WorksheetsTopic Overview: Autocoids and Related Drugs
Total questions: 30
Worksheet time: 15mins
Recall the categorization of inflammatory mediators: Which group consists of mediators stored and formed in cells? Choose the best answer based on the listed examples.
Bradykinin, Kallidin, Angiotensin
Histamine, 5-HT (Hydroxy Tryptamine), Substance P, VIP (Vasoactive Intestinal Peptide)
Prostaglandins, Leukotrienes, PAF (Platelet Activating Factor)
Which set of inflammatory mediators is derived from precursor molecules in cell membrane phospholipids?
Histamine, 5-HT (Hydroxy Tryptamine), Substance P, VIP
Prostaglandins, Leukotrienes, Platelet Activating Factor (PAF)
Bradykinin, Kallidin, Angiotensin
Recall: Which statement best describes how histamine is formed in the body?
Decarboxylation of histidine via histidine decarboxylase
Oxidation of tyrosine via monoamine oxidase
Phosphorylation of serine by protein kinase A
Hydrolysis of arginine by nitric oxide synthase
Apply: A patient develops a drug-induced allergic reaction after receiving penicillin. According to the mechanism described, what process most directly explains the rapid release of histamine in this scenario?
Drug-triggered calcium release driving mast cell exocytosis
Direct inhibition of histidine decarboxylase preventing histamine synthesis
Binding of histamine to heparin reducing bioavailability
Suppression of IgE production in basophils
Reason: A wheal-and-flare reaction appears after a skin allergen test. Based on the histamine triple response, which sequence of effects most plausibly produces the observed signs?
Vessel dilatation causing redness, plasma extravasation producing edema, and tissue swelling
Bronchoconstriction causing wheeze, cardiac vasodilation increasing heart rate, and CNS activation leading pruritus
Smooth muscle relaxation reducing blood pressure, gastric acid suppression, and nerve blockade
Heparin displacement preventing histamine binding, decreased calcium influx, and reduced neurotransmission
Apply: An antihistamine is described as a competitive inhibitor at histamine receptors. Which consequence best follows from this mechanism during an allergic reaction?
Reduced interaction between histamine and its receptors, attenuating receptor-mediated effects
Irreversible inactivation of histidine decarboxylase, stopping histamine synthesis
Direct neutralization of circulating IgE, preventing mast cell activation
Enhanced calcium release from mast cells, increasing histamine exocytosis
Recall the receptor targets of histamine described in the material. Which statement is accurate?
Histamine acts only on H1 receptors of target cells
Histamine acts on H1 and H2 target cell receptors
Histamine acts primarily on β2 adrenergic receptors
Histamine acts exclusively on muscarinic receptors
Identify the correct pairing of histamine receptor subtype with the listed agonist based on the text.
H1 agonist: betazole; H2 agonist: methyl-histamine
H1 agonist: methyl-histamine; H2 agonist: betazole
H1 agonist: atropine; H2 agonist: epinephrine
H1 agonist: cimetidine; H2 agonist: ranitidine
Select the classification that correctly matches each drug group with examples from the content.
H1 blockers: metiamide, cimetidine, ranitidine; H2 blockers: antazoline, diphenhydramine
Sympathomimetics: antazoline, chlorpheniramine; H1 blockers: epinephrine, norepinephrine
H1 blockers: antazoline, diphenhydramine, mepyramine maleate, chlorpheniramine maleate (CTM), promethazine HCl, tripelennamine HCl; H2 blockers: metiamide, cimetidine, ranitidine
Histamine release inhibition: epinephrine; Classic antihistamines: Na-cromoglycate
A patient seeks an over-the-counter product for nasal congestion and allergic symptoms. According to the mechanism and advised usage provided, which choice best aligns with recommended practice?
Use a systemic H1 antagonist combined with a β2 agonist; systemic route is preferred over topical
Use topical agents containing H1 receptor antagonists and α1 adrenergic receptor agonists; topical application is generally preferred
Use H2 receptor antagonists to reduce capillary permeability; choose oral tablets for faster onset
Avoid agents that block histamine effects; vasodilation helps reduce exudate volume
Recall: Which receptor subtype is primarily targeted by first-generation antihistamines used for allergic rhinitis and urticaria?
H1 receptors
H2 receptors
H3 receptors
H4 receptors
Skill/Concept: A patient with nighttime itching is prescribed diphenhydramine. Which mechanism best explains both symptom relief and drowsiness with this drug?
Peripheral H1 receptor antagonism plus central muscarinic receptor blockade
Central H1 receptor antagonism with high blood–brain barrier penetration
Selective H2 receptor antagonism reducing gastric acid and CNS histamine
Partial agonism at H1 receptors increasing histamine release
Strategic Thinking: A patient with peptic ulcer disease requires reduced gastric acid secretion. Which antihistamine class and representative drug would be most appropriate?
H1 antagonists; chlorpheniramine
H2 antagonists; ranitidine or famotidine
H1 antagonists; cetirizine
H3 antagonists; cimetidine
Recall: In the diagram titled “Angiotensin and the Renin-Angiotensin System,” which immediate hormonal effect is triggered by angiotensin II that contributes to blood pressure regulation?
Stimulation of aldosterone secretion from the adrenal cortex
Suppression of renin release from the juxtaglomerular cells
Inhibition of antidiuretic hormone (ADH) release from the pituitary
Activation of atrial natriuretic peptide (ANP) release
Application: Based on the RAS schematic, which therapy most directly reduces angiotensin II–mediated vasoconstriction by blocking its formation?
ACE inhibitors that prevent conversion of angiotensin I to angiotensin II
Beta-blockers that reduce sympathetic tone at the heart
Aldosterone antagonists that block mineralocorticoid receptors
Loop diuretics that inhibit sodium reabsorption in the thick ascending limb
Strategic thinking: A patient has high blood pressure and elevated aldosterone. Using the RAS diagram, which intervention best targets the mechanism driving both findings?
Administer an ACE inhibitor to lower angiotensin II, reducing vasoconstriction and aldosterone secretion
Give a direct vasodilator to relax arterioles without changing aldosterone
Start a thiazide diuretic to increase sodium excretion independently of RAS
Provide an alpha-1 blocker to reduce peripheral resistance without affecting hormones
Examine the arachidonic acid pathway diagram. Which product downstream of COX-1/COX-2 contributes to inflammation and pain while also playing a role in gastroprotection?
Prostaglandins generated from PGH2.
Leukotriene B4 from the 5-LOX pathway.
Cysteinyl leukotrienes from the 5-LOX pathway.
Thromboxanes derived directly from phospholipase A2 action.
Recall: Which adenylyl compound is administered intravenously to acutely terminate certain supraventricular tachyarrhythmias by transiently blocking AV nodal conduction?
Adenosine
Adenosine triphosphate (ATP)
Adenosine diphosphate (ADP)
Strategic Thinking: A patient on antiplatelet therapy shows exaggerated bleeding after a drug that modulates purinergic pathways is added. Which mechanism best explains the interaction?
Exogenous ATP enhances platelet aggregation through conversion to ADP, reinforcing P2Y12 signaling
Adenosine increases thromboxane A2 synthesis, amplifying platelet activation
ADP reduces cyclic AMP in platelets via A2A receptor stimulation, impairing aggregation
Refer to the diagram showing arachidonic acid metabolism. Which enzyme family converts arachidonic acid into prostaglandins (e.g., PGE2, PGI2)?
Cyclooxygenase (COX) enzymes
Lipoxygenase (LOX) enzymes
Monoamine oxidase (MAO) enzymes
Acetylcholinesterase (AChE) enzymes
In the visual of the arachidonic acid pathway, which product class is primarily formed via lipoxygenase (LOX) activity?
Prostacyclins (PGI2)
Thromboxanes (TXA2)
Leukotrienes (e.g., LTB4, LTC4)
Prostaglandin E series (PGE2)
Based on the pathway overview, inhibition of COX enzymes by NSAIDs most directly reduces which inflammatory mediator and is linked to gastric ulcer risk?
Leukotriene B4, decreasing neutrophil chemotaxis
Prostaglandin E2, decreasing gastric mucosal protection
Histamine release, decreasing vascular permeability
Interleukin-1β, decreasing fever
Recall the pathway depicted: In platelets, phospholipids are converted to arachidonic acid, which via cyclooxygenase (COX) leads to thromboxane A2 (TXA2) formation that promotes platelet aggregation. Which step is directly inhibited by NSAIDs to reduce TXA2 synthesis?
Conversion of phospholipids to arachidonic acid
Cyclooxygenase-mediated transformation of arachidonic acid
Binding of TXA2 to platelet receptors
Initial platelet adhesion to damaged endothelium
Paracetamol (acetaminophen) is described as a potent analgesic and antipyretic but weak anti-inflammatory. Which pharmacologic feature best explains its limited anti-inflammatory action compared with typical NSAIDs?
It primarily inhibits endoperoxidase enzymes rather than peripheral COX at inflammatory sites
It irreversibly inhibits COX-1 in platelets, reducing inflammation
It is rapidly degraded in the stomach, limiting systemic distribution
It strongly induces glucuronidase and glutathione enzymes in the liver
Recall the kinetic and toxicity profile stated for ibuprofen used in animals: Which statement is correct based on the provided information?
It has a wide margin of safety and is excreted unchanged in urine within 8 hours
It is absorbed orally, metabolized in the liver with an elimination half-life of about 74 hours, and is toxic to liver and kidneys
It is primarily metabolized by the kidneys and causes minimal gastric irritation in dogs
It is administered parenterally and has negligible hepatic involvement
A veterinarian considers carprofen for a dog with osteoarthritis but is concerned about gastrointestinal side effects. Which property of carprofen supports this choice?
Nonselective COX inhibition that increases gastric prostaglandin suppression
Selective inhibition of the COX-2 isoform, helping minimize gastrointestinal side effects
Primary COX-1 selectivity that enhances gastric mucosal protection
Leukotriene pathway activation that reduces ulcer risk
Strategic application scenario: A patient stops daily acetyl salicylic acid (ASA) therapy. According to the provided material, which plan best maintains antithrombotic protection considering platelet enzyme regeneration?
Discontinue ASA indefinitely because platelets rapidly regenerate cyclooxygenase within 24 hours
Resume ASA only after two weeks because new platelets immediately restore full hemostasis
Continue daily ASA because platelets cannot synthesize protein to regenerate cyclooxygenase; the antithrombotic effect persists for the platelet lifespan (8–10 days), and hemostasis operates at ~20% with new platelets after discontinuation
Switch to intermittent ASA every third day to allow cyclooxygenase recovery in existing platelets
Refer to the diagram of the clotting chain reaction. Which step is primarily affected by Aspirin to slow blood clotting?
Initiation trigger that starts the cascade
Conversion of prothrombin to thrombin
Formation of the fibrin ‘net’
Platelets becoming sticky and aggregating
Based on the diagram, which immediate physiological outcome best explains Aspirin’s anti-thrombotic effect?
Enhanced fibrin cross-linking forming a denser net
Reduced platelet aggregation leading to fewer blood clots
Accelerated thrombin generation increasing clot formation
Increased calcium availability that amplifies the clotting cascade
Which statement correctly contrasts Flunixin meglumine with Etodolac as shown in the Nicotinic & Pyranocarboxylic Acid derivatives slide?
Flunixin is orally absorbed and undergoes enterohepatic metabolism, while Etodolac is given IV with fast onset and long duration
Flunixin is approved in cattle and horses and is compatible with morphine, while Etodolac is recently approved for dogs and inhibits both COX-1 and COX-2
Flunixin is contraindicated in dogs due to hypoproteinemia, while Etodolac causes CNS stimulation and ataxia in horses
Flunixin is excreted in feces after hepatic metabolism, while Etodolac is mainly renally excreted with short duration
