General Pharmacology Practice Questions

Q: All of the following can cause histamine release except?

Propranolol. **Explanation:** The question tests your knowledge of drugs that cause **non-immunological (direct) histamine release** from mast cells. **1. Why Propranolol is the Correct Answer:** Propranolol is a non-selective beta-blocker. It does not possess the chemical structure or pharmacological property to trigger direct histamine release. In fact, in the context of allergy, beta-blockers are significant because they can **worsen** anaphylaxis and make it resistant to adrenaline, but they do not cause histamine release themselves. **2. Analysis of Incorrect Options:** * **D-tubocurarine:** This skeletal muscle relaxant is a classic example of a drug that causes direct histamine release, often leading to hypotension, flushing, and bronchospasm [1]. * **Morphine:** Opioids (especially morphine and codeine) trigger mast cell degranulation via a non-IgE mediated pathway [1]. This often results in "morphine itch" (pruritus) or urticaria. * **Vancomycin:** This antibiotic is notorious for causing **"Red Man Syndrome"** (or Red Neck Syndrome). This is a rate-dependent infusion reaction caused by direct histamine release, characterized by intense flushing of the upper body. **3. NEET-PG High-Yield Clinical Pearls:** * **Direct Histamine Releasers (Mnemonic: "M-A-V-E-D"):** **M**orphine, **A**mphotericin B, **V**ancomycin, **E**pinephrine (rarely), **D**-tubocurarine/Radiocontrast media [1]. * **Red Man Syndrome Prevention:** Slow the infusion rate of Vancomycin (administer over at least 60 minutes) and/or pre-treat with antihistamines. * **Clinical Sign:** Direct histamine release usually causes localized or systemic flushing, hypotension, and pruritus, but unlike true Type I hypersensitivity, it is not IgE-mediated and often depends on the dose or rate of administration [1].

Q: What is the site of action of vecuronium?

Myoneural junction. **Explanation:** **Vecuronium** is a non-depolarizing neuromuscular blocking agent (NMBA) belonging to the aminosteroid group. **1. Why the Correct Answer is Right:** The primary site of action for vecuronium is the **myoneural junction** (also known as the neuromuscular junction or NMJ). It acts as a competitive antagonist at the **nicotinic acetylcholine receptors (Nm)** located on the post-junctional motor endplate. By binding to these receptors, vecuronium prevents acetylcholine from triggering depolarization, thereby leading to flaccid skeletal muscle paralysis. **2. Why the Other Options are Incorrect:** * **Cerebrum & Reticular Formation (Options A & B):** Vecuronium is a quaternary ammonium compound, making it highly polar and lipid-insoluble. Consequently, it **cannot cross the blood-brain barrier (BBB)**. It has no effect on the Central Nervous System (CNS), meaning it provides no sedation or analgesia. * **Motor Neuron (Option C):** Vecuronium does not inhibit the electrical conduction along the nerve axon or the release of acetylcholine from the pre-synaptic terminal; its action is strictly post-synaptic at the muscle endplate. **3. Clinical Pearls for NEET-PG:** * **Metabolism:** It is primarily excreted via **bile** (undergoes hepatic metabolism), making it safer than pancuronium in renal failure, though caution is still advised. * **Cardiovascular Stability:** Unlike tubocurarine or pancuronium, vecuronium has minimal histamine release and lacks significant vagolytic effects, ensuring high cardiovascular stability. * **Reversal:** Its effects can be reversed using acetylcholinesterase inhibitors (e.g., **Neostigmine**) or the specific chelating agent **Sugammadex**. * **Intermediate Acting:** It has an intermediate duration of action (approx. 30–40 minutes).

Q: FK-506 is a

macrolide antibiotic. **Explanation:** **FK-506**, commonly known as **Tacrolimus**, is a potent immunosuppressant. Chemically, it is classified as a **macrolide antibiotic** (Option A) because it contains a large macrocyclic lactone ring in its structure. Although it shares a structural class with antibiotics like Erythromycin, it lacks significant antibacterial activity and is used exclusively for its immunosuppressive properties. **Mechanism of Action:** Tacrolimus acts as a **Calcineurin Inhibitor**. It binds to an intracellular protein called **FK-binding protein (FKBP-12)**. This complex inhibits calcineurin, preventing the dephosphorylation of the Nuclear Factor of Activated T-cells (NFAT). Consequently, the transcription of **Interleukin-2 (IL-2)** is blocked, inhibiting T-lymphocyte activation. **Analysis of Incorrect Options:** * **Option B:** It is a small molecule drug, not a protein-based immunoglobulin or monoclonal antibody. * **Option C:** It has no effect on the neuromuscular junction; examples of non-depolarizing relaxants include Vecuronium or Atracurium. * **Option D:** It does not act on opioid receptors; examples include Morphine or Fentanyl. **High-Yield Clinical Pearls for NEET-PG:** * **Potency:** Tacrolimus is 10–100 times more potent than Cyclosporine. * **Indications:** Preferred drug for preventing organ rejection in liver, kidney, and heart transplants; also used topically for atopic dermatitis. * **Side Effects:** Nephrotoxicity (most common), neurotoxicity (tremors, seizures), and **new-onset diabetes after transplantation (NODAT)**. * **Comparison:** Unlike Cyclosporine, Tacrolimus does **not** typically cause hirsutism or gum hyperplasia.

Q: Secukinumab is:

Anti IL-17. **Explanation:** **Secukinumab** is a high-affinity recombinant human monoclonal antibody that selectively binds to and neutralizes **Interleukin-17A (IL-17A)**. IL-17 is a pro-inflammatory cytokine produced primarily by Th17 cells; it plays a critical role in the pathogenesis of plaque psoriasis, ankylosing spondylitis, and psoriatic arthritis by inducing the production of chemokines and mediators of tissue inflammation. **Analysis of Options:** * **Option A (Anti IL-1):** Drugs targeting IL-1 include **Anakinra** (IL-1 receptor antagonist), **Canakinumab**, and **Rilonacept**. These are primarily used in cryopyrin-associated periodic syndromes (CAPS) and refractory Rheumatoid Arthritis. * **Option B (Anti IL-6):** **Tocilizumab** and **Sarilumab** are the classic IL-6 receptor antagonists used in Rheumatoid Arthritis and Giant Cell Arteritis. * **Option C (Correct):** Secukinumab (along with Ixekizumab) targets IL-17A. Brodalumab is another related drug that targets the IL-17 receptor. * **Option D (Anti IL-23):** Drugs targeting the p40 subunit of IL-12/23 include **Ustekinumab**, while **Guselkumab** and **Risankizumab** specifically target IL-23. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Moderate-to-severe Plaque Psoriasis, Psoriatic Arthritis, and Ankylosing Spondylitis. * **Side Effects:** Increased risk of infections (especially upper respiratory tract) and a notable association with **Mucocutaneous Candidiasis** (since IL-17 is essential for host defense against fungi). * **Contraindication:** It may exacerbate **Inflammatory Bowel Disease (IBD)**, so it should be avoided in patients with Crohn’s disease or Ulcerative Colitis.

Q: Sir Alexander Fleming received the Nobel Prize for which discovery?

Penicillin. Explanation: Correct Answer: C. Penicillin Sir Alexander Fleming, a Scottish bacteriologist, discovered Penicillin in 1928 at St. Mary's Hospital, London [2]. He observed that the mold Penicillium notatum produced a substance that inhibited the growth of Staphylococcus aureus [2]. This discovery ushered in the "Antibiotic Era." For this monumental achievement, Fleming shared the Nobel Prize in Physiology or Medicine in 1945 with Howard Florey and Ernst Chain, who were instrumental in the mass production and clinical application of the drug [1], [4]. Analysis of Incorrect Options: * A. Insulin: Discovered by Frederick Banting and Charles Best in 1921 [3]. Banting and John Macleod received the Nobel Prize for this in 1923. * B. CT scan: Developed by Godfrey Hounsfield and Allan Cormack, who shared the Nobel Prize in 1979. * D. ECG: The first practical electrocardiogram was developed by Willem Einthoven in 1903, for which he received the Nobel Prize in 1924. High-Yield Clinical Pearls for NEET-PG: * Mechanism of Action: Penicillin is a Beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to Penicillin-Binding Proteins (PBPs), preventing the cross-linking of peptidoglycan. * Source: Originally derived from Penicillium notatum (now P. chrysogenum) [1], [2]. * Serendipity: Fleming’s discovery is a classic example of "serendipity" (accidental discovery) in pharmacology [2]. * Resistance: The most common mechanism of resistance against Penicillins is the production of Beta-lactamase enzymes by bacteria.

Q: A farmer presented in the OPD clinic with sweating, lacrimation, and pinpoint pupils. What type of poisoning is suspected?

Organophosphate poisoning. **Explanation:** The clinical presentation of **sweating, lacrimation, and pinpoint pupils (miosis)** represents a classic **Cholinergic Toxidrome**. This occurs due to the excessive accumulation of acetylcholine at the synaptic cleft, leading to overstimulation of muscarinic and nicotinic receptors [1]. **Why Organophosphate (OP) Poisoning is Correct:** Organophosphates are irreversible inhibitors of the enzyme **Acetylcholinesterase** [3]. In a rural setting, a farmer is frequently exposed to these compounds via pesticides [1], [4]. The symptoms follow the **DUMBELS** mnemonic: Diarrhea, Urination, Miosis, Bradycardia/Bronchospasm, Emesis, Lacrimation, and Salivation/Sweating [1]. The presence of pinpoint pupils and excessive secretions is pathognomonic for OP poisoning. **Why Other Options are Incorrect:** * **Dhatura and Atropine Poisoning:** These are **Anticholinergic** agents. They present with the exact opposite symptoms: dry skin (no sweating), dry mouth, and **mydriasis** (dilated pupils). The classic description is "Dry as a bone, Red as a beet, Blind as a bat, Mad as a hatter." * **Cocaine Poisoning:** Cocaine is a sympathomimetic stimulant. It causes **mydriasis** (dilated pupils) due to increased sympathetic activity, along with tachycardia and hypertension [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** The specific antidote is **Atropine** (to reverse muscarinic effects) and **Pralidoxime (2-PAM)** (to regenerate cholinesterase, must be given before "aging" of the enzyme occurs) [5]. * **Monitoring:** The adequacy of atropinization is best monitored by the **drying of pulmonary secretions** and an increase in heart rate, rather than pupil size alone. * **Diagnosis:** Confirmed by measuring **Red Blood Cell (RBC) cholinesterase levels**, which is more specific than plasma cholinesterase.

Question 1

All of the following can cause histamine release except?

Accepted Answer

Propranolol

Answer

D-tubocurarine

Answer

Morphine

Answer

Vancomycin

Question 2

What is the site of action of vecuronium?

Accepted Answer

Myoneural junction

Answer

Cerebrum

Answer

Reticular formation

Answer

Motor neuron

Question 3

What is acute or rapidly developing tolerance to a drug?

Accepted Answer

Teratogenic effects

Answer

Anaphylaxis

Answer

Induction

Answer

Supersensitivity

Question 4

Which of the following is calculated as the ratio of the area under the curve (AUC) obtained by oral administration versus the AUC for intravenous administration of the same drug?

Accepted Answer

Bioavailability

Answer

Absorption

Answer

Clearance

Answer

Elimination rate constant

Question 5

FK-506 is a

Accepted Answer

macrolide antibiotic

Answer

Immunoglobulin antibody

Answer

Non-depolarizing muscle relaxant

Answer

Opioid analgesic

Question 6

A widely used drug that suppresses cellular immunity, inhibits prostaglandin and leukotriene synthesis, and increases the catabolism of IgG antibody is:

Accepted Answer

Prednisone

Answer

Cyclophosphamide

Answer

Cyclosporine

Answer

Infliximab

Question 7

Secukinumab is:

Accepted Answer

Anti IL-17

Answer

Anti IL-1

Answer

Anti IL-6

Answer

Anti IL-23

Question 8

Most essential medicines should be formulated as which of the following?

Accepted Answer

Single compound

Answer

No compound

Answer

Multiple compounds

Answer

Fixed dose combinations

Question 9

Sir Alexander Fleming received the Nobel Prize for which discovery?

Accepted Answer

Penicillin

Answer

Insulin

Answer

CT scan

Answer

ECG

Question 10

A farmer presented in the OPD clinic with sweating, lacrimation, and pinpoint pupils. What type of poisoning is suspected?

Accepted Answer

Organophosphate poisoning

Answer

Dhatura poisoning

Answer

Atropine poisoning

Answer

Cocaine poisoning

General Pharmacology — MCQs

General Pharmacology — MCQs

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