Pharmacology ATI Review

Pharmacology ATI Review Notes

Pharmacokinetics and Routes of Administration

Absorption

• Definition: Transmission of medications from the location of administration into the systemic circulation.

• Oral Administration: Absorption varies due to several factors:
    - Gastric pH: Influences solubility and stability of medications.
    - Other Medications: Interaction can hinder absorption.
    - Presence of Food: Can affect absorption rates and extent.
    - Form of Medication: For instance, coated pills may dissolve differently.

• Sublingual and Buccal:
    - Quick absorption systemically through mucous membranes.

• Other Mucous Membranes:
    - Rectal/Vaginal: Offer easy absorption, providing both local and systemic effects.

• Inhalation via Mouth, Nose:
    - Rapid absorption through alveolar capillary networks.

• Intradermal and Topical:
    - Slow, gradual absorption, primarily resulting in local effects; can sometimes have systemic effects.

• Subcutaneous and Intramuscular:
    - The rate of absorption depends on:
      - Solubility in Water: Poorly soluble medications result in slow absorption.
      - Blood Perfusion: Blood flow to the site of injection influences absorption speed.

• Intravenous (IV):
    - Immediate and complete absorption; medication enters directly into the bloodstream.

Distribution

• Definition: The transportation of medications to sites of action via bodily fluids.
• Impacting factors:
    - Circulation: Conditions that inhibit blood flow can slow distribution.
    - Permeability of Cell Membrane: Medications must be able to pass through tissues and membranes to reach their targets.
    - Plasma Protein Binding: Medications often compete for binding sites within the bloodstream.

Metabolism

• Definition: The process that changes medications into less active or inactive forms through enzyme action.
• Factors Influencing Metabolism Rate:
    - Age: Infants have limited capacity to metabolize medications, and hepatic metabolism declines with age.
    - First Pass Effect: The liver may inactivate some medications on their first pass through, necessitating nonenteral routes (sublingual, IV).
    - Similar Metabolic Pathways: When two medications use the same pathway, one may alter the metabolism of the other, possibly leading to medication accumulation.
    - Nutritional Status: Malnourished clients can lack necessary factors to produce specific medication-metabolizing enzymes.

Excretion

• Definition: The elimination of medications from the body, primarily through the kidneys.
• Other routes: Can also occur through the liver, lungs, intestines, and exocrine glands.
• Kidney Dysfunction: Can lead to increased duration and intensity of a medication’s response; monitoring of BUN (Blood Urea Nitrogen) and creatinine levels is important.

Medication Responses

Therapeutic Index

• Definition: A measure of a drug's safety, medications with a low therapeutic index require close monitoring of medication levels.
    - Monitoring Peaks:
      - Route of administration influences peak levels (e.g., oral medications peak 1 to 3 hours after administration, IV medications may peak within 10 minutes).

Half-Life

• Definition: The time required for the body to reduce the amount of medication by half.
    - Influenced by liver and kidney function.

Receptor Interactions

• Agonists:
    - Medications that bind to and mimic the actions of endogenous compounds that regulate receptor activity.
• Antagonists:
    - Medications that block the usual receptor activity or the receptor activity of other medications.
• Partial Agonists:
    - Have mixed effects, acting as both agonists and antagonists.

Safe Medication Administration

Knowledge Required Before Administration

• Medication Class: Understanding the properties and category of the medication being administered.
• Mechanism of Action: Knowledge of how the medication affects the body.
• Therapeutic Effects: Expected benefits of the medication.
• Adverse Effects: Potential negative reactions.
• Toxic Effects: Possible severe harmful reactions.
• Medication Interactions: Awareness of how different substances affect each other.
• Contraindications/Precautions: Conditions under which the medication should not be used or monitored closely.
• Preparation, Dosage, Administration: Correct protocols for effective delivery of the medication.
• Nursing Implications: Consideration of nursing responsibilities associated with the medication.

Rights of Medication Administration

1. Right Client
2. Right Medication
3. Right Dose
4. Right Time
5. Right Route
6. Right Documentation
7. Right Client Education
8. Right to Refuse
9. Right Assessment
10. Right Evaluation

Common Medication Errors

• Types of Errors:
    - Wrong medication or IV fluid.
    - Incorrect dose or IV rate.
    - Wrong client, route, or time.
    - Administration of an allergy-inducing medication.
    - Omission of a dose or administration of an extra dose.
    - Incorrect discontinuation of medication or IV fluid.
    - Inaccurate prescribing.
    - Inadvertently giving a medication with a similar name.

Medication Errors Protocol

• Notify the provider of all medication errors and implement corrective measures.
• Incident Report: Complete within the timeframe specified (typically 24 hours), including:
    - Client identification.
    - Name and dose of medication.
    - Time and place of incident.
    - Who was notified.
    - Actions taken and your signature.
• Ensure the report is completed by the staff member who discovers the error.
• Do not reference the incident report in the client’s medical record.
• Post-Error Assessment: Assess the client after a medication error occurs.

Intravenous Therapy

Advantages

• Rapid effects.
• Precise amounts of medication delivery.
• Consistent therapeutic blood levels.
• Less irritation compared to subcutaneous and muscle tissue.
• Permits usage of large volumes of fluids for medications poorly soluble.

Disadvantages

• Possibility of fluid overload.
• Immediate absorption allows minimal time for error correction.
• Irritation to the vein lining can occur.
• Poor aseptic techniques can lead to local or systemic infection.

Guidelines for Safe IV Medication Administration

• Use an infusion pump to administer medications causing serious adverse reactions.
• Add medications to a new IV fluid container, not to currently hanging fluids.
• Never administer medications through tubing that infuses blood products or parenteral nutrition (TPN).
• Verify medication compatibility with IV solutions prior to infusion.
• Use the IV port closest to the patient for medication administration.
• Caution: Avoid placing IV in a limb with a dialysis fistula or on the side of a previous mammogram.

Complications of IV Therapy

• Infiltration:
    - Signs include pallor, local swelling, decreased skin temperature, damp dressings, slowed infusion.
    - Nursing Action: Stop infusion, remove catheter, apply appropriate compress (cold or warm depending on solution), restart IV if necessary in a new site.

• Extravasation:
    - Signs include pain, burning, redness, swelling.
    - Nursing Action: Stop infusion, notify provider, follow facility protocols, may require administration of an antidote prior to catheter removal, follow similar treatment protocol as for infiltration.

Factors Affecting Medication Dosages and Responses

• Body Weight
• Age
• Sex
• Genetics
• Tolerance
• Accumulation
• Diet
• Medical Problems Affecting Absorption, Metabolism, or Excretion

Medications for Infection

Aminoglycosides

• Prototype drugs: Gentamicin
• Indications: Treatment of susceptible infections.
• Action: Disrupts bacterial protein synthesis.
• Contraindications/Cautions: Known allergy, pregnancy, lactation, renal impairment.
• Adverse Effects: Ototoxicity, nephrotoxicity, hypersensitivity.
• Nursing Considerations: Monitor for hearing loss, complete the entire course of therapy, dosing based on serum levels (draw peak and trough).

Carbapenems

• Prototype drugs: Meropenem, Imipenem
• Indications: Treatment of susceptible infections; broad-spectrum antibiotic.
• Action: Destroys bacterial cell wall.
• Contraindications/Cautions: Known allergy (possible cross-sensitivity with penicillin); renal impairment.
• Adverse Effects: Allergy, GI upset, suprainfection (colitis).
• Nursing Considerations: Monitor for allergic reactions after administration, complete the entire course of therapy.

Cephalosporins

• Prototype drugs: Cefazolin, Ceftriaxone, Cephalexin
• Indications: Broad-spectrum antibiotic for susceptible infections.
• Action: Destroys bacteria by weakening the cell wall.
• Contraindications/Cautions: Known allergy (risk of cross-sensitivity with penicillin allergy).
• Adverse Effects: Allergy, renal impairment, colitis, pain at injection site, disulfiram reaction with alcohol.
• Nursing Considerations: Monitor for allergic reactions, complete the entire course of therapy, take oral forms with food.

Fluoroquinolones

• Prototype drugs: Ciprofloxacin
• Indications: Treatment of susceptible infections; broad-spectrum.
• Action: Inhibits DNA replication in bacteria.
• Contraindications/Cautions: Known allergy; do not give to children.
• Adverse Effects: Achilles tendon rupture, suprainfection (thrush, yeast), GI discomfort.
• Nursing Considerations: Complete the entire course of therapy, reduce doses for patients with renal impairment.

Penicillins

• Prototype drugs: Amoxicillin, Penicillin, Ampicillin
• Indications: Treatment of susceptible infections, prophylaxis for surgery, dental procedures.
• Action: Destroys bacteria by weakening the cell wall.
• Contraindications/Cautions: Known allergy, renal disease.
• Adverse Effects: Allergy/anaphylaxis, renal impairment, hyperkalemia, hypernatremia.
• Nursing Considerations: Monitor for allergic reactions, complete the entire course of therapy, may reduce effectiveness of oral contraceptives.

Sulfonamides

• Prototype drugs: Trimethoprim
• Indications: Treatment of susceptible infections; UTIs.
• Action: Prevents bacterial growth.
• Contraindications/Cautions: Known allergy; folate deficiency; pregnancy and lactation.
• Adverse Effects: Hypersensitivity, hyperkalemia, blood dyscrasias.
• Nursing Considerations: Complete the entire course of therapy; may decrease the effectiveness of oral contraceptives.

Urinary Tract Antiseptics

• Prototype drugs: Nitrofurantoin
• Indications: Treatment of susceptible urinary tract infections; UTIs.
• Action: Damages bacterial DNA.
• Contraindications/Cautions: Known allergy; impaired renal function; do not use in third trimester of pregnancy or in lactation (infants <1 month).
• Adverse Effects: GI discomfort; agranulocytosis, peripheral neuropathy.
• Nursing Considerations: Complete the entire course of therapy; may turn urine rust-yellow to brown; avoid crushing capsules due to staining effect.

Tetracyclines

• Prototype drugs: Tetracycline, Doxycycline
• Indications: Acne, Lyme disease, other infections.
• Action: Broad-spectrum; inhibit bacterial growth.
• Contraindications/Cautions: Known allergy; renal impairment; pregnancy; children under age 8.
• Adverse Effects: Allergy; GI discomfort, tooth discoloration in children, photosensitivity.
• Nursing Considerations: Monitor for allergic reactions, complete the entire course of therapy, may decrease effectiveness of oral contraceptives.

Antimycobacterial Agents

• Prototype drugs: Isoniazid

• Indications: Treatment of tuberculosis.

• Action: Prevents cell wall synthesis.

• Contraindications/Cautions: Liver disease; caution in those with alcohol use disorder.

• Adverse Effects: Peripheral neuropathy; hepatotoxicity; hyperglycemia.

• Nursing Considerations: Complete the entire course of therapy; may decrease oral contraceptive effectiveness.

• Prototype drugs: Rifampin

• Indications: Treatment of tuberculosis in combination; treatment of other susceptible infections.

• Action: Inhibits bacterial protein synthesis.

• Contraindications/Cautions: Use cautiously in patients with liver dysfunction.

• Adverse Effects: Discoloration of body fluids; hepatotoxicity; mild GI discomfort, colitis.

• Nursing Considerations: Complete the entire course; can decrease efficacy of oral contraceptives; inform patients about potential discoloration of urine and sweat.

Macrolides

• Prototype drugs: Erythromycin, Azithromycin
• Indications: Treatment of susceptible infections like pneumonia, chlamydia, pertussis.
• Action: Inhibits bacterial protein synthesis.
• Contraindications/Cautions: Known allergy; liver disease; prolonged QT interval.
• Adverse Effects: GI discomfort; prolonged QT interval; ototoxicity.
• Nursing Considerations: Monitor for hearing loss, complete the entire course, may decrease effectiveness of oral contraceptives.

Other Anti-infectives

• Prototype drugs: Vancomycin
• Indications: Treatment of serious infections; treatment of MRSA, colitis.
• Action: Destroys bacterial cell wall.
• Contraindications/Cautions: Known allergy; renal impairment.
• Adverse Effects: Allergy; ototoxicity; infusion reaction (Red man syndrome).
• Nursing Considerations: Monitor for allergic reactions, complete the course of therapy, administer slowly to prevent red man syndrome, monitor for renal toxicity.

Antivirals

• Prototype drugs: Acyclovir; Oseltamivir
• Indications: Treatment of viral infections (herpes, varicella, influenza).
• Action: Prevents reproduction of viral DNA.
• Contraindications/Cautions: Renal impairment.
• Adverse Effects: Nephrotoxicity; phlebitis and inflammation at infusion site.
• Nursing Considerations: Complete the entire course, use barrier contraception, refrain from sexual contact while lesions are present.

Antifungals

• Prototype drugs: Ketoconazole, Amphotericin B
• Indications: Treatment of systemic and superficial fungal infections.
• Action: Acts on fungal cell membranes.
• Contraindications/Cautions: Liver or kidney impairment; caution in anemia.
• Adverse Effects: Nephrotoxicity; electrolyte imbalances; hepatotoxicity; gynecomastia; bone marrow suppression.
• Nursing Considerations: Complete the entire course, can decrease oral contraceptive effectiveness; Amphotericin B is highly toxic - reserve for severe infections.

Antiprotozoal

• Prototype drugs: Metronidazole
• Indications: Treatment of protozoal infections; prophylaxis for surgery.
• Action: Broad-spectrum antimicrobial.
• Contraindications/Cautions: First trimester of pregnancy; caution in renal disease.
• Adverse Effects: GI discomfort, darkening of urine, neurotoxicity.
• Nursing Considerations: Complete the entire course, may decrease oral contraceptive effectiveness; refrain from intercourse for STD treatment until partners are treated.

Medications for Pain and Inflammation

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

• Prototype drugs: Aspirin, Ibuprofen, Naproxen, Celecoxib (Cox-2).
• Indications: Inflammation suppression, analgesia, fever reduction.
• Action: Inhibit COX-1 and COX-2 enzymes.
• Contraindications/Cautions: Pregnancy, peptic ulcer disease, bleeding disorders.
• Adverse Effects: GI discomfort, impaired kidney function, increased risk of heart attack, Reye's syndrome (use of ASA in children with viral illness).
• Nursing Considerations: Avoid aspirin in children, take NSAIDs with food to reduce GI discomfort; do not chew or crush enteric-coated aspirin.

Non-Opioid Analgesics

• Prototype drugs: Acetaminophen
• Indications: Analgesia, fever reduction.
• Action: Slows production of prostaglandins in the CNS.
• Contraindications/Cautions: Hypersensitivity, liver impairment, chronic alcohol use.
• Adverse Effects: Acute toxicity; elevated liver enzymes, liver damage.
• Nursing Considerations: Read medication labels carefully; notify provider if pain or fever persists beyond 3 days.

Opioid Agonists

• Prototype drugs: Morphine
• Indications: Relief of moderate to severe pain; sedation, cough suppression.
• Action: Acts on mu and kappa receptors.
• Contraindications/Cautions: Biliary tract surgery, premature infants, asthma, hepatic and renal disease.
• Adverse Effects: Respiratory depression, constipation, orthostatic hypotension, sedation.
• Nursing Considerations: Monitor pain level and document client’s response; notify provider if respiratory rate <12; double-check doses with another nurse.

Opioid Antagonists

• Prototype drugs: Naloxone
• Indications: Reversal of effects of opioids, treatment of opioid overdose.
• Action: Competes for the same receptors as opioids.
• Contraindications/Cautions: Opioid dependency, acute hepatitis or liver failure.
• Adverse Effects: Tachycardia, tachypnea, withdrawal symptoms.
• Nursing Considerations: Can be given IV, IM, or subcutaneously; observe for withdrawal symptoms; avoid rapid infusion to prevent hypertension.

Medications Affecting the Nervous System

CNS Agents

• Benzodiazepines:
    - Prototype drugs: Alprazolam, Diazepam.
    - Indications: Anxiety disorders, panic disorder, muscle spasms, alcohol withdrawal, seizures.
    - Action: Relief of anxiety by inhibiting GABA effects.
    - Adverse Effects: CNS depression, amnesia, toxicity, withdrawal effects.
    - Nursing Considerations: Use caution in those with abuse history; take at bedtime to minimize daytime sedation.

• Atypical Antidepressants:
    - Prototype drugs: Bupropion.
    - Indications: Depression, smoking cessation.
    - Action: Inhibits norepinephrine and dopamine uptake.
    - Adverse Effects: Headache, dry mouth, constipation, seizures.
    - Nursing Considerations: Do not administer within 2 weeks of MAOIs.

Mood Stabilizers

• Prototype drugs: Lithium Carbonate.
• Indications: Bipolar disorder.
• Action: Produces neurochemical changes in the brain.
• Contraindications/Cautions: Pregnancy, renal dysfunction, thyroid disease.
• Adverse Effects: GI distress, hand tremors, weight gain, lithium toxicity.
• Nursing Considerations: Monitor lithium levels (therapeutic range: 0.6-1.2), avoid dehydration.

Antipsychotics

• First-Generation: Chlorpromazine, Haloperidol.
    - Indications: Acute and chronic psychotic disorders.
    - Action: Block dopamine, acetylcholine, histamine, norepinephrine receptors.
    - Adverse Effects: EPS, parkinsonism, NMS, sedation.
    - Nursing Considerations: Monitor side effects with AIMS scale, therapeutic effects take up to 2 weeks.

• Second-Generation: Risperidone, Clozapine.
    - Indications: Acute and chronic psychotic disorders.
    - Action: Block serotonin and dopamine receptors.
    - Adverse Effects: Diabetes risk, agranulocytosis with Clozapine.
    - Nursing Considerations: Monitoring WBCs with Clozapine.

Medications Affecting Seizures

• Prototype drugs: Phenytoin, Lamotrigine.
• Indications: Seizure disorders, mood disorders.
• Adverse Effects: CNS effects, hepatotoxicity.
• Nursing Considerations: Monitor therapeutic levels; caution due to sedative effects.

Other CNS Agents

• Centrally Acting Muscle Relaxants:
    - Prototype drugs: Baclofen, Cyclobenzaprine.
    - Indications: Relief of muscle spasm.
    - Adverse Effects: CNS effects, risk of dependency.
    - Nursing Considerations: Avoid driving; take with meals to avoid GI upset.

• Cholinesterase Inhibitors:
    - Prototype drugs: Neostigmine, Donepezil.
    - Indications: Myasthenia gravis (neostigmine), Alzheimer's (Donepezil).
    - Action: Prevents inactivation of acetylcholine, increasing available acetylcholine at receptor sites.
    - Contraindications/Cautions: Obstruction of GI/renal system, clients receiving succinylcholine.
    - Adverse Effects: Increased GI motility, bradycardia, ch olinergic crisis symptoms.
    - Nursing Considerations: Monitor for toxicity; assess symptom improvement.