NEET PG Endocrine Pharmacology Glossary 2026: Insulin Types, Antidiabetics, Thyroid Drugs and Corticosteroids — High-Yield Drug Mechanisms, Side Effects and MCQ Mnemonics

You're staring at another endocrine pharmacology MCQ, and your brain freezes. Was it metformin that causes lactic acidosis, or was that something else? Which insulin peaks at 2-4 hours again? And dont even get started on remembering whether carbimazole or methimazole is the first-line antithyroid drug.

NEET PG 2026 tests endocrine pharmacology heavily — about 8-12 questions per paper. These arent just recall questions anymore. The pattern has shifted to mechanism-based MCQs that test your understanding of drug actions, contraindications, and clinical scenarios. You need more than rote memorization.

This glossary breaks down the 47 highest-yield endocrine drugs into memorable chunks with mnemonics that actually stick. Each drug entry includes the mechanism, key side effects, contraindications, and the exact clinical scenarios NEET PG loves to test.

Insulin and Antidiabetic Drugs

Insulin Classifications and Mechanisms

Insulin remains the cornerstone of diabetes management and a consistent NEET PG favorite. Understanding onset, peak, and duration patterns is crucial for clinical MCQs.

Rapid-Acting Insulins (Mnemonic: "LAG" - Lispro, Aspart, Glulisine)

• Onset: 15 minutes

• Peak: 1-3 hours

• Duration: 3-5 hours

• Clinical use: Pre-meal boluses, DKA management

• NEET PG pearl: These are the only insulins safe for IV administration in DKA

Short-Acting Insulin (Regular)

• Onset: 30 minutes

• Peak: 2-4 hours

• Duration: 6-8 hours

• Mnemonic: "Regular = 2-4-6" (peak at 2-4, lasts 6-8)

• Clinical note: Can be given IV or SC, traditional choice for sliding scale

Intermediate-Acting Insulin (NPH)

• Onset: 1-2 hours

• Peak: 4-8 hours

• Duration: 12-18 hours

• Mnemonic: "NPH = Night Protection for 12 Hours"

• NEET PG trap: NPH causes dawn phenomenon if dose is too low

Long-Acting Insulins

• Glargine: No peak, 24-hour duration ("Glargine = Gradual")

• Detemir: 12-24 hours, weight-neutral

• Degludec: Ultra-long 42-hour duration

Oral Antidiabetic Agents

Metformin (Biguanide)

• Mechanism: Decreases hepatic glucose output, increases insulin sensitivity

• Side effects: GI upset (30% patients), lactic acidosis (rare but fatal)

• Contraindications: eGFR <30, contrast studies, severe illness

• NEET PG favorite: First-line therapy, contraindicated in renal failure

• Mnemonic: "Met-for-min = Meets minimum glucose by blocking liver output"

Our Indian Medical PG endocrine pharmacology lessons dive deeper into metformin's cellular mechanisms and the specific contraindication scenarios that appear in MCQs. Sulfonylureas (Mnemonic: "GLITTERING" - Glipizide, Glyburide, Gliclazide)

• Mechanism: Block K-ATP channels → insulin release

• Side effects: Hypoglycemia (major), weight gain, SIADH-like syndrome

• Contraindications: Kidney/liver disease, elderly (glyburide)

• NEET PG pearl: Cause prolonged hypoglycemia, especially glyburide in elderly

DPP-4 Inhibitors (Mnemonic: "SITAGLIPTIN = SIT A GLIP TIN")

• Mechanism: Prevent GLP-1 degradation

• Side effects: Upper respiratory infections, pancreatitis (rare)

• Advantage: Weight neutral, low hypoglycemia risk

• NEET PG note: Safe in elderly, renal dosing required

SGLT-2 Inhibitors (Mnemonic: "FLOZA drugs" - dapagliflozin, empagliflozin)

• Mechanism: Block glucose reabsorption in kidney

• Side effects: UTIs, genital infections, DKA (euglycemic)

• Benefits: Weight loss, CV protection, HF benefits

• NEET PG trap: Can cause euglycemic DKA even with normal glucose

Practice these drug mechanisms with targeted endocrine pharmacology MCQs that mirror the NEET PG question style.

Thyroid Pharmacology

Antithyroid Agents

Carbimazole/Methimazole

• Mechanism: Inhibits thyroid peroxidase → blocks T3/T4 synthesis

• Side effects: Agranulocytosis (0.3%), hepatotoxicity, skin rash

• Monitoring: CBC every 2 weeks initially

• NEET PG pearl: Carbimazole is prodrug of methimazole

• Mnemonic: "Carb-imazole Carbs the thyroid (blocks synthesis)"

Propylthiouracil (PTU)

• Mechanism: Blocks synthesis + peripheral conversion T4→T3

• Preferred in: Pregnancy (1st trimester), thyroid storm

• Side effects: Hepatotoxicity (black box warning), vasculitis

• NEET PG scenario: Always choose PTU for pregnant hyperthyroid patients

Radioactive Iodine (I-131)

• Mechanism: Beta radiation destroys thyroid follicles

• Contraindications: Pregnancy, breastfeeding, ophthalmopathy

• Side effects: Hypothyroidism (inevitable), worsening eye disease

• NEET PG note: Treatment of choice for Graves disease in non-pregnant adults

Thyroid Hormone Replacement

Levothyroxine (T4)

• Mechanism: Converted to active T3 in tissues

• Dosing: 1.6 μg/kg ideal body weight

• Monitoring: TSH every 6-8 weeks until stable

• Drug interactions: Iron, calcium, PPI reduce absorption

• Mnemonic: "Levo-T4 = Level out T4 slowly"

The thyroid drugs lessons include detailed drug interaction tables that frequently appear in NEET PG MCQs. Liothyronine (T3)

• Use: Myxedema coma, T4→T3 conversion defects

• Onset: Rapid (hours vs days for T4)

• NEET PG scenario: Emergency hypothyroidism treatment

Corticosteroid Pharmacology

Glucocorticoid Classifications

Short-Acting (Mnemonic: "CHAMP" - Cortisone, Hydrocortisone, And Mother Pred)

• Hydrocortisone: Duration 8-12 hours, high mineralocorticoid activity

• Prednisolone: Duration 12-36 hours, intermediate anti-inflammatory

• Clinical use: Replacement therapy (hydrocortisone), inflammation (prednisolone)

Intermediate-Acting

• Methylprednisolone: 12-36 hours, minimal mineralocorticoid activity

• Use: IV pulse therapy, organ transplant rejection

• NEET PG pearl: Preferred for high-dose IV therapy

Long-Acting

• Dexamethasone: 36-72 hours, potent anti-inflammatory

• Betamethasone: 36-72 hours, crosses placenta

• Clinical use: Cerebral edema, fetal lung maturation

• Mnemonic: "Dexa = Deluxe steroid (most potent, longest)"

Corticosteroid Side Effects (High-Yield for MCQs)

Metabolic: Hyperglycemia, weight gain, buffalo hump, moon face Cardiovascular: Hypertension, fluid retention, hypokalemia Musculoskeletal: Osteoporosis, myopathy, growth retardation Immune: Increased infection risk, impaired wound healing Psychiatric: Mood changes, psychosis, insomnia Ocular: Cataracts, glaucoma Dermatologic: Skin atrophy, striae, delayed healing NEET PG mnemonic for steroid side effects: "CUSHINGOID"

• Cataracts

• Ulcers (peptic)

• Skin atrophy

• Hypertension

• Infections

• Necrosis (avascular)

• Growth retardation

• Osteoporosis

• Insomnia/psychiatric

• Diabetes

Our corticosteroid mechanisms lessons include the molecular pathways tested in mechanism-based MCQs.

Mineralocorticoids

Fludrocortisone

• Mechanism: Aldosterone receptor agonist

• Use: Addison disease, orthostatic hypotension

• Side effects: Hypertension, hypokalemia, edema

• Monitoring: Blood pressure, serum K+

• NEET PG note: Only synthetic mineralocorticoid in clinical use

Advanced Antidiabetic Agents

GLP-1 Receptor Agonists

Exenatide, Liraglutide, Semaglutide

• Mechanism: Mimic incretin hormone → glucose-dependent insulin release

• Route: Subcutaneous injection

• Side effects: Nausea (50%), pancreatitis, delayed gastric emptying

• Benefits: Weight loss, CV protection

• NEET PG pearl: Contraindicated in gastroparesis

• Mnemonic: "GLP = Gut Loses Pounds (weight loss effect)"

Alpha-Glucosidase Inhibitors

Acarbose, Miglitol

• Mechanism: Block intestinal α-glucosidases → delay carbohydrate absorption

• Side effects: Flatulence, diarrhea, abdominal pain

• Advantage: No hypoglycemia, no weight gain

• NEET PG note: Treat hypoglycemia with glucose only (not sucrose)

High-Yield MCQ Scenarios and Mnemonics

Scenario 1: Diabetic Emergency Management

Question type: "A diabetic patient presents with DKA. Which insulin should be used?" Answer: Regular insulin IV (only regular and rapid-acting can be given IV) Mnemonic: "DKA = Don't Keep Asking, use Regular IV"

Scenario 2: Thyroid Storm Treatment

Question pattern: "Pregnant woman with thyroid storm needs urgent treatment" Answer: PTU (not carbimazole in pregnancy) Mnemonic: "PTU = Pregnancy Treatment Usually"

Scenario 3: Steroid Withdrawal

Clinical scenario: "Patient on chronic steroids needs surgery" Key point: Stress dose steroids needed to prevent crisis Mnemonic: "Stress = Steroid up the dose"

Scenario 4: Drug Interactions

Common MCQ: "Levothyroxine absorption is decreased by..." Answers: Iron, calcium, PPIs, coffee Mnemonic: "LICC up absorption" (Levo needs empty stomach - no Iron, Calcium, Coffee, Caffeine)

Test your understanding with comprehensive endocrine pharmacology flashcards that use spaced repetition to cement these high-yield facts.

Drug Dosing and Clinical Pearls

Insulin Dosing Calculations

• Initial dose: 0.5-1 unit/kg/day

• Basal:bolus ratio: 50:50

• Correction factor: 1800 ÷ total daily dose

• NEET PG formula: If total daily dose = 36 units, correction factor = 1800 ÷ 36 = 50 (1 unit drops glucose by 50 mg/dL)

Steroid Equivalency (Relative Potency)

• Hydrocortisone: 1 (reference)

• Prednisolone: 4x

• Methylprednisolone: 5x

• Dexamethasone: 25-30x

• NEET PG calculation: 20mg prednisolone = 5mg hydrocortisone × 4 = 80mg hydrocortisone

Thyroid Hormone Conversion

• T4 to T3 ratio: 4:1 by weight

• TSH suppression: Goal <0.1 for thyroid cancer, 0.1-0.5 for benign disease

• Replacement dose: 1.6 μg/kg lean body weight

Contraindications and Drug Safety

Metformin Contraindications (NEET PG High-Yield)

• eGFR <30 mL/min/1.73m²

• Contrast procedures (hold 48 hours)

• Severe illness (shock, sepsis, MI)

• Alcohol abuse

• Mnemonic: "Met CRASHES" - Contrast, Renal failure, Alcohol, Shock, Heart failure, Elderly sick

Steroid Contraindications

• Systemic fungal infections

• Live vaccines (while on steroids)

• Psychotic disorders (relative)

• Peptic ulcer disease (relative)

Thyroid Drug Monitoring

• Carbimazole: CBC (agranulocytosis), LFTs (hepatotoxicity)

• PTU: LFTs mandatory (black box warning for hepatotoxicity)

• Levothyroxine: TSH every 6-8 weeks, cardiac symptoms in elderly

Frequently Asked Questions

Which insulin can be given IV in DKA?

Only regular insulin and rapid-acting insulins (lispro, aspart, glulisine) can be administered intravenously. NPH and long-acting insulins are never given IV.

What's the first-line antithyroid drug in pregnancy?

PTU is preferred in the first trimester due to lower teratogenicity risk. Carbimazole can be used in second and third trimesters.

How long before surgery should metformin be stopped?

Hold metformin 48 hours before any contrast procedure or major surgery. Resume after confirming normal renal function.

Which steroid has the longest duration of action?

Dexamethasone has the longest half-life (36-72 hours) and is most potent. Its used for cerebral edema and fetal lung maturation.

Can SGLT-2 inhibitors cause DKA?

Yes, SGLT-2 inhibitors can cause euglycemic DKA (normal glucose levels but ketosis). This is a unique and dangerous side effect.

What's the mechanism of sulfonylurea-induced hypoglycemia?

Sulfonylureas block K-ATP channels on pancreatic beta cells, causing sustained insulin release regardless of glucose levels. This leads to prolonged hypoglycemia, especially in elderly patients.

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