Lesson
Insulin Physiology and Regimen Architecture
Insulin replacement recreates basal restraint, meal coverage, and correction while preserving flexibility and safety.
- Basal secretion
- Meal response
- Correction
- Pattern management
- High-alert risk
Restrain hepatic glucose output
Match food, timing, and active insulin
Return glucose without stacking
Rebuild physiologic roles
Basal insulin restrains hepatic glucose output between meals and overnight. Prandial insulin covers expected nutrient absorption. Correction insulin addresses glucose above an individualized target. A dose can serve more than one purpose in premixed regimens, but the purposes still need to be understood.
Separate pattern from noise
Adjust the component that explains a repeated pattern. Fasting glucose primarily evaluates basal exposure when overnight food, exercise, illness, and late boluses are considered. Postmeal glucose evaluates meal timing, carbohydrate coverage, meal composition, and active insulin.
Treat insulin as high alert
Wrong product, wrong concentration, wrong device, dose transcription, duplicate correction, interrupted pump delivery, and skipped food can cause severe harm. Every transition requires product, concentration, units, timing, device, and recent glucose verification.
Quick check
Lesson
Insulin Products and Action Profiles
Human and analog insulins differ in onset, peak, duration, concentration, route, and device, so product names cannot be treated as interchangeable labels.
- Rapid and ultra-rapid
- Regular
- NPH
- Long and ultra-long
- Concentrated insulin
Rapid, ultra-rapid, regular, or inhaled
NPH, long acting, or ultra-long acting
Verify U-100, U-200, U-300, or U-500
Distinguish meal insulins
Rapid and ultra-rapid analogs act earlier and for less time than regular human insulin. The best administration time depends on the exact product, current glucose, anticipated food, gastric emptying, and risk of delayed intake. Inhaled insulin has distinct pulmonary screening and is not basal replacement.
Distinguish basal profiles
NPH has a clinically relevant peak and greater timing variability. Long-acting analogs provide flatter basal exposure, while glargine U-300 and degludec extend duration and can reduce nocturnal hypoglycemia compared with shorter basal formulations in appropriate populations.
Respect concentrations
U-100, U-200, U-300, and U-500 products differ in delivery devices and pharmacology. Never withdraw concentrated pen insulin into a syringe. U-500 regular insulin has both prandial and basal characteristics and requires dedicated prescribing, dispensing, education, and monitoring.
Quick check
Lesson
Dose Design and Calculations
Weight, current exposure, carbohydrate intake, correction sensitivity, renal function, and glucose patterns support an initial estimate that must be clinically tested and refined.
- Total daily dose
- Basal fraction
- Carbohydrate ratio
- Correction factor
- Quantity calculation
Create a cautious starting estimate
Account for food, target, and active insulin
Calculate total need and round containers up
Estimate without pretending certainty
A metabolically stable adult with newly diagnosed type 1 diabetes may begin near 0.5 units/kg/day, while current ADA guidance describes a broader 0.2 to 0.6 units/kg/day range at diagnosis and approximately 30 to 50 percent as basal. Illness, puberty, pregnancy, kidney decline, residual secretion, and prior therapy change the estimate.
Calculate meal and correction doses
An insulin-to-carbohydrate ratio estimates grams covered by one unit. A correction factor estimates the glucose reduction from one unit. Both require pattern-based validation. Subtract active insulin when the delivery system or plan requires it to avoid stacking.
Calculate supply accurately
Convert the prescribed units per day into total units for the intended days, include labeled priming or waste when policy supports it, divide by units per pen or vial, and round containers up. State beyond-use dating separately because days supply and in-use stability answer different questions.
Quick check
Lesson
Type 1 Diabetes: Basal-Bolus and Pattern Adjustment
Type 1 diabetes requires uninterrupted basal insulin plus meal and correction coverage adapted to food, activity, illness, and glucose trends.
- Basal-bolus
- Carbohydrate matching
- Correction
- Exercise
- Ketone prevention
Prevent fasting and pump-interruption ketosis
Adjust for food, trend, activity, and timing
Change the dose that explains the pattern
Preserve basal insulin
Near-absent beta-cell function makes insulin essential. Holding all insulin during fasting can precipitate ketosis. If intake changes, prandial dosing changes, but basal coverage generally continues with individualized adjustment and monitoring.
Match bolus to context
Mealtime education includes carbohydrate, and when relevant fat and protein, current glucose, trend arrows, anticipated activity, delayed gastric emptying, and active insulin. The optimal premeal interval depends on the exact insulin and whether food is certain.
Adjust from patterns
Recurrent fasting lows call for review of basal exposure, overnight corrections, exercise, alcohol, and food. Recurrent postmeal highs call for review of timing, ratio, meal estimation, infusion function, and missed doses before increasing every component.
Quick check
Lesson
Type 2 Diabetes: Basal Initiation and Titration
Basal insulin is commonly started when noninsulin therapy is insufficient or when symptomatic or severe hyperglycemia requires prompt insulinization.
- Initiation thresholds
- Starting dose
- Fasting titration
- Overbasalization
- Deintensification
Use weight, severity, and current therapy
Review several days and nocturnal safety
Fasting at goal redirects the plan
Know when insulin is needed
Symptoms of hyperglycemia, catabolism, crisis, A1C above 10 percent, or glucose at least 300 mg/dL can support insulin initiation. Without severe hyperglycemia or crisis, GLP-1-based therapy is generally considered before insulin when clinically appropriate.
Start and titrate basal insulin
For type 2 diabetes, ADA guidance describes basal initiation near 0.1 to 0.2 units/kg/day with individualized titration. Adjust from fasting patterns while evaluating nocturnal hypoglycemia, adherence, injection technique, concurrent medicines, and changing kidney function.
Recognize overbasalization
Escalating basal insulin despite fasting glucose at goal, nocturnal lows, a large bedtime-to-morning fall, or persistent postmeal hyperglycemia can add hypoglycemia and weight without solving meal exposure. Reassess prandial needs and regimen design.
Quick check
Lesson
Prandial, Premixed, and Combination Intensification
When basal therapy no longer controls the complete day, intensification should fit meal regularity, flexibility, dexterity, hypoglycemia risk, and treatment burden.
- Basal plus
- Basal-bolus
- Premixed insulin
- GLP-1 combination
- Simplification
Add one targeted meal dose
Adjust meals independently
Accept fixed proportions and meal regularity
Add targeted prandial coverage
A common approach adds 4 units or about 10 percent of the basal dose at the largest meal or greatest excursion, then titrates from postmeal patterns. Progress to additional meals only when needed.
Compare flexibility and simplicity
Basal-bolus plans allow independent meal adjustment. Premixed insulin can reduce injection decisions but fixes basal and prandial proportions, requires more consistent meal timing, and can increase hypoglycemia when intake varies.
Simplify when burden exceeds value
Basal insulin combined with appropriate GLP-1-based therapy can reduce prandial requirements for some people. Older age, cognitive or functional change, recurrent hypoglycemia, food insecurity, and changing goals can justify deliberate simplification.
Quick check
Lesson
Pens, Pumps, CGM, and Automated Insulin Delivery
Delivery technology can improve outcomes and reduce burden when device selection, training, backup plans, and data interpretation match the user and caregiver.
- Pens
- Connected pens
- Pumps
- CGM
- Automated delivery
Match device to skill, preference, and access
Use trend and pattern data
Understand settings, failure, ketones, and injections
Choose the delivery system with the user
Pens are preferred for many people using multiple daily injections, while syringes remain appropriate in selected contexts. Vision, dexterity, cognition, numeracy, caregiver support, coverage, product availability, and dose size shape the choice.
Use automation without surrendering judgment
Current ADA guidance prefers automated insulin delivery for people with type 1 diabetes and offers it broadly to insulin-treated adults when needs and preferences fit. The system still requires meal interaction, site care, alerts, supply management, and manual-mode understanding.
Prepare for device failure
Pump interruption removes rapid-acting basal delivery and can produce ketosis quickly. Users need backup long-acting and injection instructions, ketone supplies, correction guidance, emergency thresholds, current settings, and access to replacement supplies.
Quick check
Lesson
Administration, Mixing, Storage, and Disposal
Correct preparation, injection, site rotation, storage, labeling, and disposal preserve dose accuracy and absorption while preventing injury and product failure.
- Priming
- Injection technique
- Site rotation
- Mixing
- Storage
Product, concentration, units, and device
Rotate sites and avoid lipohypertrophy
Track open date, temperature, and discard date
Prepare and inject accurately
Use a new needle, prime a pen according to its label, dial the intended units, inject subcutaneously, and hold the needle in place for the required device time. Never share pens, even when the needle is changed.
Protect tissue and absorption
Rotate within a consistent anatomic region and avoid lipohypertrophy, scarring, inflammation, and intramuscular injection. Injecting repeatedly into lipohypertrophy makes absorption unpredictable and can change insulin needs when healthy tissue is resumed.
Store and mix by product
Unopened insulin is generally refrigerated within the product's labeled range. In-use room-temperature stability varies by product and device and must be checked, not memorized as one universal 28-day rule. When compatible NPH and short-acting insulin are mixed, draw clear before cloudy. Never mix glargine, degludec, or detemir with other insulins.
Quick check
Lesson
Hypoglycemia, Exercise, Illness, and Sick-Day Safety
Insulin safety requires proactive recognition, rescue access, dose adaptation, and explicit rules for food, activity, alcohol, illness, vomiting, and ketones.
- Hypoglycemia levels
- Glucagon
- Exercise
- Alcohol
- Sick days
Confirm, treat, and find the cause
Keep ready-to-use rescue with trained supporters
Change monitoring, food, and insulin deliberately
Treat and investigate hypoglycemia
Treat conscious hypoglycemia with measured fast-acting glucose, recheck, and repeat as needed. Severe events require help and glucagon. Every person taking insulin should have glucagon available, preferably a ready-to-use formulation, with trained supporters.
Plan exercise and alcohol
Activity can increase insulin sensitivity during and after exercise. Adapt insulin, carbohydrate, and monitoring to timing and intensity. Alcohol can suppress hepatic glucose release and create delayed hypoglycemia, particularly without food.
Use sick-day rules
Continue basal insulin, monitor glucose more often, check ketones when indicated, maintain fluids and carbohydrate as tolerated, and know emergency thresholds. Vomiting, rising ketones, dyspnea, altered mental status, inability to keep fluids down, or persistent severe glucose abnormalities require urgent care.
Quick check
Lesson
Hospital, Procedure, and Transition Safety
Nutrition, organ function, stress, steroids, procedures, and changes of care alter insulin needs quickly and make reconciliation essential.
- Basal-prandial-correction
- NPO care
- Steroids
- IV transition
- Medication reconciliation
Basal, prandial, and individualized correction
Preserve basal and prevent duplicate dosing
Insulin, concentration, supplies, rescue, and follow-up
Use scheduled inpatient insulin
For most noncritically ill hospitalized people who are eating, basal, prandial, and correction insulin is preferred. With poor intake, basal plus correction may fit. Prolonged correction-only treatment is discouraged because it reacts after hyperglycemia instead of preventing it.
Adapt to changing physiology
Critical illness, glucocorticoids, nutrition support, kidney injury, dialysis, and procedures change needs. Match insulin timing to the glucose effect of nutrition and steroids, and reduce exposure when intake or clearance declines.
Reconcile transitions
When moving from intravenous to subcutaneous insulin, provide overlap based on the selected basal product and protocol. At discharge, reconcile stopped and resumed medicines, exact insulin products, concentrations, devices, supplies, monitoring, hypoglycemia rescue, affordability, and follow-up.
Quick check
Module test
Check the connections.
Each attempt draws 10 questions from the complete 100 question bank.
Each attempt draws a fresh set and rearranges the answer choices.
References
Current clinical foundation.
Lecture material was synthesized with the following contemporary guidance. Verify local policy and current guidance before applying clinical information.