# Thyroid, Steroid, Sex Hormone and Bone Drugs for NEET PG Pharmacology: Levothyroxine (ICMR), Antithyroid Drugs, SERMs, Bisphosphonates Source: https://tracknation.in/story/thyroid-steroid-sex-hormone-and-bone-drugs-for-neet-pg-pharmacology-levothyroxine-icmr-antithyroid-drugs-serms-bisphosphonates (TrackNation — free UPSC notes with PYQs) > NEET PG Pharmacology: levothyroxine dosing under India's ICMR hypothyroidism workflow, methimazole vs propylthiouracil in pregnancy, corticosteroid side effects and tapering, estrogen, raloxifene, tamoxifen, letrozole, clomiphene, DMPA, alendronate and denosumab, with a diagram, hooks, vignette MCQs and cards. ## Start Here 🎯 **Exam priority: High.** *Expect: levothyroxine starting dose in an elderly cardiac patient, the antithyroid drug in the first trimester, steroid withdrawal, tamoxifen and the endometrium, raloxifene and clots, and how to take alendronate.* CBME mapping: **PH 7.3–7.9**. Indian protocol: **ICMR Hypothyroidism workflow (July 2022)**. ## Hypothyroidism: Levothyroxine (ICMR) *Levothyroxine starting doses by type of hypothyroidism, from the ICMR workflow (2022). Drawn by TrackNation.* - **Diagnosis**: overt = high TSH with low FT4; subclinical = high TSH with normal FT4. Billewicz score ≥ 6 suggests hypothyroidism. Newborn screening: TSH > 30 mU/L. - **Take** it on an empty stomach, 30–60 minutes before breakfast, and at least 4 hours apart from drugs that block its absorption. - **Central hypothyroidism**: give hydrocortisone first if there is adrenal insufficiency — thyroxine alone can precipitate an adrenal crisis. - Never use thyroid hormone for obesity or weight loss (boxed warning). ## Hyperthyroidism: Antithyroid Drugs - **Methimazole**: life-threatening agranulocytosis (report sore throat or fever at once); in the first trimester it can cause birth defects such as aplasia cutis and craniofacial malformations. - **Propylthiouracil**: boxed severe liver injury and liver failure, but it may be the drug of choice **during or just before the first trimester**. ## Corticosteroids - **Adrenal insufficiency**: hydrocortisone or cortisone is the first choice. - **Withdrawal**: taper gradually; drug-induced adrenal insufficiency can last months after stopping, so restart steroids during any stress in that period. - **Adverse effects**: unmasked diabetes, posterior subcapsular cataract, raised eye pressure, osteoporosis, growth suppression in children; no smallpox (live) vaccination while on steroids. ## Sex Hormones and Modulators | **Drug** | **Class (label)** | **Key warning (label)** | | Estradiol | Estrogen | Endometrial cancer if unopposed; not for preventing heart disease; probable dementia in women ≥ 65 (WHI) | | Raloxifene | SERM | Boxed: venous thromboembolism and death from stroke | | Tamoxifen | SERM | Uterine malignancies, stroke and pulmonary embolism (in DCIS and risk-reduction use) | | Letrozole | Aromatase inhibitor | Adjuvant treatment of postmenopausal hormone-receptor-positive breast cancer | | Clomiphene | Ovulation inducer | Ovarian hyperstimulation syndrome; visual blurring or flashes | | DMPA (Depo-Provera) | Injectable progestin contraceptive | Boxed: bone mineral density loss; not beyond 2 years unless other methods unsuitable | ## Bone: Bisphosphonates and Denosumab - **Alendronate**: swallow with plain water at least 30 minutes before the first food, drink or medicine of the day, and do not lie down for 30 minutes. Watch for osteonecrosis of the jaw and atypical femur fractures (new thigh or groin pain). - **Denosumab**: RANKL inhibitor; boxed severe hypocalcaemia in advanced kidney disease (eGFR < 30). ## Traps the Examiner Sets - Elderly or cardiac patient: levothyroxine 12.5–25 mcg/day, not full dose. - First trimester: propylthiouracil; methimazole later. - Fever and sore throat on methimazole: check for agranulocytosis. - Tamoxifen raises uterine cancer risk; raloxifene raises clot risk. - Alendronate: upright for 30 minutes, empty stomach. ## Memory Hooks & Shortcuts *Shortcuts to lock in this article's numbers and lists. Each one only re-packages facts proven above.* - 🧠 **Old heart, Low start (12.5–25)** — levothyroxine in the elderly or cardiac - 🧠 **Steroids before Thyroxine in central disease** — avoid adrenal crisis - 🧠 **PTU for the Pregnant first Trimester** — methimazole causes defects then - 🧠 **Methimazole: Mind the Marrow** — agranulocytosis - 🧠 **Tamoxifen Troubles the uTerus** — uterine malignancy - 🧠 **Raloxifene Raises clots** — VTE - 🧠 **Fosamax: 30-30 rule** — 30 minutes before food, 30 minutes upright ## Rapid-Revision Cards - 1.6–1.8 mcg/kg/day, fasting. - 12.5–25 mcg/day, +12.5–25 every 3–4 wk. - 10–15 mcg/kg/day, powdered with breast milk. - 1.3 mcg/kg/day after hydrocortisone. - Young 1–2.5; middle-aged 1.5–3. - Empty stomach, 30–60 min before breakfast; 4 h from binders. - Not for obesity/weight loss. - Agranulocytosis; 1st-trimester defects (aplasia cutis). - Boxed liver failure; choice in 1st trimester. - Hydrocortisone or cortisone first. - Gradual; HPA suppression for months. - Posterior subcapsular cataract; raised IOP. - No smallpox/live vaccine. - Endometrial cancer (unopposed); not for CVD prevention. - SERM; VTE, stroke death. - Uterine cancer, stroke, PE. - Aromatase inhibitor; HR+ breast cancer. - OHSS; visual flashes. - Bone loss; ≤ 2 years. - Water, 30 min before food, upright 30 min. - ONJ, atypical femur fracture. - RANKL; hypocalcaemia in CKD. ## Sources *Facts in this article were checked against these documents.* - Standard Treatment Workflow: Hypothyroidism — Indian Council of Medical Research / Department of Health Research, MoHFW, July 2022 - Prescribing labels: levothyroxine, methimazole, propylthiouracil, prednisone, Solu-Cortef, estradiol, Evista, tamoxifen, Femara, clomiphene, Depo-Provera, Fosamax, Prolia — DailyMed, US National Library of Medicine, current labels, accessed November 2026 (link) - Competency Based Undergraduate Curriculum, Pharmacology (PH 7.3–7.9) — National Medical Commission, 2024 ## Test Yourself: Practice Questions Twenty-four questions in NEET PG style, most of them clinical vignettes. ## Practice Questions (NEET PG pattern) *Original questions written in the style of the exam: +4 for a correct answer, −1 for a wrong one. Every answer was checked against the sources listed above. NEET PG papers are not published by NBEMS, so these are not past-paper questions.* **Q1.** A 35-year-old woman, 60 kg, has overt primary hypothyroidism. ICMR's starting levothyroxine dose is about - (a) 10–15 mcg/kg/day - (b) 300 mcg weekly - (c) 1.6–1.8 mcg/kg/day (about 100 mcg) - (d) 12.5 mcg/day **Answer: (c)** — Primary hypothyroidism: 1.6–1.8 mcg/kg/day as a single fasting dose. **Q2.** A 72-year-old with angina is diagnosed with hypothyroidism. ICMR advises starting levothyroxine at - (a) 200 mcg/day - (b) 12.5–25 mcg/day, increased every 3–4 weeks - (c) full replacement at once - (d) only after angioplasty **Answer: (b)** — Elderly and CAD patients start low and go slow. **Q3.** A newborn's screening TSH is high and confirmed. ICMR's levothyroxine dose is - (a) wait until 6 months - (b) 1.3 mcg/kg/day - (c) 10–15 mcg/kg/day, powdered, with breast milk - (d) 25 mcg weekly **Answer: (c)** — Congenital hypothyroidism: start promptly. **Q4.** A woman with a pituitary tumour has low FT4 and a low cortisol. Before levothyroxine, ICMR says to - (a) start hydrocortisone first - (b) nothing else - (c) give methimazole - (d) give radioactive iodine **Answer: (a)** — Thyroxine alone may precipitate an adrenal crisis. **Q5.** A patient takes levothyroxine with breakfast and calcium tablets; TSH stays high. The label advice is to take it - (a) on an empty stomach 30–60 minutes before breakfast, 4 hours apart from interfering drugs - (b) twice weekly - (c) at bedtime with milk - (d) with iron **Answer: (a)** — Levothyroxine label. **Q6.** A slimming clinic prescribes levothyroxine to a euthyroid woman for weight loss. The label's boxed warning says - (a) only with metformin - (b) only for men - (c) thyroid hormone must not be used for obesity or weight loss - (d) this is approved **Answer: (c)** — Boxed warning. **Q7.** A woman with Graves' disease is 6 weeks pregnant. The antithyroid drug of choice now is - (a) methimazole - (b) propylthiouracil - (c) levothyroxine - (d) radioactive iodine **Answer: (b)** — PTU may be the drug of choice during or just before the first trimester; methimazole can cause birth defects then. **Q8.** A baby born to a mother who took methimazole in the first trimester has aplasia cutis. This is - (a) a recognised methimazole first-trimester malformation - (b) a forceps injury - (c) neonatal lupus - (d) unrelated **Answer: (a)** — Methimazole label. **Q9.** Three weeks after starting methimazole, a woman has fever and a sore throat. The priority is to - (a) check a white cell count for agranulocytosis - (b) add PTU - (c) double the dose - (d) start antibiotics only **Answer: (a)** — Agranulocytosis is potentially life-threatening; patients must report fever or sore throat immediately. **Q10.** Propylthiouracil carries a boxed warning for - (a) agranulocytosis only - (b) severe liver injury and liver failure - (c) QT prolongation - (d) lactic acidosis **Answer: (b)** — Some cases needed transplant or were fatal. **Q11.** A man stops prednisone 40 mg abruptly after 3 months and collapses after a minor operation a few weeks later. The cause is - (a) hyperthyroidism - (b) allergy - (c) drug-induced secondary adrenal insufficiency - (d) hyperkalaemia from surgery alone **Answer: (c)** — Taper gradually; insufficiency can last months, so steroids should be restarted in any stress during that time. **Q12.** For replacement in primary adrenal insufficiency, the label's first choice is - (a) dexamethasone - (b) hydrocortisone or cortisone - (c) fludrocortisone alone - (d) prednisone alone **Answer: (b)** — Synthetic analogues may be added with mineralocorticoids where needed. **Q13.** Long-term oral steroids in an asthmatic cause cloudy vision; the lens change typical of steroids is - (a) retinal detachment - (b) anterior polar cataract - (c) posterior subcapsular cataract - (d) nuclear sclerosis **Answer: (c)** — Steroid ophthalmic effects: posterior subcapsular cataracts, raised intraocular pressure. **Q14.** A postmenopausal woman with an intact uterus wants estrogen alone for hot flushes. The boxed warning is - (a) estrogens increase the risk of endometrial cancer - (b) estrogens cause hypoglycaemia - (c) estrogens prevent heart disease - (d) no risk **Answer: (a)** — Also: not for preventing cardiovascular disease; probable dementia in women ≥ 65 (WHI). **Q15.** A woman on raloxifene for osteoporosis develops a swollen painful calf. The label's boxed warning covers - (a) hypercalcaemia - (b) osteonecrosis of jaw - (c) venous thromboembolism (and death from stroke) - (d) agranulocytosis **Answer: (c)** — Raloxifene is a SERM. **Q16.** A woman taking tamoxifen to reduce breast-cancer risk asks about its serious risks. The label lists - (a) uterine malignancies (and stroke, pulmonary embolism) - (b) hypothyroidism - (c) bone loss only - (d) ovarian hyperstimulation **Answer: (a)** — Serious events in risk-reduction and DCIS use (NSABP P-1). **Q17.** A postmenopausal woman with hormone-receptor-positive early breast cancer is given adjuvant letrozole. Letrozole is - (a) a GnRH agonist - (b) a SERM - (c) an aromatase inhibitor - (d) a progestin **Answer: (c)** — Femara label. **Q18.** A woman on clomiphene for ovulation induction develops abdominal pain and distension, nausea and weight gain. Suspect - (a) appendicitis - (b) ovarian hyperstimulation syndrome - (c) ectopic pregnancy only - (d) fibroid **Answer: (b)** — Clomiphene also causes visual blurring or flashes. **Q19.** A 17-year-old asks to use Depo-Provera injections for 4 years. The label warns of - (a) lactic acidosis - (b) hyperkalaemia - (c) loss of bone mineral density; not beyond 2 years unless other methods are unsuitable - (d) endometrial cancer **Answer: (c)** — Boxed warning. **Q20.** A woman starting alendronate asks how to take it. Correct advice: - (a) with milk at bedtime - (b) with food to avoid nausea - (c) lying down to absorb better - (d) with plain water, 30 minutes before the first food or drink, and stay upright 30 minutes **Answer: (d)** — Fosamax label. **Q21.** After 6 years of alendronate, a woman develops new thigh pain with minimal trauma. Suspect - (a) muscle strain only - (b) gout - (c) an atypical femur fracture - (d) DVT **Answer: (c)** — Evaluate new thigh or groin pain; also watch for osteonecrosis of the jaw. **Q22.** A dialysis patient with osteoporosis is given denosumab. The boxed risk is - (a) hypercalcaemia - (b) agranulocytosis - (c) severe hypocalcaemia - (d) QT prolongation **Answer: (c)** — Advanced CKD (eGFR < 30) including dialysis. **Q23.** Denosumab works by inhibiting - (a) aromatase - (b) osteoclast H+ pump - (c) RANK ligand (RANKL) - (d) PTH receptor **Answer: (c)** — Prolia label. **Q24.** In ICMR's hypothyroidism workflow, a young patient's target TSH on treatment is - (a) < 0.1 mU/L - (b) 5–10 mU/L - (c) 1–2.5 mU/L - (d) 10–20 mU/L **Answer: (c)** — Middle-aged 1.5–3 mU/L. ### Active Recall From memory: give ICMR's levothyroxine starting doses for primary, elderly or cardiac, congenital and central hypothyroidism; compare methimazole and propylthiouracil; list corticosteroid adverse effects and why tapering matters; and give the key warning for estrogen, raloxifene, tamoxifen, letrozole, clomiphene, DMPA, alendronate and denosumab.