What is the name of the mumps vaccine?
As per RNTCP guidelines, Multi drug resistance (MDR) TB is defined as resistance to:
What is the primary reason for using a combination of four drugs in Anti-Koch's Treatment (AKT) for tuberculosis?
Which of the following is not a selective serotonin reuptake inhibitor?
Which of the following medications does not interact with warfarin?
What is the best drug for open-angle glaucoma?
Which type of vaccine is used for chicken pox?
Which of the following is a synthetic estrogen?
What is the standard amount of diphtheria toxoid in the DT vaccine?
What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 11: What is the name of the mumps vaccine?
- A. Jeryl Lynn (Correct Answer)
- B. Moraten
- C. Edmonston-Zagreb
- D. Schwarz
Explanation: ***Jeryl Lynn*** - The **Jeryl Lynn strain** is a widely used and highly effective **live attenuated mumps vaccine virus** found in many combined MMR (measles, mumps, rubella) vaccines. - It was developed by **Maurice Hilleman** and is known for its **low reactogenicity** and good safety profile. *Edmonston-Zagreb* - The **Edmonston-Zagreb strain** is a specific type of **live attenuated measles vaccine virus**, not mumps. - It is used in some combinations of the **MMR vaccine** but is distinct from the mumps component. *Schwarz* - The **Schwarz strain** is another variant of **live attenuated measles vaccine virus**, primarily distinguished by its passage history. - Like Edmonston-Zagreb, it targets **measles prevention** and is not used for mumps. *Moraten* - The **Moraten strain** is a specific **live attenuated measles vaccine virus** that is derived from the **Edmonston B strain**. - It is one of the most common measles vaccine strains, also used in **MMR vaccines**, but it does not protect against mumps.
Question 12: As per RNTCP guidelines, Multi drug resistance (MDR) TB is defined as resistance to:
- A. Rifampicin
- B. Rifampicin, isoniazid and ethambutol
- C. None of the above
- D. Rifampicin and isoniazid (Correct Answer)
Explanation: ***Rifampicin and isoniazid*** - According to **RNTCP guidelines** (now NTEP), **MDR-TB** is specifically defined as tuberculosis that is resistant to at least both **rifampicin** and **isoniazid**. - These two drugs are the **most potent first-line anti-TB medications**, and resistance to both significantly complicates treatment. *Rifampicin* - While resistance to **rifampicin alone** is a serious concern, it is classified as **rifampicin-resistant TB (RR-TB)**, not full **MDR-TB**. - **MDR-TB** requires resistance to at least two key first-line drugs. *Rifampicin, isoniazid and ethambutol* - Resistance to **rifampicin**, **isoniazid**, and **ethambutol** would be a form of **MDR-TB** (as it includes resistance to rifampicin and isoniazid), but it is a more extensive form of resistance. - The minimum definition of **MDR-TB** focuses on the two most crucial first-line drugs. *None of the above* - This option is incorrect because there is a specific definition for **MDR-TB** that aligns with one of the provided choices. - The guidelines clearly define **MDR-TB** based on resistance to specific drugs.
Question 13: What is the primary reason for using a combination of four drugs in Anti-Koch's Treatment (AKT) for tuberculosis?
- A. To decrease the risk of resistance due to mutation. (Correct Answer)
- B. To decrease the risk of resistance due to conjugation.
- C. To enhance overall treatment efficacy.
- D. To simplify treatment.
Explanation: ***To decrease the risk of resistance due to mutation*** - **Tuberculosis bacteria** can spontaneously develop resistance to a single drug through **random genetic mutations**. - Using multiple drugs simultaneously significantly reduces the probability that a bacterium will spontaneously develop resistance to **all drugs** in the regimen. - This is the **primary rationale** for multi-drug therapy in TB, as emphasized by WHO guidelines. *To decrease the risk of resistance due to conjugation* - **Conjugation** is a mechanism of horizontal gene transfer in bacteria, primarily involving the transfer of plasmids. - While important for antibiotic resistance in some bacteria, it is **not the primary mechanism** of resistance development in *Mycobacterium tuberculosis*. - TB resistance develops mainly through **chromosomal mutations**, not plasmid transfer. *To enhance overall treatment efficacy* - While multi-drug regimens do enhance treatment efficacy by targeting different bacterial populations (actively dividing, slow-growing, dormant), this is a **consequence** of the multi-drug approach. - The **primary reason** for using four drugs specifically is to prevent the emergence of **drug-resistant mutants**. - Enhanced efficacy is achieved *because* resistance is prevented, making this a secondary benefit. *To simplify treatment* - A four-drug regimen actually makes treatment more **complex** due to multiple pills, potential drug interactions, and increased side effects. - The complexity is a necessary trade-off for **resistance prevention** and treatment success.
Question 14: Which of the following is not a selective serotonin reuptake inhibitor?
- A. Buspirone (Correct Answer)
- B. Citalopram
- C. Fluoxetine
- D. Fluvoxamine
Explanation: ***Buspirone*** - **Buspirone** is an anxiolytic that primarily acts as a **serotonin 5-HT1A receptor partial agonist**, not an SSRI. - It does not significantly affect the reuptake of serotonin, distinguishing it from SSRIs. *Fluoxetine* - **Fluoxetine** is a well-known and widely used **SSRI**. - It works by selectively inhibiting the reuptake of serotonin, thereby increasing its concentration in the synaptic cleft. *Fluvoxamine* - **Fluvoxamine** is another antidepressant classified as an **SSRI**. - It is often used for the treatment of **obsessive-compulsive disorder (OCD)** due to its strong serotonin reuptake inhibition. *Citalopram* - **Citalopram** is an **SSRI** frequently prescribed for depression and anxiety disorders. - Its mechanism involves potent and selective inhibition of **serotonin reuptake**.
Question 15: Which of the following medications does not interact with warfarin?
- A. Barbiturate
- B. Oral contraceptive
- C. Cephalosporins
- D. Benzodiazepines (Correct Answer)
Explanation: ***Benzodiazepines*** - **Benzodiazepines** are generally considered safe to use with warfarin as they are extensively metabolized in the liver, but they do not typically alter the **cytochrome P450 enzymes** responsible for warfarin metabolism. - They also do not interfere with **vitamin K recycling** or **platelet function**, which are key mechanisms through which other drugs interact with warfarin. *Barbiturate* - **Barbiturates** are **potent inducers of hepatic enzymes**, particularly CYP2C9, which is responsible for metabolizing warfarin. - This enzyme induction leads to **increased warfarin metabolism**, reducing its anticoagulant effect and necessitating higher warfarin doses. *Oral contraceptive* - **Oral contraceptives** can **reduce the anticoagulant effect of warfarin** by inducing clotting factors or inhibiting warfarin metabolism. - This interaction can increase the risk of **thromboembolic events** in patients on warfarin. *Cephalosporins* - Certain **cephalosporins**, especially those with a **methylthiotetrazole (MTT) side chain** (e.g., Cefamandole, Cefoperazone, Moxalactam), can **inhibit vitamin K epoxide reductase**. - This inhibition leads to a **decrease in vitamin K-dependent clotting factors**, thus potentiating the anticoagulant effect of warfarin and increasing bleeding risk.
Question 16: What is the best drug for open-angle glaucoma?
- A. Latanoprost (Correct Answer)
- B. Pilocarpine
- C. Physostigmine
- D. Apraclonidine
Explanation: Latanoprost - Latanoprost is a prostaglandin analog and is often considered a first-line treatment for open-angle glaucoma due to its efficacy in reducing intraocular pressure (IOP) and its once-daily dosing. - It works by increasing the outflow of aqueous humor through the uveoscleral pathway, thereby lowering IOP. Pilocarpine - Pilocarpine is a cholinergic agonist that causes miosis and ciliary muscle contraction [3], increasing the outflow of aqueous humor through the trabecular meshwork [4]. - While effective, its side effects (e.g., accommodative spasm, miosis) [1] and more frequent dosing make it generally a second-line or third-line agent for long-term management compared to prostaglandins. Physostigmine - Physostigmine is an acetylcholinesterase inhibitor that indirectly increases acetylcholine, mimicking cholinergic stimulation. - Although it can lower IOP, it is generally not used for open-angle glaucoma due to significant side effects and the availability of safer, more effective alternatives [1]. Apraclonidine - Apraclonidine is an alpha-2 adrenergic agonist [2] used primarily for short-term control of IOP, especially before or after ocular surgery, or as an adjunct therapy. - Its efficacy as a long-term monotherapy for open-angle glaucoma is limited by tachyphylaxis and potential for significant systemic side effects with chronic use.
Question 17: Which type of vaccine is used for chicken pox?
- A. Live vaccine (Correct Answer)
- B. Killed vaccine
- C. Conjugated vaccine
- D. Toxoid vaccine
Explanation: ***Live vaccine*** - The chickenpox vaccine (Varicella vaccine) is a **live-attenuated vaccine**, meaning it contains a weakened form of the **Varicella-zoster virus** (Oka strain). - This weakened virus can still replicate in the body, stimulating a strong and long-lasting immune response similar to natural infection but without causing severe disease. *Killed vaccine* - **Killed (inactivated) vaccines** use viruses or bacteria that have been inactivated through heat or chemicals, making them unable to replicate. - While effective for some diseases (e.g., inactivated polio, influenza), they typically require **multiple doses** and might provide less durable immunity compared to live vaccines. *Conjugated vaccine* - **Conjugated vaccines** are designed to improve the immune response to polysaccharide antigens (e.g., bacterial capsules) by linking them to a carrier protein. - This technology is primarily used for **bacterial infections** like *Haemophilus influenzae* type b (Hib) or pneumococcal disease, not viral illnesses like chickenpox. *Toxoid vaccine* - **Toxoid vaccines** contain inactivated bacterial toxins (toxoids) rather than the whole organism. - Examples include **tetanus and diphtheria vaccines**, which protect against diseases caused by bacterial toxins, not viral infections like chickenpox.
Question 18: Which of the following is a synthetic estrogen?
- A. Estrone
- B. Estriol
- C. Estradiol
- D. Diethylstilbestrol (Correct Answer)
Explanation: ***Diethylstilbestrol*** - **Diethylstilbestrol (DES)** is a **synthetic non-steroidal estrogen** that was historically used as a medication, particularly to prevent miscarriage. - Its use was discontinued after being linked to various adverse effects, including **vaginal clear cell adenocarcinoma** in female offspring whose mothers took DES during pregnancy. *Estrone* - **Estrone** is one of the three major **naturally occurring endogenous estrogens** in humans. - It is the primary estrogen during **menopause** and is derived from androstenedione. *Estriol* - **Estriol** is another of the three major **naturally occurring estrogens**, predominantly produced during **pregnancy** by the placenta. - It is often used as a marker for fetal well-being. *Estradiol* - **Estradiol** is the **most potent and abundant naturally occurring estrogen** in women during their reproductive years. - It plays a crucial role in the development and maintenance of female reproductive tissues and secondary sexual characteristics.
Question 19: What is the standard amount of diphtheria toxoid in the DT vaccine?
- A. 5 Lf
- B. 10 Lf
- C. 15 Lf
- D. 30 Lf (Correct Answer)
Explanation: ***30 Lf*** - The **DT vaccine** (pediatric diphtheria-tetanus vaccine) contains **30 Lf** of **diphtheria toxoid** per dose according to traditional formulations, along with tetanus toxoid. - This higher diphtheria toxoid content is standardized for vaccines administered to children younger than 7 years. - Note: Modern vaccine standards often express potency in **International Units (IU)** where ≥30 IU corresponds to approximately 15-25 Lf, though 30 Lf was the traditional specification. *5 Lf* - This reduced amount of diphtheria toxoid is present in adult formulations like **Tdap vaccine** and **Td vaccine** (typically 2-5 Lf). - The lower diphtheria toxoid content in adult vaccines is sufficient to maintain immunity in individuals with pre-existing immunity from childhood vaccination. *10 Lf* - This amount of diphtheria toxoid is not a standard specification for DT, Td, or Tdap vaccines. - Standard diphtheria toxoid amounts are typically 15-30 Lf for pediatric formulations (DT/DTP) and 2-5 Lf for adult formulations (Td, Tdap). *15 Lf* - While approximately 15 Lf may correspond to the minimum potency when measured in International Units (≥30 IU), the traditional standard specification for DT vaccine is **30 Lf**. - Vaccine formulations are precisely standardized to ensure optimal immunogenicity and safety.
Question 20: What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?
- A. 500 mg/week
- B. 400 mg once weekly
- C. 500 mg once weekly (Correct Answer)
- D. 500 mg BD/week
Explanation: ***500 mg once weekly*** - The recommended dosage for chloroquine chemoprophylaxis in malaria prevention is **500 mg salt** (or equivalent to 300 mg base) administered **once weekly**. - This regimen ensures adequate blood concentrations to prevent malarial infection in endemic areas. *500 mg/week* - While the 500 mg dose is correct, simply stating "500 mg/week" without specifying "once weekly" could be misinterpreted. - Chloroquine is generally taken as a **single weekly dose**, not divided doses. *400 mg once weekly* - A dosage of **400 mg** is **sub-therapeutic** for weekly chloroquine chemoprophylaxis. - This dose would likely not provide sufficient protection against malaria. *500 mg BD/week* - Taking chloroquine **twice weekly (BD/week)** at 500 mg is excessive for chemoprophylaxis. - This regimen can lead to increased side effects and toxicity without providing additional prophylactic benefit.