Comprehensive Undergraduate Pharmacology and University Pharmacology Study Guide: Pharmacology and the Nursing Process

Nursing Process and Drug Therapy Fundamentals

• Human Needs Statement: This occurs during the Assessment phase of the nursing process, specifically as part of the collection of patient data.
• Phase of the Nursing Process:
  • Assessment: Focuses on the collection of patient data, including subjective and objective information.
  • Subjective Data: Information shared by the patient through the spoken word (e.g., a patient reporting they use the herbal product ginkgo).
  • Objective Data: Information gathered via the senses, such as sight, sound, feel, or smell (e.g., weight of $155\,pounds$, pulse of $72\,beats/minute$, and laboratory results).
  • Planning: Involves deciding on patient outcomes and setting specific, measurable goals. An outcome criterion must be specific and measurable (e.g., "The patient will demonstrate correct blood glucose testing technique").
  • Implementation: The phase where interventions are carried out, including administering medications and providing patient education (e.g., teaching a patient to keep a blood pressure journal).
  • Evaluation: Monitoring the patient‘s progress and response to medications (e.g., documenting therapeutic responses).
• The Rights of Medication Administration: Includes the Right Drug, Right Dose, Right Time, Right Route, Right Patient, Right Documentation, Right Reason, Right Response, and the Right to Refuse.
• The "Right Time" Rule: Medications must be given within a standard window of the scheduled time. Administering a drug $2\,hours$ late violates the "Right Time" principle (generally, a dose is late if given more than $30\,minutes$ after the scheduled time).
• Medication Order Completion: A complete order must include the route of administration. If missing, the nurse must contact the prescriber to clarify; the nurse should not assume or hold the medication indefinitely.
• Timing Considerations: When deciding the timing of a drug dose, the nurse must consider the patient‘s last meal due to pharmacokinetic (PK) and pharmacodynamic (PD) properties.
• Sequential Order of the Nursing Process:
  1. Assessment
  2. Human Needs Statement
  3. Planning
  4. Implementation
  5. Evaluation

Pharmacologic Principles

• Bioequivalent: Two drugs absorbed into circulation in the same amount and possessing the same bioavailability are bioequivalent.
• Steady State: The physiologic state where the amount of drug removed via elimination is equal to the amount absorbed from each dose.
• Synergistic Effect: Two drugs given together that result in an effect greater than the sum of their individual effects ($1 + 1 > 2$).
• Prodrug: An inactive drug dosage form that is converted into an active metabolite via biochemical reactions once inside the body.
• Routes of Administration:
  • Intravenous (IV): Provides the fastest absorption and bypasses the first-pass effect (metabolism in the liver before reaching circulation).
  • Parenteral: Includes IV, IM, and Subcutaneous; these bypass the first-pass effect.
  • Enteral (Oral): Absorbed from the GI tract and subject to first-pass effect. Forms from fastest to slowest absorption: Powder > Tablet > Capsule > Enteric-coated.
  • Subcutaneous (Subq): Injection into fatty tissue under the dermal layer.
  • Intradermal: Injection into superficial skin layers under the epidermis.
  • Intramuscular (IM): Injection into the muscle.
  • Transdermal: Applied via adhesive patch.
  • Buccal: Placed between the cheek and the gum.
  • Sublingual: Placed under the tongue.
• Pharmacokinetic Phases:
  • Absorption: Movement of drug into the blood.
  • Distribution: Transport by the bloodstream to its site of action.
  • Metabolism: Biotransformation, primarily in the liver.
  • Excretion: Removal of drug from the body, primarily via the kidneys. Renal failure significantly impairs excretion.
• Half-Life: The time required for one-half ($50\%$) of the original amount of drug to be removed from the body. If $10\,mg$ is given and the half-life is $5\,hours$, $5\,mg$ remains after the first half-life.
• Specific Drug Effects:
  • Onset of Action: Time required for a drug to elicit a therapeutic response.
  • Peak Effect: Time required for a drug to reach its maximum therapeutic response.
  • Duration of Action: The time period during which drug concentration is sufficient to cause a response.
• Drug Interactions and Toxicity:
  • Pharmacologic Reaction: An extension of a drug‘s normal effect (e.g., BP dropping too low from an antihypertensive).
  • Selective Enzyme Interaction: A drug binds to an enzyme to inhibit or enhance its action, protecting target cells.
  • Protein Binding: Highly protein-bound drugs have a longer duration of action because only "free" drugs are active.
• Types of Therapy:
  • Palliative: Goal is comfort (e.g., end-of-life opioid use).
  • Maintenance: Used for chronic illnesses (e.g., hypertension).
  • Empiric: Based on probabilities before cultures/results are known.
  • Supplemental: Replaces a substance (e.g., insulin for diabetes).

Lifespan Considerations

• Pregnancy:
  • Last Trimester: Drug transfer to the fetus is most likely due to enhanced blood flow to the fetus and increased free (unbound) drug in maternal circulation.
  • FDA Categories:
    • Category A: No risk to human fetus.
    • Category B: No risk to animal fetus; human info unavailable.
    • Category C: Adverse effects in animal fetus; human info unavailable.
    • Category D: Possible fetal risk, but benefits may outweigh risks.
    • Category X: Fetal abnormalities; risk outweighs benefit.
• Pediatrics:
  • Dosing: Most commonly calculated using $milligrams\,per\,kilogram\,(mg/kg)$ of body weight.
  • Pharmacokinetics: Neonates have immature livers (risk for toxicity) and slowed gastric emptying due to irregular peristalsis.
  • Total Body Water: Greater in children than adults.
  • Medication Administration: Mix unpleasant-tasting liquid with nonessential food like ice cream; do not use the word "candy."
• Geriatrics:
  • Polypharmacy: The simultaneous use of multiple medications.
  • Physiological Changes: Reduced hydrochloric acid (decreased gastric acidity), increased fat content, decreased lean body mass, and decreased intact nephrons/renal blood flow.
  • Dosing Principle: "Start low and go slow."
  • Diuretics (Thiazide): In the elderly, may cause leg cramps, dehydration, and fatigue.
  • Sedatives/Hypnotics: Increase risk for confusion, forgetfulness, and falls.

Cultural, Legal, and Ethical Considerations

• New Drug Development:
  • Placebo: Used to prevent researcher bias or unrealistic expectations.
  • Phase I: Small number of healthy volunteers; used to determine PK and optimal dosage.
• Controlled Substances (Schedules):
  • C-I: Only used with approved protocols; high abuse potential, no accepted medical use.
  • C-II: Written prescription only; no refills.
  • C-III: No more than $5$ refills in a $6-month$ period.
• Ethical Principles:
  • Beneficence: Actively promoting good.
  • Autonomy: Self-determination (e.g., a patient deciding on a living will).
  • Justice: Being fair and equal.
  • Veracity: Duty to tell the truth.
  • Nonmaleficence: Duty to do no harm.
• Legal Definitions:
  • Nursing Negligence: Failure to act as a reasonably prudent nurse would in similar circumstances.
  • Legend Drug: Refers specifically to prescription drugs.
• Cultural Concepts:
  • Drug Polymorphism: Variation in drug response due to age, gender, size, or body composition (influenced by diet, genetics, and culture).
  • Cultural Beliefs: Native Americans (harmony with nature); Hispanics (important to assess religious/medication beliefs).

Medication Errors: Prevention and Response

• Medication Error: A preventable adverse drug event.
• Notation Rules:
  • Leading Zeros: Always use a zero before a decimal (e.g., $0.75\,mg$) to prevent overdose.
  • Trailing Zeros: Never use a zero after a decimal (e.g., use $2\,mg$, not $2.0\,mg$).
• Verification Procedures:
  • Always listen to the patient if they question a pill.
  • For verbal/telephone orders, repeat the order back to the prescriber.
  • If an order is illegible, contact the prescriber; do not ask a colleague to guess.
• Reporting: Near-misses (errors caught before reaching the patient) must be reported per facility protocol.

Patient Education

• Learning Domains:
  • Cognitive: Problem-solving, recall, and facts (e.g., listing signs/symptoms).
  • Affective: Expresses feelings, beliefs, and values (e.g., adhering to a drug regimen).
  • Psychomotor: Performing a skill (e.g., self-injection or using an inhaler).
• Evaluation: Use "return demonstration" to verify psychomotor learning.
• measurable outcomes: Use verbs like "demonstrate" rather than "understand" or "know."
• Geriatric Education: Address visual/hearing changes (large print) and memory deficits (pill calendars).

OTC Drugs and Herbal Supplements

• Regulations: Dietary Supplement and Health Education Act ($1994$) classifies herbs as dietary supplements; producers don‘t need to prove efficacy.
• Cautions:
  • OTC drugs may mask symptoms of serious underlying disease (e.g., acid reducers delaying ulcer diagnosis).
  • Herb-Drug Interactions:
    • Kava: Interacts with sedatives (CNS depression).
    • Garlic: Interacts with hypoglycemics (lowers blood sugar) and anticoagulants (bleeding risk).
    • Ginkgo: Increases bleeding risk with antiplatelet drugs (ASA, warfarin).
    • Cranberry: Reduces renal drug elimination.

Analgesics

• Pain Classification:
  • Somatic: Skeletal muscle/joints; responds to NSAIDs.
  • Chronic: Long duration, slow onset (e.g., cancer pain).
  • Breakthrough: Pain between scheduled doses of long-acting meds; treat with immediate-release opioids.
• Opioids:
  • Adverse Effects: Respiratory depression (assess rate first), constipation, urinary retention, itching.
  • Antidote: Naloxone (Narcan) for respiratory depression ($< 10\,breaths/min$).
• Acetaminophen (Tylenol):
  • Toxicity: Hepatic necrosis (liver failure). Contraindicated in liver disease.
  • Dosage: Maximum dose is $3000\,mg/day$ (some sources state $4000\,mg$; follow transcript limits if specific).
  • Antidote: Acetylcysteine (smells like rotten eggs; dilute with soda).
• Adjuvants: Gabapentin (neuropathic pain), Corticosteroids (inflammation).

Anesthetics and NMBDs

• General Anesthesia:
  • Adverse Effect: Malignant Hyperthermia (sudden fever, muscle rigidity). Treatment: Dantrolene.
  • Elderly: Higher risk due to declining organ function.
• Neuromuscular Blocking Drugs (NMBDs): Paralyze all skeletal muscles including respiratory muscles; mechanical ventilation is mandatory. They provide no sedation or analgesia.
• Moderate Sedation: Patient maintains their own airway and responds to commands but has reduced anxiety and recall.

CNS Stimulants and Related Drugs

• ADHD (Methylphenidate): Give $4$ to $6\,hours$ before bedtime; monitor height and weight in children due to growth slowing risk.
• Weight Loss (Orlistat): Non-stimulant; limit fat to $< 30\%$) of calories to prevent oily spotting/fecal incontinence.
• Migraines (Triptans): Taken to treat migraines when they start; not for prevention.

Antiepileptic Drugs (AEDs)

• Phenytoin (Dilantin):
  • Therapeutic Level: $10$ to $20\,mcg/mL$.
  • Administration: IV only with Normal Saline; slow push ($< 50\,mg/min$).
  • Side Effect: Gingival hyperplasia (require dental care).
• Status Epilepticus: Treatment of choice is Diazepam or Lorazepam.
• Autoinduction: Associated with Carbamazepine; leads to lower-than-expected drug levels over time.

Cardiovascular Drugs

• Adrenergic Drugs: Mimic the Sympathetic Nervous System.
  • Beta1 stimulation: Positive chronotropic (increase HR), Positive inotropic (increase contractility).
• Adrenergic Blockers:
  • Beta Blockers: Cardioselective (Atenolol) vs. Non-selective (Propranolol). Mask hypoglycemia. Side effects: Bradycardia, impotence.
  • Alpha Blockers (Phentolamine): Treatment for IV extravasation of vasopressors.
• Heart Failure:
  • Digoxin: Negative chronotropic, positive inotropic. Therapeutic level $0.5$ to $2\,ng/mL$. Hypokalemia increases toxicity. Antidote: Digoxin immune Fab (Digifab).
• Antidysrhythmics:
  • Adenosine: Extremely short half-life ($< 10\,seconds$); give as fast IV push; asystole may occur for seconds.

Antibiotics and Specialty Medications

• Drug Classes and Considerations:
  • Sulfonamides: High concentrations in kidneys; used for UTIs. Interaction with Warfarin.
  • Aminoglycosides: Nephrotoxicity (BUN/creatinine) and Ototoxicity (tinnitus/dizziness).
  • Vancomycin: Drug of choice for MRSA. Trough levels: $10$ to $20\,mcg/mL$. Risk: Red Man Syndrome (slow infusion to prevent).
  • Antivirals: Acyclovir (Herpes); Zidovudine (HIV, safe for pregnancy to prevent infant transmission).
  • Antitubercular: Isoniazid (INH) can cause peripheral neuropathy (prevent with Vitamin B6/Pyridoxine). Rifampin colors urine/tears orange.
  • Immunosuppressants: Cyclosporine (no Styrofoam containers). Mycophenolate (Black Box: pregnancy risk).

Dosage Calculations (Selected Examples)

• Amoxicillin: Child weights $55\,lbs$ ($25\,kg$). Order: $50\,mg/kg/day$ divided into two doses. Result: $625\,mg/dose$. Calculation: $25\,kg \times 50\,mg/kg = 1250\,mg/day$. $1250 / 2 = 625\,mg$.
• Glycopyrrolate: $220\,lbs$ ($100\,kg$). Order: $4\,mcg/kg$. Result: $400\,mcg$ ($0.4\,mg$).