p.12
Antimicrobial Stewardship
Which receptors do ADP bind to during platelet activation?
ADP binds to P2Y1 and P2Y12 receptors.
p.13
Antimicrobial Stewardship
What role do platelets play in clotting?
Platelets are critical in haemostasis and the development of arterial thrombi.
p.14
Mechanisms of Antibiotic Action
What is the primary mechanism of action of aspirin as an anti-platelet agent?
Aspirin irreversibly acetylates and inhibits the enzyme COX, changing the balance between prostacyclin and thromboxane, thus preventing platelet aggregation.
p.10
Heparin Types and Uses
What is the mechanism of action of Heparin?
Binds to antithrombin III (ATIII) reversibly, increasing the rate at which ATIII binds to thrombin by 1000x.
p.3
Gentamicin Administration and Cautions
What formula is used to estimate creatinine clearance?
Cockcroft and Gault formula.
p.12
Antimicrobial Stewardship
What is the role of fibrinogen in platelet aggregation?
Fibrinogen cross-linking leads to platelet aggregation.
p.1
Pharmacokinetics of Antibiotics
What is the minimum bactericidal concentration (MBC)?
The lowest concentration of antibiotic required to kill a particular bacterium in vitro.
p.5
Mechanisms of Antibiotic Action
What is the function of glycopeptides in antibiotic action?
They inhibit bacterial cell wall synthesis and are bacteriocidal.
p.7
Heparin Types and Uses
What is the common practice for administering UFH?
A bolus of 5000 IU followed by a continuous infusion based on the patient's weight.
p.12
Antimicrobial Stewardship
How is thromboxane A2 (TXA2) produced?
TXA2 is produced from arachidonic acid through conversion by cyclo-oxygenase-1.
p.5
Antibiotic Resistance Mechanisms
Which antibiotics are susceptible to β-lactamase?
Benzylpenicillin, Amoxicillin, Ceftriaxone, and others.
p.6
Heparin Types and Uses
What is naturally occurring heparin?
A highly sulphated glycosaminoglycan carbohydrate weighing between 3000 and 50,000 daltons, produced by basophils and mast cells.
p.10
Heparin Types and Uses
What factors are inhibited by Heparin at higher doses?
Factors IXa, XIa, and XIIa.
p.9
Warfarin Mechanism and Interactions
Why is warfarin contraindicated in pregnancy?
Due to its teratogenic effects and risk of maternal bleeding.
p.20
Pharmacokinetics of Antibiotics
What are biphasic insulins?
Ready mixed combinations of rapid- or short-acting insulins with intermediate-acting insulins.
p.16
Blood Transfusion Risks and Benefits
How should platelets be stored?
At room temperature (20–24 °C) on shaking platforms.
p.3
Gentamicin Administration and Cautions
In which patient group should gentamicin be used with caution?
During pregnancy, as it can cross the placenta and cause fetal ototoxicity.
p.12
Antimicrobial Stewardship
What receptors are activated by thromboxane A2?
The TXA2 receptor (TP) is activated by TXA2 and prostaglandin endoperoxides PGG2 and PGH2.
p.12
Antimicrobial Stewardship
What is the significance of membrane glycoproteins GPia/IIa, GPV, and GPV in platelets?
They function as receptors in platelet adhesion to collagen.
p.20
Pharmacokinetics of Antibiotics
How are insulins categorized?
According to onset of action, peak, and duration of action.
p.16
Blood Transfusion Risks and Benefits
At what temperature must plasma be stored after separation?
Frozen as soon as possible to under –18 °C.
p.7
Heparin Types and Uses
What is the half-life of UFH compared to LMWH?
UFH has a half-life of 30–150 minutes, while LMWH has a half-life 2–3 times longer for an equivalent dose.
p.10
Heparin Types and Uses
What are the primary uses of Heparin?
Prophylaxis of DVT, prevention of clot propagation in DVT/PE/vessel occlusion, and to prevent clot formation on extra-corporeal membranes.
p.19
Blood Transfusion Risks and Benefits
What is a restrictive red cell transfusion trigger?
Accepting a lower hemoglobin level that is safe for the individual patient, e.g., 10 g/dL for a patient with ischemic heart disease or as low as 7 g/dL for a fit 20-year-old.
p.12
Antimicrobial Stewardship
What is the function of thrombin in platelet activation?
Thrombin binds to protease-activated receptors (PAR-1 and PAR-4), promoting platelet activation.
p.13
Antimicrobial Stewardship
What is the function of von Willebrand factor (vWF) in platelet activation?
vWF binds to GP Ibα and collagen, activating platelets.
p.4
Antibiotic Resistance Mechanisms
What is one mechanism by which bacteria develop resistance to penicillins?
Drug inactivation through bacterial production of β-lactamase, leading to hydrolysis of the β-lactam ring.
p.5
Mechanisms of Antibiotic Action
What is the mode of action of β-lactams?
They inhibit bacterial cell wall synthesis.
p.7
Heparin Types and Uses
What is the typical monitoring method for UFH therapy?
Activated partial thromboplastin time (APTT) is measured.
p.18
Blood Transfusion Risks and Benefits
What is the metabolism rate of citrate in a healthy adult liver?
The liver metabolizes 3 g of citrate every 5 minutes.
p.14
Mechanisms of Antibiotic Action
How does aspirin affect thromboxane and prostacyclin synthesis?
Aspirin inhibits the conversion of arachidonic acid to endoperoxide, preventing the synthesis of thromboxane (TXA2) in platelets and prostacyclin (PGI2) in endothelial cells.
p.5
Mechanisms of Antibiotic Action
What is the primary action of antibiotics that inhibit bacterial protein synthesis?
They bind to the 30S or 50S subunit of bacterial ribosomes.
p.1
Principles of Good Antibiotic Prescribing
What should be done before starting antibiotic therapy?
Collect specimens for culture (e.g., blood, urine).
p.7
Heparin Types and Uses
What is the bioavailability of subcutaneous doses for UFH and LMWH?
UFH has 40% bioavailability, while LMWH has 90%.
p.3
Gentamicin Administration and Cautions
What effect do aminoglycosides have on non-depolarising muscle relaxants?
They can potentiate their action or cause recurrence of the blockade.
p.17
Blood Transfusion Risks and Benefits
What is a serious immune-related complication of blood transfusion?
Graft-versus-host disease.
p.6
Heparin Types and Uses
How does activated antithrombin III function?
It inhibits thrombin and other serine proteases that promote blood clotting.
p.10
Heparin Types and Uses
Why is Heparin not given orally?
Due to low lipid solubility, it does not cross the blood-brain barrier or placenta.
p.8
Heparin Types and Uses
What is a major side effect of heparin therapy?
Haemorrhage, which can be fatal if given in overdose.
p.7
Heparin Types and Uses
How does LMWH differ in administration compared to UFH?
LMWH is given as a twice-daily or once-daily subcutaneous injection.
p.3
Penicillin Structure and Mechanism
How are penicillins categorized based on their spectrum of action?
Narrow spectrum, β-lactamase resistant, broad spectrum, and anti-pseudomonal.
p.8
Heparin Types and Uses
What is non-immune thrombocytopenia and when does it occur?
It occurs after approximately 4 days of therapy and platelets recover spontaneously.
p.16
Blood Transfusion Risks and Benefits
What is the effect of adding adenine to blood storage solutions?
It increases red cell survival to 35 days.
p.1
Antimicrobial Stewardship
What is antimicrobial stewardship?
A coordinated program that promotes appropriate prescribing and use of antimicrobials to reduce microbial resistance and improve patient outcomes.
p.1
Principles of Good Antibiotic Prescribing
What are the main principles of good antibiotic prescribing?
Prescribe only when clinically indicated, collect specimens for culture before therapy, follow local guidelines, choose the correct antibiotic class, use narrow-spectrum agents when possible, de-escalate broad-spectrum therapy, ensure correct treatment duration and dose, switch to oral preparations promptly, source control where applicable, and ensure surgical prophylaxis compliance.
p.15
Antimicrobial Stewardship
What is the recommended time to discontinue aspirin monotherapy for primary prevention before surgery?
7–10 days before surgery.
p.20
Pharmacokinetics of Antibiotics
What type of insulin has largely replaced animal insulin?
Genetically engineered human insulin analogues.
p.9
Warfarin Mechanism and Interactions
What impact does severe sepsis have on warfarin binding?
Changes in plasma pH alter protein structure, reducing binding sites.
p.18
Blood Transfusion Risks and Benefits
How quickly do 2,3 DPG levels rise after transfusion?
They rise rapidly, usually restoring normal oxygen affinity in a few hours.
p.3
Penicillin Structure and Mechanism
What is the basic structure of penicillin?
A thiazolidine ring nucleus attached to a β-lactam ring.
p.9
Warfarin Mechanism and Interactions
What is the specific treatment for major bleeding due to warfarin overdose?
Stop warfarin, administer vitamin K, and consider prothrombin complex concentrate or fresh frozen plasma.
p.15
Antimicrobial Stewardship
What is the relative risk associated with regional anaesthesia in patients on anti-platelet agents?
Carries a relative risk of bleeding.
p.8
Heparin Types and Uses
How can unfractionated heparin (UFH) be reversed?
With protamine; 1 mg of protamine reverses 100 IU of heparin.
p.18
Blood Transfusion Risks and Benefits
What metabolic disturbance can occur due to citrate metabolism?
Profound metabolic alkalosis may ensue.
p.16
Blood Transfusion Risks and Benefits
What is the purpose of acid-citrate-dextrose in blood storage?
Citrate acts as an anticoagulant by binding calcium, while dextrose serves as an energy source for glycolysis.
p.17
Blood Transfusion Risks and Benefits
What is the principal benefit of red cell transfusion?
Improvement in oxygen-carrying capacity by increasing hemoglobin levels.
p.3
Gentamicin Administration and Cautions
How are aminoglycosides, including gentamicin, excreted?
They are excreted unchanged by the kidneys, primarily by glomerular filtration.
p.9
Warfarin Mechanism and Interactions
How does thyroid status affect warfarin?
Hypothyroidism reduces the effect of warfarin.
p.14
Mechanisms of Antibiotic Action
What is the mechanism of action of dipyridamole?
Dipyridamole inhibits cellular uptake of adenosine, increasing extracellular adenosine levels, which elevates cAMP levels in platelets and inhibits their activation.
p.13
Antimicrobial Stewardship
What substances do activated platelets release?
TXA2 and ADP, which recruit and activate surrounding platelets.
p.17
Blood Transfusion Risks and Benefits
What defines a massive transfusion?
Transfusion of 10 units of blood within 6 hours or replacement of the entire circulating volume within 24 hours.
p.6
Heparin Types and Uses
What are low molecular weight heparins (LMWH)?
Newer drugs weighing between 2000 and 8000 daltons that directly inhibit factor Xa.
p.13
Antimicrobial Stewardship
What inhibits platelet activation, adhesion, and aggregation?
Nitric oxide (NO) and prostacyclin (PGI2).
p.9
Warfarin Mechanism and Interactions
What is Rivaroxaban?
A direct factor Xa inhibitor that can be taken orally once daily.
p.19
Blood Transfusion Risks and Benefits
What is pre-donation in the context of blood conservation?
Patients for planned surgery with significant expected blood loss may be candidates for pre-donation of blood followed by intra-operative transfusion of their own blood.
p.15
Antimicrobial Stewardship
What procedures carry the greatest risk of haematoma?
Epidural with a catheter, one-shot epidural, spinal, paravertebral blocks.
p.20
Pharmacokinetics of Antibiotics
How can episodes of hypoglycaemia be minimized in insulin treatment?
By using rapid-acting analogues instead of short-acting human insulins.
p.2
Gentamicin Administration and Cautions
What are the potential toxicities associated with high plasma concentrations of aminoglycosides?
Ototoxicity and nephrotoxicity.
p.17
Blood Transfusion Risks and Benefits
How does raising the hematocrit benefit trauma and septic patients?
It improves microcirculation.
p.10
Heparin Types and Uses
What happens when thrombin is complexed with ATIII?
Clot formation is inhibited.
p.15
Antimicrobial Stewardship
When should dual anti-platelet therapy be discontinued before surgery in low-risk situations?
5–7 days before surgery, while continuing aspirin.
p.20
Pharmacokinetics of Antibiotics
What are the main groups of insulin?
Rapid-, short-, intermediate-, and long-acting.
p.4
Antibiotic Resistance Mechanisms
What is a third mechanism of resistance to penicillins?
Alteration of bacterial cell wall permeability, which prevents antibiotics from penetrating the cell wall.
p.17
Blood Transfusion Risks and Benefits
What is a common problem encountered during massive transfusion?
Dilutional thrombocytopenia.
p.1
Principles of Good Antibiotic Prescribing
What factors should be considered when ensuring the correct dose of antibiotics?
Weight, renal function, liver function, and if on renal replacement therapy.
p.10
Heparin Types and Uses
What hematological effects does Heparin have?
Increases APTT, TT, and ACT; no effect on bleeding time; can cause thrombocytopenia (Type I and Type II).
p.8
Heparin Types and Uses
What should be done with heparin dosage in patients with renal failure?
The dose should be reduced due to potential accumulation.
p.19
Blood Transfusion Risks and Benefits
What is hypotensive anaesthesia used for?
To reduce blood loss in certain types of surgery such as middle ear surgery or neurosurgery.
p.5
Antibiotic Resistance Mechanisms
What is the significance of β-lactamase inhibitors like clavulanic acid?
They protect β-lactam antibiotics from being broken down by β-lactamase.
p.18
Blood Transfusion Risks and Benefits
What complications can hypothermia cause during transfusion?
It can lead to reduced citrate and lactate metabolism, hypocalcaemia, and increased cardiac dysrhythmias.
p.8
Warfarin Mechanism and Interactions
How does warfarin exert its anticoagulant effect?
By inhibiting the synthesis of vitamin K-dependent clotting factors (II, VII, IX, and X).
p.2
Gentamicin Administration and Cautions
What is the recommended dose of gentamicin?
3–5 mg/kg/day, given in divided doses every eight hours.
p.12
Antimicrobial Stewardship
What is the role of GPIIb/IIIa in platelet aggregation?
GPIIb/IIIa is a receptor for fibrinogen and von Willebrand factor, facilitating platelet aggregation.
p.17
Blood Transfusion Risks and Benefits
What infections can be transmitted through blood transfusions?
HIV, hepatitis A, B, C, malaria, variant CJD, CMV, syphilis, HTLV.
p.17
Blood Transfusion Risks and Benefits
What metabolic complications can arise from blood transfusions?
Hyperkalemia and hypocalcemia.
p.5
Antibiotic Resistance Mechanisms
What type of antibiotics are resistant to β-lactamase?
Carbapenems and monobactams.
p.7
Heparin Types and Uses
How is UFH administered clinically?
As an infusion to prevent DVT and PE, during cardiopulmonary bypass, ECMO, vascular surgery, and for thrombosis prophylaxis.
p.3
Gentamicin Administration and Cautions
Why are aminoglycosides contraindicated in patients with myasthenia gravis?
Due to their effect on neurotransmission, interfering with calcium entry and acetylcholine release.
p.14
Mechanisms of Antibiotic Action
How long does it take for platelet function to return to normal after administration of GP IIb/IIIa inhibitors?
Platelet function returns to normal in 48 hours with abciximab and in 6–8 hours with tirofiban.
p.15
Antimicrobial Stewardship
What is a potential requirement during emergency surgery if anti-platelet therapy is not discontinued?
May require platelet transfusion in life-threatening bleeding.
p.8
Heparin Types and Uses
How is heparin administered to avoid complications?
Subcutaneously, to avoid intramuscular haematoma.
p.6
Heparin Types and Uses
What is the role of smaller heparin molecules?
They can only inhibit the activity of other proteases such as factor Xa.
p.13
Antimicrobial Stewardship
What is the effect of anti-platelet agents?
They are most effective in the treatment or prevention of arterial clots composed largely of platelets.
p.18
Blood Transfusion Risks and Benefits
What is the recommended ratio for blood product administration in major hemorrhage?
1:1:1 ratio of packed red cells, FFP, and platelets.
p.19
Blood Transfusion Risks and Benefits
Are artificial oxygen carriers widely used in the UK?
No, no artificial oxygen carriers are used extensively within the UK at present.
p.8
Warfarin Mechanism and Interactions
Why is heparin often started alongside warfarin?
Because it takes at least 48 hours for warfarin to achieve its clinical effect.
p.17
Blood Transfusion Risks and Benefits
What is a major risk associated with blood transfusions?
Hemolytic transfusion reactions, such as life-threatening ABO incompatibility.
p.14
Mechanisms of Antibiotic Action
What is the effect of ADP receptor blockers like ticlopidine and clopidogrel?
They inhibit the ADP-dependent pathway of platelet activation by preventing binding of ADP to its receptor on the platelet surface.
p.14
Mechanisms of Antibiotic Action
What distinguishes ticagrelor from other ADP receptor blockers?
Ticagrelor indirectly inhibits ADP by acting on an independent ligand-binding site on the P2Y12 receptor, resulting in reversible non-competitive binding.
p.1
Pharmacokinetics of Antibiotics
What is the minimum inhibitory concentration (MIC)?
The lowest concentration of antibiotic required to completely inhibit the growth of a particular bacterium in vitro.
p.13
Antimicrobial Stewardship
How do platelets adhere to the endothelium?
Bound vWF activates GP IIb/IIIa glycoproteins, allowing them to bind fibrinogen.
p.4
Antibiotic Resistance Mechanisms
What is another mechanism of penicillin resistance?
Alteration of penicillin binding proteins, preventing antibiotics from binding to the bacterial cell wall.
p.1
Principles of Good Antibiotic Prescribing
What is the ideal timing for administering surgical prophylaxis antibiotics?
Ideally 30 minutes prior to skin incision.
p.11
Warfarin Mechanism and Interactions
What is the typical dosage range for Warfarin?
Usually 2–9 mg/day, patient-specific and titrated to effect.
p.3
Penicillin Structure and Mechanism
What is the mechanism of action of penicillin?
It inhibits bacterial cell wall synthesis by binding to cell wall proteins and preventing peptidoglycan cross-links.
p.15
Antimicrobial Stewardship
What guidelines are recommended for performing neuraxial and peripheral nerve blocks?
Performed by experienced clinicians and under ultrasound guidance where possible.
p.10
Heparin Types and Uses
What is a key advantage of low molecular weight heparin?
It inhibits factor Xa via ATIII and only needs once daily dosing without requiring monitoring.
p.2
Pharmacokinetics of Antibiotics
What are the three important pharmacokinetic parameters when evaluating antibiotic efficacy?
Peak serum level (C max), Trough serum level (C min), Area under the serum concentration–time curve (AUC).
p.19
Blood Transfusion Risks and Benefits
What is recombinant factor VII used for?
Used in hemophilia and in massive bleeding, provided platelet count is adequate.
p.8
Heparin Types and Uses
What are some other side effects of heparin?
Hypotension, osteoporosis with long-term use, and alopecia.
p.16
Blood Transfusion Risks and Benefits
What is the composition of the saline-adenine-glucose-mannitol storage solution?
Saline (140 mmol/l), adenine (1.5 mmol/l), glucose (50 mmol/l), mannitol (30 mmol/l).
p.8
Warfarin Mechanism and Interactions
What effect do antibiotics that affect gut flora have on warfarin?
They increase the effect of warfarin by affecting vitamin K production.
p.9
Warfarin Mechanism and Interactions
What dietary factors can potentiate the action of warfarin?
Foodstuffs and supplements like St John's wort, ginger, and ginseng.
p.4
Antibiotic Resistance Mechanisms
How does resistance to penicillins develop?
Inappropriate use of antibiotics and poor prescribing play a vital role in propagating antibiotic resistance.
p.18
Blood Transfusion Risks and Benefits
What effect does massive transfusion of stored blood have on oxygen delivery?
It adversely affects oxygen delivery to the tissues due to high oxygen affinity.
p.6
Heparin Types and Uses
What is unfractionated heparin (UFH)?
A synthetic agent weighing between 5000 and 25,000 daltons that binds to and potentiates the action of antithrombin III 1000-fold.
p.10
Heparin Types and Uses
How is Heparin metabolized and excreted?
Metabolized in the liver, kidney, and reticuloendothelial system; excreted in urine.
p.18
Blood Transfusion Risks and Benefits
What causes hypocalcaemia during blood transfusion?
Citrate in each unit of blood binds ionised calcium.
p.1
Principles of Good Antibiotic Prescribing
What should be done if broad-spectrum therapy is commenced?
De-escalate as soon as possible based on microbiology-sensitivity data.
p.16
Blood Transfusion Risks and Benefits
What is leuco-depletion?
The process of removing white blood cells via filtration.
p.18
Blood Transfusion Risks and Benefits
What is a common issue related to potassium levels during transfusion?
Hypokalaemia is more common as red cells restart potassium uptake.
p.5
Mechanisms of Antibiotic Action
What is the role of antifolates in antibiotic therapy?
They act as bacteriostatic agents.
p.7
Heparin Types and Uses
Is monitoring required for LMWH therapy?
Usually no monitoring is required, but anti-factor Xa levels can be measured as needed.
p.19
Blood Transfusion Risks and Benefits
What is intra-operative blood salvage?
The use of cell savers in certain types of surgery to recover and reinfuse a patient's own blood.
p.19
Blood Transfusion Risks and Benefits
What are artificial oxygen carriers?
Perfluorocarbons and modified hemoglobins that transport oxygen differently than blood.
p.7
Heparin Types and Uses
What is the primary difference in Xa inhibition between unfractionated heparin (UFH) and low molecular weight heparins (LMWH)?
UFH has + Xa inhibition, while LMWH has +++ Xa inhibition.
p.15
Antimicrobial Stewardship
In what situation should aspirin be continued despite the risk of bleeding?
Secondary prevention with low risk of bleeding.
p.16
Blood Transfusion Risks and Benefits
What are the main components of whole blood after centrifugation?
Red cells, plasma, and platelets.
p.14
Mechanisms of Antibiotic Action
What is the role of GP IIb/IIIa inhibitors in platelet aggregation?
They inhibit the final common pathway of platelet aggregation by blocking fibrinogen binding to the GP IIb/IIIa receptor, providing the greatest antiplatelet activity.
p.13
Antimicrobial Stewardship
What mediates platelet aggregation?
Fibrinogen binds to GP IIb/IIIa receptors and converts to fibrin, stabilizing the thrombus.
p.4
Principles of Good Antibiotic Prescribing
What are the major side effects of penicillins?
Hypersensitivity, gastrointestinal disturbances, encephalopathy in renal failure patients, and rash with ampicillin in infectious mononucleosis.
p.13
Antimicrobial Stewardship
How can anti-platelet agents be classified?
They decrease platelet aggregation and inhibit thrombus formation.
p.3
Penicillin Structure and Mechanism
What is the effect of probenecid on penicillin?
It inhibits the tubular secretion of penicillin, increasing plasma levels significantly.
p.18
Blood Transfusion Risks and Benefits
What acid load does stored blood contribute to the recipient?
Stored blood can give an acid load of up to 30–40 mmol/L of lactic acid.
p.9
Warfarin Mechanism and Interactions
What are the methods to reverse warfarin's action?
Intravenous vitamin K, fresh frozen plasma, or prothrombin complex concentrate.
p.2
Pharmacokinetics of Antibiotics
What does the Peak/MIC ratio represent?
It is the C max divided by the MIC.
p.18
Blood Transfusion Risks and Benefits
How often should calcium levels be checked during massive transfusion?
After every 10 units of blood products.
p.2
Gentamicin Administration and Cautions
What are the target 'peak' and 'trough' plasma gentamicin levels?
'Peak' levels should be 5–10 mg/L and 'trough' levels should be less than 2 mg/L.
p.6
Heparin Types and Uses
How are doses of LMWH and UFH calculated?
In units of activity rather than weight.
p.11
Warfarin Mechanism and Interactions
What are the primary uses of Warfarin?
Prophylaxis of DVT/PE, clot formation on prosthetic heart valves, and prevention of clot propagation.
p.16
Blood Transfusion Risks and Benefits
Why is leuco-depleted blood beneficial?
It minimizes alloimmunisation, reduces febrile transfusion reactions, and decreases cytomegalovirus (CMV) transmission.
p.9
Warfarin Mechanism and Interactions
How can heparin's action be reversed?
Using protamine sulphate.
p.19
Blood Transfusion Risks and Benefits
What are anti-fibrinolytic agents?
Agents like tranexamic acid and aprotinin that inhibit clot breakdown.
p.8
Heparin Types and Uses
What should be done if HIT is suspected?
Discontinue heparin and send blood for a HIT screen; alternative anticoagulation should be used.
p.8
Heparin Types and Uses
What are the advantages of low molecular weight heparin (LMWH)?
Requires once or twice daily dosing, does not need monitoring, and is less likely to cause HIT.
p.8
Warfarin Mechanism and Interactions
What is the purpose of monitoring warfarin therapy?
It is monitored via the international normalized ratio (INR).
p.3
Penicillin Structure and Mechanism
What types of organisms are penicillins active against?
Most gram-positive organisms and some gram-negative cocci.
p.9
Warfarin Mechanism and Interactions
What is a major drawback of Dabigatran?
There is no way to reverse its effect.
p.4
Mechanisms of Antibiotic Action
How do penicillins and aminoglycosides act synergistically?
Penicillins weaken the bacterial cell wall, allowing aminoglycosides to penetrate the cell and inhibit protein synthesis.
p.8
Heparin Types and Uses
What is heparin-induced thrombocytopenia (HIT)?
An immune-mediated process that usually develops around 5 days after heparin exposure.
p.2
Pharmacokinetics of Antibiotics
What is T > MIC?
The percentage of a dosage interval in which the serum level exceeds the MIC.
p.19
Blood Transfusion Risks and Benefits
How do perfluorocarbon emulsions differ from blood in oxygen transport?
Blood exhibits a sigmoidal oxygen dissociation curve, while perfluorocarbon emulsions have a linear relationship between oxygen partial pressure and oxygen content.
p.18
Blood Transfusion Risks and Benefits
What may be required to boost coagulation in major hemorrhage cases?
Recombinant factor (rFVII).
p.2
Mechanisms of Antibiotic Action
What is the mode of action of aminoglycosides like gentamicin?
They bind irreversibly to the 30S subunit of the bacterial ribosome and inhibit bacterial protein synthesis.
p.6
Heparin Types and Uses
What is the significance of the size of heparin molecules in thrombin inactivation?
To inactivate thrombin, the heparin molecule must bind both antithrombin III and thrombin, requiring a size greater than 18 saccharide ternary units.
p.13
Antimicrobial Stewardship
What are the main types of anti-platelet agents in clinical use?
COX inhibitors, ADP receptor inhibitors, dipyridamole, and GPIIb/IIIa inhibitors.
p.16
Blood Transfusion Risks and Benefits
What changes occur in stored blood?
Fall in 2,3-DPG levels, left shift of the oxyhemoglobin dissociation curve, fall in pH (to approximately 7.0), rise in potassium concentration.
p.11
Warfarin Mechanism and Interactions
How long does it take for Warfarin to start working?
It takes 72 hours to work as it only affects the synthesis of new factors.
p.2
Pharmacokinetics of Antibiotics
Which pharmacokinetic index correlates best with the efficacy of concentration-dependent killing antibiotics?
The 24-h AUC/MIC ratio and the Peak/MIC ratio.
p.2
Gentamicin Administration and Cautions
What is an alternative dosing regimen for gentamicin?
A once-daily regimen where the full dose is given as a single dose, adjusted according to 'trough' levels using a nomogram.
p.5
Mechanisms of Antibiotic Action
Which antibiotics are classified as bacteriostatic?
Tetracyclines, macrolides, and lincosamides.
p.7
Heparin Types and Uses
What does APTT measure in the context of heparin therapy?
APTT measures the activity of the intrinsic clotting cascade and is prolonged by UFH.
p.11
Warfarin Mechanism and Interactions
What should be done with Warfarin before elective surgery?
Stop Warfarin 1 week before and replace with heparin if necessary; INR should be < 2 to operate.
p.11
Warfarin Mechanism and Interactions
What is the mechanism of action of Warfarin?
Inhibits synthesis of vitamin K dependent clotting factors II, VII, IX, and X.
p.8
Heparin Types and Uses
What happens in HIT regarding platelets?
IgG antibodies bind to the heparin-PF4 complex, activating platelets and forming thrombi.
p.2
Mechanisms of Antibiotic Action
How do antibiotics exert their effects?
By inhibiting (bacteriostatic) or killing (bacteriocidal) bacteria.
p.8
Warfarin Mechanism and Interactions
Which drugs may potentiate the action of warfarin?
NSAIDs and simvastatin, as they compete for protein binding sites.
