NEET-PG 2012 - Pharmacology Practice Questions

Q: Which drug is used as a treatment for sickle cell anemia by promoting fetal hemoglobin production?

Hydroxyurea. ***Hydroxyurea*** - **Hydroxyurea** is the primary drug used to treat sickle cell anemia by promoting **fetal hemoglobin (HbF)** production - It is a **ribonucleotide reductase inhibitor** that increases HbF levels, which reduces sickling of red blood cells - Clinical benefits include reduced frequency of **vaso-occlusive crises**, decreased need for transfusions, and improved survival - Mechanism: Increases **HbF** production, which dilutes the abnormal **HbS** and prevents polymerization *Trypsin* - **Trypsin** is a **proteolytic enzyme** involved in protein digestion in the gastrointestinal tract - It has no role in the treatment of **sickle cell anemia** or in promoting **fetal hemoglobin** production *L-glutamine* - **L-glutamine** is an **amino acid** (not a drug that promotes HbF) approved for sickle cell disease - Its mechanism involves reducing **oxidative stress** by increasing NAD+ levels and improving red blood cell energy metabolism - It reduces complications but does not primarily work by increasing **fetal hemoglobin** production *Glucose 6-phosphate dehydrogenase* - **G6PD** is an **enzyme** in the **pentose phosphate pathway**, not a therapeutic agent - **G6PD deficiency** causes hemolytic anemia but is unrelated to sickle cell disease treatment or fetal hemoglobin production

Q: Which of the following substances is known to cause predominantly sensory neuropathy?

Cisplatin. ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug well-known for causing **dose-dependent peripheral neuropathy**, primarily affecting sensory neurons. - Patients often present with **numbness**, **tingling**, and **loss of proprioception** in a glove-and-stocking distribution. - This is the **most characteristic** drug for **predominantly sensory neuropathy** among chemotherapeutic agents. *Pyridoxine excess* - While **pyridoxine (vitamin B6) excess** can cause sensory neuropathy, it is less commonly observed as a primary cause compared to cisplatin in the context of drug-induced neuropathies. - High doses of pyridoxine can lead to **dorsal root ganglionopathy**, affecting sensory nerve fibers. *Suramin* - **Suramin** is an anthelmintic agent primarily used for treating sleeping sickness, and it is known to cause a variety of side effects, including **renal toxicity** and **neurological symptoms**. - While neurological side effects can occur, they are not typically characterized as a **predominantly sensory neuropathy** in the same way as cisplatin. *Vincristine* - **Vincristine** is a vinca alkaloid chemotherapy agent that causes peripheral neuropathy. - However, vincristine typically causes **mixed motor and sensory neuropathy** with prominent motor involvement (foot drop, wrist drop). - This differs from cisplatin's **predominantly sensory** presentation.

Q: Tibolone is a ?

Synthetic steroid hormone. ***Synthetic steroid hormone*** - **Tibolone** is a **synthetic steroid** with **estrogenic, progestogenic, and weak androgenic properties** used for hormone therapy in postmenopausal women. - Its structure is derived from **nortestosterone**, making it a synthetic compound rather than naturally occurring. *Natural steroidal hormone* - Natural steroidal hormones like **estrogen** and **progesterone** are produced endogenously by the body and have specific steroidal molecular structures. - Tibolone is not a naturally occurring hormone but is manufactured in a lab. *Natural non-steroidal hormone* - Natural non-steroidal hormones typically include peptides (e.g., insulin) or amines (e.g., thyroid hormones). - Tibolone's chemical structure is clearly steroidal, not non-steroidal. *Synthetic non-steroidal hormone* - Synthetic non-steroidal hormones are compounds like **diethylstilbestrol** (DES) that mimic hormone action but lack the steroid nucleus. - Tibolone possesses a distinct steroid backbone, classifying it as a synthetic steroid.

Q: Oximes are contraindicated in which poisoning:

Carbamate. ***Carbamate*** - Traditionally, oximes were considered **contraindicated** in carbamate poisoning based on concerns they could worsen the **cholinergic crisis** by reactivating carbamylated acetylcholinesterase. - Carbamates spontaneously **decarbamylate** from acetylcholinesterase within minutes to hours, so their inhibition is typically **short-lived and reversible**. - **Clinical relevance**: While modern evidence suggests oximes are more likely **ineffective** rather than harmful in carbamate poisoning, they are generally **not recommended** as they provide no therapeutic benefit. For exam purposes, particularly in historical contexts (NEET 2012-2013), carbamate poisoning is the answer for oxime contraindication. *Diazinon* - Diazinon is an **organophosphate**, and oximes like pralidoxime are **strongly indicated** for reactivating **acetylcholinesterase** inhibited by organophosphates. - Oximes are a crucial part of recommended antidotal therapy alongside **atropine** for severe organophosphate poisoning. - Must be administered early (within 24-48 hours) before **aging** of the phosphorylated enzyme occurs. *Phorate* - Phorate is a highly toxic **organophosphate pesticide**, and oximes are **indicated** for treatment of phorate poisoning. - Oximes work by **dephosphorylating** (nucleophilic attack on) the acetylcholinesterase enzyme, which has been inhibited by the organophosphate, restoring its catalytic function. *Malathion* - Malathion is an **organophosphate insecticide**, and oxime reactivators are **effective** in malathion poisoning. - The mechanism involves **cleaving the phosphate bond** from the serine residue on the acetylcholinesterase enzyme, allowing it to metabolize acetylcholine again and reverse cholinergic toxicity.

Question 1

Which drug is used as a treatment for sickle cell anemia by promoting fetal hemoglobin production?

Accepted Answer

Hydroxyurea

Answer

Trypsin

Answer

L-glutamine

Answer

Glucose 6-phosphate dehydrogenase

Question 2

Which of the following substances is known to cause predominantly sensory neuropathy?

Accepted Answer

Cisplatin

Answer

Pyridoxine excess

Answer

Suramin

Answer

Vincristine

Question 3

What is the best skin disinfectant for central line insertion?

Accepted Answer

Chlorhexidine

Answer

Alcohol

Answer

Cetrimide

Answer

Povidone iodine

Question 4

Tibolone is a ?

Accepted Answer

Synthetic steroid hormone

Answer

Natural steroidal hormone

Answer

Natural non-steroidal hormone

Answer

Synthetic non-steroidal hormone

Question 5

Oximes are contraindicated in which poisoning:

Accepted Answer

Carbamate

Answer

Diazinon

Answer

Phorate

Answer

Malathion

NEET-PG 2012 — Pharmacology