Emergency Pharmacology — MCQs

A patient presented to the emergency department with an overdose of a drug, exhibiting increased salivation and increased bronchial secretions. On examination, the blood pressure was 88/60 mmHg, and the RBC cholinesterase level was reduced to 50% of normal. What should be the treatment for this individual?

Emergency Pharmacology Indian Medical PG Practice Questions and MCQs

Question 81: What is the best drug for control of acute esophageal variceal bleeding?

A. Vasopressin
B. GnRH
C. Octreotide (Correct Answer)
D. Propranolol

Explanation: ***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 82: Which of the following is least commonly used in the management of status epilepticus?

A. Phenobarbitone (Correct Answer)
B. Phenytoin
C. Valproate
D. Lorazepam

Explanation: ***Correct: Phenobarbitone*** - **Phenobarbitone** is a long-acting barbiturate that is effective as an anticonvulsant but is **least commonly used** in status epilepticus management. - It is reserved for **refractory status epilepticus** (third-line therapy) due to significant sedative effects, risk of respiratory depression, and slower onset compared to benzodiazepines and other second-line agents. - Its use has declined in favor of agents with better safety profiles and more rapid onset, though it remains an option when first-line and second-line therapies fail. *Incorrect: Phenytoin* - **Phenytoin** is a common **second-line agent** used to prevent recurrence of seizures in status epilepticus after initial benzodiazepine administration. - It works by **blocking voltage-gated sodium channels**, thus stabilizing neuronal membranes and preventing seizure propagation. *Incorrect: Valproate* - **Valproate** is an effective broad-spectrum anticonvulsant that can be used intravenously as a **second-line agent** in status epilepticus. - It is considered a good alternative, particularly when phenytoin is contraindicated or has failed, and acts through various mechanisms including **GABAergic enhancement** and sodium channel blockade. *Incorrect: Lorazepam* - **Lorazepam** is a **benzodiazepine** and is the **first-line treatment** for status epilepticus due to its rapid onset, longer duration of action compared to diazepam, and high efficacy in stopping active seizures. - It exerts its anticonvulsant effects by enhancing **GABA-A receptor-mediated inhibitory neurotransmission** in the brain.

Question 83: What is the recommended treatment for strychnine poisoning?

A. Flumazenil
B. Supportive care and benzodiazepines (Correct Answer)
C. Naloxone
D. Activated charcoal

Explanation: ***Supportive care and benzodiazepines*** - **Supportive care**, which includes airway management, breathing support, and circulation maintenance, is crucial due to the rapid onset and severity of strychnine toxicity. - **Benzodiazepines** act on GABA receptors to reduce neuronal excitability, effectively counteracting the glycine receptor antagonism caused by strychnine, thereby controlling seizures and muscle spasms. *Flumazenil* - **Flumazenil** is a benzodiazepine receptor antagonist used to reverse the effects of benzodiazepine overdose. - It would be ineffective and potentially harmful in cases of **strychnine poisoning**, as strychnine primarily affects glycine receptors. *Naloxone* - **Naloxone** is an opioid receptor antagonist used to reverse opioid overdose. - It has no role in treating **strychnine poisoning**, which does not involve the opioid system. *Activated charcoal* - **Activated charcoal** can be used for initial decontamination after poison ingestion to adsorb toxins in the gastrointestinal tract. - However, for strychnine poisoning, it should only be considered if the patient presents early and can maintain a protected airway; it is not the primary treatment for established neurological symptoms.

Question 84: Oximes are contraindicated in which type of poisoning?

A. Organophosphate poisoning
B. Carbamate poisoning (Correct Answer)
C. Methanol poisoning
D. Cyanide poisoning

Explanation: ***Carbamate poisoning*** - Oximes are generally **not recommended** (and sometimes considered contraindicated) in carbamate poisoning - Carbamates cause **reversible carbamylation** of acetylcholinesterase that spontaneously reverses within **minutes to hours** [1, 4] - Since the enzyme-carbamate bond breaks down spontaneously, oxime reactivation provides **no additional benefit** - Some evidence suggests oximes may be **harmful in specific carbamate poisonings** (e.g., carbaryl), though the mechanism is debated - **Clinical principle:** The spontaneous reactivation makes oxime therapy unnecessary and potentially risky [3] *Organophosphate poisoning* - Oximes (e.g., **pralidoxime, obidoxime**) are the **primary antidotes** for organophosphate poisoning - They **reactivate acetylcholinesterase** by breaking the phosphate-enzyme bond before "aging" occurs [4] - Must be administered **early** (within 24-48 hours) before the enzyme-organophosphate complex undergoes aging (becomes irreversible) - Reverses **nicotinic and muscarinic** symptoms of cholinergic crisis [3] *Methanol poisoning* - Treatment involves **fomepizole** (first-line) or **ethanol** to competitively inhibit alcohol dehydrogenase [2] - This prevents conversion of methanol to toxic metabolites (formaldehyde and formic acid) - **Hemodialysis** for severe cases and acidosis correction - Oximes have **no role** in alcohol poisoning management *Cyanide poisoning* - Treated with **hydroxocobalamin** (binds cyanide to form cyanocobalamin), **sodium thiosulfate** (converts cyanide to thiocyanate), or **sodium nitrite** (forms methemoglobin) - Oximes are **not indicated** and have no mechanism of action against cyanide toxicity

Question 85: What is the primary use of Ulipristal acetate?

A. Emergency contraception (Correct Answer)
B. Treatment of breast cancer
C. Management of endometriosis
D. Management of abnormal uterine bleeding

Explanation: ***Emergency contraception*** - **Ulipristal acetate** is a selective progesterone receptor modulator primarily used as a **highly effective form of emergency contraception**. - It works by delaying or inhibiting **ovulation**, even when luteinizing hormone levels are already rising. - Available up to **120 hours** after unprotected intercourse, making it more effective than levonorgestrel in the later time window. *Treatment of breast cancer* - While some hormonal therapies are used for breast cancer (e.g., tamoxifen, aromatase inhibitors), **Ulipristal acetate** is not indicated for this use. - Its mechanism of action is targeted at progesterone receptors for contraceptive effects, not anti-estrogen or anti-androgen effects relevant to breast cancer. *Management of endometriosis* - Endometriosis management often involves suppressing ovarian function with GnRH agonists or progestins, but **Ulipristal acetate** is not a standard treatment for this condition. - Its primary role is acute prevention of pregnancy, not chronic management of gynecological pain. *Management of abnormal uterine bleeding* - While **Ulipristal acetate** has been approved in some countries for treatment of uterine fibroids and associated heavy menstrual bleeding (marketed as Esmya®), this is **not its primary or most common use**. - Its **primary indication globally** remains emergency contraception, making this option incorrect for a question asking about primary use. - Other hormonal therapies like progestins, COCs, or GnRH agonists are more commonly used first-line for abnormal uterine bleeding.

Question 86: Which drug is given to prevent acute mountain sickness?

A. Acetazolamide (Correct Answer)
B. Diltiazem
C. Digoxin
D. Dexamethasone

Explanation: ***Acetazolamide*** - This drug is a **carbonic anhydrase inhibitor** that acidifies the blood and causes compensatory hyperventilation, increasing oxygenation. - It is the **first-line prophylactic agent** for acute mountain sickness (AMS) and is best started 24-48 hours before ascent. - Most effective and widely recommended for AMS prevention. *Digoxin* - This is a **cardiac glycoside** used to treat heart failure and irregular heartbeats. - Its mechanism of action is unrelated to the physiological changes that cause acute mountain sickness. *Diltiazem* - This is a **calcium channel blocker** primarily used for hypertension, angina, and certain arrhythmias. - It has no known role in the prevention or treatment of acute mountain sickness. *Dexamethasone* - While **dexamethasone** can be used for AMS prophylaxis, it is typically reserved as an **alternative agent** when acetazolamide is contraindicated or not tolerated. - It is more commonly used for **treatment** of severe altitude illness including **High Altitude Cerebral Edema (HACE)** and **High Altitude Pulmonary Edema (HAPE)**. - **Acetazolamide remains the preferred first-line prophylactic agent** due to its mechanism of action that directly addresses the underlying pathophysiology of AMS.

Question 87: In the context of neonatal resuscitation, naloxone would be indicated for a child whose mother is taking which of the following substances?

A. Methadone (Correct Answer)
B. Cocaine
C. Amphetamine
D. Phenylcyclidine (PCP)

Explanation: ***Methadone*** - Methadone is a **long-acting opioid** used in opioid maintenance therapy. - A neonate born to a mother on methadone may experience **respiratory depression** due to in utero opioid exposure. - Naloxone is an **opioid antagonist** and may be used in severe cases of neonatal respiratory depression from opioid exposure, though careful titration is needed to avoid precipitating acute withdrawal syndrome. *Amphetamine* - Amphetamine is a **stimulant**, not an opioid. - Naloxone is ineffective for amphetamine toxicity. - Neonatal exposure presents with **irritability**, **tachycardia**, and **poor feeding**, not opioid-related respiratory depression. *Cocaine* - Cocaine is a **stimulant** and does not respond to naloxone. - Infants exposed to cocaine may exhibit **irritability**, **jitteriness**, **poor feeding**, and **cardiovascular instability**. - These effects are not mediated by opioid receptors. *Phencyclidine (PCP)* - PCP is a **dissociative anesthetic**, not an opioid. - Naloxone has no role in PCP toxicity. - Overdose may cause **behavioral disturbances**, **nystagmus**, **hypertension**, and **seizures**.

Question 88: What is the antidote for organophosphorus poisoning?

A. Atropine (Correct Answer)
B. Neostigmine
C. Succinylcholine
D. D-Tubocurarine

Explanation: ***Atropine*** - **Atropine** is the correct answer as it is a competitive antagonist at **muscarinic acetylcholine receptors**, directly counteracting the excessive acetylcholine effects in organophosphorus poisoning - It rapidly reverses life-threatening **muscarinic symptoms** such as **bronchospasm**, **bradycardia**, **excessive secretions**, and **miosis** - **Note:** In clinical practice, atropine is used along with **Pralidoxime (2-PAM)**, which reactivates acetylcholinesterase and addresses nicotinic symptoms. However, atropine is the primary antidote asked in the question *Neostigmine* - **Neostigmine** is an **acetylcholinesterase inhibitor** that increases acetylcholine levels at the synapse - This would **worsen** the symptoms of organophosphorus poisoning, which is already characterized by excessive acetylcholine accumulation due to acetylcholinesterase inhibition - Absolutely contraindicated in this condition *Succinylcholine* - **Succinylcholine** is a **depolarizing neuromuscular blocker** that acts as an acetylcholine receptor agonist - It would exacerbate the **muscle fasciculations** and **paralysis** seen in organophosphorus poisoning - Contraindicated as it would worsen nicotinic receptor overstimulation *D-Tubocurarine* - **D-Tubocurarine** is a **nondepolarizing neuromuscular blocker** that acts as a competitive antagonist at nicotinic receptors at the neuromuscular junction - While it blocks nicotinic receptors, it does **not address the life-threatening muscarinic effects** (bronchospasm, bradycardia, secretions) - Can cause **histamine release** and **hypotension**, complicating management - Not considered an antidote for organophosphorus poisoning

Question 89: Which drug is the specific antidote for organophosphorus poisoning?

A. EDTA
B. BAL
C. Atropine
D. Pralidoxime (PAM) (Correct Answer)

Explanation: ***Pralidoxime (PAM)*** - **Pralidoxime (PAM)** reactivates the enzyme **acetylcholinesterase** by detaching the organophosphate from the enzyme's active site. - It is most effective when administered early, ideally within a few hours of exposure, to prevent **aging** of the enzyme-inhibitor complex. *EDTA* - **EDTA** (ethylenediaminetetraacetic acid) is a chelating agent primarily used in the treatment of **heavy metal poisoning**, such as lead poisoning. - It is not effective against organophosphorus compounds, which act by inhibiting acetylcholinesterase. *BAL* - **BAL** (British Anti-Lewisite, or dimercaprol) is another chelating agent used to treat poisoning by **heavy metals** such as arsenic, mercury, and gold. - It does not have a mechanism of action that addresses the enzyme inhibition caused by organophosphates. *Atropine* - **Atropine** is used in organophosphorus poisoning, but it is not a specific antidote as it does not address the cause of poisoning. - It acts to counteract the **muscarinic effects** of excessive acetylcholine, such as bradycardia, bronchospasm, and excessive secretions, but does not reactivate acetylcholinesterase.

Question 90: A patient presented to the emergency department with an overdose of a drug, exhibiting increased salivation and increased bronchial secretions. On examination, the blood pressure was 88/60 mmHg, and the RBC cholinesterase level was reduced to 50% of normal. What should be the treatment for this individual?

A. Atropine (Correct Answer)
B. Physostigmine
C. Flumazenil
D. Neostigmine

Explanation: ***Atropine*** - The patient exhibits symptoms of **cholinergic crisis** (increased salivation, bronchial secretions, hypotension) and reduced RBC esterase, strongly indicative of **organophosphate poisoning**. - **Atropine** is the primary antidote, as it competitively blocks muscarinic acetylcholine receptors, reversing the parasympathetic effects. *Neostigmine* - **Neostigmine** is an **acetylcholinesterase inhibitor**, meaning it would worsen the cholinergic crisis by increasing acetylcholine levels further. - It is used in conditions like **myasthenia gravis** to improve muscle strength, not in organophosphate poisoning. *Flumazenil* - **Flumazenil** is an **antagonist of benzodiazepine receptors** and is used to reverse benzodiazepine overdose. - It has no role in treating organophosphate poisoning or cholinergic symptoms. *Physostigmine* - **Physostigmine** is also an **acetylcholinesterase inhibitor** that can cross the blood-brain barrier. - While it has some ophthalmic uses, it would exacerbate the cholinergic symptoms of organophosphate poisoning due to increased acetylcholine.

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