• The memory mnemonics from your notes (like PYARA PATI, SITA ALOK LINA, BMW) are already incorporated
• For 10-mark questions: write headings clearly — Classification → MOA → PK → Uses → ADR
• The "Quick Revision Table" at the end is perfect for last-minute reading before the exam

---

📝 HORMONES PHARMACOLOGY — IMPORTANT POINT NOTES

MUHS 2nd Year MBBS

---

🔵 TOPIC 1: THYROID HORMONES

• T — Trapping (iodide taken into follicular cells via NIS — sodium/iodide symporter)
• O — Oxidation (iodide → iodine by peroxidase)
• I — Iodination (iodine + tyrosine → MIT and DIT)
• H — Hormone formation / Coupling (MIT+DIT = T3 / DIT+DIT = T4) — by thyroid peroxidase
• R — Release (controlled by TSH; endocytosis + proteolysis of thyroglobulin)

• Most hormone released from thyroid is T4 (less potent)
• T4 → T3 conversion occurs in liver and kidney
• T3 is more potent than T4

---

🔵 TOPIC 2: ANTITHYROID DRUGS

Classification (easy):

• Block synthesis → Thioamides (PTU, Methimazole, Carbimazole)
• Block iodide trapping → Ionic inhibitors (Thiocyanate, Perchlorate, Nitrate)
• Block hormone release → Iodine/Iodides (Lugol's iodine, KI)
• Destroy thyroid tissue → Radioactive iodine (¹³¹I)

---

A) THIOAMIDES — PTU, Methimazole, Carbimazole

1. Iodide → Iodine conversion blocked
2. Iodination of tyrosine blocked
3. Coupling of MIT + DIT blocked

• Also blocks peripheral T4 → T3 conversion (that's why PTU used in thyroid storm)

• All well absorbed orally
• Carbimazole is a prodrug → converted to methimazole in body
• Accumulate in thyroid gland

• Skin rashes — most common
• Agranulocytosis — rare but dangerous
• Joint pain, fever, hepatitis, nephritis

1. Long-term hyperthyroidism (Graves' disease, toxic nodular goitre)
2. Preoperatively before thyroidectomy → to make patient euthyroid
3. With radioactive iodine → for initial control (¹³¹I is slow)
4. Thyroid storm (PTU preferred)

• Carbimazole/Methimazole preferred for long-term → long acting, not hepatotoxic
• PTU preferred in thyroid storm and pregnancy (crosses placenta less)

---

B) IODINE AND IODIDES

• Oldest antithyroid agents
• Most rapid acting antithyroid drugs
• Preparations: Lugol's iodine (5% iodine + 10% KI), Ipodate sodium, Iopanoic acid

• Preoperatively before thyroidectomy (makes gland firm, small, less vascular → less bleeding during surgery)
• Thyroid storm
• KI as expectorant (mucolytic)
• Tincture of iodine as antiseptic
• Iodized salt → prophylaxis of endemic goitre

• Type III hypersensitivity → angioedema, laryngeal oedema, arthralgia, fever, eosinophilia

---

C) RADIOACTIVE IODINE (¹³¹I)

• ¹³¹I half-life = 8 days → therapeutic use
• ¹²³I half-life = 13 hours → diagnostic scan

• Hyperthyroidism (Graves' disease, toxic nodular goitre) — especially elderly + cardiac patients
• Adenoma/carcinoma when surgery not feasible

---

🔵 TOPIC 3: THYROID STORM (THYROID CRISIS)

• Hyperpyrexia (very high fever)
• Cardiac arrhythmias (atrial fibrillation)
• Nausea, vomiting, diarrhoea
• Mental confusion / coma

1. Hospitalization + supportive care (cooling, hydration, sedation, antibiotics)
2. Propranolol IV 1-2 mg every 4 hours → controls tachycardia, tremors; blocks T4→T3 conversion
3. PTU via nasogastric tube → blocks synthesis + T4→T3 conversion
4. Sodium ipodate 0.5 g orally → blocks hormone release + T4→T3 conversion
5. Diltiazem → if propranolol is contraindicated
6. Hydrocortisone 100 mg IV every 8 hrs → blocks T4→T3; corrects adrenal insufficiency

---

🔵 TOPIC 4: INSULIN

Basic Facts:

• Made by β-cells of pancreatic islets
• Route: preproinsulin → proinsulin → insulin (C-peptide removed)
• Structure: A chain + B chain connected by 2 disulphide bridges

Actions:

• ↑ glucose uptake, glycogen synthesis, protein synthesis, lipogenesis
• ↓ gluconeogenesis, glycogenolysis, lipolysis, ketogenesis

Mechanism of Action:

• Receptor = Tyrosine kinase receptor (2α + 2β subunits)
• α subunit = extracellular (binds insulin)
• β subunit = transmembrane with tyrosine kinase activity
• Binding → tyrosine kinase activation → phosphorylation cascade → glucose enters cell

Pharmacokinetics:

• Destroyed in gut → NOT oral
• Route: SC (subcutaneous) usually; IV only in emergencies (regular insulin)
• Half-life after IV = ~6 minutes (liver + kidney metabolize)

Insulin Preparations (by duration):

Indications:

1. Type 1 DM (all patients, always)
2. DKA
3. Non-ketotic hyperglycaemic coma
4. Diabetes in pregnancy
5. Stress (surgery, infection, trauma) in diabetics
6. Type 2 DM when oral drugs fail

Site of Injection (SC): Abdomen, buttock, anterior thigh, dorsal arm

Complications:

---

🔵 TOPIC 5: DIABETIC KETOACIDOSIS (DKA)

• Anorexia, nausea, vomiting
• Polyuria, abdominal pain
• Hypotension, tachycardia
• Kussmaul breathing (hyperventilation)
• Altered consciousness → coma

1. Insulin — Regular insulin IV bolus 0.2–0.3 U/kg → then 0.1 U/kg/hr infusion
   • Blood glucose should ↓ by 10% in first hour
   • Once conscious → shift to SC insulin
2. Fluids — Normal saline 1 L/hr → reduce gradually
   • When blood glucose reaches ~250 mg/dL → switch to 5% dextrose + normal saline (prevents hypoglycaemia + cerebral oedema)
3. Potassium — After insulin, K⁺ shifts into cells → hypokalaemia
   • Give KCl 10–20 mEq/hr after 4 hours of insulin
   • Monitor serum K⁺ and ECG
4. Sodium bicarbonate — IV if severe acidosis
5. Phosphate — If severe hypophosphataemia
6. Antibiotics — For associated infection

---

🔵 TOPIC 6: ORAL ANTIDIABETIC DRUGS

Classification (Simple):

---

A) SULPHONYLUREAS

1. Hypoglycaemia — MC complication (especially glibenclamide, chlorpropamide — long acting); avoid glibenclamide in elderly
2. GI disturbances (nausea, vomiting, flatulence)
3. Weight gain
4. Skin rashes, photosensitivity
5. Teratogenic — NOT safe in pregnancy

---

B) METFORMIN (Biguanide)

1. Activates AMPK → ↓ hepatic gluconeogenesis (main action)
2. ↑ peripheral glucose utilization in muscle and fat
3. ↓ intestinal absorption of glucose

• Does NOT stimulate insulin secretion → improves insulin sensitivity

• Metallic taste, nausea, vomiting, diarrhoea, weight loss
• Lactic acidosis — most serious (rare)
• Vitamin B12 deficiency — on prolonged use (malabsorption)
• Does NOT cause hypoglycaemia ✅

• Drug of choice in obese Type 2 DM
• Protects against vascular complications
• No hypoglycaemia

---

C) PIOGLITAZONE (Thiazolidinedione)

---

D) ACARBOSE (α-Glucosidase inhibitor)

• Must be taken just before food
• Best for obese Type 2 DM patients
• Side effects: flatulence, fullness, diarrhoea (all GI — because undigested carbs ferment in colon)

---

🔵 TOPIC 7: CORTICOSTEROIDS

Classification:

• Short acting: Hydrocortisone (Cortisol)
• Intermediate acting: Prednisolone, Methylprednisolone, Triamcinolone, Deflazacort
• Long acting: Dexamethasone, Betamethasone
• Mineralocorticoids: Aldosterone, Fludrocortisone, DOCA

---

Pharmacological Actions:

• Dexamethasone, betamethasone, triamcinolone → NO Na⁺ retention

---

Adverse Effects — Remember "COME BUGS":

• C — Cushing's (moon face, buffalo hump)
• O — Osteoporosis + fractures
• M — Muscle weakness, myopathy
• E — Electrolyte changes (Na⁺↑, K⁺↓), oedema
• B — Blood sugar ↑ (diabetes aggravated)
• U — Ulcer (peptic)
• G — Growth retardation in children; Glaucoma + cataract
• S — Suppression of immunity → infections (TB reactivation, candidiasis, herpes)

---

Therapeutic Uses — All 14:

1. Rheumatoid arthritis — symptomatic relief (doesn't stop progression)
2. Osteoarthritis — intra-articular injection
3. Rheumatic fever with carditis + CCF
4. Gout — reserve drug (when NSAIDs fail)
5. Allergic diseases — hay fever, urticaria, angioedema, anaphylaxis
6. Bronchial asthma — IV hydrocortisone (acute); inhaled beclomethasone/budesonide (chronic)
7. Collagen diseases — polymyositis, polyarteritis nodosa, dermatomyositis
8. Nephrotic syndrome — first-line drug
9. Ocular diseases — topical/subconjunctival/systemic
10. Skin diseases — topical preferred
11. Haematological — autoimmune haemolytic anaemia; lymphomas, leukaemia, Hodgkin's, myeloma
12. Cerebral oedema — very effective for brain tumours, metastasis, TB meningitis; least effective in head injury
13. Ulcerative colitis — methylprednisolone retention enema
14. Septic shock — prompt IV glucocorticoids may be life-saving

---

🔵 TOPIC 8: HORMONAL CONTRACEPTIVES

Types:

• Combined pill (Oestrogen + Progestin)
• Mini pill (Progestin only)
• Emergency/Postcoital pill
• Injectable

---

Combined Pill — Schedule:

• 1 tablet daily for 21 days → 7-day gap → repeat
• Efficacy: 98–99.9%

Mini Pill — Schedule:

• 1 tablet daily continuously (no gap)
• Efficacy: 96%

---

Mechanism of Combined Pill — 4 ways:

1. ↓ FSH + LH by negative feedback on hypothalamus-pituitary → no ovulation (main action)
2. Tubal + uterine contractions → interfere with fertilization
3. Endometrium made unsuitable for implantation
4. Progestin → thick cervical mucus → blocks sperm penetration

---

Emergency Contraception (Morning After Pill):

• Used within 72 hours of unprotected intercourse
• Levonorgestrel 0.75 mg × 2 doses (most common)
• Mifepristone 600 mg single dose (antiprogestin)
• Ulipristal — can be used up to 120 hours
• Mechanism: interferes with implantation + anti-ovulatory

---

Beneficial Effects:

• ↓ Dysmenorrhoea + premenstrual tension
• ↓ Iron deficiency anaemia (less menstrual loss)
• ↓ Pelvic inflammatory disease + endometriosis
• ↓ Risk of ovarian and endometrial cancer ✅

---

Adverse Effects:

• Early: Nausea, vomiting, headache, breakthrough bleeding
• Late: Weight gain, fluid retention, acne, skin pigmentation, BP ↑
• Serious (long-term): Venous thromboembolism (especially smokers), risk of MI + stroke (in diabetes/hypertension), gallstones, breast cancer, benign liver tumours
• Impaired glucose tolerance (rare with low-dose)

---

Injectable Contraceptives:

---

🔵 TOPIC 9: UTERINE RELAXANTS (TOCOLYTICS)

Classification:

• β₂-agonists: Ritodrine, Salbutamol, Terbutaline, Isoxsuprine
• Calcium channel blockers: Nifedipine
• Oxytocin antagonist: Atosiban
• Others: Magnesium sulfate, Progesterone, Nitrates, Halothane

Uses:

1. Preterm labour — to delay it
2. Threatened abortion
3. Dysmenorrhoea

β₂-agonists — Key Points:

• Adverse effects: Tachycardia, palpitations, arrhythmias, pulmonary oedema, hyperglycaemia, hypokalaemia
• Avoid in: Pregnant women with diabetes or heart disease

NSAIDs (Indomethacin) as tocolytic:

• Blocks PG synthesis → uterine relaxation
• NOT used for preterm labour → risk of premature closure of ductus arteriosus → pulmonary hypertension
• OK for dysmenorrhoea only

---

🔵 TOPIC 10: UTERINE STIMULANTS (OXYTOCICS)

Classification:

• Posterior pituitary: Oxytocin, Desamino-oxytocin
• Ergot alkaloids: Ergometrine, Methylergometrine
• Prostaglandins: PGE₂ (Dinoprostone), PGF₂α (Dinoprost), Carboprost (15-methyl PGF₂α), Misoprostol
• Others: Ethacridine, Quinine

---

OXYTOCIN — Most Important

• Binds to G-protein coupled receptor on myometrium
• → ↑ IP₃ → releases Ca²⁺ from intracellular stores
• → ↑ PG production by endometrium
• → Uterine contraction

---

Uses of Oxytocin — 4 main:

• Given by IV infusion
• Start low dose, monitor and adjust
• Monitor: uterine contractions, BP, fetal + maternal heart rate

• Contracts uterine muscle → compresses blood vessels → stops bleeding
• Preferred over ergot derivatives (fewer side effects)
• Given IM (prevention) or IV infusion (treatment)

---

⚡ SUPER QUICK REVISION — ALL TOPICS

---

📌 Exam formula: Classification → Mechanism → Uses → Adverse Effects = full marks on any question

⚡ HORMONES PHARMACOLOGY — SHORT IMPORTANT POINTS

---

🔵 1. THYROID HORMONES

• Thyroid makes T3, T4, Calcitonin
• Synthesis steps: Trapping → Oxidation → Iodination → Coupling → Release
• Iodide trapped by NIS (sodium/iodide symporter)
• Oxidation by peroxidase enzyme
• Coupling: MIT+DIT = T3, DIT+DIT = T4
• Most hormone released = T4 (less potent)
• T4 → T3 conversion in liver and kidney
• T3 is more potent than T4

---

🔵 2. ANTITHYROID DRUGS

Thioamides (PTU, Methimazole, Carbimazole)

• Block thyroid peroxidase → no iodination, no coupling
• PTU only → also blocks peripheral T4→T3 conversion
• Carbimazole = prodrug → converts to methimazole
• All accumulate in thyroid gland
• ADR: Skin rashes (MC), agranulocytosis, hepatitis
• Carbimazole preferred for long-term (not hepatotoxic)
• PTU preferred in thyroid storm + pregnancy

Iodine/Iodides

• Oldest + most rapid acting antithyroid drugs
• Used preoperatively → makes gland firm, small, less vascular
• KI = expectorant; Tincture iodine = antiseptic; Iodized salt = endemic goitre prevention
• ADR: Type III hypersensitivity (angioedema, laryngeal oedema)

Radioactive Iodine (¹³¹I)

• Half-life = 8 days (therapeutic); ¹²³I = 13 hrs (diagnostic)
• Used in elderly + cardiac patients
• CI: Pregnancy, children, nursing mothers
• Advantage: Permanent cure, no surgery
• Disadvantage: Slow, high incidence of hypothyroidism

---

🔵 3. THYROID STORM

• Severe hyperthyroidism with hyperpyrexia, atrial fibrillation, mental confusion
• Precipitants: infection, trauma, surgery, DKA, MI

Treatment:

1. Hospitalization + supportive care
2. Propranolol → controls tachycardia + blocks T4→T3
3. PTU via NG tube
4. Sodium ipodate → blocks release + T4→T3
5. Diltiazem if propranolol contraindicated
6. Hydrocortisone 100 mg IV 8 hrly → blocks T4→T3 + corrects adrenal insufficiency

---

🔵 4. INSULIN

• Made by β-cells of pancreas; preproinsulin → proinsulin → insulin (C-peptide removed)
• A chain + B chain joined by 2 disulphide bridges
• Destroyed in gut → NOT oral; given SC (IV only in emergency)
• Receptor = Tyrosine kinase receptor (2α + 2β subunits)
• Half-life IV = ~6 min

Preparations:

Indications:

• Type 1 DM, DKA, pregnancy, stress (surgery/infection), Type 2 DM (oral drugs failed)

Complications:

• Hypoglycaemia — MC + most dangerous
• Lipodystrophy — rotate injection sites to prevent
• Allergic reactions, oedema

---

🔵 5. DIABETIC KETOACIDOSIS (DKA)

• Complication of Type 1 DM
• Features: vomiting, polyuria, Kussmaul breathing, hypotension, coma

Management:

1. Regular insulin IV — 0.2-0.3 U/kg bolus → 0.1 U/kg/hr infusion
2. Normal saline 1 L/hr → when BG ~250 switch to 5% dextrose + NS
3. KCl 10-20 mEq/hr after 4 hrs (insulin causes hypokalaemia)
4. Sodium bicarbonate if severe acidosis
5. Antibiotics for infection

---

🔵 6. ORAL ANTIDIABETIC DRUGS

Sulphonylureas (Glibenclamide, Glipizide, Glimepiride)

• Block K⁺-ATP channels → insulin secretion (secretagogue)
• ADR: Hypoglycaemia (MC — especially glibenclamide, avoid in elderly), weight gain, teratogenic
• NOT safe in pregnancy

Metformin (Biguanide)

• Activates AMPK → ↓ hepatic gluconeogenesis (main)
• No hypoglycaemia ✅
• ADR: Metallic taste, GI upset, lactic acidosis (rare), Vit B12 deficiency (long-term)
• DOC in obese Type 2 DM

Pioglitazone (Thiazolidinedione)

• Activates PPAR-γ → ↑ insulin sensitivity
• ADR: Oedema, heart failure, bladder cancer (rare)

Acarbose (α-Glucosidase inhibitor)

• Blocks α-glucosidase → ↓ carbohydrate absorption → ↓ postprandial sugar
• Taken just before food
• ADR: Flatulence, diarrhoea (only GI)

---

🔵 7. CORTICOSTEROIDS

Classification:

• Short: Hydrocortisone
• Intermediate: Prednisolone, Methylprednisolone
• Long: Dexamethasone, Betamethasone
• Mineralocorticoid: Aldosterone, Fludrocortisone

Key Actions:

• Carbohydrate → ↑ gluconeogenesis → hyperglycaemia
• Fat → Moon face, buffalo hump, thin limbs
• Protein → Catabolic → muscle wasting, osteoporosis, poor wound healing
• Electrolytes → Na⁺ + water retention, K⁺ loss (Dexamethasone has NO Na⁺ retention)
• Calcium → Anti-Vit D → osteoporosis, fractures
• Anti-inflammatory → via lipocortin → inhibits phospholipase A₂ → ↓ PGs + LTs

Adverse Effects (COME BUGS):

• C — Cushing's (moon face, hump)
• O — Osteoporosis
• M — Muscle weakness
• E — Electrolyte imbalance + oedema
• B — Blood sugar ↑
• U — Ulcer (peptic)
• G — Growth retardation; Glaucoma + cataract
• S — Suppressed immunity → TB reactivation, candidiasis, herpes

Important Uses:

• Nephrotic syndrome — first-line
• Bronchial asthma — IV hydrocortisone (acute); inhaled beclomethasone (chronic)
• Cerebral oedema — best for tumours/TB meningitis; least for head injury
• Septic shock — life-saving IV glucocorticoids
• Rheumatoid arthritis, allergic diseases, haematological malignancies

---

🔵 8. HORMONAL CONTRACEPTIVES

Combined Pill (Oestrogen + Progestin)

• Mechanism: ↓ FSH + LH → no ovulation (main); thick cervical mucus; hostile endometrium
• Schedule: 21 days on → 7 days gap → repeat
• Efficacy: 98–99.9%

Mini Pill (Progestin only)

• Continuous — no gap; Efficacy: 96%

Emergency Pill (within 72 hrs):

• Levonorgestrel 0.75 mg × 2 doses
• Mifepristone 600 mg single dose
• Mechanism: interferes with implantation + blocks ovulation

Non-contraceptive Benefits:

• ↓ Dysmenorrhoea, ↓ anaemia, ↓ PID, ↓ ovarian + endometrial cancer

Adverse Effects:

• Early: Nausea, headache, breakthrough bleeding
• Late: Weight gain, acne, BP ↑
• Serious: Venous thromboembolism (smokers), MI, stroke, breast cancer

Injectable:

• DMPA — 150 mg IM every 3 months
• NET-EN — 200 mg IM every 2 months
• Fertility returns after 6–8 months delay

---

🔵 9. UTERINE RELAXANTS (TOCOLYTICS)

• Uses: Preterm labour, threatened abortion, dysmenorrhoea

Drugs:

• β₂-agonists: Salbutamol, Ritodrine, Terbutaline — ADR: tachycardia, pulmonary oedema, hyperglycaemia, hypokalaemia; avoid in diabetes + heart disease
• Nifedipine (Ca²⁺ channel blocker)
• Atosiban (oxytocin antagonist)
• Magnesium sulfate, Progesterone

NSAIDs (Indomethacin):

• Tocolytic but NOT used for preterm labour
• Risk: premature closure of ductus arteriosus → pulmonary hypertension
• OK only for dysmenorrhoea

---

🔵 10. UTERINE STIMULANTS (OXYTOCICS)

Classification:

• Posterior pituitary: Oxytocin
• Ergot alkaloids: Ergometrine, Methylergometrine
• Prostaglandins: Misoprostol, Dinoprostone, Carboprost

Oxytocin — Key Points:

• Made in hypothalamus, stored in posterior pituitary
• Mechanism: G-protein receptor → IP₃ → Ca²⁺ release → uterine contraction
• Oestrogen ↑ sensitivity; Progesterone ↓ sensitivity

4 Actions:

• Uterus → contracts pregnant uterus
• Breast → milk ejection (myoepithelial cells)
• Kidney (high dose) → ADH-like → water intoxication
• CVS (high dose) → vasodilation → hypotension → reflex tachycardia

Uses:

1. Induction of labour — DOC → IV infusion, low dose, monitor carefully
2. PPH — prevention (IM) + treatment (IV); preferred over ergot
3. Uterine inertia — strengthen weak contractions
4. Breast engorgement — intranasal → milk let-down

---

🟡 FINAL FLASH POINTS