insulin: start 10-12 units before the largest meal or split before breakfast and dinner. Titrate based on glucose pattern.
DKA: 0.1 units/kg/hour Regular insulin IV infusion (after initial bolus if used per protocol). Switch to subcutaneous when stable.
Sliding scale (hospital): Regular insulin based on blood glucose readings -- being replaced by scheduled basal-bolus protocols in modern practice.
Important Drug Interactions
- Beta-blockers: mask hypoglycaemia symptoms (tachycardia, tremor) but sweating is preserved
- Corticosteroids: raise blood glucose, may necessitate insulin dose increase
- Thiazides: may worsen glycaemic control
- ACE inhibitors: may enhance insulin sensitivity, increasing hypoglycaemia risk
- Thiazolidinediones: additive hypoglycaemia and fluid retention risk
- Alcohol: can cause delayed hypoglycaemia
- Sulphonylureas: additive hypoglycaemia when combined with insulin
Side Effects and Monitoring
Common: hypoglycaemia (the most important and most dangerous side effect), weight gain (typically 2-4 kg with insulin initiation), injection site reactions (lipodystrophy, lipohypertrophy).
Serious: severe hypoglycaemia (seizures, coma, death), hypokalemia (during DKA treatment).
Lipohypertrophy: common in India due to injection site reuse. Rotate injection sites systematically.
Monitoring: self-monitoring of blood glucose (SMBG), HbA1c every 3-6 months, injection sites (check for lipohypertrophy), weight, renal function (dose adjustment may be needed as renal function declines).
Storage in Indian Conditions
Unopened: refrigerate at 2-8 degrees Celsius. Do NOT freeze.
In use: can be kept at room temperature below 30 degrees Celsius for up to 28 days (check specific product instructions). In Indian summers where temperatures regularly exceed 40 degrees Celsius, advise patients to use insulated pouches or clay pot storage if refrigeration is not available.
Never expose to direct sunlight or leave in parked cars.
Special Populations
Pregnancy: Insulin is the first-line pharmacotherapy for both gestational and pre-existing diabetes in pregnancy. Regular insulin and NPH have the longest safety track record. Rapid-acting analogues (lispro, aspart) are also approved. Long-acting analogues (glargine, detemir) are used but with less pregnancy data.
Renal impairment: Insulin clearance decreases with declining GFR. Reduce dose and monitor frequently as GFR falls below 30 mL/min. Risk of hypoglycaemia increases significantly.
Elderly: Start low, titrate slowly. Less stringent HbA1c targets (under 8%) to avoid hypoglycaemia. Simplify regimens (premixed or basal-only when possible).
NEET PG High-Yield Points
- Insulin binds receptor tyrosine kinase (NOT a GPCR)
- Insulin promotes GLUT4 translocation in muscle and adipose tissue
- Hypoglycaemia is the most important adverse effect
- Regular insulin is the only insulin given IV (used in DKA)
- NPH (isophane) contains protamine -- turbid appearance
- Glargine: precipitates at physiological pH in subcutaneous tissue, providing slow release (pH 4 solution)
- Insulin lispro: reversal of proline-lysine at B28-B29 positions
- DKA protocol: IV insulin 0.1 U/kg/hr, monitor K+ (replace before insulin if K+ < 3.3)
- Somogyi effect vs Dawn phenomenon -- classic exam question
- Insulin resistance criteria: requiring more than 200 units/day
Indian Regulatory Status
Insulin is a Schedule H drug under the Drugs and Cosmetics Act. It is included in the NLEM of India. India is a major global insulin manufacturer, with Biocon being one of the world's largest biosimilar insulin producers. Biosimilar insulins (Basalog, Insugen) have made insulin significantly more affordable in India. The CDSCO regulates insulin as a biological product. Insulin does not require a controlled substance license but does require a prescription. Cold chain maintenance during distribution is regulated.
Frequently Asked Questions
What is the starting dose of insulin for type 2 diabetes?
For most type 2 diabetes patients initiating basal insulin, start at 10 units or 0.1-0.2 units/kg at bedtime or in the morning. Titrate by 2-4 units every 3-7 days based on fasting blood glucose. Indian guidelines (RSSDI) follow a similar approach.
How should insulin be stored in India's hot climate?
Unopened insulin should be refrigerated at 2-8 degrees Celsius. Once opened, insulin pens and vials can be kept at room temperature (below 30 degrees Celsius) for up to 28 days (varies by product). In India's hot climate, avoid leaving insulin in cars, direct sunlight, or near heat sources. Insulin should never be frozen.
What are the commonly available insulin brands in India?
Major brands include Lantus and Apidra (Sanofi), NovoRapid and Tresiba (Novo Nordisk), Humalog and Basaglar (Eli Lilly), Insugen and Basalog (Biocon -- India's major biosimilar insulin manufacturer), and Wosulin (Wockhardt).
What is the difference between human insulin and analogue insulin?
Human insulin (Regular and NPH) is structurally identical to endogenous insulin. Analogue insulins are modified to alter pharmacokinetics -- rapid-acting analogues (lispro, aspart, glulisine) have faster onset, and long-acting analogues (glargine, detemir, degludec) have flatter, longer profiles. Analogues reduce hypoglycaemia risk but are more expensive.
When is insulin necessary in type 2 diabetes?
Insulin is needed when oral agents fail to achieve glycaemic targets (HbA1c persistently above 8-9% on maximum oral therapy), in acute illness, perioperatively, in pregnancy (GDM/pre-existing), with severe hyperglycaemia at presentation (glucose above 300 mg/dL or ketosis), and in pancreatic insufficiency.
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