Emergency Pharmacology Practice Questions

Q: According to traditional teaching, dopamine is preferred over dobutamine in treatment of renal shock because:

Renal vasodilatory effect. ***Renal vasodilatory effect*** - In traditional teaching, low-dose **dopamine** was thought to selectively stimulate **D1 dopamine receptors** in the kidneys, leading to **renal vasodilation** and improved renal blood flow. - This effect was believed to be beneficial in preventing or treating **acute kidney injury (AKI)** in the context of shock, thus making it a preferred agent for "renal shock." *Increased cardiac output* - While dopamine can increase **cardiac output** through beta-1 agonism at intermediate doses, dobutamine is generally considered a more potent inotropic agent for this purpose. - The primary reason for preferring dopamine in renal shock was not its inotropic effect but its purported renal-specific action. *Peripheral vasoconstriction* - At higher doses, dopamine stimulates **alpha-1 adrenergic receptors**, leading to **peripheral vasoconstriction**, which can increase **systemic vascular resistance (SVR)** and blood pressure. - This generalized vasoconstrictive effect is typically avoided in renal shock if the goal is to improve renal perfusion, as it can potentially compromise renal blood flow. *Prolonged action* - Neither dopamine nor dobutamine has a particularly **prolonged action**; both are typically administered via continuous infusion due to their short half-lives. - The duration of action was not the primary factor in preferring dopamine for renal shock.

Q: Which of the following drugs is not used for the treatment of hyperkalemia?

Magnesium sulphate. ***Magnesium sulphate*** - **Magnesium sulphate** is primarily used to treat conditions like **hypomagnesemia**, eclampsia, and certain arrhythmias, but it does not directly lower serum potassium levels. - While magnesium can affect potassium channels indirectly, it is not a recommended treatment for **hyperkalemia**. *Sodium bicarbonate* - **Sodium bicarbonate** promotes an intracellular shift of potassium by increasing blood pH, which activates the **Na+/H+ antiporter** on cell membranes, exchanging H+ out and Na+ in. - This influx of Na+ then activates the **Na+/K+ ATPase pump**, moving Na+ out of the cell and K+ into the cell. *Salbutamol* - **Salbutamol**, a **beta-2 adrenergic agonist**, stimulates the **Na+/K+ ATPase pump**, causing a shift of potassium from the **extracellular** to the **intracellular** space. - It is often administered via nebulization for **hyperkalemia** treatment, particularly in patients without renal failure. *Calcium gluconate* - **Calcium gluconate** does not lower serum potassium levels, but it **stabilizes the cardiac membrane** by increasing the action potential threshold, thereby protecting the heart from the adverse effects of hyperkalemia. - It is typically the **first-line emergency treatment** for severe hyperkalemia, especially with ECG changes, to prevent arrhythmias.

Q: The safe intramuscular dose of adrenaline for anaphylaxis in a patient with compromised cardiac condition is:

0.2 mg. ***0.2 mg*** - For patients with **compromised cardiac conditions** experiencing anaphylaxis, a slightly reduced initial IM dose of **0.2 mg** (compared to the standard 0.3-0.5 mg) may be considered to minimize cardiovascular stress. - This dose provides adequate **bronchodilation** and **vasopressor** effect while reducing the risk of **tachyarrhythmias**, **myocardial ischemia**, or severe **hypertension**. - The dose can be repeated every 5-15 minutes if needed based on clinical response. *0.02 mg* - This dose is far too low for **intramuscular administration** in anaphylaxis and would be **therapeutically inadequate**. - Doses this small (0.01-0.05 mg) are only used for **slow IV push** in specific contexts like refractory hypotension, not for anaphylaxis treatment. *0.04 mg* - This dose is also **subtherapeutic** for IM administration in anaphylaxis. - Such a low dose would fail to reverse the life-threatening manifestations of anaphylaxis including **bronchospasm**, **laryngeal edema**, and **cardiovascular collapse**. *0.4 mg* - This is within the **standard dosing range** (0.3-0.5 mg IM) for anaphylaxis in patients with healthy hearts. - While not contraindicated in cardiac patients, a slightly lower dose like **0.2 mg** is often preferred initially to allow for careful monitoring and dose titration based on response and tolerance.

Q: Dose of Human Rabies Immunoglobulin (HRIG) is:

20 IU/kg. ***20 IU/kg*** - The standard dose for **Human Rabies Immunoglobulin (HRIG)** is **20 IU/kg** of body weight, administered once. - This dose is critical for providing immediate passive immunity by neutralizing the rabies virus at the wound site. *30 IU/kg* - This dosage is higher than the recommended standard for HRIG and is not typically used. - Administering an unnecessarily high dose could potentially lead to more adverse effects without additional benefit. *40 IU/kg* - This dosage is double the recommended amount and is significantly higher than necessary. - Overdosing immunoglobulin can increase the risk of adverse reactions and is not supported by guidelines for rabies post-exposure prophylaxis. *10 IU/kg* - This dosage is below the recommended amount and would be insufficient to provide effective passive immunity against the rabies virus. - Underdosing could compromise the protective effect, leaving the patient vulnerable to disease progression.

Q: Which of the following is the most effective antagonist for morphine overdose?

Naloxone. ***Naloxone*** - **Naloxone** is a pure opioid antagonist that rapidly reverses the effects of opioid overdose by competing for and displacing opioids from the **mu-opioid receptors** - Its rapid onset of action (1-2 minutes IV) and high affinity for opioid receptors make it the drug of choice for treating **morphine overdose**, particularly in emergency settings - Has no intrinsic agonist activity, making it safe and effective for acute reversal *Buprenorphine* - **Buprenorphine** is a partial opioid agonist, meaning it produces some opioid effects but to a lesser degree than full agonists like morphine - While it can displace full agonists from receptors, it is primarily used in **opioid dependence treatment** rather than acute overdose reversal - Has a ceiling effect for respiratory depression and is not the first-line agent for emergency overdose management *Nalorphine* - **Nalorphine** is an older mixed agonist-antagonist that was historically used for opioid overdose - It has largely been replaced by **naloxone** due to its own opioid-like effects (agonist activity at kappa receptors) and less favorable side effect profile - Can cause respiratory depression itself, making it unsuitable for emergency use *Pentazocine* - **Pentazocine** is an opioid agonist-antagonist (kappa agonist, mu antagonist), meaning it acts as an agonist at some opioid receptors and an antagonist at others - This mixed action means it can precipitate **withdrawal symptoms** in opioid-dependent individuals and is not suitable for reversing a full opioid overdose - Used primarily for analgesia, not overdose reversal

Q: Which agent is used to reverse opioid overdose?

Naloxone. ***Naloxone*** - **Naloxone** is an **opioid receptor antagonist** that competitively binds to opioid receptors, reversing the effects of opioid agonists. - It rapidly restores respiratory function and consciousness in individuals experiencing an **opioid overdose**. *Atropine* - **Atropine** is an **anticholinergic agent** used to treat bradycardia, organophosphate poisoning, and as a pre-anesthetic medication. - It does not have any direct action on opioid receptors and is ineffective in reversing an opioid overdose. *Protamine* - **Protamine** is a **heparin antagonist** used to reverse the anticoagulant effects of heparin. - It acts by forming a stable complex with heparin, thereby neutralizing its activity, and is unrelated to opioid overdose. *Flumazenil* - **Flumazenil** is a **benzodiazepine receptor antagonist** used to reverse the sedative effects of benzodiazepines. - While it reverses the effects of another class of central nervous system depressants, it has no activity on opioid receptors and is not indicated for opioid overdose.

Q: In anaphylaxis, adrenaline is the drug of choice. What is its mechanism of action in this emergency?

Stimulate adrenergic receptors. ***Stimulate adrenergic receptors*** - **Adrenaline (epinephrine)** is a potent agonist of **alpha-1, beta-1, and beta-2 adrenergic receptors**, leading to widespread physiological effects that counteract anaphylaxis. - By stimulating these receptors, adrenaline causes **vasoconstriction** (alpha-1), increases **heart rate and contractility** (beta-1), and induces **bronchodilation** (beta-2). - These combined actions rapidly reverse the life-threatening manifestations of anaphylaxis: **hypotension, bronchospasm, and angioedema**. *Activate histamine receptors* - Histamine is a primary mediator released during anaphylaxis, causing vasodilation, increased vascular permeability, and bronchoconstriction. - Adrenaline does not activate histamine receptors; rather, it **antagonizes the effects of histamine** through its adrenergic actions. *Block muscarinic receptors* - Blocking muscarinic receptors would lead to effects like bronchodilation and increased heart rate, similar to some effects of adrenaline. - However, adrenaline primarily acts on **adrenergic receptors**, not muscarinic receptors, and its broader effects in anaphylaxis are not due to muscarinic blockade. *Inhibit prostaglandin synthesis* - Inhibition of prostaglandin synthesis is the primary mechanism of action for **NSAIDs** (Non-Steroidal Anti-Inflammatory Drugs). - While prostaglandins can play a role in inflammatory responses, they are not the primary target for acute management of anaphylaxis, and adrenaline does not act through this mechanism.

Q: Which drug is used to counteract opioid overdose because of its high affinity for opioid receptors?

Naloxone. ***Naloxone*** - **Naloxone** is an **opioid antagonist** with a high affinity for opioid receptors, making it effective in rapidly reversing the effects of an opioid overdose [1]. - Its mechanism of action involves competitively binding to and blocking opioid receptors, thereby displacing opioids and reversing respiratory depression and other overdose symptoms [3]. *Naltrexone* - **Naltrexone** is also an **opioid antagonist**, but it has a longer duration of action and is primarily used for preventing relapse in opioid-dependent individuals and treating alcohol dependence [1][3]. - While it blocks opioid effects, its slower onset and longer action make it less suitable for emergency overdose reversal compared to naloxone. *Buprenorphine* - **Buprenorphine** is a **partial opioid agonist**, meaning it produces some opioid effects while also blocking other opioids from binding to receptors [4]. - It is used in medication-assisted treatment for opioid use disorder to reduce cravings and withdrawal symptoms, but it is not used to reverse an acute opioid overdose. *Methadone* - **Methadone** is a **long-acting full opioid agonist** used primarily for pain management and in medication-assisted treatment for opioid use disorder [2]. - It significantly occupies opioid receptors and can prevent other opioids from having an effect, but it is an opioid itself and would exacerbate, not reverse, an opioid overdose [2].

Q: What is the recommended dose of diphtheria antitoxin for adults?

20000 to 50000 IU. ***20000 to 50000 IU*** - For adults with **diphtheria**, the recommended dose of **diphtheria antitoxin (DAT)** in the range of 20,000 to 50,000 IU is appropriate for **pharyngeal or laryngeal diphtheria** of moderate severity (typically disease present for 48-72 hours). - This dosage aims to neutralize the **diphtheria toxin** circulating in the bloodstream and prevent further tissue damage. - **Note:** More severe or extensive disease (>3 days duration or with bull neck) may require higher doses (80,000-120,000 IU). *1000 to 2000 IU* - This dosage is **too low** for therapeutic treatment of diphtheria in adults. - Such a low dose would be insufficient to neutralize the substantial amount of **toxin** produced during an active infection, regardless of disease severity. *10000 to 20000 IU* - This dose is **suboptimal** for most forms of diphtheria in adults. - Even for **mild cutaneous diphtheria**, doses typically start at 20,000 IU or higher. - For respiratory diphtheria, this range would be inadequate to effectively counteract the toxin. *None of the options* - This is incorrect because **20,000 to 50,000 IU** is a recognized and recommended range for diphtheria antitoxin in adult treatment of moderate pharyngeal/laryngeal disease. - Diphtheria antitoxin is a crucial and **specific treatment** for diphtheria, and evidence-based dosage ranges exist based on disease severity and location.

Q: What is the typical initial dose of diazepam when starting treatment for alcohol withdrawal symptoms?

20 mg. ***20 mg*** - The typical initial dose of diazepam for alcohol withdrawal is **10-20 mg orally**, with 20 mg being the standard starting dose for **moderate to severe withdrawal symptoms**. - This dosing is based on **CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol) protocol**, the most widely used symptom-triggered regimen for alcohol withdrawal management. - The dose can be **repeated every 1-2 hours** based on symptom severity (tremors, anxiety, agitation, autonomic hyperactivity) to prevent progression to **seizures or delirium tremens**. - This approach balances efficacy with safety, minimizing risks of over-sedation and respiratory depression. *40 mg* - An initial dose of **40 mg** is above standard evidence-based protocols and not routinely recommended as a starting dose. - While some severe cases may eventually require cumulative doses in this range over several hours, starting with 40 mg carries **unnecessary risk of over-sedation** and is not consistent with **CIWA-Ar or other established guidelines**. - Standard practice is to start lower (10-20 mg) and titrate upward based on clinical response. *50 mg* - An initial dose of **50 mg** is excessive and well above recommended starting doses, significantly increasing the risk of **respiratory depression, hypotension, and over-sedation**. - Such high doses would require intensive monitoring and are not part of standard initial management protocols. *80 mg* - An initial dose of **80 mg of diazepam** is dangerously high and carries severe risk of **over-sedation, respiratory arrest, and cardiovascular collapse**. - This dose far exceeds any standard initial dosing protocol and would only be considered as a **cumulative dose over many hours** in refractory cases under intensive care monitoring, never as an initial single dose.

Question 1

According to traditional teaching, dopamine is preferred over dobutamine in treatment of renal shock because:

Accepted Answer

Renal vasodilatory effect

Answer

Increased cardiac output

Answer

Peripheral vasoconstriction

Answer

Prolonged action

Question 2

Which of the following drugs is not used for the treatment of hyperkalemia?

Accepted Answer

Magnesium sulphate

Answer

Sodium bicarbonate

Answer

Salbutamol

Answer

Calcium gluconate

Question 3

The safe intramuscular dose of adrenaline for anaphylaxis in a patient with compromised cardiac condition is:

Accepted Answer

0.2 mg

Answer

0.02 mg

Answer

0.4 mg

Answer

0.04 mg

Question 4

Dose of Human Rabies Immunoglobulin (HRIG) is:

Accepted Answer

20 IU/kg

Answer

30 IU/kg

Answer

40 IU/kg

Answer

10 IU/kg

Question 5

Which of the following is the most effective antagonist for morphine overdose?

Accepted Answer

Naloxone

Answer

Buprenorphine

Answer

Nalorphine

Answer

Pentazocine

Question 6

Which agent is used to reverse opioid overdose?

Accepted Answer

Naloxone

Answer

Atropine

Answer

Protamine

Answer

Flumazenil

Question 7

In anaphylaxis, adrenaline is the drug of choice. What is its mechanism of action in this emergency?

Accepted Answer

Stimulate adrenergic receptors

Answer

Activate histamine receptors

Answer

Block muscarinic receptors

Answer

Inhibit prostaglandin synthesis

Question 8

Which drug is used to counteract opioid overdose because of its high affinity for opioid receptors?

Accepted Answer

Naloxone

Answer

Buprenorphine

Answer

Methadone

Answer

Naltrexone

Question 9

What is the recommended dose of diphtheria antitoxin for adults?

Accepted Answer

20000 to 50000 IU

Answer

1000 to 2000 IU

Answer

10000 to 20000 IU

Answer

None of the options

Question 10

What is the typical initial dose of diazepam when starting treatment for alcohol withdrawal symptoms?

Accepted Answer

20 mg

Answer

80 mg

Answer

40 mg

Answer

50 mg

Emergency Pharmacology — MCQs

Emergency Pharmacology — MCQs

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