Emergency Pharmacology Practice Questions

Q: In the treatment of shock, why is dobutamine preferred over dopamine?

All the above.. **Explanation:** Dobutamine is often preferred over Dopamine in specific shock scenarios (particularly cardiogenic shock) due to its more favorable pharmacological profile and lower side-effect burden. **1. Why the Correct Answer (D) is Right:** * **Fewer Arrhythmias (Option A):** While both are inotropes, Dopamine significantly increases endogenous norepinephrine release. This, combined with its strong $\beta_1$ and $\alpha$ effects at higher doses, makes it more **arrhythmogenic** than Dobutamine. * **Less Renal Vasodilation (Option B):** This is a comparative pharmacological fact. While low-dose Dopamine acts on $D_1$ receptors to cause renal vasodilation, Dobutamine lacks this specific dopaminergic activity. In the context of the question, the absence of this "distracting" vasodilator effect allows for more predictable hemodynamic management in heart failure. * **Less Coronary Vasoconstriction (Option C):** At higher doses, Dopamine stimulates $\alpha_1$ receptors, leading to systemic and **coronary vasoconstriction**, which increases myocardial oxygen demand and can worsen ischemia. Dobutamine has mild $\beta_2$ activity which promotes vasodilation, reducing afterload and improving coronary perfusion. **2. Clinical Pearls for NEET-PG:** * **Mechanism:** Dobutamine is a relatively selective **$\beta_1$ agonist** (Inotrope > Chronotrope). * **Drug of Choice:** Dobutamine is the preferred inotrope for **Cardiogenic Shock** and is used in **Stress Echocardiography**. * **The "Dopamine Myth":** Modern trials (like the SOAP II trial) have shown that Dopamine is associated with higher mortality and more arrhythmic events compared to Norepinephrine/Dobutamine, leading to its declining use in clinical practice. * **Side Effect:** The most common side effect of Dobutamine is tachycardia.

Q: What is the recommended dilution of epinephrine for anaphylactic shock?

All the above. **Explanation:** The management of anaphylaxis requires different concentrations and routes of administration for Epinephrine (Adrenaline) based on the severity and clinical setting. While the **Intramuscular (IM) route** is the first-line treatment for acute anaphylaxis in the community or emergency department, all three options listed are clinically valid applications of epinephrine. 1. **1:1000, IM route (Option B):** This is the **standard first-line treatment** for anaphylaxis. The 1:1000 concentration (1 mg/mL) allows for a small volume (0.5 mg for adults) to be injected into the vastus lateralis, providing rapid peak plasma concentrations and a high safety profile. 2. **1:10000, IV route (Option C):** This dilute concentration (0.1 mg/mL) is reserved for **severe anaphylactic shock** or cardiac arrest where there is profound hypotension and poor peripheral perfusion. It must be administered slowly by experienced clinicians to avoid life-threatening arrhythmias or hypertensive crises. 3. **1:100, Inhalational route (Option A):** While less common for systemic anaphylaxis, high-concentration epinephrine (10 mg/mL) is used via nebulization for **refractory upper airway obstruction (laryngeal edema)** or severe croup. **Clinical Pearls for NEET-PG:** * **Site of Choice:** The **anterolateral thigh (vastus lateralis)** is preferred over the deltoid due to better absorption. * **Adult Dose (IM):** 0.5 mg of 1:1000. * **Pediatric Dose (IM):** 0.01 mg/kg (max 0.3 mg) of 1:1000. * **Mechanism:** Epinephrine acts as an agonist at $\alpha_1$ (vasoconstriction), $\beta_1$ (increased cardiac output), and $\beta_2$ (bronchodilation and stabilization of mast cells) receptors.

Q: Which of the following is the drug of choice for treating anaphylactic shock?

Adrenaline. **Explanation:** **Adrenaline (Epinephrine)** is the drug of choice for anaphylactic shock because it acts as a **physiological antagonist** to histamine and other inflammatory mediators. Its efficacy lies in its potent action on multiple adrenergic receptors: * **$\alpha_1$ action:** Causes vasoconstriction, which increases peripheral vascular resistance to combat hypotension and reduces mucosal edema (laryngeal edema). * **$\beta_1$ action:** Exerts positive inotropic and chronotropic effects, improving cardiac output. * **$\beta_2$ action:** Causes bronchodilation and, crucially, **stabilizes mast cells**, preventing further release of histamine and leukotrienes. **Why other options are incorrect:** * **Isoprenaline:** A pure $\beta$-agonist ($\beta_1 + \beta_2$). While it causes bronchodilation, its potent $\beta_2$ vasodilatory effect can worsen hypotension, making it dangerous in shock. * **Noradrenaline:** Primarily an $\alpha$-agonist with some $\beta_1$ action. It lacks the $\beta_2$ activity required for bronchodilation and mast cell stabilization. * **Terbutaline:** A selective $\beta_2$ agonist. While it helps with bronchospasm, it does not provide the necessary $\alpha_1$ vasoconstriction to treat systemic hypotension or laryngeal edema. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Choice:** **Intramuscular (IM)** in the anterolateral thigh (vastus lateralis) is preferred over SC or IV in an emergency due to faster and more reliable absorption. * **Concentration:** Use **1:1000** for IM and **1:10,000** for IV (reserved for cardiac arrest or severe refractory shock). * **Standard Adult Dose:** 0.5 mg (0.5 ml of 1:1000 solution). * **Drug of Choice for other conditions:** Adrenaline is also the DOC for Cardiac Arrest and Glaucoma (Dipivefrine prodrug).

Question 1

In the treatment of shock, why is dobutamine preferred over dopamine?

Accepted Answer

All the above.

Answer

It causes fewer arrhythmias.

Answer

It causes less renal vasodilation.

Answer

It causes less coronary vasoconstriction.

Question 2

What is the recommended dilution of epinephrine for anaphylactic shock?

Accepted Answer

All the above

Answer

1:100, inhalational route

Answer

1:1000, intramuscular (IM) route

Answer

1:10000, intravenous (IV) route

Question 3

A 70-year-old man was administered penicillin intravenously. Within 5 minutes, he developed generalized urticaria, swelling of lips, hypotension, and bronchospasm. What is the first choice of treatment?

Accepted Answer

Epinephrine injection

Answer

Chlorpheniramine injection

Answer

High dose hydrocortisone tablet

Answer

Nebulized salbutamol

Question 4

A patient develops facial puffiness, rash, hypotension, and breathing difficulty after the administration of antibiotics. What is the immediate treatment?

Accepted Answer

0.5 ml of adrenaline IM (1:1000 dilution)

Answer

1 ml of adrenaline IV (1:10,000 dilution)

Answer

1 ml of adrenaline IV (1:10,000 dilution)

Answer

0.5 ml of adrenaline IV (1:1000 dilution)

Question 5

Which of the following is the drug of choice for treating anaphylactic shock?

Accepted Answer

Adrenaline

Answer

Isoprenaline

Answer

Noradrenaline

Answer

Terbutaline

Emergency Pharmacology — MCQs

Emergency Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?