NEET-PG 2013 - Pharmacology Practice Questions

Q: Which of the following drugs has not been withdrawn from the Indian market for safety reasons?

Cotrimoxazole. ### Cotrimoxazole - Cotrimoxazole, a combination of **trimethoprim and sulfamethoxazole**, remains a widely used and available antibiotic in India [1], [2]. - It treats various bacterial infections, including **urinary tract infections** and respiratory infections, and has not been withdrawn for safety reasons [1]. ### Gatifloxacin - **Gatifloxacin** was withdrawn from the Indian market due to concerns about **severe glycemic disturbances**, including both hypo- and hyperglycemia. - These side effects posed significant risks, especially in patients with diabetes or those predisposed to blood sugar fluctuations. ### Rofecoxib - **Rofecoxib**, an NSAID, was withdrawn globally, including from India, due to an increased risk of **cardiovascular events** such as heart attack and stroke. - Its selective inhibition of COX-2 was found to disturb the balance of prostaglandins, leading to adverse cardiovascular outcomes. ### Phenformin - **Phenformin**, an oral antidiabetic drug, was withdrawn from the Indian market due to its association with a high incidence of **lactic acidosis**, a severe and often fatal metabolic complication. - This serious side effect made its risk-benefit profile unacceptable for continued use.

Q: Which of the following is an antipsychotic drug?

Flupenthixol. ***Flupenthixol*** - **Flupenthixol** is a **first-generation (typical) antipsychotic** used primarily for managing **schizophrenia** and other psychotic disorders. - It acts by blocking **dopamine D2 receptors** in the brain, reducing positive symptoms like **hallucinations and delusions**. *Rasagiline* - **Rasagiline** is a **monoamine oxidase-B (MAO-B) inhibitor** used in the treatment of **Parkinson's disease**. - It works by preventing the breakdown of **dopamine** in the brain, thereby improving motor symptoms, and is not an antipsychotic. *Clobazam* - **Clobazam** is a **benzodiazepine** primarily indicated for the treatment of **epilepsy** (specifically Lennox-Gastaut syndrome) and **anxiety**. - Its mechanism involves enhancing the effect of **GABA** in the brain, producing sedative and anticonvulsant effects, distinct from antipsychotic action. *Divalproex* - **Divalproex** is a combination product of **valproic acid** and **sodium valproate**, typically used as a **mood stabilizer** for **bipolar disorder**, an **antiepileptic**, and for **migraine prophylaxis**. - It modulates **GABAergic** transmission and sodium channels, but it is not classified as an antipsychotic drug.

Q: What serious side effect may lead to the discontinuation of felbamate?

Aplastic anemia. ***Aplastic anemia*** - Felbamate is known to cause **aplastic anemia**, a severe and life-threatening condition where the **bone marrow stops producing enough new blood cells**. - Felbamate carries a **black box warning** for both aplastic anemia and **hepatotoxicity (severe liver failure)**, which are the two most serious adverse effects leading to discontinuation. - Due to this significant risk, felbamate is reserved for severe, refractory epilepsy cases, and patients require **regular monitoring** of blood counts and liver function tests. *Renal impairment* - While some medications can cause renal impairment, **felbamate is not primarily associated** with this side effect to the extent of requiring discontinuation. - Its metabolism and excretion are predominantly **hepatic (liver)**, and renal effects are less common or severe. *Gastrointestinal disorder* - Gastrointestinal side effects like nausea or vomiting are **common with many medications**, including felbamate, but are generally **mild and manageable**, rarely leading to discontinuation. - These effects are usually **dose-dependent** and can often be mitigated with supportive care. *Seizures* - Felbamate is an **antiepileptic drug (AED)**, so it is used to treat seizures, not cause them. - If a patient experiences seizures while on felbamate, it usually indicates **inadequate treatment response** or seizure exacerbation, rather than a direct side effect necessitating discontinuation for toxicity.

Q: Botulinum toxin type B is used in which disease?

Cervical dystonia. ***Cervical dystonia*** * **Botulinum toxin type B (Myobloc/NeuroBloc)** is specifically approved for the treatment of **cervical dystonia**, which involves involuntary contractions of neck muscles. * It works by blocking the release of **acetylcholine** at the neuromuscular junction, leading to muscle relaxation. *Strabismus* * **Botulinum toxin type A (Botox, Dysport, Xeomin)** is the preferred and most commonly used form for treating **strabismus** by temporarily weakening specific extraocular muscles. * Type B is generally not indicated for strabismus due to differences in potency and duration of action. *Blepharospasm* * **Botulinum toxin type A** (e.g., Botox) is the primary treatment for **blepharospasm**, an involuntary forceful closure of the eyelids. * While both types inhibit acetylcholine release, type A has a more established and concentrated use in treating localized muscle spasms like blepharospasm. *Glabellar lines* * **Botulinum toxin type A** is widely used for cosmetic applications such as reducing **glabellar lines** (frown lines between the eyebrows). * Its efficacy and safety for cosmetic indications are well-established, making type A the standard choice over type B.

Q: Which of the following is a tricyclic antidepressant?

Doxepin. ***Doxepin*** - **Doxepin** is a **tricyclic antidepressant (TCA)** that inhibits the reuptake of **serotonin** and **norepinephrine**, and also has significant **histaminergic** and **cholinergic** blocking effects. - TCAs, including doxepin, are commonly used for treating **depression**, **anxiety**, and certain pain conditions. *Venlafaxine* - **Venlafaxine** is a **serotonin-norepinephrine reuptake inhibitor (SNRI)**, not a tricyclic antidepressant. - SNRIs selectively block the reuptake of both **serotonin** and **norepinephrine**, but lack the broad receptor affinity of TCAs. *Fluoxetine* - **Fluoxetine** is a **selective serotonin reuptake inhibitor (SSRI)**, which specifically targets serotonin reuptake. - SSRIs are generally considered a first-line treatment for depression due to a more favorable side effect profile compared to TCAs. *Citalopram* - **Citalopram** is also a **selective serotonin reuptake inhibitor (SSRI)**, much like fluoxetine. - It works by increasing the levels of **serotonin** in the brain by blocking its reuptake, differentiating it from tricyclic antidepressants.

Q: All of the following are adverse effects of nicotinic acid except:

Pancreatitis. ***Pancreatitis*** - **Pancreatitis** is not a commonly reported adverse effect of nicotinic acid (niacin) therapy. - While other gastrointestinal side effects like nausea and vomiting can occur, pancreatic inflammation is not characteristic. *Vasodilation* - **Cutaneous flushing** and **vasodilation** are very common adverse effects of nicotinic acid, mediated by prostaglandin release. - This effect can cause a sensation of warmth, redness, and itching, especially at the start of therapy. *Liver dysfunction* - **Liver dysfunction**, including elevated liver enzymes and rare cases of **hepatotoxicity**, can occur with high doses of nicotinic acid. - Regular monitoring of liver function tests is recommended for patients on niacin therapy. *Hyperpigmentation* - **Hyperpigmentation**, particularly **acanthosis nigricans**, is a known cutaneous side effect of nicotinic acid. - This typically presents as dark, velvety patches on the skin, especially in skin fold areas.

Q: What is a potential risk associated with the use of thiazolidinediones in the treatment of type 2 diabetes?

Heart failure. ***Heart failure*** - Thiazolidinediones (TZDs), such as **pioglitazone** and **rosiglitazone**, can cause **fluid retention** and **volume expansion**, which may precipitate or worsen congestive heart failure. - This risk is higher in patients with pre-existing cardiac conditions and is a significant concern for these drugs. *Pulmonary fibrosis* - **Pulmonary fibrosis** is not a known or common adverse effect associated with thiazolidinedione use. - This condition is typically linked to certain other medications (e.g., **amiodarone**, **methotrexate**) or systemic diseases. *Myocarditis* - **Myocarditis**, inflammation of the heart muscle, is not a recognized side effect of thiazolidinediones. - Myocarditis is more commonly caused by viral infections, autoimmune diseases, or hypersensitivity reactions to certain drugs, but not TZDs. *Renal dysfunction* - While TZDs can cause fluid retention, they do not directly cause **renal dysfunction** or damage the kidneys. - In fact, some studies suggest they may have renoprotective effects due to reduced proteinuria, although fluid balance needs careful monitoring in patients with impaired renal function.

Q: Which anticancer drug is known to inhibit spindle formation during cell division?

Vinca alkaloids. ***Vinca alkaloids*** - **Vinca alkaloids**, such as **vincristine** and **vinblastine**, bind to **tubulin** and prevent its polymerization into microtubules. - This action effectively **inhibits the formation of the mitotic spindle**, leading to metaphase arrest and ultimately cell death. *Busulfan* - **Busulfan** is an **alkylating agent** that **cross-links DNA**, thereby interfering with DNA replication and transcription. - Its primary mechanism is **DNA damage**, not direct inhibition of spindle formation. *5-FU* - **5-fluorouracil (5-FU)** is an **antimetabolite** that inhibits **thymidylate synthase**, thereby impairing DNA synthesis and repair. - It acts by **mimicking pyrimidine bases** and incorporating into DNA and RNA, leading to cellular dysfunction. *Methotrexate* - **Methotrexate** is an **antifolate** drug that inhibits **dihydrofolate reductase**, an enzyme crucial for the synthesis of purines and pyrimidines. - This enzyme inhibition leads to **impaired DNA and RNA synthesis**, impacting rapidly dividing cells.

Q: Gynaecomastia is caused by which drug?

Spironolactone. ***Spironolactone*** - Spironolactone is a **well-established cause of gynaecomastia**, occurring in 5-10% of patients in a dose-dependent manner. - It acts as an **anti-androgen** by blocking androgen receptors and inhibiting testosterone synthesis, thereby increasing the estrogen to androgen ratio. - It is a **potassium-sparing diuretic** and aldosterone antagonist, commonly used in heart failure, hypertension, and conditions requiring androgen blockade. *Rifampicin* - Rifampicin is an **antibiotic** primarily used to treat tuberculosis and acts as a **strong inducer of cytochrome P450 enzymes**. - While rare hormonal effects have been reported, it is **not a recognized common cause** of gynaecomastia. - Main side effects include hepatotoxicity, orange discoloration of bodily fluids, and drug interactions. *Thiazide* - Thiazide diuretics work by inhibiting the **sodium-chloride cotransporter** in the distal convoluted tubule. - They are **not commonly associated** with gynaecomastia; typical side effects include hypokalemia, hyponatremia, and hyperglycemia. *Propranolol* - Propranolol is a **non-selective beta-blocker** used for hypertension, angina, arrhythmias, and anxiety. - While beta-blockers have rarely been implicated, propranolol is **not a well-established cause** of gynaecomastia compared to spironolactone. - Common side effects include bradycardia, fatigue, and bronchospasm.

Q: What is the best drug for control of acute esophageal variceal bleeding?

Octreotide. ***Octreotide*** - **Octreotide** is a somatostatin analog that causes **splanchnic vasoconstriction**, reducing portal venous inflow and pressure, which is crucial in controlling **esophageal variceal bleeding**. - Its mechanism involves inhibiting the release of **vasodilatory hormones** like glucagon, leading to a decrease in portal pressure without significant systemic side effects. *Vasopressin* - **Vasopressin** is a potent vasoconstrictor that can reduce portal pressure but has significant systemic side effects such as **myocardial ischemia** and **bowel ischemia** due to widespread vasoconstriction. - It is generally no longer considered the first-line pharmacological treatment for variceal bleeding due to its **adverse effect profile**. *GnRH* - **GnRH** (Gonadotropin-releasing hormone) plays a role in regulating the reproductive system by controlling the release of FSH and LH from the pituitary. - It has **no direct role** in the management or control of esophageal bleeding. *Propranolol* - **Propranolol** is a non-selective beta-blocker primarily used for **prophylaxis** of variceal bleeding by reducing portal pressure chronically. - It works by reducing cardiac output and causing splanchnic vasoconstriction, but it is **not used for acute control** of active bleeding.

Question 1

Which of the following drugs has not been withdrawn from the Indian market for safety reasons?

Accepted Answer

Cotrimoxazole

Answer

Gatifloxacin

Answer

Phenformin

Answer

Rofecoxib

Question 2

Which of the following is an antipsychotic drug?

Accepted Answer

Flupenthixol

Answer

Rasagiline

Answer

Clobazam

Answer

Divalproex

Question 3

What serious side effect may lead to the discontinuation of felbamate?

Accepted Answer

Aplastic anemia

Answer

Seizures

Answer

Renal impairment

Answer

Gastrointestinal disorder

Question 4

Botulinum toxin type B is used in which disease?

Accepted Answer

Cervical dystonia

Answer

Blepharospasm

Answer

Strabismus

Answer

Glabellar lines

Question 5

Which of the following is a tricyclic antidepressant?

Accepted Answer

Doxepin

Answer

Fluoxetine

Answer

Citalopram

Answer

Venlafaxine

Question 6

All of the following are adverse effects of nicotinic acid except:

Accepted Answer

Pancreatitis

Answer

Liver dysfunction

Answer

Vasodilation

Answer

Hyperpigmentation

Question 7

What is a potential risk associated with the use of thiazolidinediones in the treatment of type 2 diabetes?

Accepted Answer

Heart failure

Answer

Pulmonary fibrosis

Answer

Myocarditis

Answer

Renal dysfunction

Question 8

Which anticancer drug is known to inhibit spindle formation during cell division?

Accepted Answer

Vinca alkaloids

Answer

Busulfan

Answer

5-FU

Answer

Methotrexate

Question 9

Gynaecomastia is caused by which drug?

Accepted Answer

Spironolactone

Answer

Rifampicin

Answer

Thiazide

Answer

Propranolol

Question 10

What is the best drug for control of acute esophageal variceal bleeding?

Accepted Answer

Octreotide

Answer

Vasopressin

Answer

GnRH

Answer

Propranolol

NEET-PG 2013 — Pharmacology