Emergency Pharmacology — MCQs

Emergency Pharmacology Indian Medical PG Practice Questions and MCQs

Question 101: What is the preferred route of administration for epinephrine in the treatment of anaphylactic shock?

A. Subcutaneous route
B. Inhalational administration
C. Intramuscular (IM) (Correct Answer)
D. Intravenous (IV)

Explanation: ***Intramuscular (IM)*** - **Intramuscular (IM)** injection is the preferred and fastest route for epinephrine in anaphylaxis due to its rapid absorption into the bloodstream. - Administering epinephrine IM into the **anterolateral aspect of the thigh** ensures quick systemic distribution to counteract the life-threatening symptoms. *Inhalational administration* - **Inhalational epinephrine** is not effective for systemic anaphylaxis, as it primarily targets the airways and does not provide sufficient systemic absorption or rapid cardiovascular support. - This route is typically reserved for localized bronchodilation and cannot reverse the widespread vasodilation and shock associated with anaphylaxis. *Subcutaneous route* - The **subcutaneous route** has a slower absorption rate compared to IM injection, which can delay the therapeutic effect of epinephrine during an acute anaphylactic reaction. - Delayed absorption can be critical in anaphylaxis, where rapid reversal of symptoms is necessary to prevent severe complications, including death. *Intravenous (IV)* - While **intravenous (IV)** epinephrine can be used in severe, refractory cases or in a hospital setting, it carries a higher risk of adverse cardiac events, such as arrhythmias or myocardial ischemia, especially if not carefully titrated. - For initial, pre-hospital management of anaphylaxis, the IM route is safer and more practical due to its rapid effect and lower risk profile compared to IV administration.

Question 102: Which medication is the primary treatment for muscarinic effects in acute organophosphate poisoning?

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

Explanation: ***Atropine*** - **Atropine** is a **muscarinic receptor antagonist** that directly blocks the effects of excessive acetylcholine at muscarinic sites, thereby reversing symptoms like bradycardia, bronchospasm, and excessive secretions seen in organophosphate poisoning. - It is the **primary agent** used to manage the muscarinic symptoms and is titrated until bronchorrhea and bronchospasm resolve. *Neostigmine* - **Neostigmine** is an **acetylcholinesterase inhibitor**, which would worsen the condition by increasing acetylcholine levels further. - It is used in conditions like **myasthenia gravis** to improve muscle strength, not in organophosphate poisoning. *Tubocurarine* - **Tubocurarine** is a **nicotinic receptor antagonist**, specifically a competitive neuromuscular blocker. - While organophosphate poisoning can affect nicotinic receptors, tubocurarine is not the primary treatment for muscarinic effects and could worsen respiratory depression in this context. *Pralidoxime* - **Pralidoxime** (2-PAM) is an **acetylcholinesterase reactivator** that can regenerate the enzyme, thereby reversing both muscarinic and nicotinic effects. - While crucial for reversing nicotinic effects and preventing 'aging' of the enzyme, it is **not the primary treatment for acute muscarinic crisis**; atropine is.

Question 103: The patient who developed a rash on the skin, hypotension, and difficulty in breathing after being given 2 g of ampicillin intravenously should be managed by.

A. 0.5 ml of 1:1000 adrenaline by intravenous injection
B. 0.5 ml of 1:10000 adrenaline by intramuscular injection
C. 0.5 ml of 1:10000 adrenaline by intravenous injection
D. 0.5 ml of 1:1000 adrenaline by intramuscular injection (Correct Answer)

Explanation: ***0.5 ml of 1:1000 adrenaline by intramuscular injection*** - This presentation describes **anaphylaxis**, characterized by a rapid onset of rash, **hypotension**, and **difficulty breathing** following drug administration. - The immediate and definitive treatment for anaphylaxis is **intramuscular adrenaline (epinephrine)**, typically at a concentration of **1:1000** for rapid absorption and systemic effect. *0.5 ml of 1:1000 adrenaline by intravenous injection* - **Intravenous adrenaline** is generally reserved for patients who are unresponsive to intramuscular administration or are in **cardiac arrest**, as it carries a higher risk of adverse effects like arrhythmias. - The initial, first-line treatment in an evolving anaphylactic reaction should be **intramuscular injection** due to its safer profile and rapid onset of action. *0.5 ml of 1:10000 adrenaline by intramuscular injection* - A concentration of **1:10,000 adrenaline** is typically used for **intravenous administration** during advanced cardiac life support (ACLS) protocols, not for initial intramuscular injection in anaphylaxis. - Administering 1:10,000 adrenaline intramuscularly would provide a **suboptimal dose** for treating severe anaphylaxis effectively. *0.5 ml of 1:10000 adrenaline by intravenous injection* - While intravenous adrenaline uses a **1:10,000 concentration**, it's not the initial route for managing anaphylaxis unless the patient is in **cardiac arrest** or unresponsive to IM adrenaline. - Starting with IV adrenaline carries a higher risk of **cardiac complications** and can be difficult to administer promptly in an emergency outside of a controlled setting.

Question 104: Which of the following medications is contraindicated in head trauma patients?

A. Furosemide
B. Thiopentone
C. Mannitol
D. Corticosteroids (Correct Answer)

Explanation: ***Corticosteroids*** - While previously used, **corticosteroids** are now contraindicated in traumatic brain injury (TBI) due to evidence suggesting they may increase mortality. - **CRASH trial** showed that corticosteroids increased the risk of death in patients with head injury, possibly by exacerbating secondary brain injury. *Furosemide* - **Furosemide** can be used in certain situations to reduce intracranial pressure by inducing diuresis and reducing cerebral edema, especially when combined with mannitol. - It works by inhibiting the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, leading to increased water excretion. *Thiopentone* - **Thiopentone** (a barbiturate) can be used in severe head trauma to reduce cerebral metabolic rate, thereby decreasing cerebral blood flow and intracranial pressure. - It induces a **pharmacological coma** and provides neuroprotection by scavenging free radicals and stabilizing cell membranes. *Mannitol* - **Mannitol** is an osmotic diuretic commonly used to reduce intracranial pressure in head trauma by creating an osmotic gradient that draws water out of the brain parenchyma. - It is administered intravenously and works rapidly to decrease brain volume and improve cerebral perfusion pressure.

Question 105: Which of the following is an antagonist used to reverse the effects of benzodiazepines?

A. Alprazolam
B. Naltrexone
C. Propofol
D. Flumazenil (Correct Answer)

Explanation: ***Flumazenil*** - **Flumazenil** is a **competitive antagonist** at the **GABA-A receptor**, specifically binding to the benzodiazepine site. - By blocking benzodiazepines from binding, it rapidly **reverses their sedative and anxiolytic effects**, making it useful in overdose or to awaken patients post-procedure. *Alprazolam* - **Alprazolam** is a **benzodiazepine** itself, acting as a **GABA-A receptor agonist** rather than an antagonist. - It would **potentiate** the effects of other benzodiazepines, leading to increased sedation and respiratory depression, not reversal. *Propofol* - **Propofol** is an **intravenous anesthetic** that works by enhancing the effects of **GABA**, but it is not a specific benzodiazepine antagonist. - It would **deepen sedation** and anesthesia, which is the opposite of reversing benzodiazepine effects. *Naltrexone* - **Naltrexone** is a **mu-opioid receptor antagonist** used to block the effects of opioids in cases of overdose or addiction. - It has **no pharmacological effect** on the benzodiazepine receptor or its actions.

Question 106: What is the drug of choice for managing status epilepticus?

A. Propofol
B. Thiopentone
C. Phenytoin
D. Lorazepam (Correct Answer)

Explanation: ***Lorazepam*** - **Lorazepam** is the preferred first-line agent for status epilepticus due to its rapid onset of action and relatively long duration of anticonvulsant effect (12-24 hours), making it highly effective in stopping ongoing seizures. - Its **lipophilicity** allows it to quickly cross the blood-brain barrier while having less redistribution than diazepam, providing sustained seizure control. - Dose: **0.1 mg/kg IV** (typically 4 mg) administered at 2 mg/min. *Propofol* - **Propofol** is an anesthetic agent used in **refractory status epilepticus** when first and second-line agents have failed. - It carries risks of **hemodynamic instability**, **propofol infusion syndrome** with prolonged use, and requires ICU monitoring with intubation. - Reserved for third-line therapy, not appropriate as initial management. *Thiopentone* - **Thiopentone** is a barbiturate used for **refractory status epilepticus** as a third-line agent. - It has a longer half-life and recovery time compared to benzodiazepines, with significant **cardiovascular depression** and respiratory suppression. - Requires ICU setting with mechanical ventilation and hemodynamic support. *Phenytoin* - **Phenytoin** (or fosphenytoin) is a **second-line agent** used after benzodiazepines if seizures persist. - It has a **slower onset of action** (15-30 minutes) compared to benzodiazepines and requires cardiac monitoring due to risk of arrhythmias. - Loading dose: **20 mg/kg IV** at maximum rate of 50 mg/min to avoid cardiovascular complications.

Practice by Chapter

Management of Anaphylaxis

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Drugs in Cardiac Arrest

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Status Epilepticus Management

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Acute Stroke Therapeutics

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Toxicological Emergencies

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Antidotes in Emergency Medicine

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Pain Management in Emergency

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Sedation and Paralysis in Emergency

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Drugs in Traumatic Emergencies

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Thrombolysis in Emergency Settings

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