General Pharmacology Practice Questions

Q: Which of the following is NOT a prodrug?

Imipramine. **Explanation:** A **prodrug** is a pharmacologically inactive compound that must undergo metabolic conversion (usually in the liver) to become an active metabolite. **Why Imipramine is the correct answer:** **Imipramine** is an active drug belonging to the Tricyclic Antidepressant (TCA) class. While it is metabolized into an active metabolite (**Desipramine**), the parent compound itself possesses significant pharmacological activity. Therefore, it is not classified as a prodrug. **Analysis of Incorrect Options:** * **Enalapril:** It is a classic prodrug converted by hepatic esterases into **Enalaprilat** (the active ACE inhibitor). Note: Captopril and Lisinopril are the only two ACE inhibitors that are *not* prodrugs. * **Sulphasalazine:** This drug is cleaved by colonic bacteria into **Sulphapyridine** and **5-Aminosalicylic acid (5-ASA)**. The 5-ASA is the active moiety used in treating Ulcerative Colitis. * **Cyclophosphamide:** An anticancer alkylating agent that is inactive in vitro. It requires activation by hepatic Cytochrome P450 enzymes (CYP2B6) into **Aldophosphamide** and **Phosphoramide mustard**. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Prodrugs:** "**All P**referred **D**rugs **C**an **L**ower **B**lood **P**ressure **I**n **M**ost **S**ubjects" (**A**ce inhibitors except captopril/lisinopril, **P**urines/Pyrimidines, **D**opa/Levodopa, **C**yclophosphamide, **L**osartan, **B**acampicillin, **P**roguanil, **I**rinotecan, **M**ethyldopa, **S**ulindac/Sulphasalazine). * **Advantage of Prodrugs:** They are often designed to improve bioavailability, reduce gastric irritation, or prolong the duration of action. * **Exception:** Most ACE inhibitors are prodrugs *except* **Captopril** and **Lisinopril**.

Q: Which of the following is a prodrug?

Enalapril. **Explanation:** A **prodrug** is a pharmacologically inactive compound that must undergo metabolic conversion (usually in the liver) to become an active metabolite. **Enalapril (Option B)** is a classic example of a prodrug. It is an ester that is hydrolyzed in the liver to its active form, **Enalaprilat**. This conversion is necessary because the active form (Enalaprilat) has poor oral bioavailability, whereas the prodrug (Enalapril) is well-absorbed from the GI tract. **Analysis of Incorrect Options:** * **Lisinopril (Option A):** This is a critical high-yield exception. Unlike most ACE inhibitors, Lisinopril (and Captopril) is **not** a prodrug; it is active as administered. * **Chlorpromazine (Option C):** This is a typical antipsychotic that is active in its parent form. * **Dopamine (Option D):** This is a direct-acting catecholamine. However, its precursor, **Levodopa**, is a famous prodrug used in Parkinsonism because it can cross the blood-brain barrier, whereas dopamine cannot. **High-Yield NEET-PG Pearls:** 1. **ACE Inhibitor Rule:** All ACE inhibitors are prodrugs **EXCEPT** Captopril and Lisinopril. 2. **Common Prodrugs (Mnemonic: "All Prefer Doing Most Medications In Simple Every Day"):** **A**CEIs (except Capto/Lisinopril), **P**roguanil, **D**ipivefrine, **M**ercaptopurine, **M**ethyldopa, **I**rinos/Isosorbide, **S**ulindac, **E**nalapril, **D**iazepam (some metabolites). 3. **Advantage:** Prodrugs are often designed to improve absorption, reduce side effects, or increase the duration of action.

Q: Which of the following drugs is an enzyme inducer?

Rifampicin. **Explanation** The correct answer is **Rifampicin**. **1. Why Rifampicin is correct:** Rifampicin is a potent inducer of the **Cytochrome P450 (CYP450)** enzyme system, specifically the CYP3A4 isoenzyme. [3] Enzyme inducers work by increasing the synthesis of microsomal enzymes in the liver. This leads to an accelerated metabolism of co-administered drugs (e.g., oral contraceptives, warfarin, theophylline), resulting in decreased plasma concentrations and potential therapeutic failure. [1] **2. Why the other options are incorrect:** * **Isoniazid (INH):** Unlike Rifampicin, Isoniazid is a known enzyme **inhibitor**. It inhibits the metabolism of drugs like phenytoin and carbamazepine, leading to their toxicity. * **Ketoconazole:** This is a classic, potent enzyme **inhibitor** (specifically CYP3A4). [1, 2] It is often used in pharmacology questions to demonstrate drug-drug interactions that lead to increased levels of drugs like statins or benzodiazepines. * **Erythromycin:** This macrolide antibiotic is a well-known enzyme **inhibitor**. [2] It can lead to dangerous elevations of drugs like theophylline or cisapride. (Note: Azithromycin is the only macrolide that does not significantly inhibit CYP enzymes). **3. NEET-PG High-Yield Pearls:** To remember these for the exam, use these popular mnemonics: * **Enzyme Inducers (GPRS Cell Phone):** **G**riseofulvin, **P**henytoin, **R**ifampicin, **S**moking, **C**arbamazepine, **P**henobarbitone. * **Enzyme Inhibitors (VITAMIN K):** **V**alproate, **I**soniazid, **T**imetidine (Cimetidine), **A**miodarone, **M**acrolides (except Azithromycin), **I**ndinavir, **N**etwork (Azoles/Ketoconazole), **K**rapefruit juice (Grapefruit). **Clinical Tip:** Rifampicin-induced enzyme induction can lead to **contraceptive failure** in women on OCPs; patients should be advised to use alternative barrier methods.

Q: According to the Drugs and Cosmetics Rules, match the following medications with their corresponding schedules: 1. Insulin, 2. Hepatitis B vaccine, 3. Morphine, 4. Veterinary drugs. Schedules: A. Schedule H, B. Schedule Z, C. Schedule G, D. Schedule X.

1-C, 2-A, 3-D, 4-B. ***1-C, 2-A, 3-D, 4-B*** - **Insulin** (1) is properly categorized under **Schedule G** (C), specifying drugs that must be taken only under the supervision of a registered medical practitioner. - The **Hepatitis B vaccine** (2) falls under **Schedule H** (A - general prescription drugs), **Morphine** (3) is correctly placed under **Schedule X** (D - narcotics/psychotropics), and **Veterinary drugs** (4) are covered by **Schedule Z** (B - proprietary veterinary medicines). *1-C, 2-D, 3-B, 4-A* - This option incorrectly assigns the **Hepatitis B vaccine** (2) to Schedule D (which deals with standards of imported drugs) instead of Schedule H. - It incorrectly places **Morphine** (3) under Schedule B (fees for tests and analysis) instead of the appropriate Schedule X. *1-B, 2-A, 3-D, 4-C* - This option incorrectly assigns **Insulin** (1) to Schedule B (fees for test or analysis by the Central Drugs Laboratory) instead of Schedule G. - It incorrectly places **Veterinary drugs** (4) under Schedule C (which deals with biological products intended for parenteral administration). *1-D, 2-B, 3-A, 4-C* - This option incorrectly assigns **Insulin** (1) to Schedule D (rules regarding the importation of drugs) and **Morphine** (3) to Schedule A (forms of application for licenses). - It also incorrectly links the **Hepatitis B vaccine** (2) to Schedule B (fees for tests rather than a drug category).

Q: Which is correct about the marked area in the blister strip of Paracetamol (PCM)? (Recent NEET Pattern 2016-17)

Expiry date of last day of Feb 2014. **Understanding Pharmaceutical Expiry Dates:** When a drug expiry date lists only the month and year (without a specific day), pharmaceutical regulations specify that the product remains valid through the last day of that stated month. ***Expiry date of last day of Feb 2014*** - When an expiration date specifies only the month and year (e.g., **FEB.14**), it signifies that the product is considered stable and potent up to and including the **last day of that month** (February 28/29, 2014). - This ensures that the medication remains effective and safe throughout the entire month indicated, allowing for proper use until its conclusion. - This follows **WHO guidelines** and **pharmaceutical regulatory standards** worldwide. *Expiry date of first day of Feb 2014* - This interpretation would incorrectly limit the product's usability to the very beginning of the month, which is not the standard practice for drug expiration dates. - The standard is to consider the product viable for the **entire duration of the stated month**, not just the first day. *Expiry date extending 3 months from last day of Feb 2014* - There is no information or standard convention that would extend the expiration date by an additional three months beyond the stated month. - This option incorrectly adds a time period that is not indicated on the packaging and could lead to the use of an expired product. *Expiry date extending 3 months from the first day of Feb 2014* - Similar to the previous incorrect option, this adds an unfounded three-month extension to the expiration date. - Expiration dates are precisely determined by manufacturers based on stability testing and should be followed as printed, without arbitrary extensions.

Q: The image given below shows:

Dermojet. ***Dermojet*** - This image displays a **dermojet**, which is a needle-free injection device used to administer medications, particularly for intradermal or subcutaneous injections, by forcing liquid medication through the skin at high pressure. - It's commonly used in dermatology for procedures like injecting local anesthetics or corticosteroids. *EpiPen* - An **EpiPen** is a brand name for an auto-injector specifically designed to deliver a dose of **epinephrine** rapidly during a severe allergic reaction (anaphylaxis). - Its appearance is distinct, typically a pen-like device with a safety cap and a clearly marked injection end, which is different from the device shown. *Glucometer* - A **glucometer** is a device used to measure the **concentration of glucose** in the blood, primarily by diabetics for monitoring their blood sugar levels. - It usually involves a small screen, a port for test strips, and a button, which does not resemble the metallic, pen-like device with a lever shown. *Intradermal pen* - While dermojets perform intradermal injections, an "intradermal pen" is not a standard, widely recognized medical device term for this specific instrument. - The device in the image is specifically known as a **dermojet**, characterized by its needle-free mechanism and pressure delivery system.

Q: What is the recommended dose regimen of Vitamin A for the treatment of early stages of Xerophthalmia?

2 lac IU on two successive days. ***2 lac IU on two successive days*** - The **WHO-recommended treatment protocol** for xerophthalmia (including early stages) involves a **3-dose regimen**: 200,000 IU immediately, followed by 200,000 IU the next day, and a third dose at least 2 weeks later. - The **first two doses on consecutive days** represent the critical initial treatment phase to rapidly replenish vitamin A stores and prevent progression to sight-threatening corneal damage. - This regimen applies to children **12 months and older and adults**; infants under 12 months receive 100,000 IU doses. *Single massive dose of 2 lac International Units (IU)* - While a high dose is essential, **a single dose alone is insufficient** for treating xerophthalmia according to WHO guidelines. - The second dose on the consecutive day is critical to ensure adequate tissue saturation and prevent progression of corneal lesions. - Single-dose regimens are used for **prophylaxis in high-risk populations**, not for active treatment of xerophthalmia. *2 doses of 1 lac IU at a gap of one week* - **100,000 IU doses** are recommended for **infants under 12 months of age**, not for older children and adults with xerophthalmia. - The one-week interval does not match the WHO protocol, which requires the second dose on the **very next day** to ensure rapid correction. *2 doses of 1 lac IU in two successive days* - This dosing regimen is appropriate for **infants aged 6-12 months** with xerophthalmia, where each dose is 100,000 IU. - For children **12 months and older and adults**, the standard dose is **200,000 IU (2 lac IU)**, making this dosage insufficient for the typical patient population.

Question 1

Which of the following is NOT a prodrug?

Accepted Answer

Imipramine

Answer

Enalapril

Answer

Sulphasalazine

Answer

Cyclophosphamide

Question 2

Which of the following is a prodrug?

Accepted Answer

Enalapril

Answer

Lisinopril

Answer

Chlorpromazine

Answer

Dopamine

Question 3

What advice should be given to a lactating mother regarding drug intake?

Accepted Answer

Advise the mother to breastfeed just before she takes the next dose, when the plasma concentration of the drug would be lowest.

Answer

No advice is needed as most drugs are not secreted into breast milk.

Answer

Administer drugs with a longer half-life.

Answer

Advise the mother to breastfeed when the drug is least efficacious.

Question 4

What is true about inverse agonism?

Accepted Answer

It binds to the same receptor binding site as an agonist but exerts the opposite pharmacological effect.

Answer

Its action on the target receptors is similar to that of an agonist.

Answer

It is effective against receptors having intrinsic activity without acting of a ligand upon them.

Answer

None of the above.

Question 5

Which of the following drugs is an enzyme inducer?

Accepted Answer

Rifampicin

Answer

Isoniazid

Answer

Ketoconazole

Answer

Erythromycin

Question 6

Which of the following is an alkaloid?

Accepted Answer

Neostigmine

Answer

Morphine

Answer

Emetine

Answer

Atropine

Question 7

According to the Drugs and Cosmetics Rules, match the following medications with their corresponding schedules: 1. Insulin, 2. Hepatitis B vaccine, 3. Morphine, 4. Veterinary drugs. Schedules: A. Schedule H, B. Schedule Z, C. Schedule G, D. Schedule X.

Accepted Answer

1-C, 2-A, 3-D, 4-B

Answer

1-D, 2-B, 3-A, 4-C

Answer

1-C, 2-D, 3-B, 4-A

Answer

1-B, 2-A, 3-D, 4-C

Question 8

Which is correct about the marked area in the blister strip of Paracetamol (PCM)? (Recent NEET Pattern 2016-17)

Accepted Answer

Expiry date of last day of Feb 2014

Answer

Expiry date of first day of Feb 2014

Answer

Expiry date extending 3 months from last day of Feb 2014

Answer

Expiry date extending 3 months from the first day of Feb 2014

Question 9

The image given below shows:

Accepted Answer

Dermojet

Answer

EpiPen

Answer

Glucometer

Answer

Intradermal pen

Question 10

What is the recommended dose regimen of Vitamin A for the treatment of early stages of Xerophthalmia?

Accepted Answer

2 lac IU on two successive days

Answer

Single massive dose of 2 lac International Units (IU)

Answer

2 doses of 1 lac IU at a gap of one week

Answer

2 doses of 1 lac IU in two successive days

General Pharmacology — MCQs

General Pharmacology — MCQs

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