Pharmacology Exam flashcards

All 98 cards

1. Card 1

   Define 'Pharmacology' and explain its primary goal.

   Pharmacology is the scientific study of drugs and their effects in living organisms. Its primary goal is to understand drug actions to predict both therapeutic effects and potential adverse effects, thereby informing safe and effective drug use.

2. Card 2

   Distinguish between 'Pharmacotherapeutics' and 'Toxicology'.

   Pharmacotherapeutics involves the use of drugs to prevent, treat, or manage disease, linking drug action to clinical practice and treatment outcomes. Toxicology, in contrast, is the study of the harmful effects of chemicals, including drugs, poisons, and environmental toxins, investigating mechanisms of toxicity and safety assessment.

3. Card 3

   What are the four phases of clinical development (SEAL) for a new drug, and what is the primary objective of each phase?

   The four phases are Safety (Phase I), Efficacy (Phase II), Approval (Phase III), and Long-term (Phase IV). Phase I focuses on safety in healthy individuals, Phase II assesses efficacy in patients with the condition, Phase III aims for approval by replicating exact settings in a larger group, and Phase IV collects post-market data.

4. Card 4

   Which Australian legislation provides federal control over the standards, manufacture, supply, and registration of all therapeutic goods?

   The Therapeutic Goods Act 1989 provides federal control over the standards, manufacture, supply, presentation, registration, and availability of all therapeutic goods in Australia, ensuring their safety, quality, and efficacy.

5. Card 5

   A new drug candidate has been identified as a possible therapeutic agent against a specific disease. What is the immediate next step in the drug discovery process?

   The immediate next step is Preclinical research, where the candidate compound is tested on cell cultures, animal models, and animals to assess its safety and efficacy before human trials.

6. Card 6

   Which of the following schedules under The Poisons Standard describes 'Pharmacy medicines'?

   A) Schedule 2. Schedule 2 specifically describes 'Pharmacy medicines', such as antihistamines, which are available from a pharmacy without a prescription.

7. Card 7

   A patient requires rapid relief for an acute, painful condition. Which oral formulation would be most suitable, and why?

   A gelatine capsule would be most suitable. The drug is in liquid form inside a soft gel capsule, allowing it to dissolve quickly in the stomach, leading to faster absorption and a rapid onset of action, which is ideal for acute pain relief.

8. Card 8

   Explain the concept of the 'hepatic first-pass effect' and its impact on drug bioavailability.

   The hepatic first-pass effect occurs when orally administered drugs are absorbed from the GI tract, enter the hepatic portal vein, and are extensively metabolized by the liver before reaching systemic circulation. This process significantly converts the drug into inactive metabolites, thereby reducing its bioavailability.

9. Card 9

   What is the primary advantage of the sublingual route of administration over the oral route regarding drug metabolism?

   The primary advantage of the sublingual route is that it bypasses first-pass metabolism. Drugs absorbed sublingually enter the systemic circulation directly, avoiding initial breakdown by the liver, which can lead to higher bioavailability and a more rapid onset of action compared to oral administration.

10. Card 10

    Which of the following routes of administration is generally preferred for drugs that need to maintain a sustained plasma concentration over a long period and avoid first-pass metabolism?

    C) Transdermal. The transdermal route, typically via an adhesive patch, allows for sustained drug release and absorption into the systemic circulation, effectively maintaining plasma concentrations and avoiding the hepatic first-pass effect.

11. Card 11

    A drug is formulated as an enteric-coated tablet. What is the characteristic of this formulation, and what is its purpose?

    An enteric-coated tablet has a special coating that resists stomach acid and dissolves only in the intestines. Its purpose is to delay absorption, bypass the stomach, and reduce gastric irritation or the risk of ulcers, making it suitable for chronic conditions requiring long-term treatment.

12. Card 12

    Why is the inhalation route of administration beneficial for respiratory drugs?

    The inhalation route is beneficial for respiratory drugs because it allows for rapid onset due to the large surface area and high blood flow in the lungs. It also localizes the drug to the target organ, minimizing systemic side effects and permitting lower doses to be used.

13. Card 13

    What is the difference between a drug's 'generic name' and its 'trade name'?

    The generic name is the common or general name assigned to the drug, often related to its chemical structure. The trade name (or brand name) is the proprietary name by which a pharmaceutical company identifies and markets its specific product.

14. Card 14

    Which of the following factors is NOT typically considered when determining the route of administration for a drug?

    C) The drug's original discovery date. Factors determining ROA include drug characteristics, type of use, patient condition, age, co-morbid diseases, and patient/doctor choice, but not the discovery date.

15. Card 15

    Why might the rectal route of administration be chosen over the oral route for certain patients?

    The rectal route can be chosen when oral administration is not possible, such as in patients who are unconscious, vomiting, or experiencing diarrhea. It also offers partial avoidance of the first-pass effect, providing both local and systemic effects.

16. Card 16

    What is the main disadvantage of dermal drug administration regarding systemic effects?

    The main disadvantage of dermal drug administration regarding systemic effects is its limited penetration. While it provides targeted local effects and minimizes systemic side effects, it is not ideal for achieving significant systemic drug levels due to poor absorption for many compounds.

17. Card 17

    A substance classified as Schedule 8 under The Poisons Standard is known as a 'Controlled Drug'. What implications does this classification have for its availability?

    A Schedule 8 'Controlled Drug' (e.g., Benzodiazepines) has strict controls on its availability. It is prescription-only and subject to additional regulations concerning prescribing, dispensing, storage, and record-keeping due to its potential for dependence or misuse.

18. Card 18

    What is the primary function of the 'Narcotic Drugs Act 1967' in Australia?

    The primary function of the Narcotic Drugs Act 1967 is to safeguard against the illegal manufacture, supply, and use of narcotic drugs in Australia, ensuring strict control over these substances to prevent diversion and abuse.

19. Card 19

    When considering drug classification, what are the three main categories used?

    The three main categories used for drug classification are therapeutic use (what it treats), mode of action (how it works in the body), and molecular structure (its chemical composition).

20. Card 20

    A drug is described as having a 'rapid onset' and being 'localised to the target organ for respiratory drugs'. Which route of administration is most likely being described?

    The inhalation route of administration is most likely being described. It offers a rapid onset due to the large surface area and high blood flow in the lungs, and it allows for localized delivery to the respiratory tract, minimizing systemic side effects.

21. Card 21

    Which of the following is an advantage of the oral route of administration?

    D) Cost-effective and convenient. The oral route is generally convenient, non-invasive, self-administered, suitable for long-term use, and cost-effective, despite its slower onset and susceptibility to first-pass metabolism.

22. Card 22

    Why is patient compliance required for buccal drug administration?

    Patient compliance is required for buccal drug administration because the drug needs to remain in place in the buccal cavity until absorbed. If the patient swallows the drug prematurely, its absorption characteristics and effectiveness may be altered, potentially leading to reduced efficacy or increased first-pass metabolism.

23. Card 23

    What is the main disadvantage of transdermal drug administration regarding the speed of effect?

    The main disadvantage of transdermal drug administration regarding the speed of effect is its slow onset. While it provides sustained release, the drug must first penetrate the skin layers to reach systemic circulation, which is a gradual process.

24. Card 24

    A substance like MDMA is listed under Schedule 9 of The Poisons Standard. What does 'Prohibited Substance' imply about its use and availability?

    A 'Prohibited Substance' under Schedule 9 implies that its manufacture, possession, sale, or use is prohibited except for approved research or legitimate medical purposes under very strict controls. It has no recognized therapeutic use and a high potential for abuse.

25. Card 25

    What is the role of the TGA (Therapeutic Goods Administration) in Australia?

    The TGA regulates all therapeutic goods in Australia, which includes medicines, medical devices, and other health-related products. Its role is to ensure that these goods are safe, of high quality, and effective for their intended purpose before they can be supplied to the public.

26. Card 26

    What are the key advantages of the inhaled route of administration for respiratory drugs?

    The inhaled route offers rapid onset due to the large surface area and high blood flow in the lungs. It allows for localized drug delivery to the target organ, minimizing systemic side effects and enabling lower doses. Additionally, dose regulation is possible, and effects can be terminated rapidly.

27. Card 27

    Distinguish between a gelatine capsule and an enteric-coated tablet in terms of their absorption characteristics and typical purpose.

    A gelatine capsule contains the drug in liquid form, leading to fast dissolution in the stomach and rapid absorption, typically used for acute, painful conditions. An enteric-coated tablet has a special coating that resists stomach acid, dissolving only in the intestines, resulting in delayed absorption and is used for chronic conditions to reduce gastric irritation.

28. Card 28

    Explain the concept of the hepatic first-pass effect and its significance for orally administered drugs.

    The hepatic first-pass effect describes the metabolism of orally administered drugs by the liver before they reach systemic circulation. Drugs absorbed from the GI tract enter the hepatic portal vein and are extensively converted to inactive metabolites in the liver, significantly reducing their bioavailability. This often necessitates higher oral doses or makes some drugs unsuitable for oral use.

29. Card 29

    Which of the following is NOT a characteristic of the sublingual route of administration? A) Rapid onset of action B) Bypasses first-pass metabolism C) Suitable for irritant and lipid-insoluble drugs D) Action can be terminated by spitting out the drug

    C) Suitable for irritant and lipid-insoluble drugs. The sublingual route is not suitable for irritant and lipid-insoluble drugs, as these can cause local irritation or be poorly absorbed.

30. Card 30

    Why is the intravenous (IV) route of administration considered to have 100% bioavailability?

    The intravenous route delivers the drug directly into the bloodstream, bypassing any absorption phases. This means that the entire administered dose immediately enters the systemic circulation in an unchanged form, resulting in 100% bioavailability.

31. Card 31

    A patient requires rapid relief for an acute condition but cannot swallow. Which oral formulation would be most appropriate, and why?

    While the patient cannot swallow, if an oral formulation were considered, a gelatine capsule would be most appropriate for rapid relief if they could somehow take it, as the liquid formulation dissolves quickly for faster absorption. However, if swallowing is impossible, other non-oral rapid routes like sublingual or IV would be preferred.

32. Card 32

    How does the pH of the environment affect the absorption of weak acid and weak base drugs across cell membranes?

    Changes in pH alter the proportion of a drug that is non-ionised, which is the form that can easily cross lipid-rich cell membranes. Weak acids are less ionised in low pH environments, favoring their absorption, while weak bases are less ionised in high pH environments, promoting their absorption.

33. Card 33

    Define 'bioavailability' and explain its relationship to routes of administration that bypass the liver.

    Bioavailability refers to the fraction of an administered drug that enters the systemic circulation unchanged. Routes that bypass the liver, such as sublingual, buccal, or intravenous, avoid first-pass metabolism, thereby increasing the drug's bioavailability and often reducing the required dose compared to oral administration.

34. Card 34

    What is 'ion trapping' and how does it relate to drug movement within the body?

    Ion trapping occurs when a drug moves from one environment to another with a different pH, causing it to become more ionised. Once ionised, the drug becomes more water-soluble and less able to cross lipid-rich membranes, effectively 'trapping' it in that compartment and hindering its further movement or reabsorption.

35. Card 35

    Which of the following factors would generally lead to slower absorption of a drug administered via the subcutaneous route? A) Increased blood flow to the injection site B) Higher temperature at the injection site C) Shock or low perfusion states D) A highly lipid-soluble drug formulation

    C) Shock or low perfusion states. Subcutaneous absorption is dependent on blood flow; in states of shock or low perfusion, blood flow to the subcutaneous tissue is reduced, leading to slower absorption.

36. Card 36

    Explain how plasma protein binding (PPB) influences a drug's availability for action, metabolism, and excretion.

    Only the free (unbound) fraction of a drug is available to exert its pharmacological action, be metabolized, or excreted. Drugs bound to plasma proteins act as a reservoir; as free drug concentration decreases, bound drug is released, thus prolonging the drug's half-life and duration of action.

37. Card 37

    A drug has a high volume of distribution (>40L). What does this indicate about its presence in the body, and what are the implications for its loading dose and half-life?

    A high volume of distribution indicates that the drug has a high concentration in the extracellular tissues, meaning most of the drug has left the plasma compartment. This implies that a larger loading dose will be required to achieve therapeutic concentrations in the plasma, and it also suggests a longer half-life because the drug is widely distributed and slowly released back into circulation.

38. Card 38

    Why are some drugs unsuitable for oral use despite the convenience of this route?

    Some drugs are unsuitable for oral use due to several factors, including destruction by stomach acid, extensive hepatic first-pass metabolism reducing bioavailability, unpalatability, or high irritancy to the GI tract. Additionally, oral administration is not feasible for unconscious or uncooperative patients, or those experiencing vomiting or diarrhea.

39. Card 39

    What is the primary advantage of the intraosseous route of administration, and when is it typically utilized?

    The primary advantage of the intraosseous route is its rapid and reliable access to systemic circulation, providing an onset comparable to IV administration. It is typically utilized in emergencies when intravenous access is difficult or delayed, serving as a life-saving alternative.

40. Card 40

    How does molecular weight affect a drug's ability to cross cell membranes?

    Molecular weight inversely affects a drug's ability to cross cell membranes. Smaller molecules cross cell membranes more easily, often via passive diffusion, whereas larger drugs cross very slowly or not at all, frequently requiring specialized transport mechanisms due to the densely packed nature of the plasma membrane.

41. Card 41

    A patient is on a drug with high plasma protein binding. If a second drug that also has high plasma protein binding is co-administered, what potential clinical consequence might arise?

    If a second drug with high plasma protein binding is co-administered, it may compete for the same protein binding sites. This competition can displace the first drug from its binding sites, leading to an increase in the amount of free (unbound) drug in the plasma, which could potentially increase its pharmacological effect and risk of toxicity.

42. Card 42

    Explain the role of lipid solubility in a drug's ability to cross cell membranes and its distribution within the body.

    Lipid solubility is crucial for drug transfer across cell membranes; the more lipid-soluble a drug is, the more easily it can diffuse through the lipid-rich phospholipid bilayer. In terms of distribution, highly lipid-soluble drugs tend to be taken up and stored in body fat stores, while water-soluble drugs remain predominantly in the blood/plasma.

43. Card 43

    What are the characteristics of an intramuscular (IM) injection that make it suitable for depot formulations?

    Intramuscular injections are suitable for depot (long-acting) formulations because the drug is injected into skeletal muscle and absorbed via the local blood supply. The moderate onset of action and the ability to formulate drugs to be slowly released from the muscle tissue allow for sustained absorption over an extended period.

44. Card 44

    Why is patient compliance a significant factor for the buccal route of administration?

    Patient compliance is significant for the buccal route because the drug must be held in the buccal pouch until it dissolves and is absorbed. If the patient swallows the drug prematurely, it may be subjected to first-pass metabolism, reducing its effectiveness and altering its intended absorption profile.

45. Card 45

    A drug has a low volume of distribution (3-10L). What does this imply about its location in the body, and how does it affect the loading dose calculation?

    A low volume of distribution implies that the drug remains predominantly in the plasma compartment, with limited distribution into extracellular tissues. This means that a smaller loading dose will typically be required to achieve therapeutic concentrations in the plasma, as less drug is needed to fill other body compartments.

46. Card 46

    What is the main disadvantage of the oral route of administration concerning emergency situations?

    The main disadvantage of the oral route for emergency situations is its slow onset of action. The drug must first be swallowed, dissolve, and then be absorbed via the GI tract, which takes time, making it unsuitable for conditions requiring immediate therapeutic effects.

47. Card 47

    How does renal failure potentially affect the plasma free drug concentration of highly plasma protein-bound drugs?

    Renal failure can lead to a decrease in the number of plasma proteins, such as albumin, due to impaired synthesis or increased loss. This reduction in available binding sites means that a larger proportion of a highly plasma protein-bound drug will remain in its free, unbound form, potentially increasing its plasma free drug concentration and the risk of toxicity.

48. Card 48

    Which of the following is a disadvantage of the inhaled route of administration? A) Rapid onset B) Localized to target organ C) Can cause local irritation D) Dose regulation is possible

    C) Can cause local irritation. While the inhaled route has many advantages, a potential disadvantage is that the drug or its formulation can cause local irritation in the respiratory tract.

49. Card 49

    What is the primary difference in absorption between sublingual and buccal routes, and how does this affect their onset of action?

    Both sublingual and buccal routes involve absorption through the oral mucosa, bypassing first-pass metabolism. However, the sublingual route generally offers a more rapid onset of action because the drug is placed under the tongue where the mucosa is thinner and highly vascularized, allowing for faster absorption compared to the buccal route where absorption is typically slower and more sustained.

50. Card 50

    Explain the concept of 'ion trapping' in drug distribution.

    Ion trapping occurs when a drug moves from one environment to another with a different pH. In the new environment, the drug may become more ionized (charged). Since ionized drugs are more water-soluble and cross lipid-rich membranes poorly, they become 'trapped' in that compartment, unable to easily diffuse back.

51. Card 51

    DEFINITION: Define the term 'Volume of Distribution' (Vd) and explain its primary role in pharmacokinetics.

    Volume of Distribution (Vd) is a pharmacokinetic parameter that indicates how much of the total body drug has been retained in the plasma versus how much has been distributed into other tissue compartments. Its primary role is to help determine the correct loading dose for a drug; a higher Vd typically requires a larger loading dose because more of the drug leaves the plasma to enter tissues.

52. Card 52

    Which of the following factors would lead to an increased amount of free drug in the plasma, potentially increasing toxicity?

    A) Increased plasma protein levels B) Decreased affinity of the drug for plasma proteins C) Co-administration of a drug that competes for the same protein binding sites D) Decreased body fat percentage C) Co-administration of a drug that competes for the same protein binding sites. This competition can displace the original drug from its binding sites, increasing its free concentration in the plasma and potentially leading to enhanced effects or toxicity.

53. Card 53

    How does the lipid solubility of a drug influence its distribution within the body?

    Lipid solubility significantly impacts drug distribution. Water-soluble drugs tend to remain predominantly in the blood and plasma, while lipid-soluble drugs are more readily taken up and stored in body fat stores. Furthermore, non-ionized (uncharged) drugs, which are more lipid-soluble, cross lipid-rich membranes more easily, facilitating broader distribution.

54. Card 54

    DEFINITION: What is the Blood Brain Barrier (BBB) and what characteristic allows drugs to cross it?

    The Blood Brain Barrier (BBB) is a protective barrier formed by specialized endothelial cells between capillaries and brain tissue, safeguarding the brain from noxious substances. Only highly lipophilic drugs or those actively transported can effectively pass into the Central Nervous System (CNS) through this barrier.

55. Card 55

    A drug with a high volume of distribution (>40L) would typically exhibit which of the following characteristics?

    A) It remains predominantly in the plasma. B) It has a high concentration in the extracellular tissue. C) It requires a smaller loading dose. D) It has a shorter half-life. B) It has a high concentration in the extracellular tissue. A high Vd indicates that a significant portion of the drug has left the plasma and distributed into other body compartments, such as extracellular tissues.

56. Card 56

    Explain how plasma protein binding can influence a drug's duration of action.

    Plasma protein binding can significantly increase a drug's duration of action. Bound drugs act as a reservoir; only the free, unbound drug is available for action, metabolism, and excretion. As free drug concentration decreases, bound drug is released, effectively prolonging the drug's presence and therapeutic effect in the body.

57. Card 57

    DEFINITION: What is a 'prodrug' and what is one advantage of using a prodrug?

    A prodrug is an inactive drug that is converted into an active metabolite within the body through metabolism. One advantage of using a prodrug is increased bioavailability, as it may be designed to be absorbed more efficiently before being converted to its active form.

58. Card 58

    Which phase of metabolism primarily involves chemical alteration of the drug by oxidation, reduction, or hydrolysis to increase water-solubility?

    A) Phase I B) Phase II C) Phase III D) Phase IV A) Phase I. Phase I reactions are characterized by chemical alterations such as oxidation, reduction, or hydrolysis, which aim to increase the drug's water-solubility, often making it more amenable to subsequent Phase II reactions.

59. Card 59

    Why is it important for metabolism to convert lipid-soluble drugs into water-soluble, ionized drugs?

    It is important for metabolism to convert lipid-soluble, unionized drugs into water-soluble, ionized drugs because water-soluble, ionized drugs are not readily reabsorbed by the kidneys. This conversion facilitates their excretion from the body, preventing accumulation and potential toxicity.

60. Card 60

    DEFINITION: Distinguish between the effects of H1 and H2 histamine receptors in the body.

    H1 receptors are primarily associated with allergic responses, mediating effects like decreased blood pressure, bronchial constriction, intestinal contraction, skin capillary dilation (redness, wheal), and itching. H2 receptors are mainly involved in stomach ulcers, increasing gastric acid secretion and heart rate, and also contributing to decreased blood pressure.

61. Card 61

    Which of the following is a characteristic of first-generation antihistamines but not typically of second- and third-generation antihistamines?

    A) Minimal CNS penetration B) More selective for peripheral H1 receptors C) Causes sedation and anticholinergic effects D) Less lipid-soluble C) Causes sedation and anticholinergic effects. First-generation antihistamines are lipid-soluble and cross the BBB, blocking H1 receptors in the CNS, which leads to sedation and anticholinergic effects. Second and third generations are less lipid-soluble and have minimal CNS penetration.

62. Card 62

    Explain how corticosteroids work to treat asthma.

    Corticosteroids treat asthma by interfering with the inflammatory response. They inhibit the activity of inflammatory cells, reduce the release of mediators from mast cells, decrease the production of allergic antibodies, and lessen oedema, among other anti-inflammatory actions. This broad anti-inflammatory effect helps to reduce airway hyperreactivity and obstruction.

63. Card 63

    DEFINITION: What is the mechanism of action for leukotriene receptor antagonists in treating asthma?

    Leukotriene receptor antagonists, such as montelukast, work by inhibiting leukotriene receptors. This action prevents the effects of leukotrienes, which include bronchoconstriction, airway inflammation, and increased mucus secretion, thereby alleviating asthma symptoms.

64. Card 64

    A patient experiencing an acute asthma exacerbation would most likely be prescribed which type of drug as a 'reliever'?

    A) Corticosteroid B) Leukotriene receptor antagonist C) Beta 2 agonist D) Mast cell stabilizer C) Beta 2 agonist. Beta 2 agonists are bronchodilators, which are categorized as 'relievers' for asthma due to their rapid action in stimulating beta 2 receptors in bronchial smooth muscle, leading to bronchodilation and immediate relief of symptoms.

65. Card 65

    How does the vascularity of a tissue affect drug distribution to that area?

    The vascularity of a tissue directly affects drug distribution. Drug delivery to an area is proportional to its blood flow; higher blood flow to a particular tissue or organ results in greater drug delivery to that area, facilitating more rapid and extensive distribution.

66. Card 66

    DEFINITION: What is the clinical significance of a drug having a high plasma protein binding (PPB) affinity regarding its half-life?

    A drug with a high plasma protein binding (PPB) affinity will typically have an increased half-life and, consequently, a longer duration of action. This is because the bound drug acts as a reservoir, slowly releasing free drug as it is metabolized or excreted, thus prolonging its presence in the systemic circulation.

67. Card 67

    Which of the following is a potential consequence of drug metabolism?

    A) Conversion of an active drug to a less potent active drug. B) Conversion of an active drug to one or more inactive metabolites. C) Conversion of an inactive drug to a more toxic prodrug. D) Conversion of a lipid-soluble drug to a more lipid-soluble drug. B) Conversion of an active drug to one or more inactive metabolites. This is one of the primary consequences of metabolism, aiming to inactivate drugs and prepare them for excretion. Other consequences include active to active, inactive to active (prodrug), and active to toxic metabolites.

68. Card 68

    Explain why renal failure might increase the amount of free drug in the plasma for highly protein-bound drugs.

    Renal failure may lead to a decrease in the number of plasma proteins available for drug binding. With fewer binding sites, a larger proportion of the drug remains unbound in the plasma, increasing the plasma free drug concentration. This can potentially lead to enhanced pharmacological effects or increased toxicity.

69. Card 69

    DEFINITION: What is the primary difference in the mechanism of action between antihistamines (H1 antagonists) and antiallergic agents (mast cell stabilizers)?

    Antihistamines (H1 antagonists) work by blocking the binding of histamine to H1 receptors after histamine has already been released from mast cells. In contrast, antiallergic agents (mast cell stabilizers) act prophylactically by inhibiting the release of histamine and other mediators from mast cells, thus preventing the allergic response from initiating.

70. Card 70

    Which of the following adverse effects is commonly associated with Beta 2 agonists used for asthma treatment?

    A) Constipation B) Hypotension C) Tremors D) Weight gain C) Tremors. Beta 2 agonists can cause adverse effects such as restlessness, anxiety, hypokalemia, tremors, and arrhythmias due to their systemic sympathetic stimulation, even when selective.

71. Card 71

    How do anticholinergic/muscarinic antagonists work as bronchodilators in asthma treatment?

    Anticholinergic/muscarinic antagonists, such as ipratropium bromide, act as bronchodilators by blocking the action of acetylcholine (ACh) at muscarinic (M3) receptors in the bronchial smooth muscle. This blockade prevents ACh-induced bronchoconstriction, leading to airway relaxation and widening. They also decrease the volume of respiratory secretions.

72. Card 72

    DEFINITION: What is the main function of fibrinolytics/thrombolytic drugs, and how does urokinase achieve this?

    The main function of fibrinolytics/thrombolytic drugs is to break down existing thrombi (blood clots), rather than preventing their formation. Urokinase achieves this by acting as an enzyme found naturally in human urine, converting plasminogen to plasmin, which then directly dissolves the clot.

73. Card 73

    Which of the following is an advantage of using a prodrug?

    A) Decreased duration of action B) Reduced bioavailability C) Enhanced taste D) Increased toxicity C) Enhanced taste. Advantages of prodrugs include increased bioavailability, increased duration of action, enhanced taste, and site-specific drug delivery, not reduced bioavailability or increased toxicity.

74. Card 74

    Why might chronic use of Beta 2 agonists lead to a decrease in their effectiveness over time?

    Chronic use of Beta 2 agonists can lead to a decrease in their effectiveness over time due to down-regulation of beta 2 receptors. Prolonged exposure to the agonist can cause the cells to reduce the number of available receptors on their surface, making them less responsive to the drug and diminishing its bronchodilatory effects.

75. Card 75

    Explain how Beta 2 agonists like salbutamol achieve bronchodilation and reduce inflammatory mediators in asthma.

    Beta 2 agonists stimulate beta 2 receptors in bronchial smooth muscle, which activates adenylate cyclase and increases cyclic AMP (cAMP). This rise in cAMP leads to bronchodilation. Additionally, increased cAMP in mast cells causes a reduction in the release of inflammatory mediators, further contributing to asthma relief.

76. Card 76

    Which of the following is a common adverse effect associated with the use of anticholinergic/muscarinic antagonist bronchodilators like ipratropium bromide?

    B) Dry mouth. Anticholinergic agents block the action of acetylcholine, which can lead to reduced respiratory secretions and common anticholinergic side effects such as dry mouth and urinary retention.

77. Card 77

    DEFINITION: Distinguish between 'reliever' and 'preventer' drugs in the context of asthma treatment.

    Reliever drugs are bronchodilators used for immediate relief of asthma symptoms by opening up the airways during an acute attack. Preventer drugs, on the other hand, are anti-inflammatory agents, mast cell stabilizers, or other long-term control medications used prophylactically to reduce airway inflammation and hyperreactivity, thereby preventing future asthma attacks.

78. Card 78

    How do methylxanthines like aminophylline exert their therapeutic effects in asthma, and what are some of their notable adverse effects?

    Methylxanthines inhibit the phosphodiesterase enzyme, leading to increased cAMP levels, which results in bronchodilation and a reduction in inflammatory mediators. They also antagonize adenosine, a potent bronchoconstrictor. However, their adverse effects can include nausea, vomiting, flushing, vasodilation, and hypotension, as their actions are not limited to the airways.

79. Card 79

    A patient with asthma is prescribed fluticasone. What class of drug is this, and what is its primary mechanism of action in managing asthma?

    Fluticasone is a corticosteroid. Its primary mechanism of action is to inhibit the activity of inflammatory cells, reduce the release of mediators from mast cells, decrease the production of allergic antibodies, and alleviate oedema, among other anti-inflammatory actions, thereby reducing airway inflammation.

80. Card 80

    DEFINITION: Define 'selective toxicity' in the context of antimicrobial agents and provide an example of how it is achieved.

    Selective toxicity is the ability of an antimicrobial agent to harm a microorganism or pathogen without significantly harming the host. This is achieved by exploiting biochemical differences between microbial and human cells, such as targeting the bacterial cell wall (peptidoglycan), which is absent in human cells.

81. Card 81

    Which of the following bacterial structures is a prime drug target for antibiotics due to its absence in human cells?

    C) Peptidoglycan cell wall. Bacteria have peptidoglycan cell walls, which are entirely absent in human cells, making them an excellent and selectively toxic drug target for antibiotics.

82. Card 82

    Explain why Gram-negative bacteria often require broader antibiotic coverage compared to Gram-positive bacteria.

    Gram-negative bacteria possess a thin peptidoglycan cell wall and an outer lipid membrane. This outer membrane acts as a barrier to many drugs, making them inherently less susceptible to certain antibiotics and often necessitating broader-spectrum agents to effectively penetrate this protective layer.

83. Card 83

    DEFINITION: What is the difference between a 'bacteriostatic' and a 'bactericidal' antibiotic? Provide an example of each.

    Bacteriostatic antibiotics inhibit bacterial growth, allowing the host immune system to clear the bacteria (e.g., tetracyclines). Bactericidal antibiotics, conversely, directly kill bacteria (e.g., penicillins).

84. Card 84

    Describe two distinct mechanisms by which antibiotics inhibit bacterial growth or kill bacteria.

    Antibiotics can inhibit cell wall synthesis by blocking peptidoglycan cross-linking, causing bacteria to burst from osmotic lysis. Alternatively, they can inhibit protein synthesis by targeting bacterial ribosome subunits, thereby preventing the production of essential proteins.

85. Card 85

    A patient develops a superinfection after prolonged use of a broad-spectrum antibiotic. Explain the underlying reason for this occurrence.

    Superinfections occur because broad-spectrum antibiotics disrupt the normal flora of the body, which typically keeps opportunistic pathogens in check. When these non-resistant beneficial bacteria are killed, drug-resistant pathogens can proliferate unchecked, leading to a new infection.

86. Card 86

    Which of the following is NOT a mechanism by which bacteria develop resistance to antibiotics?

    D) Increasing the production of the antibiotic's target protein. While bacteria can change their antibiotic targets, the source notes do not mention increasing the production of the target protein as a mechanism of resistance.

87. Card 87

    How does the mechanism of action of leukotriene receptor antagonists like montelukast differ from that of corticosteroids in treating asthma?

    Leukotriene receptor antagonists specifically inhibit leukotriene receptors, preventing the actions of leukotrienes such as bronchoconstriction, airway inflammation, and increased mucus secretion. Corticosteroids, in contrast, have a broader anti-inflammatory effect, inhibiting various inflammatory cells and mediators, and reducing oedema.

88. Card 88

    DEFINITION: What is the role of cromolyn sodium in asthma management, and what is its primary mechanism of action?

    Cromolyn sodium is a mast cell stabilizer used as a preventer in asthma management. Its primary mechanism of action is to interfere with the degranulation of mast cells, thereby reducing the release of inflammatory mediators from these cells.

89. Card 89

    Explain how Omalizumab (Xolair) works to reduce the severity and frequency of asthma attacks.

    Omalizumab is a monoclonal antibody that specifically binds to and inactivates IgE. By reducing the amount of free IgE, it diminishes the immune system's response to allergen exposure, which is a key trigger for asthma attacks, thereby reducing their severity and frequency.

90. Card 90

    A doctor is considering prescribing a broad-spectrum antibiotic. Under what specific circumstances would the use of a broad-spectrum antibiotic be justified?

    Broad-spectrum antibiotic use is justified in situations such as when the pathogen is unknown (e.g., in an emergency like sepsis), when there is a mixed infection, or when initial narrow-spectrum therapy has failed. It may also be used prophylactically in specific high-risk scenarios.

91. Card 91

    Describe how the structural differences between human and bacterial ribosomes are exploited by antibiotics to achieve selective toxicity.

    Antibiotics exploit the structural differences between human and bacterial ribosomes by selectively binding to and interfering with the function of bacterial ribosomes. This inhibits bacterial protein synthesis without significantly affecting human protein synthesis, thus achieving selective toxicity.

92. Card 92

    DEFINITION: What is the significance of the outer lipid membrane in Gram-negative bacteria regarding antibiotic treatment?

    The outer lipid membrane in Gram-negative bacteria acts as a significant barrier to many drugs. This structural feature makes Gram-negative bacteria generally more resistant to certain antibiotics, often requiring different drug choices or broader-spectrum agents for effective treatment.

93. Card 93

    How do sulfonamides achieve their antibacterial effect, and what biochemical difference do they exploit between human and bacterial cells?

    Sulfonamides inhibit bacterial growth by blocking the synthesis of folate, a nutrient essential for making DNA. They exploit the biochemical difference that humans acquire folate from their diet, while bacteria must synthesize it themselves, making the bacterial folate synthesis pathway a selective drug target.

94. Card 94

    Which route of administration (ROA) is common for both antiallergic agents (mast cell stabilizers) and some bronchodilators?

    B) Oral. Both antiallergic agents (mast cell stabilizers) and certain bronchodilators can be administered orally, as well as via other routes like intranasal or intraocular for antiallergics, and inhalation for bronchodilators.

95. Card 95

    A patient is prescribed an antibiotic for a confirmed bacterial infection. Why is a narrow-spectrum antibiotic generally preferred over a broad-spectrum one if the pathogen is identified?

    A narrow-spectrum antibiotic is preferred when the pathogen is identified because it targets a limited range of bacteria, reducing the risk of antibiotic resistance development and minimizing disruption to the patient's normal flora. This helps prevent superinfections and preserves the efficacy of broader-spectrum drugs for when they are truly needed.

96. Card 96

    What is the primary mechanism by which fluoroquinolones inhibit bacterial growth, and what bacterial enzyme do they target?

    Fluoroquinolones inhibit bacterial growth by blocking enzymes that unwind DNA, specifically bacterial DNA gyrase (a type II topoisomerase). This prevents bacteria from replicating or repairing their genome, leading to their death and making them bactericidal.

97. Card 97

    DEFINITION: What are 'anti-IgE antibodies' in the context of asthma treatment, and what is their main therapeutic goal?

    Anti-IgE antibodies, such as Omalizumab, are monoclonal antibodies that bind to and inactivate IgE. Their main therapeutic goal is to reduce the immune system's response to allergen exposure, thereby decreasing the severity and frequency of asthma attacks by targeting a key mediator of allergic reactions.

98. Card 98

    Explain how the chronic use of Beta 2 agonists can lead to a reduction in their effectiveness.

    Chronic use of Beta 2 agonists can lead to down-regulation of beta 2 receptors. This means that the cells become less responsive to the drug over time, requiring higher doses for the same effect or leading to a diminished therapeutic response, a phenomenon known as tachyphylaxis or tolerance.

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