Pharmacology for Nurses Unit 2 Review: Drug Administration

Key Concepts and Terminology

• Pharmacology studies how drugs interact with the body, including their mechanisms of action, therapeutic effects, and potential adverse reactions
• Pharmacodynamics refers to the biochemical and physiological effects of drugs on the body, including receptor binding, signal transduction, and cellular responses
• Pharmacokinetics describes the absorption, distribution, metabolism, and excretion (ADME) of drugs in the body over time
• Therapeutic index is the ratio between the toxic dose and the therapeutic dose of a drug, indicating its safety margin
• Adverse drug reactions (ADRs) are unintended and harmful responses to a medication, ranging from mild side effects to severe allergic reactions or toxicity
• Drug interactions can occur when two or more drugs are taken together, potentially altering their effects or causing adverse reactions
• Medication errors are preventable incidents that may cause or lead to inappropriate medication use or patient harm, such as incorrect dosing or administration
• Controlled substances are drugs regulated by law due to their potential for abuse or dependence, such as opioids and stimulants

Routes of Drug Administration

• Oral administration is the most common and convenient route, involving swallowing tablets, capsules, or liquids
  • Advantages include ease of use, patient compliance, and gradual absorption
  • Disadvantages include potential for first-pass metabolism and gastrointestinal irritation
• Parenteral administration involves delivering drugs directly into the body, bypassing the gastrointestinal tract
  • Intravenous (IV) route delivers drugs directly into the bloodstream for rapid onset of action
  • Intramuscular (IM) route injects drugs into the muscle tissue for slower absorption than IV
  • Subcutaneous (SC) route injects drugs into the fatty tissue beneath the skin for sustained release
• Topical administration applies drugs directly to the skin or mucous membranes for local effects
  • Transdermal patches deliver drugs systemically through the skin for prolonged periods
  • Ophthalmic drops or ointments treat eye conditions such as glaucoma or infections
• Inhalation route delivers drugs directly to the lungs via aerosols or nebulizers, often used for respiratory conditions (asthma)
• Rectal or vaginal suppositories deliver drugs locally or systemically, useful when oral administration is not feasible

Dosage Calculations and Measurement

• Dosage calculations ensure accurate and safe administration of medications based on the patient's weight, age, and clinical condition
• Metric system is used for most dosage measurements, including grams (g), milligrams (mg), and micrograms (mcg)
• Liquid medications are measured in milliliters (mL) or liters (L), often using syringes or calibrated cups
• Dosage conversion may be necessary when changing routes of administration or formulations
  • Example: converting an oral dose to an equivalent IV dose based on bioavailability
• Dosage adjustments may be required for patients with renal or hepatic impairment, as well as pediatric or geriatric populations
• Weight-based dosing is common for many medications, especially in pediatrics, using mg/kg or mcg/kg calculations
• Dosage frequency and duration are important considerations, ensuring therapeutic levels are maintained while minimizing adverse effects
• Dosage rounding may be necessary for practical administration, but should be done cautiously to avoid significant deviations from the prescribed dose

Pharmacokinetics and Drug Absorption

• Absorption refers to the process by which a drug moves from the site of administration into the bloodstream
  • Factors affecting absorption include the drug's physicochemical properties, formulation, and route of administration
  • Bioavailability is the fraction of an administered dose that reaches the systemic circulation unchanged
• Distribution describes the movement of a drug from the bloodstream into various tissues and organs
  • Plasma protein binding can affect the distribution and activity of drugs, as only unbound drug is pharmacologically active
  • Volume of distribution (Vd) is a theoretical volume that a drug would need to be uniformly distributed in to achieve the observed plasma concentration
• Metabolism is the biochemical modification of drugs, primarily in the liver, to facilitate their elimination
  • Cytochrome P450 enzymes play a crucial role in drug metabolism, and their activity can be influenced by genetic variations or drug interactions
  • First-pass metabolism occurs when a drug is significantly metabolized before reaching the systemic circulation, reducing its bioavailability
• Excretion is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys and bile
  • Renal excretion is influenced by glomerular filtration, tubular secretion, and reabsorption
  • Half-life is the time required for the plasma concentration of a drug to decrease by 50%, which determines the dosing frequency

Safety Protocols and Precautions

• Medication reconciliation involves comparing a patient's current medication orders to all the medications they have been taking to avoid errors or interactions
• Five rights of medication administration ensure the right patient receives the right drug, at the right dose, through the right route, at the right time
• Double-check procedures involve having a second nurse independently verify the medication, dose, and patient before administration
• Aseptic technique is crucial when preparing and administering parenteral medications to prevent contamination and infection
  • Proper hand hygiene, sterile gloves, and disinfection of vials and injection sites are essential components
• Infection control measures, such as using single-dose vials and disposing of sharps properly, help prevent the spread of bloodborne pathogens
• Allergy checks and monitoring for adverse reactions are important to ensure patient safety, especially with new medications or known allergens
• High-alert medications (insulin, opioids, anticoagulants) require extra precautions and double-checks due to their potential for harm if used incorrectly
• Medication storage and expiration dates must be carefully monitored to ensure the integrity and effectiveness of drugs

Common Administration Techniques

• Oral administration techniques include instructing patients to take medications with a full glass of water, with or without food, and at specific times of day
• Parenteral administration techniques vary by route:
  • IV administration involves inserting a catheter into a vein, using aseptic technique, and monitoring for infiltration or phlebitis
  • IM injections are given at 90-degree angles into the deltoid, vastus lateralis, or gluteal muscles, using Z-track technique to prevent leakage
  • SC injections are given at 45-degree angles into the abdomen, thighs, or upper arms, using pinched skin to ensure proper depth
• Topical administration techniques include applying creams, ointments, or patches to clean, dry skin, and rotating application sites to prevent irritation
• Inhalation techniques involve using metered-dose inhalers (MDIs) or nebulizers, with proper spacer devices and breathing patterns for optimal drug delivery
• Nasogastric or enteral tube administration requires verifying tube placement, flushing the tube before and after medication delivery, and using liquid formulations when possible
• Patient positioning and comfort are important considerations for all administration techniques, ensuring proper body alignment and minimizing pain or anxiety

Patient Education and Communication

• Providing clear, understandable instructions on how to take medications, including dose, frequency, and duration
• Discussing the purpose and expected benefits of each medication, as well as potential side effects and when to seek medical attention
• Encouraging patients to ask questions and express concerns about their medications, fostering an open and trusting relationship
• Assessing patient understanding through teach-back methods, having them explain the key points in their own words
• Addressing barriers to adherence, such as cost, complexity of regimen, or cultural beliefs, and working with patients to find solutions
• Providing written materials, such as medication guides or pictorial instructions, to reinforce verbal education
• Emphasizing the importance of not sharing medications with others or stopping them abruptly without consulting a healthcare provider
• Collaborating with other healthcare professionals, such as pharmacists or physicians, to ensure consistent and comprehensive patient education

Legal and Ethical Considerations

• Prescription drug laws regulate the dispensing and administration of medications, requiring valid orders from licensed providers
• Controlled substance regulations, such as the Controlled Substances Act, impose strict requirements for storage, record-keeping, and disposal of certain drugs
• Scope of practice defines the legal boundaries within which nurses can administer medications, based on their licensure, certification, and institutional policies
• Informed consent is required before administering any medication, ensuring that patients understand the risks, benefits, and alternatives to treatment
• Patient confidentiality must be maintained when discussing or documenting medication use, in accordance with HIPAA regulations
• Medication errors or adverse events must be promptly reported through established channels, such as incident reports or quality improvement committees, to promote patient safety and system-wide learning
• Ethical principles, such as beneficence (promoting patient well-being) and non-maleficence (avoiding harm), guide decision-making in medication administration
• Professional accountability and continuous learning are essential for nurses to stay current with best practices and maintain competency in medication administration