SECTION A – MCQs (10 Marks)
Q1. Which biological agent acts specifically as a calcineurin inhibitor?
Answer:
B.
Cyclosporine
Explanation: Cyclosporine binds to cyclophilin and inhibits calcineurin phosphatase. This
prevents activation of T-lymphocytes and reduces IL-2 production, producing
immunosuppression.
Q2. Cyclophosphamide causes hemorrhagic cystitis due to which metabolite?
Answer:
A. Acrolein
Explanation: Cyclophosphamide is metabolized in the liver into two molecules, Phosphoramide mustard (anticancer action) and Acrolein (toxic metabolite). Acrolein damages urinary bladder mucosa causing hemorrhagic cystitis. Mesna is administered to prevent this toxicity.
Q3. Which antithyroid drug inhibits peripheral conversion of T4 to T3?
Answer:
B.
Propylthiouracil (PTU)
Explanation: PTU: Inhibits thyroid peroxidase, Blocks conversion of T4 → T3 in peripheral
tissues and Used in thyroid storm because of this additional action.
Q4. Macrolides bind to which ribosomal subunit?
Answer:
B. 50S
Subunit
Explanation:
Macrolides (Azithromycin, Clarithromycin, Erythromycin) bind reversibly to the
50S ribosomal subunit and inhibit bacterial protein synthesis.
Q5. PPIs reduce gastric acid secretion by?
Answer:
B.
Irreversible inhibition of H⁺/K⁺ ATPase
Explanation:
PPIs permanently inhibit the proton pump located on gastric parietal cells,
suppressing gastric acid secretion for 24–48 hours.
Q6. Which oral hypoglycaemic drug commonly causes GI upset and metallic
taste?
Answer:
C.
Biguanides Explanation: Metformin commonly causes: Nausea, Diarrhea,
Abdominal discomfort and Metallic taste
Q7. Which antiemetic selectively blocks 5-HT₃ receptors?
Answer:
B.
Ondansetron
Explanation:
Ondansetron blocks serotonin (5-HT₃) receptors in: Chemoreceptor Trigger Zone
(CTZ) and in gastrointestinal tract. It is highly effective in
chemotherapy-induced vomiting.
Q8. Sulfonamides compete with which substrate?
Answer:
C.
Para-aminobenzoic acid (PABA)
Explanation:
Sulfonamides resemble PABA and competitively inhibit dihydropteroate synthase, preventing
folic acid synthesis.
Q9. Polyene antifungal agent?
Answer:
B.
Amphotericin-B
Explanation:
Amphotericin-B binds ergosterol present in fungal cell membranes causing pore
formation and leakage of intracellular contents.
Q10. Interferon-α acts by?
Answer:
B. Host
cellular antiviral protein synthesis
Explanation: Interferon-α stimulates production of antiviral proteins that inhibit viral replication and enhance immune responses.
SECTION B (PBQ)
Q11. Problem-Based Question (PBQ)
A 38-year-old male construction worker presents to a
primary healthcare facility with a 4-week history of persistent productive
cough with occasional blood-tinged sputum (hemoptysis), low-grade evening
fever, drenching night sweats, and a significant unintended weight loss of 6
kg. Sputum microscopy using Ziehl-Neelsen staining reveals the prominent presence
of acid-fast bacilli. The patient is diagnosed with new pulmonary tuberculosis
(TB) and is registered to begin standard anti-tubercular pharmacotherapy under
the DOTS program.
Based on the clinical presentation, answer the following detailed
questions:
a) Identify the primary causative microorganism
responsible for this condition and state the specific structural component of
its cell wall that makes it "acid-fast". (1 Mark)
b) Outline the standard WHO-recommended first-line
anti-tubercular drug regimen for a newly diagnosed adult patient, clearly
detailing the specific drugs used in both the Intensive Phase and the
Continuation Phase along with their durations. (3 Marks)
c) Explain the precise molecular mechanism of action of
Isoniazid (INH) and Rifampicin. (2 Marks)
d) The patient is co-prescribed Pyridoxine (Vitamin B6)
alongside his regimen. Provide the precise pharmacological justification for
this combination. (1 Mark)
e) Define the term 'DOTS' as frame worked by the
WHO, and discuss its core execution principles and strategic clinical
significance in controlling public health complication like MDR-TB. (3 Marks)Q11. a) Identify the causative organism and
acid-fast component. (1 Mark)
Ans: Causative
organism: Mycobacterium tuberculosis and acid-fast
component is mycolic acid. Mycolic acids are long-chain fatty acids present in
the bacterial cell wall. They resist decolorization by acid alcohol during
Ziehl–Neelsen staining, making the organism acid-fast.b) WHO
First-Line Anti-Tubercular Regimen (3 Marks)
Ans: The
World Health Organization (WHO) recommends a 6-month standard first-line anti-tubercular
treatment regimen for newly diagnosed drug-sensitive pulmonary tuberculosis.
The treatment is divided into two phases: the Intensive Phase and the
Continuation Phase. During the Intensive Phase, which lasts for 2 months, the
patient receives a combination of four first-line anti-tubercular drugs:
Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), and Ethambutol (E),
collectively abbreviated as HRZE. This phase is designed to rapidly reduce the
bacterial load, eliminate actively multiplying bacilli, and prevent the
emergence of drug resistance. Following the intensive phase, the patient enters
the Continuation Phase, which lasts for 4 months. In this phase, treatment is
continued with Isoniazid (H) and Rifampicin (R), abbreviated as HR. The continuation
phase aims to eradicate any remaining dormant or persistent bacilli, thereby
preventing relapse and ensuring complete cure. Thus, the total duration of the
standard treatment regimen is 6 months, consisting of 2 months of HRZE followed
by 4 months of HR.
c) Explain the precise molecular mechanism of action of Isoniazid (INH) and Rifampicin. (2 Marks)
Ans: Isoniazid (INH) is a first-line antitubercular drug
that acts as a prodrug and is activated
inside Mycobacterium
tuberculosis by the bacterial catalase-peroxidase
enzyme (KatG). Once activated, it inhibits the synthesis of mycolic acids, which are essential components of the
mycobacterial cell wall. Inhibition of mycolic acid synthesis weakens the cell
wall, leading to the death of actively multiplying tubercle bacilli. Therefore,
isoniazid exhibits a bactericidal effect
against actively dividing M. tuberculosis.
Rifampicin is another first-line bactericidal antitubercular agent that exerts its action by selectively inhibiting the DNA-dependent RNA polymerase enzyme in Mycobacterium tuberculosis. This inhibition blocks the transcription of bacterial DNA into RNA, thereby preventing RNA synthesis. As a result, protein synthesis is interrupted, leading to the inhibition of bacterial growth and ultimately causing bacterial cell death. Due to this mechanism, rifampicin is highly effective against both intracellular and extracellular tubercle bacilli.
d) Why is Pyridoxine given? (1 Mark)
Ans:
Pyridoxine (Vitamin B6) is
routinely co-administered with Isoniazid
(INH) to prevent its neurotoxic adverse effects. Isoniazid interferes
with the metabolism of pyridoxine, leading to a functional deficiency of
Vitamin B6. This deficiency may result in peripheral neuropathy, characterized by symptoms such as tingling,
numbness, burning sensation, and pain in the hands and feet. The risk of
developing peripheral neuropathy is higher in malnourished individuals,
pregnant women, elderly patients, alcoholics, and patients with diabetes or HIV
infection. Therefore, supplementation with Pyridoxine (Vitamin B6) is recommended during isoniazid therapy to
prevent or reduce the incidence of INH-induced
peripheral neuropathy while ensuring the effectiveness of antitubercular
treatment.DOTS (Directly Observed Treatment,
Short-course) is the tuberculosis (TB) control strategy recommended by
the World Health Organization (WHO) to ensure effective
diagnosis, treatment, and prevention of tuberculosis. Under this strategy, a
trained healthcare worker or treatment supporter directly observes the patient
taking each dose of anti-tubercular medication, thereby improving treatment
adherence and reducing the risk of incomplete therapy. The DOTS framework is
based on five key principles: sustained government commitment to TB control,
early and accurate diagnosis through quality-assured bacteriological testing,
standardized short-course chemotherapy with direct observation of treatment, an
uninterrupted supply of quality-assured anti-tubercular drugs, and a
standardized recording and reporting system to monitor treatment outcomes and
evaluate program performance.
SECTION C – 5-Mark Questions
Q12.
Classify anti-ulcer drugs systematically based on their mechanisms. Elaborate
the pharmacology of Proton Pump Inhibitors (PPIs) highlighting their
therapeutic indications, drug interactions, and superior clinical benefits over
H₂ receptor antagonists.
Answer:
Anti-ulcer
drugs are classified according to their mechanism of action into several
groups. Acid
secretion inhibitors include Proton
Pump Inhibitors (PPIs) such as Omeprazole, Pantoprazole, Esomeprazole, Rabeprazole, and
Lansoprazole, as well as H₂-receptor antagonists such as Cimetidine, Ranitidine, Famotidine, and
Nizatidine. Antacids, which neutralize gastric acid,
include magnesium hydroxide, aluminium hydroxide, calcium carbonate, and sodium
bicarbonate. Mucosal
protective agents
include Sucralfate and Bismuth compounds, while cytoprotective agents include Misoprostol, a prostaglandin
analogue. Anti-Helicobacter
pylori therapy
consists of combinations of antibiotics such as Amoxicillin, Clarithromycin,
and Metronidazole with a PPI.
Proton
Pump Inhibitors (PPIs) are the most effective drugs for suppressing gastric
acid secretion. They are administered as prodrugs and become activated in the
acidic environment of gastric parietal cells. Activated PPIs irreversibly
inhibit the H⁺/K⁺-ATPase
(proton pump),
the final step in gastric acid secretion, thereby producing profound and
long-lasting suppression of gastric acid production. Because new proton pumps
must be synthesized before acid secretion resumes, their effect lasts for 24–48
hours despite a short plasma half-life.
PPIs
are indicated for the treatment of peptic ulcer disease, gastroesophageal
reflux disease (GERD), Zollinger–Ellison syndrome, stress ulcer prophylaxis,
erosive esophagitis, and eradication of Helicobacter pylori infection
as part of combination therapy. They are also used to prevent NSAID-induced
gastric ulcers in high-risk patients.
PPIs
may interact with drugs that require an acidic gastric environment for
absorption, such as ketoconazole and itraconazole. Omeprazole inhibits the
CYP2C19 enzyme and may reduce the activation of clopidogrel while increasing
plasma concentrations of drugs such as warfarin, diazepam, and phenytoin.
Long-term PPI therapy may also reduce the absorption of vitamin B12, magnesium,
calcium, and iron.
Compared
with H₂-receptor antagonists, PPIs provide more potent and prolonged
suppression of gastric acid secretion, promote faster healing of gastric and
duodenal ulcers, effectively heal erosive esophagitis, prevent nocturnal acid
breakthrough, and exhibit no significant tachyphylaxis with prolonged use.
Consequently, PPIs are considered the first-line therapy for most acid-peptic
disorders.
Q13. Provide a detailed classification of
corticosteroids based on their biological duration of action. Discuss the
diverse physiological and pharmacological actions of glucocorticoids, along
with their clinical applications and chronic adverse impacts.
Answer:
Corticosteroids
are classified according to their biological duration of action into three
groups. Short-acting
corticosteroids (8–12 hours) include Hydrocortisone and Cortisone. Intermediate-acting corticosteroids (12–36
hours) include
Prednisolone, Prednisone, Methylprednisolone, and Triamcinolone. Long-acting corticosteroids (36–72 hours) include Dexamethasone and
Betamethasone.
Glucocorticoids
produce a wide range of physiological and pharmacological effects. They
increase gluconeogenesis and reduce peripheral glucose utilization, leading to
elevated blood glucose levels. They promote protein catabolism and inhibit
protein synthesis, resulting in muscle wasting with prolonged therapy.
Glucocorticoids also increase lipolysis and cause redistribution of body fat,
producing characteristic features such as moon face and buffalo hump. They
possess potent anti-inflammatory properties by inhibiting phospholipase A₂
activity, suppressing prostaglandin and leukotriene synthesis, reducing
cytokine production, and stabilizing lysosomal membranes. In addition, they
exert immunosuppressive effects by decreasing T-lymphocyte proliferation and
suppressing antibody formation. They also reduce capillary permeability,
decrease edema, and suppress allergic and autoimmune reactions.
Glucocorticoids
are widely used in the management of bronchial asthma, rheumatoid arthritis,
systemic lupus erythematosus, inflammatory bowel disease, allergic disorders,
dermatological diseases, cerebral edema, nephrotic syndrome, autoimmune
diseases, adrenal insufficiency, prevention of organ transplant rejection, and
as adjunctive therapy in certain malignancies such as leukemia and lymphoma.
Chronic
administration of glucocorticoids is associated with several adverse effects,
including Cushingoid appearance, weight gain, hypertension, hyperglycemia,
osteoporosis, muscle wasting, delayed wound healing, increased susceptibility
to infections, peptic ulcers, cataracts, glaucoma, mood changes, adrenal
suppression, growth retardation in children, and menstrual irregularities.
Therefore, prolonged therapy should be tapered gradually to avoid acute adrenal
insufficiency.
Q14. Classify oral hypoglycaemic agents with
their representative chemical examples. Thoroughly explain the molecular
mechanism of action, therapeutic uses, and key adverse profiles (including
lactic acidosis risk) of Biguanides and Sulfonylureas.
Answer:
Oral
hypoglycaemic agents are classified into several groups. Biguanides include Metformin. Sulfonylureas include Glibenclamide (Glyburide),
Glipizide, Gliclazide, and Glimepiride. Meglitinides include Repaglinide and Nateglinide. Thiazolidinediones include Pioglitazone and
Rosiglitazone. α-Glucosidase
inhibitors
include Acarbose and Miglitol. DPP-4 inhibitors include Sitagliptin, Vildagliptin, Saxagliptin, and Linagliptin. SGLT-2 inhibitors include Dapagliflozin, Empagliflozin,
and Canagliflozin.
Metformin,
the only clinically used biguanide, lowers blood glucose primarily by
decreasing hepatic gluconeogenesis, reducing intestinal glucose absorption, and
increasing insulin sensitivity in skeletal muscle and adipose tissue through
activation of AMP-activated protein kinase (AMPK). Unlike insulin
secretagogues, metformin does not stimulate insulin release and therefore
rarely causes hypoglycemia. It is considered the first-line drug for type 2
diabetes mellitus, particularly in overweight and obese patients. It is also
used in prediabetes and polycystic ovary syndrome (PCOS). Common adverse
effects include nausea, vomiting, abdominal discomfort, diarrhea, and metallic
taste. The most serious but rare adverse effect is lactic acidosis, especially in patients with severe
renal impairment, liver disease, alcoholism, heart failure, or conditions
associated with tissue hypoxia. Long-term use may also lead to vitamin B12
deficiency.
Sulfonylureas
lower blood glucose by binding to the sulfonylurea receptor (SUR1) on
pancreatic β-cells, causing closure of ATP-sensitive potassium channels. This
leads to membrane depolarization, opening of voltage-gated calcium channels,
calcium influx, and subsequent insulin release. Sulfonylureas are effective in
patients with type 2 diabetes who retain functional pancreatic β-cells. They
may also be combined with metformin or other oral antidiabetic agents when
monotherapy is inadequate. Their major adverse effects include hypoglycemia,
weight gain, nausea, allergic skin reactions, and, rarely, hematological
abnormalities. Hypoglycemia is more common in elderly patients and those with
renal or hepatic impairment.
Q15. Systematically classify antineoplastic
agents with appropriate examples. Detail the molecular mechanism of action,
major clinical indications, and characteristically toxic adverse spectrum (such
as cardiotoxicity, myelosuppression, and ototoxicity) of Alkylating agents and
Platinum coordination complexes.
Answer:
Antineoplastic
drugs are classified into several major groups. Alkylating agents include Cyclophosphamide,
Chlorambucil, Melphalan, Busulfan, and Ifosfamide. Platinum coordination complexes include Cisplatin, Carboplatin, and
Oxaliplatin. Antimetabolites include Methotrexate, 5-Fluorouracil,
Cytarabine, and Gemcitabine. Antitumor antibiotics include Doxorubicin, Daunorubicin, Bleomycin, and
Mitomycin-C. Plant
alkaloids
include Vincristine, Vinblastine, Paclitaxel, and Docetaxel. Hormonal agents include Tamoxifen, Anastrozole,
Flutamide, and Prednisolone. Targeted therapies include Imatinib, Trastuzumab, Rituximab, and Bevacizumab.
Alkylating
agents act by forming covalent bonds with DNA, particularly at the N7 position
of guanine, resulting in DNA cross-linking, abnormal base pairing, and
inhibition of DNA replication and transcription. This ultimately leads to
apoptosis of rapidly dividing cancer cells. These drugs are used in the
treatment of leukemias, lymphomas, multiple myeloma, breast cancer, ovarian
cancer, and various solid tumors. Their major adverse effects include severe
myelosuppression, nausea, vomiting, alopecia, infertility, secondary
malignancies, and hemorrhagic cystitis with cyclophosphamide due to acrolein
formation. Mesna is administered to prevent this toxicity.
Platinum
coordination complexes such as cisplatin also form DNA cross-links, thereby
inhibiting DNA replication and inducing apoptosis. Cisplatin is widely used in
testicular, ovarian, bladder, lung, head and neck, and cervical cancers.
Carboplatin has similar activity with reduced nephrotoxicity, while oxaliplatin
is mainly used in colorectal cancer. The major toxicities include
nephrotoxicity, severe nausea and vomiting, peripheral neuropathy, ototoxicity, electrolyte disturbances, and myelosuppression, particularly with carboplatin. In
addition, cardiotoxicity is more commonly associated with
anthracycline antibiotics such as doxorubicin rather than alkylating agents or
platinum compounds.
Q16. Outline the chemical and therapeutic
classification of antifungal drugs. Discuss the mechanism of action, drug
interactions, indication and severe toxicity profiles of Polyene and Azole
antifungal agents.
Answer:
Antifungal
drugs are classified chemically into several groups. Polyenes include Amphotericin B and Nystatin. Azoles are divided into Imidazoles, such as Ketoconazole, Clotrimazole,
and Miconazole, and Triazoles, including Fluconazole, Itraconazole,
Voriconazole, Posaconazole, and Isavuconazole. Echinocandins include Caspofungin, Micafungin, and
Anidulafungin. Allylamines include Terbinafine and Naftifine,
while antimetabolites include Flucytosine. Other antifungal
agents include Griseofulvin and Ciclopirox.
Polyene
antifungal agents exert their action by binding to ergosterol, the principal sterol component of
fungal cell membranes. This interaction forms pores within the membrane,
causing leakage of intracellular electrolytes and cellular contents, ultimately
leading to fungal cell death. Amphotericin B is used for severe systemic fungal
infections such as cryptococcosis, histoplasmosis, aspergillosis, mucormycosis,
and invasive candidiasis, whereas Nystatin is used topically or orally for
mucocutaneous candidiasis. Amphotericin B is associated with serious adverse
effects, including infusion-related fever and chills, nephrotoxicity,
hypokalemia, hypomagnesemia, anemia, thrombophlebitis, and cardiac arrhythmias.
Concurrent administration with other nephrotoxic drugs such as aminoglycosides
or cyclosporine increases the risk of renal toxicity.
Azole
antifungal agents inhibit the fungal cytochrome P450 enzyme 14-α-demethylase, thereby preventing the conversion of
lanosterol to ergosterol. The resulting depletion of ergosterol disrupts fungal
cell membrane synthesis and function. Azoles are indicated for the treatment of
superficial and systemic fungal infections, including candidiasis,
dermatophytosis, cryptococcosis, and aspergillosis. Because azoles inhibit
hepatic cytochrome P450 enzymes, they interact with numerous drugs, including
warfarin, phenytoin, cyclosporine, oral hypoglycemic agents, and certain
statins, leading to increased plasma drug concentrations. Their adverse effects
include hepatotoxicity, gastrointestinal disturbances, skin rashes, QT interval
prolongation, and endocrine effects such as gynecomastia and decreased
testosterone synthesis, particularly with ketoconazole.
SECTION D – 2-Mark
Questions
Q17. Define the term 'Immunostimulants' and mention
any two examples of immunostimulant drugs utilized in modern clinical oncology.
Answer:
Immunostimulants are drugs that enhance or activate the body's immune system to
improve its ability to recognize and destroy cancer cells or infectious agents.
They are widely used in modern clinical oncology as immunotherapy to enhance
antitumor immune responses. Two commonly used immunostimulant drugs are Interferon-α and Interleukin-2 (IL-2).
Q18. Explain the biological role and clinical
rationale behind combining β-lactamase inhibitors with natural or
semi-synthetic penicillins.
Answer:
β-Lactamase inhibitors are combined with natural or semi-synthetic penicillins
to protect them from degradation by bacterial β-lactamase enzymes. These
inhibitors have little antibacterial activity of their own but prevent
enzymatic destruction of the antibiotic, thereby restoring its effectiveness
against β-lactamase-producing bacteria and broadening its antibacterial
spectrum. Common combinations include Amoxicillin–Clavulanic
acid and Piperacillin–Tazobactam.
Q19. Mention the direct chemical mechanism of action
of non-systemic antacids. List any two common examples of non-systemic
antacids.
Answer:
Non-systemic antacids act by chemically
neutralizing gastric hydrochloric acid (HCl) in the stomach, thereby
increasing gastric pH and reducing acid-related irritation and pepsin activity.
They are minimally absorbed and provide symptomatic relief in acid-peptic
disorders. Two common examples are Magnesium
hydroxide and Aluminium
hydroxide.
Q20. Name two third-generation cephalosporins. Write
one major therapeutic advantage of third-generation over first-generation
cephalosporins.
Answer:
Two commonly used third-generation cephalosporins are Ceftriaxone and Cefotaxime.
Compared with first-generation cephalosporins, they have broader activity against Gram-negative
bacteria and better penetration into the cerebrospinal fluid (CSF),
making them highly effective in the treatment of bacterial meningitis and other
serious systemic infections.
Q21. Specify the unique mechanism of action of
prokinetic drugs and name two clinically used prokinetic agents.
Answer:
Prokinetic drugs enhance gastrointestinal motility by blocking dopamine (D₂) receptors and/or stimulating serotonin (5-HT₄)
receptors, which increases acetylcholine release in the enteric nervous
system. This accelerates gastric emptying and improves gastrointestinal
motility. Two commonly used prokinetic agents are Metoclopramide and Domperidone.
Q22. Outline the primary mechanism of action of
stimulant purgatives and provide two clinically used drug examples from this
class.
Answer:
Stimulant purgatives act by directly
stimulating the enteric nerves of the colon, which increases intestinal
peristalsis and promotes the secretion of water and electrolytes into the
intestinal lumen, facilitating bowel evacuation. Two commonly used stimulant
purgatives are Bisacodyl and Senna (Sennosides).
Hi. I’m Writer of Researchsop.com. ’ ’ Please share these SOPs to all concern pharma people for their development. I like to fullfill the need of curious people. These things inspire me to make things looks better.
0 comments:
Post a Comment