NEET-PG 2012 - Pharmacology Practice Questions

Q: All of the following are correct about ketamine, EXCEPT which of the following?

It is a potent bronchoconstrictor. ***It is a potent bronchoconstrictor*** - **Ketamine** is known for its **bronchodilatory properties**, making it a suitable anesthetic for patients with asthma or reactive airway disease, rather than a bronchoconstrictor [1]. - Its ability to relax bronchial smooth muscle is mediated, in part, by its indirect sympathetic stimulation and direct effects on airways. *It functionally "dissociates" the thalamus* - Ketamine's mechanism of action involves **N-methyl-D-aspartate (NMDA) receptor antagonism**, which leads to a "dissociative" state [2]. - This results in a functional separation between the **thalamoneocortical** and **limbic systems**, explaining its unique anesthetic effects. *It increases arterial blood pressure* - Ketamine typically causes an **increase in heart rate** and **arterial blood pressure** due to its sympathomimetic effects. - This is achieved through the release of **endogenous catecholamines**, which stimulate the cardiovascular system. *It inhibits polysynaptic reflexes in the spinal cord* - Ketamine acts as a powerful **analgesic** by inhibiting ascending **polysynaptic reflexes** in the spinal cord. - This contributes to its ability to provide profound **pain relief** separate from its anesthetic effects [2].

Q: Which drug is commonly used for outpatient department (OPD) analgesia?

Paracetamol. ***Paracetamol*** - It is a widely used and generally **safe analgesic** and antipyretic often prescribed for mild to moderate pain in an outpatient setting. - Its favorable side effect profile and availability as an **over-the-counter (OTC)** medication make it a first-choice drug for many common pain conditions. *Diclofenac* - While it is an effective NSAID used for pain and inflammation, its use can be associated with **gastrointestinal side effects** like ulcers and bleeding, as well as cardiovascular risks. - It is often reserved for more significant inflammatory pain or when other analgesics are insufficient, and may require more careful monitoring in an outpatient setting. *Ibuprofen* - Similar to diclofenac, Ibuprofen is an **NSAID** which is effective for pain and inflammation. However, it also carries risks of **gastrointestinal irritation** and renal side effects, especially with prolonged use or in certain patient populations. - While available OTC, its use for routine outpatient analgesia may be less preferred than paracetamol in some cases due to its GI and renal side effect profile. *Tramadol* - Tramadol is a **central acting opioid analgesic** with a higher potential for side effects such as nausea, dizziness, constipation, and the risk of dependence or abuse. - It is typically reserved for moderate to severe pain that is not adequately managed by non-opioid analgesics, and its prescription often involves more stringent monitoring than paracetamol.

Q: Most commonly abused opioid -

Diacetylmorphine. ***Diacetylmorphine*** - **Diacetylmorphine**, commonly known as **heroin**, is synthetically derived from **morphine** but is significantly more potent and lipid-soluble, allowing it to cross the **blood-brain barrier** rapidly [1, 3]. - Its rapid onset of action and intense euphoric effects contribute to its high potential for **abuse** and addiction, making it one of the most commonly abused opioids globally, particularly through intravenous injection [1]. *Morphine* - While **morphine** is a potent opioid and has a high potential for abuse, it is often prescribed in clinical settings for severe pain. - Its slower onset and less intense "rush" compared to **heroin** make it less frequently the **primary opioid of abuse** in illicit street drug markets [1]. *Oxycodone* - **Oxycodone** is a highly abused prescription opioid, especially in the form of controlled-release formulations like **OxyContin**, but its abuse is primarily linked to prescription drug diversion rather than being the most common illicitly manufactured opioid of abuse. - While it contributes significantly to the opioid crisis, **heroin** (diacetylmorphine) remains the most commonly abused opioid in the illicit market due to its widespread availability and potency [1]. *Buprenorphine* - **Buprenorphine** is a **partial opioid agonist** used in the treatment of opioid dependence (opioid replacement therapy) due to its ceiling effect on respiratory depression and ability to block the effects of other opioids. - Although it can be abused, particularly in combination with naloxone (Suboxone) via intravenous injection, its primary role is in **medication-assisted treatment**, making it less commonly abused as a standalone illicit opioid compared to **heroin**.

Q: Which local anesthetic is known for its vasoconstrictive properties?

Cocaine. ***Cocaine*** - Cocaine is unique among local anesthetics for its inherent **sympathomimetic** properties, leading to **vasoconstriction**. - This vasoconstriction is due to its ability to block the reuptake of **norepinephrine** and other catecholamines at adrenergic nerve terminals. *Procaine* - Procaine is an **ester-type** local anesthetic that typically causes **vasodilation**, which can lead to rapid systemic absorption and a shorter duration of action. - It does not possess any inherent vasoconstrictive properties. *Lidocaine* - Lidocaine, an **amide-type** local anesthetic, generally causes **vasodilation** at clinical concentrations. - Due to this vasodilatory effect, **epinephrine** is often added to lidocaine preparations to prolong its action and reduce systemic absorption. *Chlorprocaine* - Chlorprocaine is another **ester-type** local anesthetic known for its rapid onset and short duration of action. - It primarily causes **vasodilation**, similar to procaine, and has no intrinsic vasoconstrictive effects.

Q: Which of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?

Epinephrine. ***Epinephrine*** - Epinephrine (adrenaline) is a potent direct-acting **sympathomimetic** that stimulates both **alpha and beta-adrenergic receptors**. - Its diverse effects on the cardiovascular, respiratory, and other systems make it the prototypical agent for demonstrating both receptor activities. *Norepinephrine* - While norepinephrine (noradrenaline) also acts on **alpha and beta-1 receptors**, its affinity for **beta-2 receptors** is significantly lower than epinephrine. - This results in a predominant effect on **vasoconstriction** and cardiac contractility rather than bronchodilation or peripheral vasodilation. *Isoproterenol* - Isoproterenol is a **non-selective beta-adrenergic agonist**, meaning it primarily stimulates **beta-1 and beta-2 receptors**. - It has minimal or no activity at **alpha-adrenergic receptors**, differentiating it from epinephrine's mixed activity. *Dopamine* - Dopamine's effects are **dose-dependent**; at low doses, it primarily stimulates **dopamine receptors** and at moderate doses, it activates **beta-1 receptors**. - At high doses, it can stimulate **alpha-adrenergic receptors**, but its primary and distinguishing characteristic is its agonism at **dopamine receptors**, which epinephrine does not share.

Q: What is the effect of adding epinephrine to lignocaine (a local anesthetic)?

Decreases absorption of local anesthetic. ***Decreases absorption of local anesthetic*** - Epinephrine causes **vasoconstriction** at the site of injection, which reduces the rate at which the local anesthetic is absorbed into the systemic circulation. - This slower absorption leads to a **higher concentration of the anesthetic** at the nerve fibers, prolonging its effect and reducing systemic toxicity. - This is the primary mechanism by which epinephrine enhances local anesthetic efficacy. *Increases distribution of local anesthetic* - The primary effect of epinephrine is to **localize the anesthetic** by reducing its systemic distribution. - This localization is achieved through **vasoconstriction**, which keeps the drug at the desired site rather than allowing it to distribute widely. *Decreases duration of local anesthetic* - By slowing absorption, epinephrine effectively **increases the duration of action** of the local anesthetic. - The anesthetic remains at the site of action for a longer period, providing **extended pain relief**. *Increases metabolism of local anesthetic* - Epinephrine does not directly affect the **metabolic rate** of local anesthetics. - The primary mechanism of metabolism for amides like lignocaine is in the **liver** by cytochrome P450 enzymes.

Q: Which amino acid-derived neurotransmitter is primarily targeted in the pharmacological treatment of depression?

Serotonin. ***Serotonin*** - **Serotonin** is an amino acid-derived neurotransmitter (from **tryptophan**) known to play a crucial role in mood regulation, sleep, appetite, and other functions, making it a primary target for **antidepressant medications**. - Medications like **Selective Serotonin Reuptake Inhibitors (SSRIs)** increase serotonin levels in the brain to alleviate symptoms of depression. *Histamine* - **Histamine** is an amino acid-derived neurotransmitter (from **histidine**) primarily involved in allergic reactions, inflammation, and regulating wakefulness. - While it has some central nervous system effects, its primary role is not directly in the treatment of **depression**. *Acetylcholine* - **Acetylcholine** is a neurotransmitter involved in muscle contraction, learning, memory, and attention, and is not derived from amino acids; it is synthesized from **choline** and acetyl-CoA. - It is not directly used for treating **depression**, although imbalances can play a role in cognitive aspects of some psychiatric disorders. *None of the options* - This option is incorrect because **Serotonin** is indeed an amino acid-derived neurotransmitter (from tryptophan) targeted for treating **depression**. - Many antidepressant drugs work by modulating **serotonergic pathways**.

Q: Midazolam does not cause which of the following?

Retrograde amnesia. ***Retrograde amnesia*** - Midazolam, a benzodiazepine, primarily causes **anterograde amnesia** [2], meaning patients have difficulty forming new memories after drug administration. - It does not significantly affect memories formed **before drug administration** (retrograde amnesia). *Anterograde amnesia* - Midazolam is well-known for its ability to induce **anterograde amnesia**, which is often a desirable effect in procedural sedation [2]. - This effect helps patients forget unpleasant or painful procedures performed while under its influence. *Causes tachyphylaxis during high dose infusions* - Prolonged or high-dose infusions of midazolam can lead to **tachyphylaxis**, requiring increased doses to achieve the same effect [1]. - This phenomenon is due to the **down-regulation or desensitization of GABA-A receptors** with continuous stimulation. *Decreased cardiovascular effects as compared to propofol* - Midazolam generally causes **less pronounced cardiovascular depression** (e.g., hypotension) compared to propofol, especially in standard sedative doses [1]. - This makes midazolam a safer option for sedation in some patients with **fragile cardiovascular statuses**.

Q: Drug of choice for Pneumocystis jirovecii in pregnancy?

Trimethoprim-sulfamethoxazole (SMZ/TMP). ***Trimethoprim-sulfamethoxazole (SMZ/TMP)*** - Despite being a **folate antagonist**, SMZ/TMP is considered safe and the **drug of choice** for treating **Pneumocystis jirovecii pneumonia (PJP)** in pregnant women, particularly as the benefits outweigh the risks. - It is recommended to supplement with **folic acid** during treatment to mitigate potential teratogenic risks, although these risks are generally low. *Primaquine* - **Primaquine** is primarily used for the treatment of **Plasmodium vivax** and **Plasmodium ovale malaria**, specifically targeting hypnozoites in the liver. - It is contraindicated in pregnancy due to the risk of **hemolytic anemia** in the fetus, especially if the fetus has **glucose-6-phosphate dehydrogenase (G6PD) deficiency**. *Dapsone* - **Dapsone** is used in the treatment of **leprosy**, **dermatitis herpetiformis**, and as an alternative for **PJP prophylaxis** in HIV-positive patients. - While it can be used for PJP prophylaxis, its efficacy for **active PJP treatment** is lower than SMZ/TMP, and it carries risks of **hemolytic anemia** and **methemoglobinemia**, particularly in pregnancy. *Pentamidine* - **Pentamidine** is an alternative treatment for **PJP**, especially in patients who cannot tolerate SMZ/TMP. - It is typically reserved for **severe cases** or as a second-line agent due to its potential for **significant toxicity**, including hypotension, nephrotoxicity, and hypoglycemia, which can be particularly concerning in pregnancy.

Q: What is the drug of choice for listeria meningitis?

Ampicillin. ***Ampicillin*** - **Ampicillin** is the **drug of choice** for *Listeria monocytogenes* meningitis due to its excellent in vitro activity and good central nervous system penetration. - It is often used in combination with an **aminoglycoside** (e.g., gentamicin) for synergistic bactericidal activity, especially in severe cases, though gentamicin does not penetrate the CSF well. *Cefotaxime* - **Third-generation cephalosporins** like cefotaxime have poor activity against *Listeria monocytogenes* due to the organism's intrinsic resistance to these agents. - While effective against many other bacterial causes of meningitis (e.g., *S. pneumoniae*, *N. meningitidis*), it is not appropriate for *Listeria*. *Ceftriaxone* - Similar to cefotaxime, **ceftriaxone** is a third-generation cephalosporin and is **ineffective** against *Listeria monocytogenes* due to the lack of penicillin-binding protein (PBP) affinity. - Its use for *Listeria* meningitis would lead to treatment failure. *Ciprofloxacin* - **Ciprofloxacin**, a fluoroquinolone, is generally **not recommended** as a first-line treatment for *Listeria* meningitis, despite some in vitro activity. - Its use is typically reserved for patients with severe allergies to penicillins, and even then, **trimethoprim-sulfamethoxazole** is usually preferred as an alternative to ampicillin.

Question 1

All of the following are correct about ketamine, EXCEPT which of the following?

Accepted Answer

It is a potent bronchoconstrictor

Answer

It increases arterial blood pressure

Answer

It inhibits polysynaptic reflexes in the spinal cord

Answer

It functionally "dissociates" the thalamus

Question 2

Which drug is commonly used for outpatient department (OPD) analgesia?

Accepted Answer

Paracetamol

Answer

Diclofenac

Answer

Ibuprofen

Answer

Tramadol

Question 3

Most commonly abused opioid -

Accepted Answer

Diacetylmorphine

Answer

Morphine

Answer

Oxycodone

Answer

Buprenorphine

Question 4

Which local anesthetic is known for its vasoconstrictive properties?

Accepted Answer

Cocaine

Answer

Lidocaine

Answer

Chlorprocaine

Answer

Procaine

Question 5

Which of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?

Accepted Answer

Epinephrine

Answer

Isoproterenol

Answer

Norepinephrine

Answer

Dopamine

Question 6

What is the effect of adding epinephrine to lignocaine (a local anesthetic)?

Accepted Answer

Decreases absorption of local anesthetic

Answer

Increases distribution of local anesthetic

Answer

Decreases duration of local anesthetic

Answer

Increases metabolism of local anesthetic

Question 7

Which amino acid-derived neurotransmitter is primarily targeted in the pharmacological treatment of depression?

Accepted Answer

Serotonin

Answer

Histamine

Answer

None of the options

Answer

Acetylcholine

Question 8

Midazolam does not cause which of the following?

Accepted Answer

Retrograde amnesia

Answer

Anterograde amnesia

Answer

Decreased cardiovascular effects as compared to propofol

Answer

Causes tachyphylaxis during high dose infusions

Question 9

Drug of choice for Pneumocystis jirovecii in pregnancy?

Accepted Answer

Trimethoprim-sulfamethoxazole (SMZ/TMP)

Answer

Primaquine

Answer

Dapsone

Answer

Pentamidine

Question 10

What is the drug of choice for listeria meningitis?

Accepted Answer

Ampicillin

Answer

Cefotaxime

Answer

Ciprofloxacin

Answer

Ceftriaxone

NEET-PG 2012 — Pharmacology