Drug Delivery Systems Overview
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Questions and Answers

Why is it especially important to be vigilant when giving medications to children?

  • Children's weight varies from 2 to 3 kg to 100 kg or more.
  • The Joint Commission recommends special care for pediatric patients.
  • Most drugs have not been tested in children. (correct)
  • Children have limited sites for administration of IV drugs.

    • What is one of the challenges of administering medications to children?

  • Children often require dilution and calculation for small doses. (correct)
  • Most medications are only available in liquid form.
  • Children can self-administer medications easily.
  • Children's age ranges are from birth to 18 years old.

    • Why does the need for small volumes of fluid limit the flushing between drugs in children?

  • Small volumes can cause intense pain to the child.
  • Children have multiple sites for IV drug administration.
  • There is a wide range of acceptable dosages in pediatrics.
  • Flushing may produce undesirable interactions with other drugs and IV solutions. (correct)

    • What is recommended by The Joint Commission and the World Health Organization regarding patient safety?

    <p>Prevention of errors and adverse effects.</p> Signup and view all the answers

    Why do many drugs marketed for adults require additional preparation when given to children?

    <p>Concentration and dosage forms are often unsuitable for children.</p> Signup and view all the answers

    What is a significant challenge when giving medications to children according to the text?

    <p>Children's age diversity</p> Signup and view all the answers

    Why have most drugs not been tested in children according to the text?

    <p>A lack of research funding</p> Signup and view all the answers

    What is a common issue when administering adult medications to children?

    <p>Lack of proper dosing guidelines for children</p> Signup and view all the answers

    Why does the need for small doses in children often require additional steps during medication administration?

    <p>To ensure precise calculations and administration</p> Signup and view all the answers

    What limits the ability to flush between drugs when administering medications to children?

    <p>Limited sites for administration of IV drugs in children</p> Signup and view all the answers

    Why is it crucial for nurses and healthcare institutions to maintain up-to-date medication administration skills?

    <p>To enhance patient safety and prevent adverse effects</p> Signup and view all the answers

    What does patient safety entail according to The Joint Commission and the World Health Organization?

    <p>Preventing errors, adverse effects, and providing reporting requirements</p> Signup and view all the answers

    Why might undesirable interactions with other drugs and IV solutions occur when administering medications to children?

    <p>Children's limited sites for IV drug administration.</p> Signup and view all the answers

    What complicates the preparation and administration process when giving medications to children?

    <p>The need for dilution of adult medications for pediatric use.</p> Signup and view all the answers

    Why must health care institutions ensure internal and external reporting requirements for adverse drug events in children?

    <p>To maintain patient safety and prevent adverse effects.</p> Signup and view all the answers

    What is a key reason for the high risk of medication errors when giving medications to children?

    <p>Great diversity in age and weight among children</p> Signup and view all the answers

    Why is it challenging to administer adult medications to children?

    <p>Adult medications require additional preparation for pediatric dosing</p> Signup and view all the answers

    What limitation do children have that impacts the administration of IV drugs?

    <p>Limited sites for IV administration</p> Signup and view all the answers

    Why does the need for small fluid volumes limit flushing between drugs in children?

    <p>Small fluid volumes make it difficult to maintain IV patency</p> Signup and view all the answers

    What is essential for healthcare institutions regarding internal and external reporting of medication errors?

    <p>Adhering to reporting requirements for adverse events</p> Signup and view all the answers

    Why are most drugs not tested in children according to the text?

    <p>'Off-label' use is common in pediatric patients</p> Signup and view all the answers

    What contributes to the complexity of medication administration to children?

    <p>'Best guess' dosing calculations</p> Signup and view all the answers

    How does children's limited sites for IV administration affect medication delivery?

    <p>Poses challenges when administering multiple IV drugs</p> Signup and view all the answers

    What poses a challenge when preparing and administering medication to children?

    <p>Preparing and administering small medication doses</p> Signup and view all the answers

    Why is it important for healthcare professionals to maintain up-to-date skills in medication administration?

    <p>To avoid medication errors caused by outdated practices</p> Signup and view all the answers

    What is a primary reason for the high risk of medication errors when giving medications to children?

    <p>Great diversity in age and weight among children</p> Signup and view all the answers

    Why are many drugs marketed in dosage forms and concentrations suitable for adults a challenge when administering to children?

    <p>The need for dilution increases the risk of calculation errors</p> Signup and view all the answers

    How does the limited sites for administration of IV drugs in children impact medication delivery?

    <p>It requires alternating sites for each drug administration</p> Signup and view all the answers

    What contributes to the complexity of medication administration in children?

    <p>The need for very small doses in children</p> Signup and view all the answers

    Why does the need for small volumes of fluid limit flushing between drugs in children?

    <p>Flushing may lead to potential drug interactions</p> Signup and view all the answers

    What is a significant challenge when preparing and administering medication to children?

    <p>Determining the proper dosage based on weight and age</p> Signup and view all the answers

    Why have most drugs not been tested in children, according to the text?

    <p>Lack of financial incentives for pediatric trials</p> Signup and view all the answers

    What is the main goal of thrombolytic therapy?

    <p>Limit tissue damage</p> Signup and view all the answers

    Where does metabolism of alteplase predominantly occur?

    <p>Liver</p> Signup and view all the answers

    Which drug class is given following thrombolytic therapy to decrease reformation of a thrombus?

    <p>Anticoagulants</p> Signup and view all the answers

    How does alteplase work to dissolve unwanted blood clots?

    <p>By catalyzing the conversion of plasminogen to plasmin</p> Signup and view all the answers

    In which condition is alteplase considered first-line therapy?

    <p>Acute ischemic stroke</p> Signup and view all the answers

    What is the primary action of plasmin, generated by thrombolytic drugs?

    <p>Break down fibrin</p> Signup and view all the answers

    Where does excretion of alteplase take place?

    <p>Kidneys</p> Signup and view all the answers

    What happens to more than 50% of alteplase after discontinuation of infusion?

    <p>It is cleared</p> Signup and view all the answers

    Why are anticoagulant drugs given following thrombolytic therapy?

    <p>To decrease reformation of a thrombus</p> Signup and view all the answers

    What is the main adverse effect of alteplase as mentioned in the text?

    <p>Bleeding</p> Signup and view all the answers

    What is the pharmacokinetic administration route for alteplase?

    <p>Intravenous (IV) infusion</p> Signup and view all the answers

    What age group should exercise caution when considering the use of alteplase?

    <p>Elderly patients aged 65-80 years</p> Signup and view all the answers

    In which patient population is alteplase contraindicated due to an increased risk of bleeding?

    <p>Patients with uncontrolled severe hypertension</p> Signup and view all the answers

    What is essential to check before initiating thrombolytic therapy with alteplase?

    <p>INR, aPTT, platelet count, and fibrinogen</p> Signup and view all the answers

    Where is administration of alteplase carried out according to the text?

    <p>In an emergency department or critical care unit</p> Signup and view all the answers

    What should be measured two or three hours after starting thrombolytic therapy with alteplase?

    <p>Fibrinogen level</p> Signup and view all the answers

    Which thrombolytic agents are used mainly in acute myocardial infarction to dissolve clots obstructing coronary arteries?

    <p>Reteplase and tenecteplase</p> Signup and view all the answers

    Why should alteplase not be shaken during reconstitution according to the text?

    <p>To maintain stability and prevent denaturation</p> Signup and view all the answers

    'Administration is IV as a bolus injection or infusion' means that alteplase should be administered:

    <p>Through a vein as a rapid injection or slow drip</p> Signup and view all the answers

    What is the most common adverse effect associated with the use of Reteplase and tenecteplase as mentioned in the text?

    <p>Bleeding</p> Signup and view all the answers

    Study Notes

    Drug Variables

    • Dosage refers to the frequency, size, and number of doses
    • Dosage depends on reason for use, potency, pharmacokinetics, route of administration, dosage form, and recipient
    • Loading dose: a larger dose at the beginning of drug therapy to attain a rapid blood level of the drug
    • Maintenance dose: quantity of drug needed to keep blood levels and/or tissue levels at a steady state

    Route of Administration

    • Affects drug actions and patient responses
    • Rapid response: IV (injected directly into the bloodstream) and IM (produces a fast effect)
    • Slow response: Oral (due to first-pass effect)
    • Absorption and action vary on drug formulation

    Drug-Diet Interactions

    • Used therapeutically to decrease food absorption in the intestinal tract
    • Examples: Orlistat (Xenical) decreases the absorption of fats from food, and ezetimibe (Zetia) decreases absorption of cholesterol from food
    • Undesirable interactions: food often slows absorption of oral drugs, and certain foods react with drugs (e.g., MAO inhibitors, warfarin, vitamin K, dairy, and grapefruit)

    Drug-Drug Interactions

    • Increase or decrease therapeutic or adverse effects
    • Types of interactions:
      • Additive effects: two drugs with similar pharmacological actions (e.g., ethanol and sedative drugs)
      • Synergism: two drugs produce greater effects when taken together (e.g., acetaminophen and codeine)
      • Interference: intensify effects of the second drug
      • Displacement: a drug exchanges with another, increasing the effect of the second drug
      • Antidote: given to antagonize the toxic effects of another drug
      • Decreased intestinal absorption of oral drugs when combined with other drugs

    Preparations and Dosage Forms

    • Vary according to drug's chemical characteristics, reason for use, and route of administration
    • Types of dosage forms:
      • Liquids
      • Tablets
      • Capsules
      • Suppositories
      • Transdermal and pump delivery systems

    Medication Administration Process

    • Follow the "rights" associated with medication administration consistently
    • Learn essential information about each drug to be given
    • Interpret the prescriber's order accurately
    • Question the prescriber if any information is unclear
    • Calculate doses accurately
    • Verify the identity of all patients before administering medications

    Clopidogrel

    • Antiplatelet effects similar to aspirin
    • Reversibly blocks the ADP receptor on platelet cell surface
    • Indications for use: reduction of myocardial infarction, stroke, and vascular death in patients with atherosclerosis
    • Specific uses: prevention of vascular ischemic events, acute coronary syndrome, and thrombosis following placement of an intracoronary stent

    Prasugrel and Ticagrelor

    • Other ADP receptor antagonists
    • Similar to clopidogrel but with different mechanisms and effects
    • Uses: reduction of thrombotic cardiovascular events, including stent thrombosis

    Heparin

    • Pharmaceutical preparation of the natural anticoagulant
    • Prototype anticoagulant
    • Antidote: protamine sulfate
    • Pharmacokinetics: given intravenously or subcutaneously
    • Action: combines with antithrombin III to inactivate clotting factors
    • Uses: prophylactic prevention of DVT and pulmonary embolism, management of acute thromboembolic disorders, and disseminated intravascular coagulation (DIC)### Heparin Administration
    • Heparin therapy requires platelet counts before therapy begins and every 2-3 days during therapy
    • If platelet count falls below 100,000 platelets per microliter of blood or to less than half the baseline value, heparin should be discontinued
    • Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening complication of heparin administration

    Contraindications and Administration

    • Contraindications include GI ulcerations, intracranial bleeding, dissecting aortic aneurysm, blood dyscrasias, severe kidney or liver disease
    • aPTT (activated partial thromboplastin time) should be maintained at approximately 1.5 to 2.5 times the control or baseline value

    Pharmacokinetics and Pharmacodynamics

    • Absorption: the process by which a drug enters the body and reaches the bloodstream
    • Distribution: the transport of drug molecules within the body to their sites of action, metabolism, and excretion
    • Metabolism: the method by which the body inactivates drugs
    • Excretion: the elimination of a drug from the body

    Pharmacodynamics

    • Receptors: proteins located on the surfaces of cell membranes or within cells that bind to drug molecules
    • Agonist effect: drugs that produce effects similar to those produced naturally occurring hormones, neurotransmitters, and other substances
    • Antagonist effect: drugs that inhibit cell function by occupying receptor sites

    Serum Half-life

    • Serum half-life: the time required for the serum concentration of a drug to decrease by 50%
    • Half-life is determined by the drug's rate of metabolism and excretion
    • Four to five half-lives are required to achieve steady-state concentrations and to develop equilibrium between tissue and serum concentrations
    • Dosage: the frequency, size, and number of doses; a major determinant of drug actions and responses
    • Route of administration: affects drug actions and patient responses
    • Drug-drug interactions: may be increased or decreased
    • Drug-diet interactions: used therapeutically to decrease food absorption in the intestinal tract or undesirable because food often slows absorption of oral drugs

    Dosage Forms and Drug Preparations

    • Dosage forms of systemic drugs include liquids, tablets, capsules, suppositories, and transdermal and pump delivery systems
    • Controlled-release tablets and capsules maintain more consistent serum drug levels and allow less frequent administration

    Medication Administration Process

    • The nurse adheres to the following principles: follow the "rights" associated with medication administration consistently, learn essential information about each drug, interpret the prescriber's order accurately, and calculate doses accurately### Adenosine Diphosphate (ADP) Receptor Antagonists

    • ADP receptor antagonists, including clopidogrel, prasugrel, and ticagrelor, have antiplatelet effects similar to aspirin and inhibit the ADP receptor on platelet surfaces.

    • Clopidogrel has three shortcomings: delayed onset of action, irreversible inhibitory effects on platelets with no reversing agent or antidote, and significant individual variability in platelet response.

    Pharmacokinetics of Clopidogrel

    • Clopidogrel is rapidly absorbed after oral administration and undergoes extensive first-pass metabolism in the liver.
    • It is converted to its active form by hepatic CYP2C19 and CYP3A4 enzymes.
    • Platelet inhibition may occur 2 hours after a single dose, but the onset of action is slow, so an initial loading dose is usually administered.
    • The drug has a half-life of about 8 hours and is excreted in the urine and feces.

    Action of Clopidogrel

    • Clopidogrel irreversibly blocks the ADP receptor on platelet cell surfaces.
    • Effective dose-dependent prevention of platelet aggregation can be seen within 2 hours of a single oral dose.
    • Platelet inhibition essentially lasts for the lifespan of the platelet (7-10 days).

    Use of Clopidogrel

    • Indications for use include reduction of myocardial infarction, stroke, and vascular death in patients with atherosclerosis and in those after placement of coronary stents.
    • Specific uses include prevention of vascular ischemic events in patients with symptomatic atherosclerosis or with acute coronary syndrome (with or without ST-segment elevation).
    • People with atrial fibrillation who are unable to take vitamin K antagonists take clopidogrel instead.

    Safety and Precautions of Clopidogrel

    • Older adults are more likely than younger ones to experience bleeding and other complications of antiplatelet drugs.
    • Clopidogrel may accumulate in people with hepatic impairment.
    • Caution is necessary for people with variant forms of CYP2C19, who may be poor or ultrarapid metabolizers of clopidogrel.

    Adverse Effects of Clopidogrel

    • The most common adverse effects associated with clopidogrel are pruritus, rash, purpura, and diarrhea.
    • Thrombotic thrombocytopenic purpura, hemorrhage, and severe neutropenia have also occurred.

    Prasugrel and Ticagrelor

    • Prasugrel demonstrated improved cardiac outcome compared with clopidogrel for acute coronary syndromes involving percutaneous coronary intervention.
    • Ticagrelor is the latest ADP receptor antagonist, used to reduce the rate of cardiovascular death, myocardial infarction, and stroke in patients with a history of myocardial infarction or acute coronary syndrome.
    • Ticagrelor differs from clopidogrel and prasugrel in that receptor blockade is reversible.

    Heparin

    • Heparin is a prototype anticoagulant, used to prevent and treat thromboembolic disorders.
    • It combines with antithrombin III to inactivate clotting factors IX, X, XI, and XII, inhibit the conversion of prothrombin to thrombin, and prevent thrombus formation.

    Pharmacokinetics of Heparin

    • Heparin is administered intravenously or subcutaneously, as the gastrointestinal tract does not absorb the drug.
    • After IV injection, the drug acts immediately; after subcutaneous injection, heparin acts within 20-30 minutes.
    • Metabolism takes place in the liver and the reticuloendothelial system, and excretion occurs in the urine.

    Use of Heparin

    • Prophylactically, patients at risk for certain disorders take low doses of heparin to prevent DVT and pulmonary embolism.
    • Heparin is used to manage acute thromboembolic disorders, such as DVT, thrombophlebitis, and pulmonary embolism.
    • Another use is in disseminated intravascular coagulation (DIC), a life-threatening condition characterized by widespread clotting.

    Adverse Effects of Heparin

    • Hemorrhage is a major adverse effect of heparin.
    • Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening complication of heparin administration, leading to a decrease in platelet count and detectable HIT antibodies.

    Contraindications of Heparin

    • Contraindications include GI ulcerations, intracranial bleeding, dissecting aortic aneurysm, blood dyscrasias, severe kidney or liver disease.

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    Explore different drug delivery systems including oral tablets, transdermal patches, and pump delivery systems used for administering various medications. Learn about the formulations and drugs commonly delivered through each system.

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