McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 1. |
Regarding paraquat poisoning |
| A. | The interval between ingestion and death is usually hours because of immediate pulmonary toxicity |
| B. | Mechanism of action involves single electron oxidation of the herbicide to free radical species |
| C. | Probable human lethal dosage is 50-500mg/kg |
| D. | Oxygen high flow stops the pulmonary lesions occurring |
| E. | Paraquat doesn’t affect hepatic or renal functions |
| Answer» C. Probable human lethal dosage is 50-500mg/kg | |
| 2. |
Regarding NSAIDs |
| A. | Piroxicam has a half life of >50 hours |
| B. | Aspirin reversibly inhibits COX |
| C. | Diclofenac is a selective COX1 inhibitor |
| D. | Indomethacin is relatively free of adverse side effects |
| E. | Ibuprofen is predominantly excreted unchanged in the urine |
| Answer» A. Piroxicam has a half life of >50 hours | |
| 3. |
Regarding paracetamol (acetaminophen) |
| A. | Less than 5% is excreted unchanged |
| B. | Acetaminophen has no anti-inflammatory properties |
| C. | The half life of paracetamol is 2-3 hours |
| D. | Haemolytic anaemia has rarely been noted with paracetamol |
| E. | All of the above are true |
| Answer» E. All of the above are true | |
| 4. |
Regarding lead toxicity |
| A. | Lead can induce an anaemia that is macrocytic |
| B. | Young children absorb about 10% of ingested inorganic lead |
| C. | Lead induced peripheral neuropathy often involves upper limb extensors resulting in wrist drop |
| D. | High dose organic lead poisoning usually results in severe pneumonitis |
| E. | All patients with elevated blood lead levels should have chelation treatment whether symptomatic or not |
| Answer» C. Lead induced peripheral neuropathy often involves upper limb extensors resulting in wrist drop | |
| 5. |
Regarding agents used to treat gout |
| A. | As little as 8mg of colchicine taken over 24 hours may be fatal |
| B. | Allopurinol is a xanthine oxidase stimulator |
| C. | Probenecid is an organic alkaline substance |
| D. | Colchicine may precipitate acute attacks of gout |
| E. | Aspirin is effective against gout as it inhibits urate crystal phagocytosis |
| Answer» A. As little as 8mg of colchicine taken over 24 hours may be fatal | |
| 6. |
All of the following may be seen in organophosphate poisoning EXCEPT |
| A. | Salivation |
| B. | Tachycardia |
| C. | Fibrillation of muscle fibres |
| D. | Bronchospasm |
| E. | Vomiting |
| Answer» B. Tachycardia | |
| 7. |
Regarding aspirin |
| A. | The average anti-inflammatory dose of aspirin is 0.6g up to 4 hourly |
| B. | Aspirin’s main side effect at usual doses is rash |
| C. | Aspirin’s antiplatelet effect lasts 8 – 10 days |
| D. | At low toxic doses – respiratory acidosis may occur |
| E. | Aspirin has a pka of 4.5 |
| Answer» C. Aspirin’s antiplatelet effect lasts 8 – 10 days | |
| 8. |
The main mechanism of action of colchicine is |
| A. | Inhibition of polymorphonuclear leucocytes |
| B. | Inhibition of synoviocyte phagocytosis |
| C. | Reduced formation of leukotriene D4 |
| D. | Inhibition of mononuclear phagocytes |
| E. | Decreasing the body pool of urate |
| Answer» A. Inhibition of polymorphonuclear leucocytes | |
| 9. |
Aspirin inhibits all of the following EXCEPT |
| A. | Cyclo oxygenase |
| B. | Recurrent miscarriages |
| C. | Protacyclin synthesis |
| D. | Kallikrein system |
| E. | Lipo oxygenase |
| Answer» E. Lipo oxygenase | |
| 10. |
Acetaminophen (paracetamol) can undergo all of the following biotransformation reactions EXCEPT |
| A. | Deamination |
| B. | N-oxidation |
| C. | Glucuronidation |
| D. | Sulphation |
| E. | Glutathione conjugation |
| Answer» A. Deamination | |
| 11. |
Aspirin |
| A. | Is hydrolysed to acetone and salicylate |
| B. | Exhibits first order kinetics with elimination in low doses |
| C. | Is mostly conjugated by the liver and excreted in the bile |
| D. | Reversibly blocks the cyclooxygenase enzyme |
| E. | Causes an immediate doubling of bleeding time |
| Answer» B. Exhibits first order kinetics with elimination in low doses | |
| 12. |
Regarding NSAIDs |
| A. | At high doses diclofenac demonstrates zero order kinetics |
| B. | Aspirin is a reversible inhibitor of cyclooxygenase |
| C. | Aspirin at doses of <2g/day reduces uric acid levels |
| D. | All NSAIDs can be found in synovial fluid after repeated dosing |
| E. | Use of ibuprofen and aspirin together increases the anti inflammatory effect |
| Answer» D. All NSAIDs can be found in synovial fluid after repeated dosing | |
| 13. |
The metabolic pathway of detoxification that becomes increasingly important in paracetamol toxicity is |
| A. | Conjugation with glucuronide |
| B. | Oxidation |
| C. | Reduction |
| D. | Cytochrome p-450 dependent glutathione conjugation |
| E. | Methylation |
| Answer» D. Cytochrome p-450 dependent glutathione conjugation | |
| 14. |
Which of the following NSAIDs has a t1/2 of about 1 hour |
| A. | Diclofenac |
| B. | Naproxen |
| C. | Piroxicam |
| D. | Indomethacin |
| E. | Ibuprofen |
| Answer» A. Diclofenac | |
| 15. |
Which of the following symptoms of aspirin toxicity occurs at plasma salicylate concentrations of 100mg/dl? |
| A. | Tinnitus |
| B. | Vasomotor collapse |
| C. | Metabolic acidosis |
| D. | Gastric intolerance |
| E. | Renal failure |
| Answer» C. Metabolic acidosis | |
| 16. |
All of the following drugs can cause a wide anion gap metabolic acidosis EXCEPT |
| A. | Lithium |
| B. | Methanol |
| C. | Cyanide |
| D. | Salicylates |
| E. | Isoniazid |
| Answer» A. Lithium | |
| 17. |
Which of the following drug overdoses may be amenable to the elimination technique of haemodialysis |
| A. | Calcium channel blockers |
| B. | Benzodiazepines |
| C. | Valproate |
| D. | Quinidine |
| E. | Opioids |
| Answer» C. Valproate | |
| 18. |
Which of the following antidote – drug pairings is INCORRECT |
| A. | Acetaminophen → n-acetyl cysteine |
| B. | β blockers → glucagon |
| C. | Opioids → naloxone |
| D. | Benzodiazepines → Flumazenil |
| E. | Tricyclic antidepressants → physostigmine |
| Answer» E. Tricyclic antidepressants → physostigmine | |
| 19. |
Regarding carbon monoxide poisoning |
| A. | CO has an affinity for Hb that is about 2000 times that of oxygen |
| B. | Hyperbaric oxygen is indicated as a treatment for all patients with CO Hb levels >20% |
| C. | The average concentration of CO in the atmosphere is about 0.1ppm |
| D. | With room air at 1atm the elimination half time of CO is about 80 minutes |
| E. | The foetus is resistant to the effects of CO exposure |
| Answer» C. The average concentration of CO in the atmosphere is about 0.1ppm | |
| 20. |
“Erethism” is seen in which of the following intoxications |
| A. | Lead |
| B. | Mercury |
| C. | Arsine gas |
| D. | Penicillamine |
| E. | Arsenic |
| Answer» B. Mercury | |
| 21. |
All of the following are NSAIDs EXCEPT |
| A. | Sulindac |
| B. | Piroxicam |
| C. | Gemfibrozil |
| D. | Ketorolac |
| E. | Diflunisal |
| Answer» C. Gemfibrozil | |
| 22. |
Drugs which enhance other drug metabolism include all of the following EXCEPT |
| A. | Rifampicin |
| B. | Ketoconazole |
| C. | Phenobarbital |
| D. | Griseofulvin |
| E. | Phenytoin |
| Answer» B. Ketoconazole | |
| 23. |
Which of the following has a high extraction ratio |
| A. | Trimethoprim |
| B. | Valproic acid |
| C. | Lignocaine |
| D. | Metronidazole |
| E. | Diazepam |
| Answer» C. Lignocaine | |
| 24. |
Heparin and protamine used together is an example of |
| A. | Physiologic antagonism |
| B. | Chemical antagonism |
| C. | Partial agonism |
| D. | Irreversible antagonism |
| E. | Agonal agonism |
| Answer» B. Chemical antagonism | |
| 25. |
The half life of a drug with a Vd of 200ml/70kg and clearance of 10ℓ/hr/70kg is |
| A. | 10 hours |
| B. | 14 hours |
| C. | 20 hours |
| D. | 40 hours |
| E. | Indeterminate |
| Answer» B. 14 hours | |
| 26. |
All of the following are true regarding penicillins EXCEPT |
| A. | Most penicillins only cross the blood brain barrier when the meninges are inflamed. |
| B. | Penicillins don’t require dosage adjustment in renal failure |
| C. | Penicillins inhibit cross linkage of peptidoglycans in the cell wall |
| D. | Piperacillin is a penicillin active against pseudomonas |
| E. | Only about 5 to 10% of people with a past history of penicillin allergy have a reaction on re exposure |
| Answer» B. Penicillins don’t require dosage adjustment in renal failure | |
| 27. |
Ciprofloxacin |
| A. | Is a defluorinated analogue of nalidixic acid |
| B. | Inhibits tropoisomerases 2 and 3 |
| C. | Has no gram positive cover |
| D. | Has a bioavailability of 30% |
| E. | May cause an arthropathy |
| Answer» E. May cause an arthropathy | |
| 28. |
Resistance to B lactams |
| A. | Can be due to an efflux pump |
| B. | Is most commonly due to modification of the target PBPs |
| C. | Does not involve penetration of drug to target PBPs |
| D. | Infers resistance only to penicillinc |
| E. | Can involve up to 5 different B lactamases |
| Answer» A. Can be due to an efflux pump | |
| 29. |
Macrolides |
| A. | Have enhanced activity at acidic pH |
| B. | Have little activity against legionella |
| C. | Have half lives which increase in patients with anuria |
| D. | Induce cytochrome p450 enzymes |
| E. | Are contraindicated in neonates |
| Answer» C. Have half lives which increase in patients with anuria | |
| 30. |
Flucloxacillin |
| A. | Is ineffective against streptococci |
| B. | Is active against enterococci and anaerobes |
| C. | Blocks transpeptidation and inhibits peptidoglycan synthesis |
| D. | Is poorly absorbed orally |
| E. | Has excellent penetration into CNS and prostate |
| Answer» C. Blocks transpeptidation and inhibits peptidoglycan synthesis | |
| 31. |
All of the following inhibit nucleic acid synthesis EXCEPT |
| A. | Norfloxacillin |
| B. | Chloramphenicol |
| C. | Trimethoprim |
| D. | Rifampicin |
| E. | Sulfasalazine |
| Answer» B. Chloramphenicol | |
| 32. |
Which of the following is a second generation cephalosporin? |
| A. | Cefaclor |
| B. | Ceftazidime |
| C. | Cephalexin |
| D. | Cefotaxime |
| E. | Cephalothin |
| Answer» A. Cefaclor | |
| 33. |
Regarding the pharmacokinetics of the tetracyclines |
| A. | Tetracyclines are 40 to 80 % bound by serum proteins |
| B. | Absorption is enhanced by coadministration of antacids |
| C. | Tetracyclines cross the blood brain barrier easily |
| D. | Doxycycline is excreted predominantly by the kidney |
| E. | Demeclocyline is a short acting tetracycline drug |
| Answer» A. Tetracyclines are 40 to 80 % bound by serum proteins | |
| 34. |
All of the following are recognized adverse effects of isoniazid EXCEPT |
| A. | Hepatitis |
| B. | Peripheral neuropathy |
| C. | Retrobulbar neuritis |
| D. | Decreased phenytoin metabolism – increased phenytoin blood levels / toxicity |
| E. | CNS toxicity |
| Answer» C. Retrobulbar neuritis | |
| 35. |
Vancomycin |
| A. | 90% of vancomycin is excreted by glomerular filtration |
| B. | Inhibits proteinsynthesis in bacteria |
| C. | Is bactericidal against gram negative bacilli |
| D. | Is well absorbed from the GIT |
| E. | One adverse reaction to infusions of vancomycin is the “blue man” syndrome |
| Answer» A. 90% of vancomycin is excreted by glomerular filtration | |
| 36. |
Regarding mechanisms of antiviral drug action |
| A. | blockage of viral uncoating is caused by rifampicin |
| B. | Zidovudine is a protease inhibitor |
| C. | Amantidine blocks viral DNA packaging and assembly |
| D. | Indinavir is a reverse transcriptase inhibitor |
| E. | Acyclovir inhibits viral DNA synthesis |
| Answer» E. Acyclovir inhibits viral DNA synthesis | |
| 37. |
Regarding toxicity of antibiotics |
| A. | Enamel dysplasia is common with aminoglycosides |
| B. | Gray baby syndrome occurs with rifampicin use |
| C. | Haemolytic anaemias can occur with sulphonamide use |
| D. | Nephritis is the most common adverse reaction with isoniazid |
| E. | Disulfiram like reaction can occur with macrolides |
| Answer» C. Haemolytic anaemias can occur with sulphonamide use | |
| 38. |
Chloramphenicol |
| A. | Does not penetrate the blood brain barrier |
| B. | Must be administered parenterally |
| C. | Can be safely used in premature infants |
| D. | Can cause depression of bone marrow function |
| E. | Can cause discoloration of developing teeth when given to children |
| Answer» D. Can cause depression of bone marrow function | |
| 39. |
Spironolactone |
| A. | Has a steroid structure |
| B. | Is a partial agonist |
| C. | Promotes sodium retention |
| D. | Increases potassium loss |
| E. | Is a loop diuretic |
| Answer» A. Has a steroid structure | |
| 40. |
Which of the following drugs cause diuresis by the mechanisms indicated? |
| A. | Ethanol – by preventing the reabsorption of sodium from renal tubular fluid |
| B. | Digoxin – by inhibiting release of ADH |
| C. | Dopamine – by inhibiting active transport of chloride over the entire length of the descending limb of the loop of Henle |
| D. | Frusemide – by inhibiting carbonic anhydrase |
| E. | Chlorothiazide – by inhibiting active sodium transport in the ascending limb of the loop of Henle |
| Answer» E. Chlorothiazide – by inhibiting active sodium transport in the ascending limb of the loop of Henle | |
| 41. |
All of the following antibiotics bind to the 50S subunit of the ribosome thereby inhibiting proteinsynthesis EXCEPT |
| A. | Chloramphenicol |
| B. | Erythromycin |
| C. | Linezolid |
| D. | Doxycycline |
| E. | Clindamycin |
| Answer» D. Doxycycline | |
| 42. |
Pharmacokinetics of doxycycline |
| A. | 20% bound by serum proteins |
| B. | 60-70% absorption after oral administration |
| C. | Absorption is impaired by divalent cations, Al3+, and antacids |
| D. | Widely distributed especially into the CSF |
| E. | Is eliminated via renal mechanisms |
| Answer» C. Absorption is impaired by divalent cations, Al3+, and antacids | |
| 43. |
Which of the following inhibits DNA gyrase? |
| A. | Penicillin |
| B. | Trimethoprim |
| C. | Chloramphenicol |
| D. | Ciprofloxacin |
| E. | Gentamicin |
| Answer» D. Ciprofloxacin | |
| 44. |
Resistance to Penicillin and other β lactams is due to |
| A. | Modification of target PBPs |
| B. | Impaired penetration of drug to target PBPs |
| C. | Presence of an efflux pump |
| D. | Inactivation of antibiotics by β lactamase |
| E. | All of the above |
| Answer» E. All of the above | |
| 45. |
All of the following are recognised adverse effects of isoniazid EXCEPT |
| A. | Hepatitis |
| B. | Peripheral neuropathy |
| C. | Retrobulbar neuritis |
| D. | ↓ Phenytoin metabolism → ↑ Phenytoin blood levels and toxicity |
| E. | CNS toxicity |
| Answer» C. Retrobulbar neuritis | |
| 46. |
Regarding fluoroquinolones |
| A. | Ciprofloxacin is ineffective in the treatment of gonococcus |
| B. | Norfloxacin and Ciprofloxacin are predominantly faecally excreted |
| C. | Norfloxacin and Ciprofloxacin have long half lives (12 hours) |
| D. | They have poor oral bioavailability |
| E. | May damage growing cartilage in children less than 18 years of age |
| Answer» E. May damage growing cartilage in children less than 18 years of age | |
| 47. |
Vancomycin |
| A. | Is never orally administered as it is poorly absorbed from the GIT |
| B. | Binds to the 30S unit on the ribosome and inhibits protein synthesis |
| C. | 60% of vancomycin is excreted by glomerular filtration |
| D. | Parenteral vancomycin is commonly used for treatment of infections caused by methicillin susceptible staphylococci |
| E. | Adverse reactions to vancomycin are encountered in about 10% of patients |
| Answer» E. Adverse reactions to vancomycin are encountered in about 10% of patients | |
| 48. |
Regarding the “azole” group of antifungals |
| A. | Fluconazole has low water solubility |
| B. | Ketoconazole may be given IV/PO |
| C. | Itraconazole undergoes renal elimination |
| D. | Clotrimazole is the treatment of choice for systemic candidiasis – given orally |
| E. | They work by reduction of ergosterol synthesis by inhibition of fungal cytochrome P450 enzymes |
| Answer» E. They work by reduction of ergosterol synthesis by inhibition of fungal cytochrome P450 enzymes | |
| 49. |
The fluoroquinolones |
| A. | May be administered to patients with severe campylobacter infection |
| B. | Work by inhibiting dihydrofolate reductase |
| C. | Have little effect against gram positive organisms |
| D. | Are heavily metabolised in the liver |
| E. | Are safe to give to breast feeding mothers |
| Answer» A. May be administered to patients with severe campylobacter infection | |
| 50. |
Clindamycin |
| A. | Inhibits bacterial cell wall synthesis |
| B. | Is often used for prophylaxis of endocarditis in patients with Valvular disease who are undergoing dental procedures |
| C. | Penetrates through BBB into CSF well |
| D. | Works well against enterococci and gram negative aerobic organisms |
| E. | Is 10% protein bound |
| Answer» B. Is often used for prophylaxis of endocarditis in patients with Valvular disease who are undergoing dental procedures | |
Done Studing? Take A Test.
Great job completing your study session! Now it's time to put your knowledge to the test. Challenge yourself, see how much you've learned, and identify areas for improvement. Don’t worry, this is all part of the journey to mastery. Ready for the next step? Take a quiz to solidify what you've just studied.