General Pharmacology Practice Questions

Q: What is the branch that deals with medicinal drugs obtained from plants and other natural resources?

Pharmacognosy. ### Explanation **Correct Answer: A. Pharmacognosy** **Pharmacognosy** is the branch of pharmacology that deals with the study of crude drugs derived from natural sources, such as plants, animals, and minerals. The term is derived from the Greek words *pharmakon* (drug) and *gnosis* (knowledge). It involves the identification, physicochemical characterization, and cultivation of natural medicinal substances (e.g., Morphine from *Papaver somniferum*, Digoxin from *Digitalis lanata*). **Analysis of Incorrect Options:** * **B. Pharmacogenetics:** This is the study of how a **single gene** influences an individual’s response to a specific drug (e.g., G6PD deficiency causing hemolysis with Primaquine). * **C. Pharmacogenomics:** A broader term than pharmacogenetics, it involves the study of how the **entire genome** (multiple genes) affects drug response and toxicity, aiming for "personalized medicine." * **D. Pharmacopeia:** This is an **official publication** (legal record) containing a list of medicinal drugs with their effects and directions for use, published by a recognized authority (e.g., IP, BP, USP). **High-Yield Clinical Pearls for NEET-PG:** * **Father of Pharmacology:** Oswald Schmiedeberg. * **Father of Indian Pharmacology:** Ram Nath Chopra. * **Pharmacokinetics:** What the **body does to the drug** (ADME: Absorption, Distribution, Metabolism, Excretion). * **Pharmacodynamics:** What the **drug does to the body** (Mechanism of action and pharmacological effects). * **Therapeutics:** The application of pharmacological information together with the knowledge of the disease for its prevention and cure.

Q: What is the mechanism of action of cyclosporine?

Decreases transcription of the IL-2 gene. **Mechanism of Action: Cyclosporine** **Correct Answer: C. Decreases transcription of the IL-2 gene** **Explanation:** Cyclosporine is a potent immunosuppressant belonging to the **calcineurin inhibitor** class. Its mechanism involves several steps: 1. Cyclosporine enters the T-cell and binds to a specific cytoplasmic receptor protein called **Cyclophilin**. 2. The Cyclosporine-Cyclophilin complex binds to and inhibits **Calcineurin**, a phosphatase enzyme. 3. Under normal conditions, calcineurin dephosphorylates **NFAT** (Nuclear Factor of Activated T-cells), allowing it to enter the nucleus. 4. By inhibiting calcineurin, cyclosporine prevents the dephosphorylation and nuclear translocation of NFAT. 5. Consequently, there is a failure to activate the promoter region of the **Interleukin-2 (IL-2) gene**, leading to **decreased transcription** and production of IL-2. Since IL-2 is the primary driver for T-cell proliferation, the immune response is suppressed. **Why other options are incorrect:** * **Option A:** Drugs like **Basiliximab** and **Daclizumab** are monoclonal antibodies that specifically block the IL-2 receptor (CD25). * **Option B:** TNF-alpha inhibitors include drugs like **Etanercept, Infliximab, and Adalimumab**, used primarily in Rheumatoid Arthritis and IBD. * **Option D:** Cyclosporine targets **activated** T-cells (specifically the G0 or G1 phase). It does not target inactivated cells. **High-Yield NEET-PG Pearls:** * **Side Effects:** Nephrotoxicity (most common/serious), Gingival Hyperplasia, Hirsutism, and Hypertension. * **Metabolism:** Metabolized by **CYP3A4**; avoid grapefruit juice as it increases drug levels. * **Clinical Use:** Organ transplantation (prophylaxis of graft rejection) and autoimmune disorders like Psoriasis and Uveitis. * **Comparison:** **Tacrolimus** has a similar mechanism but binds to **FK-Binding Protein (FKBP-12)** instead of cyclophilin.

Q: What is the mechanism of action of dantrolene?

Binds to ryanodine receptors to block the release of Ca++. **Explanation:** **Mechanism of Action:** Dantrolene is a direct-acting skeletal muscle relaxant. Its primary mechanism involves binding to the **Ryanodine Receptor 1 (RyR1)** located on the membrane of the **sarcoplasmic reticulum** (SR) in skeletal muscle cells [1]. By antagonizing these receptors, dantrolene inhibits the release of stored calcium ions ($Ca^{2+}$) into the cytosol. Since intracellular calcium is essential for excitation-contraction coupling, its reduction prevents muscle fiber contraction without affecting neuromuscular transmission or cardiac/smooth muscle (which utilize different RyR isoforms) [1]. **Analysis of Options:** * **Option A:** While dantrolene does reduce calcium levels in the sarcoplasm, it specifically inhibits the **release** from the SR, not "secretion" (a term usually reserved for glandular activity). * **Option C:** GABA is the primary inhibitory neurotransmitter in the CNS [1]. Drugs like benzodiazepines or baclofen act via GABA receptors, but dantrolene acts peripherally on the muscle itself [1]. * **Option D:** Inhibition of gamma motor neurons is the mechanism associated with centrally acting muscle relaxants (e.g., diazepam), not direct-acting agents like dantrolene. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Dantrolene is the life-saving treatment for **Malignant Hyperthermia** (often triggered by succinylcholine or halothane) and **Neuroleptic Malignant Syndrome (NMS)**. * **Other Uses:** Management of spasticity associated with Upper Motor Neuron lesions (e.g., Cerebral Palsy, Multiple Sclerosis). * **Side Effect:** The most significant adverse effect is **hepatotoxicity** (monitor liver function tests). * **Key Distinction:** Unlike non-depolarizing blockers (e.g., vecuronium), dantrolene does not act at the nicotinic acetylcholine receptor (nAChR).

Q: Which of the following is NOT a prodrug?

Lisinopril. **Explanation:** A **prodrug** is a pharmacologically inactive compound that must undergo metabolic conversion (usually in the liver) to become an active metabolite. **Why Lisinopril is the correct answer:** Most ACE inhibitors are prodrugs (e.g., Enalapril converts to Enalaprilat) to improve oral bioavailability. However, **Lisinopril** and **Captopril** are the two major exceptions; they are active drugs themselves and do not require hepatic activation. This makes them preferred in patients with liver dysfunction. **Analysis of Incorrect Options:** * **Levodopa:** It is the metabolic precursor of **Dopamine**. Since dopamine cannot cross the blood-brain barrier, Levodopa is administered and then converted to active dopamine in the CNS by the enzyme DOPA decarboxylase. * **Carbimazole:** This antithyroid drug is a prodrug that is rapidly converted to its active form, **Methimazole**, which inhibits the synthesis of thyroid hormones. * **Prednisolone:** While **Prednisone** is a prodrug (converted to Prednisolone in the liver), **Prednisolone** itself is the active metabolite. *Note: In some contexts, Prednisolone is considered active, but it can further convert to other metabolites; however, compared to the other options, it is frequently tested as the active form vs. Prednisone.* **High-Yield Clinical Pearls for NEET-PG:** * **ACE Inhibitor Mnemonic:** All ACE inhibitors are prodrugs **EXCEPT** Captopril and Lisinopril. * **Common Prodrugs to Remember:** Enalapril, Ramipril, Valacyclovir (to Acyclovir), Clopidogrel, Cyclophosphamide, and Sulfasalazine. * **Advantage of Prodrugs:** They often have better absorption, reduced side effects at the site of administration, or a longer duration of action.

Q: What is the concentration of Potassium in Ringer's Lactate solution?

4 mEq/L. **Explanation:** Ringer's Lactate (RL), also known as Hartmann's solution, is a balanced crystalloid solution designed to closely mimic the electrolyte composition of human plasma. It is the fluid of choice for resuscitation in burns and hemorrhagic shock. **1. Why Option B is Correct:** The concentration of **Potassium (K+) in Ringer's Lactate is 4 mEq/L**. This concentration is intentionally set to reflect the normal physiological range of potassium in human extracellular fluid (3.5–5.0 mEq/L). Because it contains potassium, RL must be used with caution in patients with renal failure or hyperkalemia. **2. Why Other Options are Incorrect:** * **Options A and C (1 & 2 mEq/L):** These concentrations are too low to maintain physiological homeostasis in a balanced salt solution. * **Option D (6 mEq/L):** This exceeds the normal physiological limit of plasma potassium. Infusing a solution with 6 mEq/L as a primary maintenance or resuscitation fluid could inadvertently induce iatrogenic hyperkalemia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Composition of RL (per Liter):** * Sodium (Na+): 130–131 mEq/L (Hypotonic compared to Normal Saline) * Chloride (Cl-): 109–111 mEq/L * Lactate: 28 mEq/L (Converted to bicarbonate in the liver; useful in metabolic acidosis) * Calcium (Ca2+): 3 mEq/L * **Contraindication:** Do not co-administer RL with blood transfusions in the same IV line. The **Calcium** in RL can bind to the **Citrate** anticoagulant in stored blood, leading to clot formation. * **Metabolic Note:** RL is contraindicated in patients with severe liver disease because they cannot metabolize lactate into bicarbonate, potentially worsening lactic acidosis.

Question 1

What is the branch that deals with medicinal drugs obtained from plants and other natural resources?

Accepted Answer

Pharmacognosy

Answer

Pharmacogenetics

Answer

Pharmacogenomics

Answer

Pharmacopeia

Question 2

What is the mechanism of action of cyclosporine?

Accepted Answer

Decreases transcription of the IL-2 gene

Answer

Inhibits IL-2 receptors

Answer

Inhibits TNF alpha

Answer

Targets inactivated T cells

Question 3

What is the mechanism of action of dantrolene?

Accepted Answer

Binds to ryanodine receptors to block the release of Ca++

Answer

Inhibits Ca++ secretion from sarcoplasm

Answer

Inhibits GABA

Answer

Inhibits the gamma motor neuron

Question 4

What is the primary purpose of an orphan drug?

Accepted Answer

To treat rare conditions with no expectation of significant profit for the manufacturer.

Answer

To treat common conditions with the expectation of significant profit for the manufacturer.

Answer

To treat rare conditions with the expectation of significant profit for the manufacturer.

Answer

None of the above.

Question 5

All of the following are true about gantacurium, except:

Accepted Answer

It is a benzylisoquinoline nondepolarizing neuromuscular blocker.

Answer

Its onset and duration are similar to succinylcholine.

Answer

It is a nondepolarizing neuromuscular blocker.

Answer

It is not metabolized by pseudocholinesterase.

Question 6

Which of the following is a common cause of electrolyte abnormalities?

Accepted Answer

Aluminum Hydroxide (Al(OH)3)

Answer

Potassium Chloride (KCl)

Answer

0.9% Sodium Chloride (NaCl)

Answer

Sodium Bicarbonate (NaHCO3)

Question 7

Which of the following is NOT a prodrug?

Accepted Answer

Lisinopril

Answer

Levodopa

Answer

Carbimazole

Answer

Prednisolone

Question 8

Allergic reactions depend on all except:

Accepted Answer

Dosage of the drug received

Answer

Previous exposure to the drug

Answer

Pharmacological action of the drug

Answer

Antigen-antibody reaction

Question 9

According to the two-state receptor theory, which of the following statements BEST explains the term "agonists"?

Accepted Answer

Strong affinity for the receptor in the active state (Ra)

Answer

Strong affinity for the receptor in the inactive state (Ri)

Answer

Equal affinity for Ra and Ri

Answer

Slightly more affinity for Ra than Ri

Question 10

What is the concentration of Potassium in Ringer's Lactate solution?

Accepted Answer

4 mEq/L

Answer

1 mEq/L

Answer

2 mEq/L

Answer

6 mEq/L

General Pharmacology — MCQs

General Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?