FMGE 2019 - Pharmacology Practice Questions

Q: Least teratogenic antiepileptic drug in pregnancy is:

Levetiracetam. ***Levetiracetam*** - **Levetiracetam** is generally considered one of the **safest antiepileptic drugs (AEDs)** during pregnancy, with a lower risk of major congenital malformations compared to other AEDs. - Studies have shown a **low incidence of neural tube defects** and other severe malformations when used as monotherapy. *Carbamazepine* - **Carbamazepine** is associated with an increased risk of **neural tube defects**, particularly **spina bifida**, during pregnancy. - It can also cause other malformations such as **facial dysmorphism** and developmental delays. *Valproate* - **Valproate** has the **highest teratogenic potential** among common AEDs, linked to a significantly increased risk of **neural tube defects**, **cardiac anomalies**, and **cognitive impairment (fetal valproate syndrome)**. - Due to its high risk, its use is generally **contraindicated in women of childbearing potential** unless no other effective alternative exists. *Phenytoin* - **Phenytoin** is associated with **fetal hydantoin syndrome**, characterized by specific facial features, **growth deficiency**, developmental delay, and increased risk of cleft lip/palate, and **cardiac defects**. - It is known for its **dose-dependent teratogenicity**, making careful monitoring crucial.

Q: Drug of choice for nasal carriers of MRSA is:

Mupirocin. ***Mupirocin*** - **Mupirocin** (Bactroban) is a **topical antibacterial agent** frequently used for the eradication of **nasal colonization with MRSA**. - It is applied directly to the **nares** and works by inhibiting bacterial protein synthesis. *Linezolid* - **Linezolid** is an **oral** or **intravenous antibiotic** used for systemic MRSA infections, not typically for nasal decolonization. - Its use for nasal carriage would be inappropriate due to the risk of systemic side effects and potential for resistance development. *Vancomycin* - **Vancomycin** is a **glycopeptide antibiotic** administered intravenously for severe MRSA infections, not for nasal decolonization. - It has poor oral bioavailability and is not effective as a topical agent for nasal carriage. *Teicoplanin* - **Teicoplanin** is another **glycopeptide antibiotic** similar to vancomycin, used for systemic MRSA infections. - Like vancomycin, it is not used for the topical eradication of nasal MRSA colonization.

Q: Which anti-asthma drug is avoided with erythromycin?

Theophylline. ***Theophylline*** - **Erythromycin** inhibits the **cytochrome P450 (CYP) enzymes** responsible for theophylline metabolism, leading to increased theophylline levels and potential toxicity. - Elevated theophylline can cause adverse effects such as **nausea**, **vomiting**, **arrhythmias**, and **seizures**. *Ipratropium* - **Ipratropium** is largely eliminated unchanged in urine, with minimal hepatic metabolism. - It does not interact significantly with **erythromycin** as its metabolism is not dependent on the CYP enzyme system. *Salbutamol* - **Salbutamol** is primarily metabolized by **sulfotransferase enzymes** in the liver and gut, not primarily by CYP enzymes. - Therefore, **erythromycin** has a negligible impact on salbutamol's metabolism and plasma levels. *Terbutaline* - **Terbutaline** is mainly metabolized by **conjugation reactions** (glucuronidation and sulfation) and excreted renally. - It also has limited interaction potential with **erythromycin** due to its distinct metabolic pathways.

Q: The drug of choice for hyperthyroidism in third trimester of pregnancy is:

Carbimazole. ***Carbimazole*** - **Carbimazole** (metabolized to methimazole) is the **drug of choice in the third trimester** of pregnancy for managing hyperthyroidism. - The teratogenic risk of methimazole/carbimazole is confined to the **first trimester** (embryopathy includes aplasia cutis, choanal atresia, esophageal atresia). By the third trimester, organogenesis is complete and this risk has passed. - **Propylthiouracil (PTU)** is associated with severe **hepatotoxicity**, which is why current guidelines recommend switching from PTU to methimazole/carbimazole after the first trimester. - Both drugs cross the placenta, but in the third trimester, the safety profile favors carbimazole over PTU. *Propylthiouracil* - **PTU** is preferred only in the **first trimester** to avoid methimazole-associated congenital anomalies during the critical period of organogenesis. - After the first trimester, patients should be switched to methimazole/carbimazole due to PTU's risk of severe **hepatotoxicity** (including fulminant hepatic failure requiring transplantation). - PTU is not the drug of choice for the third trimester despite having lower placental transfer. *Sodium iodide* - **Sodium iodide** is used acutely in **thyroid storm** or as preoperative preparation for thyroidectomy, not for chronic management of hyperthyroidism. - Prolonged use can cause the **Wolff-Chaikoff effect** (temporary inhibition of thyroid hormone synthesis) followed by escape phenomenon and worsening hyperthyroidism. - Can cause fetal goiter and hypothyroidism with chronic use, making it unsuitable for long-term pregnancy management. *Radioactive iodine* - **Radioactive iodine** is **absolutely contraindicated** in pregnancy at any stage. - It crosses the placenta after 10-12 weeks of gestation and destroys the fetal thyroid gland, causing permanent **fetal hypothyroidism** and **cretinism**. - Must be avoided in pregnancy; pregnancy should be excluded before radioactive iodine therapy.

Q: Antidote for opioid poisoning:

Naloxone. ***Naloxone*** - **Naloxone** is a pure **opioid antagonist** that reverses the effects of opioid overdose by competing for and binding to opioid receptors. - It is crucial in emergent situations to restore **respiratory drive** and consciousness in patients with opioid-induced respiratory depression. *Pethidine* - **Pethidine** is an **opioid analgesic** itself, primarily used for pain management, and would worsen opioid poisoning. - It works by binding to opioid receptors, leading to centrally mediated pain relief, making it contraindicated in overdose. *Flumazenil* - **Flumazenil** is an antagonist for **benzodiazepines**, used to reverse their sedative and respiratory depressant effects. - It has no effect on opioid receptors and would not be effective in treating opioid poisoning. *Physostigmine* - **Physostigmine** is a **cholinesterase inhibitor** used to reverse anticholinergic toxicity. - It increases acetylcholine levels at the synapse and is not indicated for opioid overdose.

Q: Preferred drug for the treatment of ventricular tachycardia is

Lignocaine. ***Lignocaine*** *(Historical Answer for FMGE-2019)* - **Lignocaine** (also known as **lidocaine**) is a **Class IB antiarrhythmic** drug that was historically the preferred treatment for **ventricular tachycardia (VT)**, especially in patients with **ischemic heart disease**. - It works by **blocking sodium channels** in the heart, specifically targeting depolarized or partially depolarized cells, which helps to stabilize the ventricular rhythm. - **⚠️ IMPORTANT UPDATE:** Current guidelines (AHA/ACC 2015 onwards) now recommend **amiodarone as the first-line antiarrhythmic** for hemodynamically stable VT, with lignocaine as a **second-line alternative**. This question reflects the teaching prevalent at the time of FMGE-2019. *Digoxin* - **Digoxin** is a **cardiac glycoside** primarily used for **atrial fibrillation** with rapid ventricular response and **heart failure**. - It is **not the preferred drug** for ventricular tachycardia and can even precipitate arrhythmias in some cases. *Propranolol* - **Propranolol** is a **beta-blocker** (Class II antiarrhythmic) typically used to treat **supraventricular tachycardias**, **hypertension**, and **angina**. - While beta-blockers can have some role in preventing recurrent VT, they are **not the first-line treatment** for acute VT. *Diltiazem* - **Diltiazem** is a **calcium channel blocker** (Class IV antiarrhythmic) primarily used for **supraventricular tachycardias** and to control ventricular rate in **atrial fibrillation**. - It is **not effective** for ventricular tachycardia and may worsen the condition in some cases.

Q: All of the following drugs are used for prophylaxis of migraine except;

Flutamide. ***Flutamide*** - **Flutamide** is an **antiandrogen** used in the treatment of prostate cancer, not for migraine prophylaxis. - Its mechanism of action involves blocking androgen receptors, which is irrelevant to migraine pathophysiology. *Flunarizine* - **Flunarizine** is a **calcium channel blocker** commonly used for migraine prophylaxis due to its vascular effects. - It helps stabilize neuronal membranes and reduce cerebral vasospasm, preventing migraine attacks. *Imipramine* - **Imipramine** is a **tricyclic antidepressant (TCA)** that can be used off-label for migraine prevention due to its neuromodulatory effects. - It works by affecting neurotransmitter levels, particularly serotonin and norepinephrine, which play a role in migraine pathways. *Propranolol* - **Propranolol** is a **beta-blocker** widely used for migraine prophylaxis, especially in patients with coexisting hypertension or anxiety. - Its mechanism involves modulating adrenergic activity and potentially stabilizing cortical excitability.

Question 1

Least teratogenic antiepileptic drug in pregnancy is:

Accepted Answer

Levetiracetam

Answer

Carbamazepine

Answer

Valproate

Answer

Phenytoin

Question 2

Drug of choice for nasal carriers of MRSA is:

Accepted Answer

Mupirocin

Answer

Linezolid

Answer

Vancomycin

Answer

Teicoplanin

Question 3

Which anti-asthma drug is avoided with erythromycin?

Accepted Answer

Theophylline

Answer

Ipratropium

Answer

Salbutamol

Answer

Terbutaline

Question 4

The drug of choice for hyperthyroidism in third trimester of pregnancy is:

Accepted Answer

Carbimazole

Answer

Sodium iodide

Answer

Radioactive iodine

Answer

Propylthiouracil

Question 5

Antidote for opioid poisoning:

Accepted Answer

Naloxone

Answer

Pethidine

Answer

Flumazenil

Answer

Physostigmine

Question 6

Preferred drug for the treatment of ventricular tachycardia is

Accepted Answer

Lignocaine

Answer

Digoxin

Answer

Propranolol

Answer

Diltiazem

Question 7

All of the following drugs are used for prophylaxis of migraine except;

Accepted Answer

Flutamide

Answer

Flunarizine

Answer

Imipramine

Answer

Propranolol

FMGE 2019 — Pharmacology