NEET-PG 2013 - Pharmacology Practice Questions

Q: The mechanism by which ergometrine stops postpartum hemorrhage is that it:

Increases tone of uterine muscle. ***Increases tone of uterine muscle*** - **Ergometrine** is an **ergot alkaloid** that directly stimulates **uterine smooth muscle contractions**. - These sustained contractions lead to **compression of blood vessels within the myometrium**, thereby reducing blood flow and controlling **postpartum hemorrhage**. *Causes vasoconstriction of uterine arteries* - While ergometrine does have some generalized **vasoconstrictive effects**, its primary mechanism of action in controlling postpartum hemorrhage is not mainly through direct vasoconstriction of large uterine arteries. - The crucial effect is the **sustained uterine contraction** which mechanically occludes blood vessels, rather than chemical constriction of the vessels themselves. *Induces platelet aggregation* - Ergometrine does not primarily act by inducing **platelet aggregation**; this is a function of specific clotting factors and platelet activators. - Its therapeutic effect against hemorrhage is mediated through its action on **uterine contractility**, not on the cellular components of coagulation. *Promotes coagulation* - Ergometrine does not directly promote the **coagulation cascade** or enhance the formation of fibrin clots. - Its mechanism of action is distinct from agents that affect intrinsic or extrinsic pathways of coagulation.

Q: Which of the following medications is not typically used for the treatment of erectile dysfunction?

Beta blockers. ***Beta blockers*** - **Beta blockers** are primarily used to treat conditions like **hypertension** and **heart disease**. - While they can cause ED as a side effect, they are **not used for its treatment**. *Sildenafil* - **Sildenafil** is a **PDE5 inhibitor** that works by increasing **blood flow to the penis**, facilitating an erection. - It is a **first-line oral medication** widely prescribed for erectile dysfunction. *PG-E* - **PG-E** refers to **Prostaglandin E1** (alprostadil), which can be administered via **intracavernosal injection** or **urethral suppository**. - It directly causes **vasodilation** in the penis, leading to an erection, and is used when oral medications are ineffective or contraindicated. *Papaverine* - **Papaverine** is a **non-specific vasodilator** that can be used as an **intracavernosal injection** for ED. - It works by relaxing **smooth muscle** in the penile arteries, increasing blood flow and inducing an erection, often used in combination with phentolamine.

Q: All are symptoms of morphine withdrawal except?

Fall in BP. ***Fall in BP*** - **Hypotension (fall in BP)** is **not** typically a symptom of opioid withdrawal; rather, **hypertension** can occur due to sympathetic overdrive. - Opioid withdrawal symptoms are primarily characterized by **hyperactivity** and increased sympathetic nervous system activity. *Mydriasis* - **Mydriasis (dilated pupils)** is a classic symptom of opioid withdrawal, resulting from reduced parasympathetic tone and increased sympathetic activity. - In contrast, opioid intoxication causes **miosis (pinpoint pupils)**. *Yawning* - **Yawning** is a very common and early symptom of opioid withdrawal, often accompanied by feelings of fatigue and restlessness. - It reflects generalized **autonomic dysregulation** during withdrawal. *Lacrimation* - **Lacrimation (tearing)** is another prominent autonomic symptom of opioid withdrawal. - This, along with rhinorrhea, contributes to the **"flu-like" symptoms** experienced during withdrawal.

Q: Which local anaesthetic is known to cause methemoglobinemia?

Prilocaine. ***Prilocaine*** - **Prilocaine** is metabolized into **ortho-toluidine**, which can oxidize hemoglobin to **methemoglobin**, especially at higher doses or in susceptible individuals. - **Methemoglobinemia** symptoms include **cyanosis**, **dyspnea**, and in severe cases, central nervous system depression, due to reduced oxygen-carrying capacity of blood. *Procaine* - **Procaine** is an ester-type local anesthetic. It is metabolized to **para-aminobenzoic acid (PABA)**, which can cause allergic reactions, but it is not associated with methemoglobinemia. - It has a relatively **short duration of action** and is less commonly used now compared to amide-type local anesthetics. *Etidocaine* - **Etidocaine** is an amide-type local anesthetic that is known for its **long duration of action** and high potency. - While it can cause systemic toxicity with high doses due to its cardiac and neurological effects, **methemoglobinemia** is not a characteristic side effect. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic similar to bupivacaine, known for its **motor-sparing effect** and use in regional anesthesia. - It is associated with a lower risk of **cardiotoxicity** compared to bupivacaine but does not cause methemoglobinemia.

Q: In pseudocholinesterase deficiency, which drug should be used cautiously?

Succinylcholine. ***Succinylcholine*** - **Succinylcholine** is primarily metabolized by **pseudocholinesterase** (also known as butyrylcholinesterase). - In individuals with **pseudocholinesterase deficiency**, the metabolism of succinylcholine is significantly delayed, leading to **prolonged neuromuscular blockade** and extended paralysis. *Barbiturates* - **Barbiturates** are mainly metabolized by the **hepatic cytochrome P450 system** and do not depend on pseudocholinesterase for their breakdown. - Their metabolism would not be significantly affected by pseudocholinesterase deficiency. *Halothane (an inhalational anesthetic)* - **Halothane** is primarily metabolized by the **hepatic cytochrome P450 system** and excreted via the lungs. - Its metabolism is unrelated to **pseudocholinesterase activity**. *Gallamine (a neuromuscular blocker)* - **Gallamine** is a **nondepolarizing neuromuscular blocker** that is primarily eliminated by **renal excretion** as an unchanged drug. - Its metabolism and elimination are independent of **pseudocholinesterase**.

Q: In ophthalmology, if a patient is allergic to aminoesters, which local anesthetic can be safely used?

Prilocaine. **Local anesthetics are classified into two chemical groups: esters (aminoesters) and amides. Allergies to esters typically do not cross-react with amides.** ***Prilocaine*** - **Prilocaine** is an **amide-type local anesthetic**, and allergies to **aminoesters** typically do not cross-react with **amides**. - It is a safe alternative in patients with a known allergy to **ester-type local anesthetics**. *Cocaine* - **Cocaine** is an **ester-type local anesthetic**, sharing a similar chemical structure with **aminoesters**. - Patients allergic to **aminoesters** are likely to experience a **cross-reaction** with **cocaine**. *Procaine* - **Procaine** is a classic **ester-type local anesthetic** (an aminoester). - An allergy to aminoesters directly implies an allergy to **procaine** due to its chemical classification. *Tetracaine* - **Tetracaine** is also an **ester-type local anesthetic** (an aminoester). - It is contraindicated in patients with an allergy to **aminoesters** due to the high risk of **allergic reaction**.

Q: Which anaesthetic belongs to the ester group?

Procaine. ***Procaine*** - **Procaine** is a classical **ester-type** local anesthetic, characterized by an ester linkage between the aromatic and amine parts of its chemical structure. - Ester-type local anesthetics are metabolized by **plasma pseudocholinesterase**, leading to a shorter duration of action compared to amides. *Benzocaine* - **Benzocaine** is also an ester local anesthetic, but it is typically used topically due to its poor water solubility and absorption. - While an ester, the question implies a common injectable agent, making procaine a more representative answer for the "ester group" in general anesthetic use. *Lignocaine* - **Lignocaine** (also known as lidocaine) is an **amide-type** local anesthetic, which can be identified by an amide linkage in its chemical structure. - Amide local anesthetics are primarily metabolized in the **liver** and generally have a longer duration of action than esters. *Propofol* - **Propofol** is a **short-acting intravenous general anesthetic** and is not classified as a local anesthetic or belonging to the ester group. - It works by potentiation of **GABA-A receptors** and is used for induction and maintenance of general anesthesia.

Q: Which drug is most commonly associated with causing exanthema?

Sulfonamide. ***Sulfonamide*** - **Sulfonamides** are among the **most common causes** of drug-induced exanthema (maculopapular/morbilliform rash). - They account for a significant proportion of cutaneous adverse drug reactions, with exanthema being the most frequent presentation. - The mechanism typically involves a **delayed hypersensitivity reaction** (Type IV) to the drug or its metabolites. - **Classic presentation:** Symmetrical, erythematous, maculopapular rash appearing 7-14 days after drug initiation. *Phenytoin* - **Phenytoin** can cause exanthematous eruptions, but it is more notably associated with **severe cutaneous adverse reactions** such as: - **DRESS syndrome** (Drug Reaction with Eosinophilia and Systemic Symptoms) - **Stevens-Johnson syndrome (SJS)** and **Toxic Epidermal Necrolysis (TEN)** - While exanthema can occur, **sulfonamides** are more frequently implicated in simple morbilliform rashes. *Atropine* - **Atropine** is an anticholinergic agent primarily causing **predictable pharmacological effects**: - Dry mouth, mydriasis, tachycardia, urinary retention - **Allergic skin reactions** with atropine are rare and not a characteristic adverse effect. - Atropine is **not recognized** as a common cause of exanthema. *All of the options* - This is incorrect because **atropine** is not commonly associated with exanthema. - While both sulfonamides and phenytoin can cause exanthema, only **sulfonamides** are considered among the **most common** causes.

Q: Which drug would be most appropriate for treating a patient with suspected chlamydia-gonorrhea coinfection?

Doxycycline. ***Doxycycline*** - **Doxycycline** is a highly effective treatment for **chlamydia**, and its broad-spectrum activity also covers potential **gonorrhea coinfection** when used as part of a dual therapy regimen. - It is often prescribed alongside a **single dose of ceftriaxone** for presumed gonorrhea coinfection, as ceftriaxone targets gonorrhea while doxycycline targets chlamydia. *Ciprofloxacin* - **Ciprofloxacin** is a **fluoroquinolone** antibiotic, which is generally not recommended as first-line treatment for uncomplicated **gonorrhea** or **chlamydia** due to increasing resistance. - It has activity against *Neisseria gonorrhoeae*, but its effectiveness against *Chlamydia trachomatis* is suboptimal compared to macrolides or tetracyclines. *Norfloxacin* - **Norfloxacin** is another **fluoroquinolone** with a narrower spectrum of activity than ciprofloxacin and is primarily used for **urinary tract infections**. - It has **poor efficacy against chlamydia** and is not a recommended treatment for either organism in this context. *Nalidixic acid* - **Nalidixic acid** is a first-generation **quinolone** with a very limited spectrum, used mainly for **gram-negative urinary tract infections**. - It has **no significant activity against chlamydia** or gonorrhea and is therefore inappropriate for treating this suspected coinfection.

Q: Depot preparations are administered by ?

Both subcutaneous and intramuscular route. ***Both subcutaneous and intramuscular route*** - **Depot preparations** are designed for **sustained release** of medication over an extended period - This is achieved by forming a 'depot' in the tissue, often facilitated by a viscous vehicle or sparingly soluble form of the drug - Both **subcutaneous** and **intramuscular** tissues can sustain depot formulations effectively - **SC depot examples:** Insulin glargine, contraceptive implants (Nexplanon), leuprolide acetate - **IM depot examples:** Haloperidol decanoate, medroxyprogesterone acetate (Depo-Provera), paliperidone palmitate, long-acting risperidone *Subcutaneous route* - While some **depot preparations** are administered **subcutaneously**, it is not the *only* route for all depot formulations - The **subcutaneous tissue** offers relatively low blood flow, suitable for slow absorption - Alone, this option is incomplete as many depot preparations require IM administration *Intramuscular route* - Many **depot preparations** are given **intramuscularly** due to the muscle tissue's vascularity and tissue volume - The **muscle tissue** provides an excellent site for drug reservoir formation - Alone, this option is incomplete as some depot preparations are given subcutaneously *Intravenous route* - **Intravenous administration** is used for immediate and rapid drug delivery directly into the bloodstream - This route is **unsuitable for depot preparations** which require sustained release over time - No 'depot' can be formed with IV route as the drug is immediately diluted and distributed throughout the body

Question 1

The mechanism by which ergometrine stops postpartum hemorrhage is that it:

Accepted Answer

Increases tone of uterine muscle

Answer

Induces platelet aggregation

Answer

Promotes coagulation

Answer

Causes vasoconstriction of uterine arteries

Question 2

Which of the following medications is not typically used for the treatment of erectile dysfunction?

Accepted Answer

Beta blockers

Answer

Papaverine

Answer

Sildenafil

Answer

PG-E

Question 3

All are symptoms of morphine withdrawal except?

Accepted Answer

Fall in BP

Answer

Yawning

Answer

Lacrimation

Answer

Mydriasis

Question 4

Which local anaesthetic is known to cause methemoglobinemia?

Accepted Answer

Prilocaine

Answer

Procaine

Answer

Ropivacaine

Answer

Etidocaine

Question 5

In pseudocholinesterase deficiency, which drug should be used cautiously?

Accepted Answer

Succinylcholine

Answer

Barbiturates

Answer

Gallamine

Answer

Halothane

Question 6

In ophthalmology, if a patient is allergic to aminoesters, which local anesthetic can be safely used?

Accepted Answer

Prilocaine

Answer

Procaine

Answer

Cocaine

Answer

Tetracaine

Question 7

Which anaesthetic belongs to the ester group?

Accepted Answer

Procaine

Answer

Lignocaine

Answer

Propofol

Answer

Benzocaine

Question 8

Which drug is most commonly associated with causing exanthema?

Accepted Answer

Sulfonamide

Answer

Atropine

Answer

Phenytoin

Answer

All of the options

Question 9

Which drug would be most appropriate for treating a patient with suspected chlamydia-gonorrhea coinfection?

Accepted Answer

Doxycycline

Answer

Ciprofloxacin

Answer

Nalidixic acid

Answer

Norfloxacin

Question 10

Depot preparations are administered by ?

Accepted Answer

Both subcutaneous and intramuscular route

Answer

Subcutaneous route

Answer

Intravenous route

Answer

Intramuscular route

NEET-PG 2013 — Pharmacology