What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
All of the following are used for treatment of *H. pylori*, except:
Which of the following is not a definite use for Prostaglandin E2 (PGE2)?
All of the following occurs because of prostaglandin use except?
What is the drug of choice for malaria in pregnancy?
What is the maximum cumulative dose of isotretinoin for acne treatment?
All of the following are correct about ketamine, EXCEPT which of the following?
Which drug is commonly used for outpatient department (OPD) analgesia?
Most commonly abused opioid -
Which anaesthetic agent is neither metabolised by liver nor by kidney?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 71: What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
- A. Beta blockade followed by alpha blockade
- B. Simultaneous alpha and beta blockade
- C. Alpha blockade followed by beta blockade (Correct Answer)
- D. Alpha blockade only
Explanation: ***Alpha blockade followed by beta blockade*** - **Alpha blockade** should always be initiated first to control **hypertension** and prevent a **hypertensive crisis** during surgery. This is critical because pheochromocytoma causes excessive catecholamine release, leading to profound vasoconstriction. - **Beta blockade** is then added only after adequate alpha blockade has been achieved to control **tachycardia** and arrhythmias, preventing **unopposed alpha-adrenergic stimulation** which could paradoxically worsen hypertension. *Simultaneous alpha and beta blockade* - Administering both simultaneously is dangerous because **beta blockade** can mask the effects of inadequate alpha blockade. - This can lead to **unopposed alpha-adrenergic stimulation** after beta blockade, causing severe **vasoconstriction** and hypertensive crisis. *Beta blockade followed by alpha blockade* - Initiating with **beta blockade** without prior **alpha blockade** is absolutely contraindicated in pheochromocytoma. - This can lead to severe and potentially fatal **hypertension** due to **unopposed alpha-adrenergic stimulation** as beta blockade prevents vasodilation. *Alpha blockade only* - While essential for initial management, **alpha blockade alone** might not fully control all symptoms, especially **tachycardia** and **arrhythmias** caused by high circulating catecholamine levels. - Adding a **beta blocker** after achieving adequate alpha blockade helps in controlling these cardiac effects, optimizing patient preparation for surgery.
Question 72: All of the following are used for treatment of *H. pylori*, except:
- A. Metronidazole
- B. Amoxicillin
- C. Clarithromycin
- D. Gentamicin (Correct Answer)
Explanation: ***Gentamicin*** - **Gentamicin** is an **aminoglycoside antibiotic** primarily used for severe Gram-negative bacterial infections and is **not effective** against *H. pylori*. - Its mechanism of action and **toxicity profile** (ototoxicity, nephrotoxicity) make it unsuitable for typical *H. pylori* eradication regimens. *Clarithromycin* - **Clarithromycin** is a **macrolide antibiotic** frequently used in **triple therapy regimens** for *H. pylori* eradication. - It works by **inhibiting bacterial protein synthesis**, significantly contributing to the eradication of the bacteria. *Metronidazole* - **Metronidazole** is an **antibiotic** and **antiprotozoal agent** commonly included in *H. pylori* **quadruple therapy** or when penicillin allergies are present. - It acts by forming **cytotoxic compounds** that disrupt bacterial DNA, making it effective against anaerobic and microaerophilic bacteria like *H. pylori*. *Amoxicillin* - **Amoxicillin** is a **beta-lactam antibiotic** that is a cornerstone of many *H. pylori* **eradication regimens**, particularly in standard triple therapy. - It works by **inhibiting bacterial cell wall synthesis**, leading to bacterial lysis.
Question 73: Which of the following is not a definite use for Prostaglandin E2 (PGE2)?
- A. Induces labour
- B. Keeps patency of PDA (Correct Answer)
- C. Contraception
- D. Therapeutic abortion
Explanation: ***Keeps patency of PDA*** - **Prostaglandin E1 (PGE1)**, not PGE2, is used to maintain the patency of the **ductus arteriosus** in neonates with certain congenital heart defects. - PGE1 causes **vascular smooth muscle relaxation**, preventing closure of the ductus arteriosus. *Contraception* - **PGE2 analogs** are used in various forms of contraception, including emergency contraception and for cervical ripening before elective abortion. - They act by inducing **uterine contractions** and can interfere with implantation or facilitate expulsion of a fertilized egg. *Induces labour* - **PGE2 (dinoprostone)** is commonly used clinically to induce labor by promoting **cervical ripening** and stimulating **uterine contractions**. - It is administered as a vaginal gel or insert to prepare the cervix for delivery. *Therapeutic abortion* - **PGE2 analogs** are used to induce therapeutic abortion, particularly in the second trimester, by causing powerful **uterine contractions** that lead to the expulsion of the fetus. - They are often used in combination with other agents to enhance their efficacy.
Question 74: All of the following occurs because of prostaglandin use except?
- A. Increased motility of bowel
- B. Nausea
- C. Excess water retention (Correct Answer)
- D. Flushes
Explanation: ***Excess water retention*** - **Prostaglandins** generally promote **diuresis** and natriuresis, meaning they help the body excrete water and sodium, rather than retain them [2]. - While some prostaglandins can affect renal blood flow, direct causation of **excess water retention** as a primary side effect is not typical. *Flushes* - **Prostaglandins**, particularly **PGE1** and **PGE2**, are potent **vasodilators** and can cause cutaneous vasodilation, leading to **flushing** and a sensation of warmth [3]. - This effect is often mediated by the relaxation of vascular smooth muscle. *Increased motility of bowel* - Many **prostaglandins**, especially **PGE** and **PGF** series, stimulate **smooth muscle contraction**, including in the gastrointestinal tract [1]. - This increased contraction can lead to **enhanced bowel motility**, sometimes causing diarrhea or abdominal cramping [1]. *Nausea* - **Prostaglandins** can have various systemic effects, and activation of pathways in the central nervous system or direct irritation of the GI tract can lead to symptoms like **nausea** and vomiting [1]. - This is a common side effect, especially with systemic administration.
Question 75: What is the drug of choice for malaria in pregnancy?
- A. Primaquine
- B. Chloroquine (Correct Answer)
- C. Artesunate
- D. Quinine
Explanation: ***Chloroquine*** - **Chloroquine** is the drug of choice for **uncomplicated malaria in pregnancy** caused by **chloroquine-sensitive** strains of *P. vivax*, *P. ovale*, *P. malariae*, and *P. falciparum* [1]. - It has an **established safety profile** in pregnancy across all trimesters and is considered safe by WHO and CDC. - While resistance has emerged in many areas for *P. falciparum*, chloroquine remains effective for *P. vivax* malaria in most regions including India. - For **severe malaria** or **chloroquine-resistant falciparum malaria**, alternative regimens like quinine or artesunate are used [1]. *Quinine* - **Quinine** (usually with clindamycin) is the preferred treatment for **severe malaria** or **chloroquine-resistant *P. falciparum*** malaria in pregnancy, especially in the **first trimester**. - It is safe and effective but can cause side effects like **cinchonism** (tinnitus, headache, nausea) and **hypoglycemia**. - While safe throughout pregnancy, it is not the first-line choice for uncomplicated chloroquine-sensitive malaria. *Primaquine* - **Primaquine** is **contraindicated in pregnancy** because it can cause **hemolytic anemia** in individuals with **G6PD deficiency**, and G6PD status of the fetus cannot be determined [3]. - It is used for **radical cure** of *P. vivax* and *P. ovale* to eliminate liver hypnozoites, but must be deferred until after delivery [3]. *Artesunate* - **Artesunate** and other **artemisinin-based combination therapies (ACTs)** are highly effective antimalarials [2]. - Current WHO guidelines support ACT use in all trimesters for severe malaria when benefits outweigh risks. - For **uncomplicated falciparum malaria**, ACTs are preferred in the **second and third trimesters** in areas with chloroquine resistance [2]. - However, chloroquine remains the classical "drug of choice" for uncomplicated, chloroquine-sensitive malaria in pregnancy [1].
Question 76: What is the maximum cumulative dose of isotretinoin for acne treatment?
- A. 30-60 mg/kg
- B. 60-90 mg/kg
- C. 90-120 mg/kg
- D. 120-150 mg/kg (Correct Answer)
Explanation: ***120-150 mg/kg*** - The goal of **isotretinoin cumulative dosing** is to achieve long-term remission and reduce the risk of relapse. - A cumulative dose in the range of **120-150 mg/kg** has been shown to optimize treatment outcomes for severe or recalcitrant acne. *30-60 mg/kg* - This range is typically considered too low to achieve the optimal **cumulative dose** for sustained remission in severe acne. - Doses within this range might be used in some cases for milder forms of acne or in patients with significant side effects, but not as the standard maximum. *60-90 mg/kg* - While this is closer to an effective cumulative dose, it still often falls short of the recommended range for maximizing the long-term efficacy and reducing relapse rates in patients with severe forms of acne. - Studies suggest that higher cumulative doses correlate with better treatment success and fewer recurrences. *90-120 mg/kg* - This range is often considered a minimal target for a **cumulative dose**, especially at the higher end of the range (120 mg/kg). - While effective for many patients, aiming for the upper end (120-150 mg/kg) often provides a more robust and durable response, particularly in more severe or nodular acne.
Question 77: All of the following are correct about ketamine, EXCEPT which of the following?
- A. It increases arterial blood pressure
- B. It inhibits polysynaptic reflexes in the spinal cord
- C. It functionally "dissociates" the thalamus
- D. It is a potent bronchoconstrictor (Correct Answer)
Explanation: ***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].
Question 78: Which drug is commonly used for outpatient department (OPD) analgesia?
- A. Diclofenac
- B. Ibuprofen
- C. Paracetamol (Correct Answer)
- D. Tramadol
Explanation: ***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.
Question 79: Most commonly abused opioid -
- A. Morphine
- B. Diacetylmorphine (Correct Answer)
- C. Oxycodone
- D. Buprenorphine
Explanation: ***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**.
Question 80: Which anaesthetic agent is neither metabolised by liver nor by kidney?
- A. Vecuronium
- B. Pancuronium
- C. Rocuronium
- D. Atracurium (Correct Answer)
Explanation: ***Atracurium*** - **Atracurium** undergoes **Hofmann elimination**, a non-enzymatic chemical degradation in plasma, and also **ester hydrolysis** by non-specific plasma esterases [2]. - This unique metabolism makes its elimination largely independent of **liver** and **kidney function**, making it a good choice for patients with organ dysfunction [2]. *Vecuronium* - Primarily metabolized by the **liver** into active and inactive metabolites [1]. - Its elimination can be prolonged in patients with **hepatic impairment** [1]. *Pancuronium* - Undergoes significant **hepatic metabolism** and subsequent **renal excretion** of both parent drug and metabolites [1]. - Its duration of action is significantly affected by both **liver** and **kidney dysfunction** [1]. *Rocuronium* - Primarily eliminated unchanged via **biliary excretion** (liver) [1]. - Its duration of action is prolonged in patients with **hepatic impairment** [1].