Endocrine Pharmacology Practice Questions

Q: Which of the following is recombinant parathyroid hormone (rPTH) used in osteoporosis treatment?

Teriparatide. ***Teriparatide*** - **Teriparatide** is a **recombinant human parathyroid hormone (rPTH)**. It is an **anabolic agent** used in osteoporosis treatment. - Unlike antiresorptive agents, teriparatide **stimulates osteoblastic activity** and new bone formation, leading to increased bone mineral density and reduced fracture risk. *Calcipotriol* - **Calcipotriol** is a vitamin D analog primarily used topically for the treatment of **psoriasis**. - It works by regulating cell proliferation and differentiation in the skin, and is **not used for osteoporosis**. *Denosumab* - **Denosumab** is a **monoclonal antibody** that targets RANKL, inhibiting osteoclast formation and function, thus **reducing bone resorption**. - While it is a treatment for osteoporosis, it is an **antiresorptive agent**, not a recombinant parathyroid hormone. *Calcitriol* - **Calcitriol** is the **active form of vitamin D** and is used to treat conditions like hypocalcemia and metabolic bone disease associated with kidney failure. - It primarily helps with **calcium absorption** and bone mineralization, but it is not a recombinant parathyroid hormone and is not a primary anabolic treatment for osteoporosis.

Q: Which of the following insulin preparations has the longest duration of action?

Insulin degludec. ***Insulin degludec*** - **Insulin degludec** forms multi-hexamer chains upon subcutaneous injection, leading to a slow and continuous release of monomers and providing the longest duration of action among available insulin preparations, often exceeding **42 hours**. - Its unique mechanism of action allows for once-daily dosing with less variability and a flatter, more stable pharmacokinetic profile compared to other basal insulins. *Insulin glargine* - **Insulin glargine** precipitates in subcutaneous tissue at physiological pH, forming micro-precipitates from which insulin is slowly absorbed, providing a duration of action of approximately **24 hours**. - Although it is a long-acting insulin, its duration is typically less than that of insulin degludec, and it usually requires once-daily administration. *Insulin detemir* - **Insulin detemir** binds reversibly to albumin in the blood, which delays its absorption and degradation, resulting in a duration of action around **12-24 hours**, depending on the dose. - Due to its variable duration, insulin detemir may sometimes require twice-daily dosing in some patients to maintain basal insulin coverage. *Isophane insulin (NPH)* - **Isophane insulin (NPH)** is an intermediate-acting insulin preparation that is formulated with protamine, which delays its absorption, giving it a duration of action of approximately **10-18 hours**. - NPH insulin has a more pronounced peak action compared to newer long-acting analogues, which can lead to a higher risk of nocturnal hypoglycemia.

Q: Which of the following is the drug of choice for Addison's disease?

Hydrocortisone. ***Hydrocortisone*** - **Hydrocortisone** is the **glucocorticoid of choice** for Addison's disease because it most closely mimics the body's natural cortisol in terms of **potency and duration of action**. - It is preferred for **physiological replacement therapy** due to its short half-life (8-12 hours), allowing for dosing schedules that mimic the normal circadian rhythm of cortisol secretion. - While hydrocortisone has **some mineralocorticoid activity**, it is usually **combined with fludrocortisone** (a synthetic mineralocorticoid) to provide complete hormone replacement in Addison's disease. - The typical regimen is hydrocortisone **15-25 mg/day in divided doses** plus fludrocortisone **0.05-0.2 mg/day**. *Betamethasone* - **Betamethasone** is a **potent long-acting synthetic glucocorticoid** with **minimal mineralocorticoid activity**. - Its **long duration of action** and high potency make it unsuitable for daily physiological replacement therapy, as it increases the risk of **cushingoid side effects** and cannot mimic normal cortisol circadian rhythm. *Dexamethasone* - **Dexamethasone** is a **very potent long-acting glucocorticoid** with **no mineralocorticoid activity**. - Its **very long half-life (36-72 hours)** makes precise titration for physiological replacement extremely difficult and increases the risk of **overreplacement and cushingoid features**. - It is not suitable for routine replacement therapy in Addison's disease. *Prednisolone* - **Prednisolone** is an intermediate-acting glucocorticoid that can be used as an **alternative to hydrocortisone** for replacement therapy. - However, **hydrocortisone remains preferred** because its pharmacokinetic profile more closely matches physiological cortisol secretion. - Like hydrocortisone, prednisolone also requires **supplementation with fludrocortisone** for complete mineralocorticoid replacement.

Q: Which of the following drugs causes osteoporosis on long-term use?

Prednisolone. ***Prednisolone*** - **Glucocorticoids** like prednisolone inhibit osteoblast function, reduce calcium absorption from the gut, and increase renal calcium excretion, all contributing to **bone loss** and **osteoporosis** with long-term use. - This effect is a significant concern in patients requiring chronic corticosteroid therapy for inflammatory or autoimmune conditions. - **Prednisolone is the most important and well-established cause of drug-induced osteoporosis.** *Etidronate* - **Etidronate** is a **bisphosphonate** drug used to treat and prevent osteoporosis by inhibiting osteoclast activity, thereby reducing bone resorption. - Therefore, it protects against osteoporosis rather than causing it. *Phenytoin* - **Phenytoin** is an antiepileptic drug that can interfere with **vitamin D metabolism** through induction of hepatic enzymes, leading to decreased calcium absorption. - Long-term use can result in **osteomalacia** (defective mineralization) and may also contribute to **osteoporosis** (decreased bone mass). - However, glucocorticoids remain the most clinically significant cause of drug-induced osteoporosis. *Calcitriol* - **Calcitriol** is the active form of **vitamin D** (1,25-dihydroxyvitamin D3), used to increase calcium absorption from the gut and promote bone mineralization. - It is used in the treatment of conditions like hypoparathyroidism, renal osteodystrophy, and osteoporosis to improve bone health and calcium balance.

Q: Which of the following drugs does not cause hypoglycemia?

Acarbose. ***Acarbose***- Acarbose is an **alpha-glucosidase inhibitor** that works by delaying carbohydrate digestion and glucose absorption in the gut.- Due to its mechanism of action, which does not stimulate insulin secretion or increase insulin sensitivity directly, it carries a **very low risk of hypoglycemia** when used as monotherapy [1].*Insulin*- **Insulin** is a direct hormone replacement therapy that lowers blood glucose by facilitating glucose uptake into cells.- Administered doses can sometimes exceed the body's needs, leading to **hypoglycemia**, especially with missed meals or increased physical activity [1].*Glimepiride*- Glimepiride is a **sulfonylurea** that stimulates insulin release from pancreatic beta cells, regardless of blood glucose levels.- This persistent stimulation can lead to **hypoglycemia**, which can be severe and prolonged.*Nateglinide*- Nateglinide is a **meglitinide**, a class of drugs that also stimulate insulin secretion from pancreatic beta cells [1, 2].- While its action is more rapid and short-lived compared to sulfonylureas, it still carries a risk of inducing **hypoglycemia**.

Q: The progestogenic emergency contraceptive pills act by:

Prevention of ovulation if not already occurred. ***Prevention of ovulation if not already occurred*** - Progestogenic emergency contraceptive pills primarily work by **delaying or inhibiting ovulation**, thereby preventing the release of an egg for fertilization. - This mechanism is effective when taken before the surge of **luteinizing hormone (LH)**, which triggers ovulation. - According to **WHO and FIGO guidelines**, this is the primary and most well-established mechanism of action. *Prevention of implantation of a fertilized egg* - Current scientific evidence from **WHO (2015)** and **ICMR guidelines** clearly establishes that progestogenic emergency contraceptives (like levonorgestrel) do **NOT prevent implantation** of a fertilized egg. - Studies show these pills are ineffective once fertilization has occurred, confirming they work solely through **pre-fertilization mechanisms** (primarily ovulation inhibition). - This distinction is important for understanding that progestogenic ECs are **contraceptives, not abortifacients**. *Induction of endometrial shedding* - This is a mechanism associated with **mifepristone (RU-486)**, an abortifacient, which causes shedding of the uterine lining, not with progestogenic emergency contraceptives. - Progestogenic emergency contraceptives do not induce endometrial shedding as their mode of action. *Modification of cervical mucus to reduce sperm penetration* - This is a known effect of **regular progestin-only contraceptives** (e.g., mini-pills taken daily) but is not the primary mechanism by which progestogenic emergency contraceptive pills prevent pregnancy. - While some cervical mucus thickening may occur, the main efficacy is due to **ovulation inhibition**, as the single high dose used in emergency contraception works differently than continuous low-dose regimens.

Q: Which of the following is a nasally acting GnRH analogue?

Nafarelin. ***Nafarelin (Correct Answer)*** - **Nafarelin** is available as a **nasal spray** (Synarel®), making it a nasally acting GnRH analogue - Administered intranasally for conditions like **endometriosis** and **central precocious puberty** - Its formulation is designed for efficient absorption through the **nasal mucosa** *Goserelin (Incorrect)* - Administered as a **subcutaneous implant** (Zoladex®) for sustained release, not nasally - Used in hormone therapy for **prostate cancer**, **breast cancer**, and **endometriosis** - Not available in nasal formulation *Triptorelin (Incorrect)* - Provided as an **intramuscular or subcutaneous injection** in sustained-release depot formulation - Used for hormone-sensitive cancers and **assisted reproductive technology** - Not formulated for **nasal administration** *Leuprolide (Incorrect)* - Administered via **subcutaneous or intramuscular injection** (Lupron®), including depot formulations - Used for prostate cancer, endometriosis, and uterine fibroids - **Not available in nasal form** for clinical use

Q: Which medication is used for suppression of lactation?

Bromocriptine. ***Bromocriptine*** - **Bromocriptine** is a **dopamine agonist** that suppresses prolactin secretion from the anterior pituitary, thereby inhibiting lactation - Acts by stimulating **D2 dopamine receptors**, which inhibits prolactin release - Historically used for lactation suppression, though its use has declined due to potential cardiovascular side effects (**hypotension**, **stroke**, **myocardial infarction**) - **Cabergoline** (another dopamine agonist) is now preferred when pharmacological suppression is needed due to better tolerability - **Non-pharmacological methods** (breast binding, ice packs, avoiding stimulation) are now first-line recommendations *Pyridoxine* - **Pyridoxine (Vitamin B6)** has been anecdotally mentioned for lactation suppression, but lacks strong scientific evidence - Does not directly affect **prolactin secretion** or milk production mechanisms - Not recommended for this indication *DMPA* - **DMPA (Depot Medroxyprogesterone Acetate)** is a **progestin-only injectable contraceptive** used postpartum - Safe for breastfeeding mothers as its primary function is **contraception**, not lactation suppression - Does not actively suppress established lactation *D-Norgestrel* - **D-Norgestrel** is a **progestin** component found in some oral contraceptive pills - Primary role is **contraception**, not lactation suppression - Progestin-only contraceptives are compatible with breastfeeding

Q: Which of the following drugs does not act on the thyroid?

Propranolol. ***Propranolol*** - **Propranolol** is a **beta-blocker** primarily used to relieve symptoms of hyperthyroidism such as palpitations, tremor, and anxiety by blocking beta-adrenergic receptors. - It does not directly affect thyroid hormone production or release, making it a symptomatic treatment rather than an antithyroid drug. *Propylthiouracil* - **Propylthiouracil (PTU)** is a **thionamide** drug that directly inhibits the synthesis of thyroid hormones by interfering with the **thyroid peroxidase enzyme**. - It also blocks the peripheral conversion of **thyroxine (T4)** to the more active **triiodothyronine (T3)**. *Sodium iodide* - High doses of **iodine**, such as **sodium iodide**, acutely inhibit thyroid hormone synthesis and release, a phenomenon known as the **Wolff-Chaikoff effect**. - It is often used in preparation for surgery in hyperthyroid patients or during thyroid storm. *Thiocyanate* - **Thiocyanate** is an **anion** that competitively inhibits the **iodide transporter (NIS)** in the thyroid gland. - By blocking the uptake of iodide into thyroid cells, it reduces the availability of iodine for thyroid hormone synthesis.

Question 1

Which of the following is recombinant parathyroid hormone (rPTH) used in osteoporosis treatment?

Accepted Answer

Teriparatide

Answer

Calcipotriol

Answer

Denosumab

Answer

Calcitriol

Question 2

Which of the following insulin preparations has the longest duration of action?

Accepted Answer

Insulin degludec

Answer

Insulin glargine

Answer

Isophane insulin (NPH)

Answer

Insulin detemir

Question 3

Which of the following is the drug of choice for Addison's disease?

Accepted Answer

Hydrocortisone

Answer

Betamethasone

Answer

Dexamethasone

Answer

Prednisolone

Question 4

Which of the following drugs causes osteoporosis on long-term use?

Accepted Answer

Prednisolone

Answer

Etidronate

Answer

Calcitriol

Answer

Phenytoin

Question 5

What are the side effects of diethylstilbestrol when used in a pregnant woman?

Accepted Answer

Infertility and development of vaginal carcinoma in female offspring

Answer

Deep vein thrombosis in pregnant woman

Answer

Feminization of external genitalia of male offspring

Answer

Virilization of the external genitalia of female offspring

Question 6

Which of the following drugs does not cause hypoglycemia?

Accepted Answer

Acarbose

Answer

Insulin

Answer

Glimepiride

Answer

Nateglinide

Question 7

The progestogenic emergency contraceptive pills act by:

Accepted Answer

Prevention of ovulation if not already occurred

Answer

Prevention of implantation of a fertilized egg

Answer

Induction of endometrial shedding

Answer

Modification of cervical mucus to reduce sperm penetration

Question 8

Which of the following is a nasally acting GnRH analogue?

Accepted Answer

Nafarelin

Answer

Triptorelin

Answer

Leuprolide

Answer

Goserelin

Question 9

Which medication is used for suppression of lactation?

Accepted Answer

Bromocriptine

Answer

DMPA

Answer

Pyridoxine

Answer

D-Norgestrel

Question 10

Which of the following drugs does not act on the thyroid?

Accepted Answer

Propranolol

Answer

Propylthiouracil

Answer

Sodium iodide

Answer

Thiocyanate

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?