Practice exam: chat my love <3

Question 1

Which immunosuppressant works by inhibiting calcineurin, thereby preventing IL-2 transcription in T cells?
A) Sirolimus
B) Methotrexate
C) Tacrolimus
D) Azathioprine

Answer 1

C) Tacrolimus
Explanation: Tacrolimus inhibits calcineurin, which prevents dephosphorylation of NFAT and ultimately blocks IL-2 transcription, suppressing T-cell activation.

Question 2

2. What is the main dose-limiting toxicity of methotrexate?
   A) Hepatotoxicity
   B) Nephrotoxicity
   C) Cardiotoxicity
   D) Pulmonary fibrosis

Answer 2

A) Hepatotoxicity
Explanation: Methotrexate can cause hepatotoxicity, especially with chronic use. Liver enzyme monitoring is crucial.

Question 3

Which drug listed acts as a purine analog and is metabolized by xanthine oxidase?
A) Azathioprine
B) Sirolimus
C) Rituximab
D) Mycophenolate mofetil

Answer 3

A) Azathioprine
Explanation: Azathioprine is a prodrug converted into 6-mercaptopurine, which is metabolized by xanthine oxidase. Allopurinol coadministration increases toxicity.

Question 4

Which drug should not be used concomitantly with allopurinol due to increased risk of myelosuppression?
A) Infliximab
B) Methotrexate
C) Azathioprine
D) Sirolimus

Answer 4

C) Azathioprine
Explanation: Allopurinol inhibits xanthine oxidase, leading to accumulation of azathioprine metabolites, increasing the risk of bone marrow suppression.

Question 5

Which of the following drugs is a TNF-α inhibitor?
A) Adalimumab
B) Glatiramer
C) Triciclib
D) Colchicine

Answer 5

A) Adalimumab
Explanation: Adalimumab is a monoclonal antibody against TNF-α, used in autoimmune diseases like rheumatoid arthritis and Crohn’s disease.

Question 6

Which of the following is a leukotriene receptor antagonist used for asthma prophylaxis?
A) Zileuton
B) Montelukast
C) Metocarbamol
D) Diclofenac

Answer 6

Montelukast
Explanation: Montelukast blocks leukotriene D4 receptors, reducing inflammation and bronchoconstriction in asthma.

Question 7

Which drug acts as a 5-lipoxygenase inhibitor?
A) Zafirlukast
B) Celecoxib
C) Zileuton
D) Naproxen

Answer 7

C) Zileuton
Explanation: Zileuton inhibits 5-lipoxygenase, blocking the formation of leukotrienes. Used in asthma prophylaxis.

Question 8

Which of the following drugs is a selective COX-2 inhibitor?
A) Piroxicam
B) Ketoprofen
C) Diclofenac
D) Celecoxib

Answer 8

D) Celecoxib
Explanation: Celecoxib selectively inhibits COX-2, reducing GI side effects compared to non-selective NSAIDs.

Question 9

Which drug listed is a monoclonal antibody targeting CD20?
A) Triciclib
B) Infliximab
C) Rituximab
D) Pegademasa

Answer 9

C) Rituximab
Explanation: Rituximab targets CD20 on B cells, leading to their destruction. Used in B-cell lymphomas and some autoimmune diseases.

Question 10

What is the mechanism of action of colchicine in the treatment of gout?
A) Inhibits uric acid synthesis
B) Inhibits microtubule polymerization
C) Inhibits COX-2
D) Blocks TNF-α

Answer 10

B) Inhibits microtubule polymerization
Explanation: Colchicine binds tubulin, inhibiting microtubule formation in neutrophils, which reduces inflammation in gout.

Question 11

A 62-year-old man with rheumatoid arthritis develops severe neutropenia after starting a new medication. His current meds include prednisone, folic acid, and methotrexate. Which medication is most likely responsible for the neutropenia?
A) Prednisone
B) Methotrexate
C) Folic acid
D) Naproxen

Answer 11

B) Methotrexate
Explanation: Methotrexate suppresses bone marrow. Neutropenia is a common dose-limiting toxicity, especially without folinic acid rescue.

Question 12

A 45-year-old woman with asthma is started on a leukotriene pathway modifier. Two weeks later, she develops abnormal liver enzymes. Which drug is the most likely cause?
A) Montelukast
B) Zileuton
C) Cetirizine
D) Metocarbamol

Answer 12

B) Zileuton
Explanation: Zileuton has been associated with hepatotoxicity. LFTs should be monitored regularly during therapy.

Question 13

A 70-year-old man with coronary artery disease and chronic pain is prescribed a pain medication. One month later, he presents with worsening hypertension and edema. Which drug is the most likely cause?
A) Celecoxib
B) Paracetamol
C) Metocarbamol
D) Colchicine

Answer 13

A) Celecoxib
Explanation: NSAIDs, especially COX-2 inhibitors like celecoxib, reduce renal perfusion and sodium excretion, increasing blood pressure and fluid retention.

Question 14

A 55-year-old renal transplant patient develops tremors, hypertension, and nephrotoxicity. Which immunosuppressive agent is most likely responsible?
A) Sirolimus
B) Tacrolimus
C) Azathioprine
D) Methotrexate

Answer 14

B) Tacrolimus
Explanation: Tacrolimus can cause neurotoxicity (tremor), nephrotoxicity, and hypertension. These are classic adverse effects.

Question 15

A 32-year-old woman is prescribed an anti-TNF agent for Crohn’s disease. Three weeks later, she presents with fever, cough, and night sweats. Chest X-ray shows cavitary lesions in the upper lobes. What should have been done before initiating therapy?
A) Start metronidazole
B) Screen for latent TB
C) Administer influenza vaccine
D) Order colonoscopy

Answer 15

B) Screen for latent TB
Explanation: TNF-α inhibitors increase the risk of reactivating latent tuberculosis. Screening with PPD or IGRA is mandatory before use.

Question 16

A patient is prescribed allopurinol and azathioprine. Two weeks later, he presents with pancytopenia. What caused this adverse event?
A) CYP3A4 induction by allopurinol
B) Competitive inhibition of folate metabolism
C) Accumulation of 6-mercaptopurine
D) Inhibition of IL-2 transcription

Answer 16

C) Accumulation of 6-mercaptopurine
Explanation: Allopurinol inhibits xanthine oxidase, which normally metabolizes 6-MP (active form of azathioprine). Toxic metabolite accumulation leads to marrow suppression.

Question 17

A 40-year-old man is prescribed diclofenac for back pain. He returns 3 weeks later with melena and anemia. What is the most likely mechanism behind his symptoms?
A) COX-2 selective inhibition
B) Inhibition of uric acid reabsorption
C) Decreased prostaglandin synthesis in the gastric mucosa
D) Direct hepatocyte toxicity

Answer 17

C) Decreased prostaglandin synthesis in the gastric mucosa
Explanation: Diclofenac is a non-selective NSAID. It inhibits COX-1, reducing protective gastric prostaglandins and leading to ulcers and GI bleeding.

Question 18

Which of the following drugs inhibits the P2Y12 receptor on platelets?
A) Acetylsalicylic acid
B) Clopidogrel
C) Abciximab
D) Warfarin

Answer 18

B) Clopidogrel
Explanation: Clopidogrel irreversibly blocks the ADP receptor (P2Y12), which is critical for platelet activation and aggregation.

Question 19

What is the mechanism of action of abciximab?
A) COX inhibition
B) ADP receptor inhibition
C) Glycoprotein IIb/IIIa receptor blockade
D) Thrombin inhibition

Answer 19

C) Glycoprotein IIb/IIIa receptor blockade
Explanation: Abciximab blocks the final common pathway for platelet aggregation: the GP IIb/IIIa receptor.

Question 20

Which of the following drugs is a direct factor Xa inhibitor?
A) Warfarin
B) Rivaroxaban
C) Heparin
D) Alteplase

Answer 20

B) Rivaroxaban
Explanation: Rivaroxaban selectively inhibits factor Xa, reducing thrombin generation and clot formation.

Question 21

What is the antidote for warfarin overdose?
A) Protamine sulfate
B) Vitamin K
C) Fibrinogen
D) Tranexamic acid

Answer 21

B) Vitamin K
Explanation: Vitamin K (phytonadione) restores hepatic synthesis of clotting factors II, VII, IX, and X, antagonizing warfarin.

Question 22

Which fibrinolytic drug is derived from Streptococcus and can cause allergic reactions?
A) Tenecteplase
B) Streptokinase
C) Alteplase
D) Heparin

Answer 22

B) Streptokinase
Explanation: Streptokinase is bacterial in origin and can provoke immune reactions due to preformed antibodies.

Question 23

What is the most appropriate therapy to reverse the effects of low molecular weight heparin (e.g., enoxaparin)?
A) Vitamin K
B) Protamine sulfate
C) Fibrinogen
D) Aminocaproic acid

Answer 23

B) Protamine sulfate
Explanation: Protamine sulfate partially neutralizes the effect of LMWH by binding to it, although less effectively than with UFH.

Question 24

Which drug should not be co-administered with acenocoumarol due to enhanced bleeding risk?
A) Iron dextran
B) Folic acid
C) Acetylsalicylic acid
D) Vitamin B12

Answer 24

C) Acetylsalicylic acid
Explanation: ASA increases bleeding risk by inhibiting platelet function and enhancing the anticoagulant effect of acenocoumarol.

Question 25

What is the primary mechanism of action of tranexamic acid? A) Inhibits plasminogen activation B) Enhances fibrinogen synthesis C) Activates factor VII D) Inhibits vitamin K recycling

Answer 25

A) Inhibits plasminogen activation Explanation: Tranexamic acid is an antifibrinolytic that prevents plasminogen from binding to fibrin, reducing clot breakdown.

Question 26

Which of the following is indicated in macrocytic anemia due to vitamin B12 deficiency? A) Fumarato ferroso B) Ácido fólico C) Hidroxocobalamina D) Epoetina alfa

Answer 26

C) Hidroxocobalamina Explanation: Hydroxocobalamin is used in the treatment of vitamin B12 deficiency, often administered intramuscularly.

Question 27

A patient receiving erythropoietin for anemia of chronic disease must be monitored for which adverse effect? A) Hypokalemia B) Neutropenia C) Hypertension D) Alopecia

Answer 27

C) Hypertension Explanation: Erythropoietin can increase blood viscosity, leading to elevated blood pressure.

Question 28

A 76-year-old woman with atrial fibrillation is prescribed an oral anticoagulant. One week later, she presents with severe epistaxis. Her INR is 6.5. What is the most appropriate next step in management? A) Administer protamine sulfate B) Give aminocaproic acid C) Administer vitamin K D) Start tranexamic acid

Answer 28

C) Administer vitamin K Explanation: In the case of warfarin overdose with elevated INR and bleeding, vitamin K is the first-line antidote.

Question 29

A 55-year-old man with a recent STEMI is given streptokinase. Twelve hours later, he develops sudden-onset hematuria and altered mental status. What is the most likely cause? A) Thrombotic stroke B) Allergic reaction to the drug C) Disseminated intravascular coagulation D) Systemic fibrinolysis and bleeding

Answer 29

D) Systemic fibrinolysis and bleeding Explanation: Streptokinase activates plasminogen systemically, which can result in widespread bleeding.

Question 30

A patient on long-term acenocoumarol develops severe hematuria after beginning clopidogrel for coronary artery disease. What is the most likely cause of the bleeding? A) Acenocoumarol overdose B) Clopidogrel monotherapy C) Synergistic antithrombotic effect D) Platelet factor IV deficiency

Answer 30

C) Synergistic antithrombotic effect Explanation: Dual therapy with antiplatelet and anticoagulant increases the bleeding risk significantly.

Question 31

A 39-year-old woman receives tenecteplase for acute MI. Her condition improves, but two days later she develops sudden hemiparesis. What is the most likely complication? A) Pulmonary embolism B) Ischemic stroke C) Intracranial hemorrhage D) Deep vein thrombosis

Answer 31

C) Intracranial hemorrhage Explanation: One of the most feared complications of thrombolytic therapy is hemorrhagic stroke.

Question 32

A 60-year-old dialysis patient develops anemia. Labs show low hemoglobin and normal B12 and folate levels. Which is the best therapeutic option? A) Iron dextran B) Methenolone C) Folic acid D) Erythropoietin

Answer 32

D) Erythropoietin Explanation: In anemia of chronic kidney disease, EPO deficiency is the main issue, best treated with recombinant erythropoietin.

Question 33

A 48-year-old trauma patient is bleeding uncontrollably despite normal platelet count. Tranexamic acid is administered. What is the mechanism of action? A) Activation of clotting factor VII B) Inhibition of fibrinolysis C) Activation of thrombin D) Vitamin K antagonism

Answer 33

B) Inhibition of fibrinolysis Explanation: Tranexamic acid inhibits the conversion of plasminogen to plasmin, preserving fibrin clots.

Question 34

A 72-year-old man with colorectal cancer and recurrent DVT is on fondaparinux. He develops acute renal failure. What is the best next step? A) Increase fondaparinux dose B) Switch to warfarin C) Discontinue anticoagulation D) Switch to unfractionated heparin

Answer 34

D) Switch to unfractionated heparin Explanation: Fondaparinux is renally cleared and contraindicated in renal failure. UFH is safer and easier to monitor.

Question 35

Which of the following drugs is a 5-HT3 receptor antagonist used for chemotherapy-induced nausea? A) Domperidone B) Metoclopramide C) Ondansetron D) Aprepitant

Answer 35

C) Ondansetron Explanation: Ondansetron is a selective 5-HT3 antagonist, especially effective in managing chemotherapy-induced emesis.

Question 36

What is the mechanism of action of loperamide? A) 5-HT3 blockade B) Mu-opioid receptor agonist acting on myenteric plexus C) Anticholinergic D) D2 receptor antagonist

Answer 36

B) Mu-opioid receptor agonist acting on myenteric plexus Explanation: Loperamide reduces intestinal motility by activating peripheral μ-opioid receptors, with minimal CNS penetration.

Question 37

Which agent is contraindicated in Parkinson's disease due to dopamine antagonism? A) Metoclopramide B) Ondansetron C) Famotidine D) Aprepitant

Answer 37

A) Metoclopramide Explanation: Metoclopramide is a D2 antagonist and can worsen Parkinsonian symptoms by blocking dopamine in the CNS.

Question 38

Which of the following drugs acts by increasing GI motility via 5-HT4 agonism? A) Domperidone B) Octreotide C) Cinitapride D) Flunarizine

Answer 38

C) Cinitapride Explanation: Cinitapride is a prokinetic that enhances GI motility via 5-HT4 receptor

Question 39

What is the role of octreotide in gastrointestinal disorders? A) Stimulates intestinal secretion B) Used for irritable bowel syndrome C) Reduces portal hypertension and inhibits GI hormone secretion D) Enhances motility in diabetic gastroparesis

Answer 39

C) Reduces portal hypertension and inhibits GI hormone secretion Explanation: Octreotide mimics somatostatin, decreasing splanchnic blood flow and secretion of GI hormones.

Question 40

Which drug is a neurokinin-1 (NK1) receptor antagonist? A) Aprepitant B) Ondansetron C) Domperidone D) Cisapride

Answer 40

A) Aprepitant Explanation: Aprepitant blocks NK1 receptors in the brain, preventing substance P-mediated nausea and vomiting.

Question 41

Which of the following drugs forms a viscous barrier protecting the gastric mucosa? A) Ranitidine B) Sucralfate C) Omeprazole D) Bismuth

Answer 41

B) Sucralfate Explanation: Sucralfate polymerizes in acid to form a protective gel-like barrier over ulcers and erosions.

Question 42

Which drug causes extrapyramidal symptoms due to central D2 antagonism? A) Ondansetron B) Metoclopramide C) Butylhyoscine D) Mesalazine

Answer 42

B) Metoclopramide Explanation: It crosses the BBB and blocks D2 receptors, potentially causing dystonia, parkinsonism, or tardive dyskinesia.

Question 43

Which of the following drugs used in IBD has the potential for inducing pancreatitis? A) Infliximab B) Mesalazine C) Azathioprine D) Adalimumab

Answer 43

C) Azathioprine Explanation: Azathioprine can cause dose-independent pancreatitis as an idiosyncratic reaction.

Question 44

What is the correct use of misoprostol in gastrointestinal pharmacology? A) Inhibits acid secretion via histamine blockade B) Induces mucosal regeneration via prostaglandin E1 analog activity C) Enhances motility via serotonin receptors D) Antagonizes aldosterone in the colon

Answer 44

B) Induces mucosal regeneration via prostaglandin E1 analog activity Explanation: Misoprostol protects gastric mucosa by increasing bicarbonate and mucus production, often used in NSAID-induced ulcers.

Question 45

A 28-year-old woman with Crohn’s disease presents with worsening diarrhea and abdominal pain. She was recently started on infliximab. Two weeks later, she develops fever and dyspnea. Chest X-ray shows bilateral infiltrates. What is the most likely cause? A) Tuberculosis reactivation B) Acute mesenteric ischemia C) Drug-induced lupus D) Pneumocystis pneumonia

Answer 45

A) Tuberculosis reactivation Explanation: TNF-α inhibitors like infliximab can reactivate latent TB. Screening prior to initiation is mandatory.

Question 46

A 65-year-old man with heart failure is given ondansetron postoperatively. Two hours later, his ECG shows a QTc interval of 520 ms. What is the most appropriate action? A) Repeat ECG in 4 hours B) Stop ondansetron and give magnesium C) Start beta-blocker D) Administer potassium

Answer 46

B) Stop ondansetron and give magnesium Explanation: Ondansetron can prolong QTc, increasing torsades risk. Magnesium is first-line in QT prolongation.

Question 47

A 54-year-old male presents with hematemesis and a history of alcohol abuse. He is given octreotide. What is the rationale for using this drug? A) Promotes clot formation B) Increases clotting factors C) Decreases portal hypertension D) Stimulates mucosal healing

Answer 47

C) Decreases portal hypertension Explanation: Octreotide reduces portal venous pressure by causing splanchnic vasoconstriction, useful in variceal bleeding.

Question 48

A 33-year-old woman with constipation-predominant IBS takes plantago psyllium daily. She complains of bloating. What is the underlying mechanism of action of her treatment? A) Osmotic laxative B) Stimulant of enteric nerves C) Bulk-forming agent D) Emollient stool softener

Answer 48

C) Bulk-forming agent Explanation: Psyllium absorbs water, forming a gel that increases stool bulk and promotes peristalsis.

Question 49

A 48-year-old man with duodenal ulcer takes pantoprazole. What would you expect as a potential long-term adverse effect of this therapy? A) Hyperkalemia B) Hypocalcemia C) Vitamin B12 deficiency D) Increased gastric acid production

Answer 49

C) Vitamin B12 deficiency Explanation: Long-term PPI use can impair B12 absorption by decreasing gastric acid needed for its release from food.

Question 50

A patient with IBD on mesalazine develops renal dysfunction. Which adverse effect is most likely responsible? A) Interstitial nephritis B) Nephrotic syndrome C) Hyperkalemia D) Ureteral obstruction

Answer 50

A) Interstitial nephritis Explanation: Mesalazine can rarely cause interstitial nephritis, necessitating renal function monitoring.

Question 51

A cancer patient on chemotherapy presents with nausea and vomiting unresponsive to ondansetron. Which drug is most appropriate to add next? A) Loperamide B) Aprepitant C) Sucralfate D) Cinitapride

Answer 51

B) Aprepitant Explanation: Aprepitant blocks NK1 receptors and is used with 5-HT3 antagonists for refractory chemo-induced nausea.

Question 52

A 29-year-old man with Crohn’s disease presents with fatigue and mild jaundice. He has been on azathioprine for 3 months. Labs reveal elevated bilirubin, ALT, and AST. What is the most likely diagnosis? A) Autoimmune hepatitis B) Pancreatitis C) Hepatotoxicity due to TPMT deficiency D) Primary sclerosing cholangitis

Answer 52

C) Hepatotoxicity due to TPMT deficiency Explanation: Thiopurines like azathioprine are metabolized by TPMT. Deficiency causes metabolite accumulation → liver injury.

Question 53

A 36-year-old woman on infliximab presents with malaise and new-onset fever. She has no cough or other symptoms. Chest X-ray shows apical infiltrates. What test should have been done before starting treatment? A) ANA B) Serum IgE C) Tuberculin skin test or IGRA D) Barium swallow

Answer 53

C) Tuberculin skin test or IGRA Explanation: TNF-α inhibitors suppress granuloma formation → screen for latent TB before therapy.

Question 54

A 43-year-old man with ulcerative colitis has been on mesalazine for 2 years. He now presents with hematuria and rising creatinine. What is the most probable adverse effect? A) Bladder cancer B) Interstitial nephritis C) Nephrolithiasis D) Prostatitis

Answer 54

B) Interstitial nephritis Explanation: Mesalazine can cause renal toxicity. Always monitor renal function regularly in long-term therapy.

Question 55

A patient with steroid-refractory ulcerative colitis is started on infliximab. Two days after the second infusion, she develops joint pain, fever, and a maculopapular rash. ANA is positive. What is the most likely cause? A) Lupus-like syndrome B) Drug-induced hepatitis C) Serum sickness D) Vasculitis

Answer 55

A) Lupus-like syndrome Explanation: Anti-TNF therapy can induce lupus-like symptoms due to autoantibody formation.

Question 56

A 25-year-old woman with moderate Crohn's disease is pregnant. Which of the following is safest to continue? A) Methotrexate B) Azathioprine C) Infliximab D) Both B and C

Answer 56

D) Both B and C Explanation: Azathioprine and infliximab can be used in pregnancy. Methotrexate is absolutely contraindicated.

Question 57

A 42-year-old male with UC is maintained on adalimumab. He complains of shortness of breath, dry cough, and fatigue. Chest CT reveals interstitial lung infiltrates. What is the next best step? A) Start corticosteroids B) Stop adalimumab C) Add azathioprine D) Administer oxygen and continue treatment

Answer 57

B) Stop adalimumab Explanation: TNF-α inhibitors can cause drug-induced interstitial lung disease. Discontinuation is the primary intervention.

Question 58

A patient receiving methotrexate for Crohn’s disease is admitted with confusion and tremors. Labs reveal elevated ammonia and AST. What complication should be suspected? A) Hepatic encephalopathy B) Acute pancreatitis C) Vitamin B12 deficiency D) Uremia

Answer 58

A) Hepatic encephalopathy Explanation: Methotrexate is hepatotoxic and can lead to liver failure with resultant encephalopathy.

Question 59

A 33-year-old man on 6-mercaptopurine for Crohn’s disease presents with fever, sore throat, and oral ulcers. His labs show neutropenia. What is the next step? A) Continue drug and monitor B) Start antibiotics C) Discontinue drug immediately D) Administer folinic acid

Answer 59

C) Discontinue drug immediately Explanation: Myelosuppression is a life-threatening complication of thiopurines. Discontinuation is urgent.

Question 60

What is the mechanism of action of infliximab? A) IL-1 receptor blockade B) TNF-α neutralizing monoclonal antibody C) Integrin inhibition D) IL-6 receptor blockade

Answer 60

B) TNF-α neutralizing monoclonal antibody Explanation: Infliximab is a chimeric monoclonal antibody against TNF-α, suppressing inflammatory signaling.

Question 61

Which of the following statements regarding mesalazine is true? A) It inhibits TNF-α directly B) It is effective for Crohn’s involving the ileum C) It acts topically on the colonic mucosa D) It requires TPMT genotyping before use

Answer 61

C) It acts topically on the colonic mucosa Explanation: Mesalazine (5-ASA) works topically on inflamed mucosa; not useful in small bowel Crohn's disease.

Question 62

Which immunosuppressant for IBD is a folate antagonist and inhibits DNA synthesis? A) Azathioprine B) 6-Mercaptopurine C) Methotrexate D) Adalimumab

Answer 62

C) Methotrexate Explanation: Methotrexate inhibits dihydrofolate reductase, impairing DNA synthesis and cell replication.

Question 63

Which drug requires TPMT enzyme activity testing prior to administration to prevent toxicity? A) Methotrexate B) Azathioprine C) Mesalazine D) Adalimumab

Answer 63

B) Azathioprine Explanation: Low TPMT activity leads to accumulation of toxic 6-TGN metabolites → bone marrow suppression.

Question 64

Which of the following statements is true about adalimumab compared to infliximab? A) It is a chimeric monoclonal antibody B) It requires IV administration C) It is less immunogenic due to being fully human D) It is contraindicated in pregnancy

Answer 64

C) It is less immunogenic due to being fully human Explanation: Adalimumab is a fully human monoclonal antibody → lower risk of anti-drug antibodies than infliximab.

Question 65

Methotrexate is contraindicated in all of the following EXCEPT: A) Liver disease B) Pregnancy C) Renal insufficiency D) UC in remission

Answer 65

D) UC in remission Explanation: Methotrexate is sometimes used in Crohn’s, not in UC. The others are absolute contraindications due to toxicity.

Question 66

What is the active metabolite of azathioprine that exerts its immunosuppressive effect? A) 6-TGN B) 6-MMP C) 5-ASA D) 6-MUA

Answer 66

A) 6-TGN Explanation: 6-thioguanine nucleotides (6-TGN) are the active cytotoxic metabolites inhibiting purine synthesis in T-cells.

Question 67

Which of the following drugs has the highest risk of producing antibodies that neutralize its action and reduce efficacy over time? A) Methotrexate B) Mesalazine C) Infliximab D) 6-Mercaptopurine

Answer 67

C) Infliximab Explanation: Infliximab is chimeric (mouse-human) → higher immunogenicity → antibodies can reduce efficacy and cause reactions.