PH-MCQ3 PDF - Past Paper

## MD2009-3 ### Page 7 of 14 43. The sodium/potassium ATPase is: - Activated by digoxin - Activated by levosimendan - Inhibited by digoxin - Inhibited by levosimendan 44. An important side effect of amiodarone (Class III antiarrhythmic drug) is: - Hyperthyroidism - Photosensitivity - Pulmonary fi...

## MD2009-3 ### Page 7 of 14 43. The sodium/potassium ATPase is: - Activated by digoxin - Activated by levosimendan - Inhibited by digoxin - Inhibited by levosimendan 44. An important side effect of amiodarone (Class III antiarrhythmic drug) is: - Hyperthyroidism - Photosensitivity - Pulmonary fibrosis - Visual disturbances 45. Which drug when used topically in the treatment of chronic open-angle glaucoma reduces intraocular pressure by decreasing formation of the aqueous humour? - Pilocarpine - Lanaprost - Timolol - Verteporfin 46. A young patient with asthma has "aspirin sensitivity" and experiences severe bronchospasm to even small doses. What is the most likely explanation of this? - Induces formation of antibodies directed against the salicylate on airway mast cells - Induces hypersensitivity of airway smooth muscle to H1 receptors - Induces hypersensitivity of airway smooth muscle to muscarinic receptors - Shunting of arachidonic acid towards synthesis of leukotrienes 47. The mechanism of action of allopurinol is through - Binding to tubulin which prevents formation of microtubules and cell division - Enhanced metabolism of uric acid - Increased uric acid secretion as a consequence of inhibiting its reabsorption - Inhibition of xanthine oxidase 48. The mechanism of action for the pharmacological effect of metronidazole is: - Activation of glutamate-gated chloride channels - **Conversion to a cytotoxic compound by pyruvate:ferredoxin oxidoreductase** - Inhibition of dihydrofolate reductase - Inhibition of ẞ-tubulin polymerisation 49. What is the pharmacological target of erlotinib - EGFR (epidermal growth factor receptor) - PDGFR (platelet derived growth factor receptor) - Proteasome - VEGF (vascular endothelial growth factor) ### Page 6 of 14 34. Which of the following mediators derived from arachidonic acid is best described as anti-inflammatory - Prostaglandins - Isoprostanes - Leukotrienes - Lipoxins 35. Desmopressin is used to reduce bleeding in mild haemophilia A because of which of the following effects - Increases in vWF release - Inhibits vitamin K epoxide reductase - Inhibits factor Xa - Increases in tissue plasminogen activator (t-PA) release 36. You prescribe a bronchodilator which is known to have adrenergic side effects on the heart. Which clinical sign should you look out for in your patient ? - Bradypnea - Tachypnea - Bradycardia - Tachycardia 37. How does cocaine act as a peripheral sympathomimetic ? - Blockade of uptake 1 - Displacement of noradrenaline from storage vesicles - Inhibition of catechol-O-methyl transferase - Inhibition of vesicular monoamine transport 38. Volume of distribution equals - Dose given/plasma concentration - Total amount of drug in the body/plasma concentration - Urine drug concentration/plasma concentration - Dose given/urine concentration 39. The pharmacological target of ritonavir is: - HIV protease - HIV reverse transcriptase - HIV viral integration - Neuraminidase 40. Sucralfate is effective in peptic ulcer disease because it: - Binds to glycoproteins forming a protective cap over the ulcer - Decreases prostaglandin synthesis - Is toxic to Helicobacter pylori - Reduces gastric acid secretion from parietal cells 41. Which histamine receptor mediates dilation of post-capillary venules? - H1 - H2 - H3 - H4 42. What is the mechanism of action of Ondansetron ? - Block of 5-HT3 receptors in the chemoreceptor trigger zone - Block of D2 receptors in the chemoreceptor trigger zone - Block of H1 receptors in vestibular nuclei - Blockade of muscarinic receptors in the cerebellum ### Page 5 of 14 26. A phosphodiesterase 5 inhibitor has which of the following effects - Increases breakdown of cGMP - Increases blood pressure - Increases vasodilation - Increases vasoconstriction 27. Insulin-like growth factor 1 (IGF-1) mediates the peripheral action of which anterior pituitary hormone - Thyroid stimulating hormone - Growth hormone - Prolactin - Adrenocorticotropin hormone 28. Which of the following agents is most likely to exacerbate hypothyroidism in a patient - Levothyroxine - Liothyronine - Adrenaline - Carbimazole 29. Denosumab is best described as a - Parathyroid hormone analogue - Pyrophosphate analogue - RANK ligand inhibitor - Selective oestrogen receptor modulator 30. Prolonged systemic use of synthetic glucocorticoids can result in which of the following effects - Increased cortisol production - Increased risk opportunistic infections - Protection from osteoporosis - Weight loss 31. Aspirin inhibits the production of which platelet activator - ADP - Thromboxane - Prostacyclin - Fibrinogen 32. Which of the following antidotes can reverse the effects of warfarin - Flumazenil - Naloxone - Vitamin K - Glucagon 33. A competitive inhibitor of HMG-CoA reductase best describes the action for which of the following lipid lowering agents - Simvastatin - Gemfibrozil - Niacin - Ezetimibe ### Page 4 of 14 18. A mosquito when it feeds on human blood - Injects sporozoites into the blood stream thus starting the malaria cycle in the human host - Injects merozoites into the blood stream thus starting the malaria cycle in the human host - Results in some injected sporozoites developing into male and female forms called gametocytes - Allows the merozoites in the salivary glands to be injected into a human host 19. In general, when a drug becomes ionized - The Log P increases - The Log P remains unchanged - The Log P decreases - The Log P can either increase or decrease 20. The time-concentration plot for a drug - Is a straight line - Can only be drawn for acidic drugs - Provides useful data such as the elimination half life - Cannot be drawn for a drug given orally 21. An adverse drug reaction - Only occurs when the medicine is used at the wrong dose - Always has serious consequences for the patients - Can be traced back to the pharmacological profile of the medicine in the majority of cases - Rarely occurs in patients less than 65 years of age 22. The Health Products Regulatory Authority - Is the national medicines regulatory authority in Ireland - Is responsible for licensing all drugs currently on the market in Ireland - Evaluates medicines for human consumption only - Undertakes animal testing as part of its remit in licensing new medicines 23. Lisinopril inhibits which one of the following enzymes - Angiotensin converting enzyme - Renin enzyme - Carbonic anhydrase II - Carbonic anhydrase IV 24. Thiazide diuretics work by inhibiting which of the following transporters in the nephron - Na+/K+/2Cl - Na+/Cl - Na+/K+ ATPase - Na+/Ca²+ exchanger 25. Which one of the following best describes the mechanism of action of Verapamil - Calcium channel blocker - Potassium channel blocker - Endothelin receptor antagonist - Alpha 1 - adrenergic antagonist ### Page 3 of 14 10. Slow metabolisers of isoniazid are more likely to experience - Increased hepatotoxicity and neurotoxicity - Increased hepatotoxicity and decreased neurotoxicity - Decreased hepatotoxicity and increased neurotoxicity - Decreased hepatotoxicity and neurotoxicity 11. Metabolism by CYP2D6 - Activates codeine - Inactivates codeine - Activates warfarin - Inactivates warfarin 12. The enantiomer selectivity of a drug is least likely to be affected by - Receptor structure - Drug structure Drug lipid solubility - Drug transporter 13. Oestrogens, after the onset of menstruation - Require sustained low concentration for about 36 hours for FSH/LH surge to release ovum - During the follicular phase require a low concentration in order to stimulate Gn/GnRH release [from pituitary/hypothalamus] - Do not influence mucus secretion - Are not involved in preparing the uterus for implantation 14. Testosterone is synthesised mainly by - The interstitial cells of the testes - Dihydrotestosterone modifying gene transcription by interacting with extracellular receptors - Working through tetrahydrotestosterone - decreasing aggressiveness in males 15. Quinine - Is the chief alkaloid of willow bark - Is a potent blood schizonticidal with ability to kill all four species of the parasite - Has a strong effect on sporozoites in the host - Is very useful for prophylaxis and radical cure 16. Dihydrotestosterone modifies gene transcription by - Stimulating ovulation at mid-cycle - Interacting with intracellular receptors - Interacting strongly with oestrogen receptors - Increasing levels of gonadotropins 17. Tibolone is a synthetic steroid - That has no androgenic properties - That has no progestogenic properties - That has oestrogenic properties - That is used in the therapy of some aplastic anaemias ### Page 2 of 14 **Section A** 1. Peptide co-transmitters include - **Substance P** - Bradykinin - Angiotensin II - Dopamine 2. The lethal effect of anticholinesterase overdose is mainly due to - Excessive cardiac slowing - Excessive tissue oedema - Impaired breathing - **Impaired central nervous system function** 3. Acetylcholine - Promotes acetylcholine release via muscarinic M2 receptors - Inhibits acetylcholine release via muscarinic M2 receptors - **Promotes acetylcholine release via nicotinic muscle receptors** - Inhibits acetylcholine release via nicotinic muscle receptors 4. Anticholinesterases - Increase depolarising neuromuscular blockade - **Increase non-depolarising neuromuscular blockade** - Do not affect depolarising neuromuscular blockade - Do not affect non-depolarizing neuromuscular blockade 5. Tubocurare acts via - The acetylcholine binding site on nicotinic receptors - The ion channel part of nicotinic receptors - **Both (a) and (b)** - Neither (a) nor (b) 6. TD50 refers to the dose that causes - A therapeutic effect in 50% of people - **A toxic effect in 50% of people** - 50% maximum therapeutic response - 50% maximum toxic response 7. Ergotamine triggers - Vasodilation via 5-HT2 receptors - Vasodilation via a-adrenergic receptors - **Vasoconstriction via 5-HT2 receptors** - Vasoconstriction via a-adrenergic receptors 8. The effector domain of a drug receptor determines the drug's - Safety - **Receptor efficacy** - Receptor affinity - Metabolism 9. The maximum effect of an agonist is reduced by - Chemical antagonism - **Down-regulation of its receptor** - Competitive antagonists - Increasing its metabolism