Emergency Pharmacology Practice Questions

Q: What is the drug of choice in the management of a life-threatening allergic reaction?

Adrenalin. ### Explanation **Correct Answer: C. Adrenalin (Epinephrine)** In a life-threatening allergic reaction (Anaphylaxis), **Adrenalin** is the drug of choice because it acts as a **physiological antagonist** to histamine and other inflammatory mediators. It works through three critical mechanisms: 1. **Alpha-1 receptors:** Causes vasoconstriction, which increases blood pressure and reduces mucosal edema (laryngeal edema). 2. **Beta-1 receptors:** Exerts positive inotropic and chronotropic effects, improving cardiac output. 3. **Beta-2 receptors:** Induces potent bronchodilation and inhibits further mediator release from mast cells and basophils [1]. **Why other options are incorrect:** * **Corticosteroids (e.g., Hydrocortisone):** These have a slow onset of action (4–6 hours). They are used to prevent **biphasic reactions** (delayed recurrence of symptoms) but cannot treat the acute, life-threatening phase. * **Antihistamines (e.g., Cetirizine, Diphenhydramine):** These only block H1/H2 receptors. They help with skin symptoms (urticaria/itching) but do not reverse airway obstruction or hypotension. * **Diazepam:** This is a benzodiazepine used for seizures or anxiety; it has no role in managing anaphylaxis. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Administration:** The preferred route in emergencies is **Intramuscular (IM)** in the anterolateral aspect of the thigh (vastus lateralis) due to rapid absorption. * **Concentration:** Use **1:1000** (1 mg/ml) for IM injection [1]. (Note: 1:10,000 is used for IV in cardiac arrest). * **Dose:** 0.5 mg for adults; 0.01 mg/kg for children. * **Mechanism:** It is the "Physiological Antagonist" of histamine (acting on different receptors to produce opposite effects).

Q: Oxygen as an emergency drug is contraindicated in which of the following conditions?

Hyperventilation. **Explanation:** **1. Why Hyperventilation is the Correct Answer:** In acute hyperventilation (often associated with anxiety or panic attacks), the patient breathes rapidly and deeply, leading to the excessive "blowing off" of Carbon Dioxide ($CO_2$). This results in **Respiratory Alkalosis** and a decrease in the partial pressure of arterial $CO_2$ ($PaCO_2$). Administering supplemental oxygen is contraindicated because it does not address the underlying pathology and may further suppress the respiratory drive. The standard treatment is to increase the $CO_2$ levels (e.g., breathing into a paper bag or simple reassurance) to restore the acid-base balance. **2. Analysis of Incorrect Options:** * **Anaphylaxis (A):** This is a medical emergency where laryngeal edema and bronchospasm can cause severe hypoxia. High-flow oxygen is a critical supportive measure alongside Adrenaline. * **Asthma (B):** Acute severe asthma leads to ventilation-perfusion mismatch and hypoxia. Oxygen is indicated to maintain $SpO_2$ between 93-95%. * **COPD (D):** While excessive oxygen can cause CO2 retention in COPD patients (due to the loss of hypoxic drive), oxygen is **not contraindicated**. It must be administered cautiously (controlled oxygen therapy) using a Venturi mask to maintain a target $SpO_2$ of 88-92%. **3. NEET-PG High-Yield Pearls:** * **Hypoxic Drive:** In chronic CO2 retainers (like COPD), the respiratory center becomes insensitive to $CO_2$. Respiration is driven by low $O_2$ levels. Giving 100% $O_2$ can abolish this drive, leading to respiratory arrest. * **Oxygen Toxicity:** Prolonged use of 100% oxygen can lead to absorption atelectasis and Retinopathy of Prematurity (in neonates). * **Drug of Choice for Hyperventilation:** Reassurance and, if necessary, a benzodiazepine (e.g., Diazepam) to reduce anxiety.

Q: Which drug should NOT be used in a patient with hyperkalemia and no ECG findings?

Calcium gluconate. ### Explanation The management of hyperkalemia is categorized into three goals: stabilizing the cardiac membrane, shifting potassium into cells, and removing potassium from the body. **Why Calcium Gluconate is the Correct Answer:** Calcium gluconate (or calcium chloride) is a **cardioprotective agent**. It antagonizes the membrane-excitability effects of hyperkalemia by stabilizing the resting membrane potential of cardiomyocytes. However, it **does not lower serum potassium levels**. Therefore, it is strictly indicated only when there are **ECG changes** (e.g., peaked T-waves, widened QRS) or severe hyperkalemia (>6.5 mEq/L). Using it in a patient with no ECG findings is unnecessary and provides no therapeutic benefit. **Analysis of Incorrect Options:** * **Glucose with Insulin (Option C):** This is the fastest way to shift potassium from the extracellular to the intracellular compartment (via stimulation of Na+/K+-ATPase pump). It is indicated regardless of ECG findings to lower serum levels. * **Sodium Bicarbonate (Option A):** It shifts potassium into cells by exchanging H+ for K+. It is particularly useful if the patient has underlying metabolic acidosis. * **Resins (Option B):** Cation-exchange resins (e.g., Kayexalate or Patiromer) bind potassium in the GI tract for excretion. These are used for definitive removal of potassium in stable patients. **NEET-PG High-Yield Pearls:** 1. **First-line for ECG changes:** Calcium gluconate (acts within 1-3 minutes; effect lasts 30-60 minutes). 2. **Fastest potassium shifter:** Insulin + Dextrose. 3. **Salbutamol (Nebulization):** Also shifts K+ intracellularly but should be used with caution in patients with tachycardia or CAD. 4. **Definitive Treatment:** Hemodialysis is the most effective method for potassium removal in refractory cases or renal failure.

Q: What is the drug of choice for anaphylactic shock?

Adrenaline. **Explanation:** **Adrenaline (Epinephrine)** is the drug of choice for anaphylactic shock [2] because it acts as a **physiological antagonist** to histamine and other inflammatory mediators. Its life-saving efficacy stems from its potent action on multiple receptors: [1], [2] * **$\alpha_1$ receptors:** Cause vasoconstriction, which increases peripheral vascular resistance to treat hypotension and reduces mucosal edema (laryngeal edema) [1], [2]. * **$\beta_1$ receptors:** Provide positive inotropic and chronotropic effects, improving cardiac output. * **$\beta_2$ receptors:** Induce bronchodilation and, crucially, **stabilize mast cells**, inhibiting further release of inflammatory mediators [1]. **Why other options are incorrect:** * **Antihistaminics (B):** These are considered **second-line** agents. They only block H1/H2 receptors and do not reverse life-threatening airway obstruction or hypotension. They have a slow onset of action. * **Corticosteroids (C):** These are used to prevent **biphasic reactions** (delayed recurrence of symptoms). They have a slow onset (4–6 hours) and are ineffective in the acute management of cardiovascular collapse. * **Epinephrine (D):** While Epinephrine is the same drug as Adrenaline, in many Indian medical examinations (including traditional NEET-PG patterns), **Adrenaline** is the preferred nomenclature used in standard textbooks like K.D. Tripathi. *Note: In clinical practice, they are synonymous.* **High-Yield Clinical Pearls for NEET-PG:** * **Route of Choice:** Intramuscular (IM) in the **anterolateral thigh** (Vastus lateralis) due to faster absorption and higher plasma levels compared to SC or IM deltoid [2]. * **Concentration:** **1:1000** (1 mg/ml) for IM; **1:10,000** (0.1 mg/ml) for IV [2]. * **Standard Dose:** 0.5 mg (0.5 ml of 1:1000) for adults; 0.01 mg/kg for children [2]. * **Mechanism:** Physiological antagonism.

Q: A patient is brought to the emergency department with signs suggesting opioid poisoning. What is the antidote of choice?

Naloxone. ***Naloxone***- **Naloxone** is the drug of choice for treating opioid poisoning, acting as a competitive antagonist at **mu**, kappa, and delta opioid receptors [1]. - It reverses the life-threatening effects of opioid overdose, primarily **respiratory depression** and **central nervous system depression**, within minutes of administration [3].*Flumazenil*- Flumazenil is the specific antagonist used to reverse the effects of **benzodiazepine overdose**, acting at the GABA-A receptor.- It is generally ineffective and not indicated for pure opioid toxicity.*Atropine*- Atropine is an **anticholinergic agent** used primarily in the treatment of symptomatic **bradycardia** and **organophosphate poisoning** [2].- It does not antagonize opioid receptors and has no direct role in reversing opioid-induced respiratory depression.*Physostigmine*- Physostigmine is a **reversible acetylcholinesterase inhibitor** used mainly for reversing severe central nervous system effects of **anticholinergic poisoning** (e.g., tricyclic antidepressants).- Increasing acetylcholine is irrelevant and potentially counterproductive in treating opioid-induced respiratory depression.

Q: What is the concentration of adrenaline used in the following route of administration?

1:10,000. ***1:10,000*** - The image depicts **intraosseous (IO) infusion** being administered. For **IV/IO administration during cardiac arrest**, adrenaline is used in a **1:10,000 concentration** (0.1 mg/mL). - This is the standard concentration for resuscitation across all age groups (pediatric and adult) as per **PALS and ACLS guidelines**. - **Pediatric dose:** 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution) IV/IO - **Adult dose:** 1 mg (10 mL of 1:10,000 solution) IV/IO - This concentration allows safe systemic delivery with appropriate cardiovascular effects during cardiac arrest. *1:1000* - The 1:1000 concentration (1 mg/mL) is used for **intramuscular (IM) injection** in the treatment of **anaphylaxis**. - **Dose:** 0.01 mg/kg IM (maximum 0.5 mg in adults, 0.3 mg in children) - This concentration is **too concentrated for direct IV/IO administration** and could cause severe hypertension, arrhythmias, and myocardial ischemia if given undiluted intravenously. *1:100* - A 1:100 concentration (10 mg/mL) is used for **topical application** or mixed with **local anesthetics** (e.g., lidocaine with epinephrine for local anesthesia). - This very high concentration is **never used for systemic administration** and would cause life-threatening cardiovascular complications if given IV/IO. *1:100,000* - The 1:100,000 concentration (0.01 mg/mL) is primarily used **mixed with local anesthetics** for prolonged local/regional anesthesia and hemostasis. - This concentration is **too dilute** for emergency resuscitation and is not the standard for IV/IO administration during cardiac arrest.

Q: A comatose person is brought to the hospital. On examination his respiratory rate is 8 / min with pulse rate of 75 bpm with BP of 110 / 70 mm Hg. His Pupils are shown below. Body temperature is 96°F. What is the probable diagnosis?

Opioid overdose. ***Opioid overdose*** - The constellation of **pinpoint pupils** (as shown in the image), **respiratory depression** (rate 8/min), and **coma** is highly characteristic of opioid overdose. - While **hypothermia** (96°F) can be seen with opioid use, the critical findings are the miosis and severe hypoventilation. *Uncal herniation* - **Uncal herniation** typically presents with a **dilated pupil** on the side of the herniation due to compression of the oculomotor nerve (CN III). - It often involves neurological deficits like hemiparesis and decerebrate posturing, along with changes in consciousness. *Pontine stroke* - A **pontine stroke** can cause pinpoint pupils due to disruption of sympathetic pathways, but it is also commonly associated with severe neurological deficits like **quadriplegia**, locked-in syndrome, and distinct respiratory patterns (e.g., apneustic breathing). - The provided vital signs and pupil presentation are more classically aligned with opioid toxicity than an isolated pontine stroke. *Metabolic encephalopathy* - **Metabolic encephalopathy** usually presents with **reactive, but often small, pupils** or normal pupils. - It leads to a global depression of brain function but rarely causes pinpoint pupils or severe respiratory depression as the primary distinguishing features.

Question 1

A young man is prescribed parenteral antibiotics for a respiratory tract infection. He collapses immediately after receiving the first dose, presenting with tachycardia, wheezing, and a drop in blood pressure. What are the most appropriate immediate interventions for this situation?

Accepted Answer

Subcutaneous epinephrine

Answer

Intravenous saline

Answer

Intravenous hydrocortisone

Answer

Nebulized salbutamol

Question 2

Calcium gluconate is not indicated in the management of which of the following conditions during CPR?

Accepted Answer

Hypokalemia

Answer

Hypocalcemia

Answer

Hyperkalemia

Answer

Calcium antagonism

Question 3

What is the drug of choice in the management of a life-threatening allergic reaction?

Accepted Answer

Adrenalin

Answer

Corticosteroids

Answer

Antihistamines

Answer

Diazepam

Question 4

Oxygen as an emergency drug is contraindicated in which of the following conditions?

Accepted Answer

Hyperventilation

Answer

Anaphylaxis

Answer

Asthma

Answer

COPD

Question 5

A patient who has undergone limb amputation is advised a stress test. What is the drug commonly used for this test?

Accepted Answer

Dobutamine

Answer

Dopexamine

Answer

Dopamine

Answer

Dipevefrine

Question 6

Which drug should NOT be used in a patient with hyperkalemia and no ECG findings?

Accepted Answer

Calcium gluconate

Answer

Sodium bicarbonate

Answer

Glucose with insulin

Answer

Resins

Question 7

What is the drug of choice for anaphylactic shock?

Accepted Answer

Adrenaline

Answer

Antihistaminic

Answer

Corticosteroids

Answer

Epinephrine

Question 8

A patient is brought to the emergency department with signs suggesting opioid poisoning. What is the antidote of choice?

Accepted Answer

Naloxone

Answer

Flumazenil

Answer

Physostigmine

Answer

Atropine

Question 9

What is the concentration of adrenaline used in the following route of administration?

Accepted Answer

1:10,000

Answer

1:100

Answer

1:1000

Answer

1:100,000

Question 10

A comatose person is brought to the hospital. On examination his respiratory rate is 8 / min with pulse rate of 75 bpm with BP of 110 / 70 mm Hg. His Pupils are shown below. Body temperature is 96°F. What is the probable diagnosis?

Accepted Answer

Opioid overdose

Answer

Uncal herniation

Answer

Pontine stroke

Answer

Metabolic encephalopathy

Emergency Pharmacology — MCQs

Emergency Pharmacology — MCQs

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