Key Terms
* Pharmacotherapeutics: Use of drugs to treat diseases.
* Pharmacokinetics: What the body does to the drug (Absorption, Distribution, Metabolism, Excretion).
* Pharmacodynamics: What the drug does to the body (effects & mechanisms).
Absorption, Distribution, Metabolism, Excretion (ADME)
* Absorption: How drug enters bloodstream (affected by route, GI health).
* Distribution: How drug spreads through body (depends on blood flow, protein binding).
* Metabolism: How liver changes drug (can activate or deactivate).
* Excretion: How kidneys remove drug (urine, feces).
Renal & Liver Issues on Elimination
* Impaired kidneys = decreased excretion → risk of toxicity.
* Impaired liver = decreased metabolism → drug buildup, increased half-life.
Definitions
* Adverse effects: Harmful, unintended effects.
* Side effects: Expected but often mild effects.
* Overdose: Too much drug → toxicity.
* Drug allergy: Immune reaction (rash, hives).
* Anaphylaxis: Severe, life-threatening allergic reaction (swelling, difficulty breathing).
Pharmacokinetic Concepts
* Half-life (t½): Time for drug level to reduce by half.
* Loading dose: Large initial dose to reach therapeutic level fast.
* Peak dose: Highest drug concentration in blood.
* Therapeutic effect: Desired effect.
* Critical concentration: Minimum blood level for effect.
Agonist vs Antagonist
* Agonist: Activates receptor → response (e.g., Morphine activates opioid receptor).
* Antagonist: Blocks receptor → no response (e.g., Naloxone blocks opioid receptor).
Routes of Administration & Absorption Speed
* Oral: Slow, affected by stomach pH.
* Mucosal/sublingual: Rapid absorption under tongue.
* Injection (IM, IV, SubQ): Fastest (IV fastest).
* Rectal: Moderate, bypasses some liver metabolism.
* Eye/ear drops, topical/patch: Local or systemic slow absorption.
* Extended-release: Slow release → longer effect, less frequent dosing.
FDA Drug Trial Phases
* Phase 1-3: Testing safety and efficacy.
* Phase 4: After market release (post-marketing surveillance).
Controlled Substance Schedules
* Schedule I (highest abuse, no medical use) to Schedule V (lowest abuse potential).
Pregnancy Categories
* A (safest) → X (contraindicated in pregnancy).
Black Box Warning
* Strongest FDA warning for serious side effects.
* Example: Isotretinoin (severe birth defects).
Brand vs Generic Names
* Brand = trademarked (Tylenol).
* Generic = chemical name (acetaminophen).
OTC & Herbal Concerns
* Risk of interactions, overdosing.
* Always educate patients to tell all meds & herbs.
Nurse’s Role in Medication Safety
* Three Checks:
1. Before pulling med
2. After pulling med
3. At bedside before administration
* Patient Rights: Right patient, drug, dose, route, time, reason, documentation, response, education.
* Common errors: Wrong dose, wrong patient, wrong route.
* If error: Assess patient → notify provider → document → incident report (not in chart).
Adrenergic & Cholinergic Agents
Sympathetic Nervous System (Adrenergic)
* Adrenergic agonist (sympathomimetic): Stimulates alpha/beta receptors → "fight or flight" effects.
* Alpha receptors: Vasoconstriction (raise BP).
* Beta 1 receptors: Increase heart rate/contractility.
* Beta 2 receptors: Bronchodilation.
* Examples: Epinephrine, Norepinephrine, Dopamine.
* Adrenergic antagonist (sympatholytic): Blocks receptors → opposite effect.
* Example: Tamsulosin (for BPH) lowers BP as side effect by blocking alpha-1 receptors.
Cholinergic System (Parasympathetic)
* Cholinergic agonist (parasympathomimetic): Stimulates nicotinic/muscarinic receptors → "rest & digest".
* Effects: Increased secretions, bradycardia, GI motility.
* Examples: Bethanechol, Pilocarpine.
* Cholinergic antagonist (anticholinergic): Blocks muscarinic receptors → "dry" effects.
* Examples: Atropine, Scopolamine, Oxybutynin.
* “Wet drugs”: Cholinergic agonists → increase secretions (saliva, tears).
* “Dry drugs”: Anticholinergics → decrease secretions, cause dry mouth.
Cholinergic Crisis
* Too much cholinergic → SLUDGE:
* Salivation, Lacrimation, Urination, Diaphoresis/Diarrhea, GI cramps, Emesis.
* Can cause respiratory failure.
Side Effects
* Cholinergic agonists: Excessive salivation, diarrhea.
* Anticholinergics: Dry mouth, urinary retention, blurred vision, tachycardia.
Specific Drugs to Know
Drug
Class
Indication
Key Side Effects
Nursing/Teaching Tips
Phenylephrine
Alpha-1 agonist
Nasal congestion, hypotension
Hypertension, rebound congestion
Monitor BP, avoid with HTN
Epinephrine
Alpha & Beta agonist
Anaphylaxis, cardiac arrest
Tachycardia, hypertension
Monitor heart, use in emergencies only
Dopamine
Dopaminergic/Adrenergic
Shock, heart failure
Tachyarrhythmias
Monitor cardiac status closely
Clonidine
Alpha-2 agonist
Hypertension
Hypotension, dry mouth
Do not stop abruptly to avoid rebound HTN
Phentolamine
Alpha blocker
Hypertensive crisis
Hypotension
Monitor BP after administration
Bethanechol
Cholinergic agonist
Urinary retention
Abdominal cramps, diarrhea
Monitor bladder function, avoid asthma
Tamsulosin
Alpha-1 blocker
BPH
Hypotension, dizziness
Monitor BP, teach about orthostatic hypotension
Metoprolol
Beta-1 blocker
HTN, angina, heart failure
Bradycardia, fatigue
Monitor HR, do not stop suddenly
Propranolol
Non-selective Beta blocker
HTN, arrhythmias
Bronchospasm, fatigue
Caution in asthma patients
Timolol
Beta blocker
Glaucoma
Eye irritation
Teach eye drop administration
Atenolol
Beta-1 blocker
HTN, angina
Bradycardia, fatigue
Monitor HR
Pilocarpine
Cholinergic agonist
Glaucoma, dry mouth
Sweating, nausea
Avoid in asthma, monitor vision
Donepezil (Aricept)
Acetylcholinesterase inhibitor
Alzheimer’s disease
Nausea, diarrhea
Take at bedtime, monitor cognition
Pyridostigmine
Acetylcholinesterase inhibitor
Myasthenia gravis
SLUDGE symptoms
Monitor muscle strength, watch for cholinergic crisis
Oxybutynin
Anticholinergic
Overactive bladder
Dry mouth, constipation
Encourage fluids, monitor for urinary retention
Scopolamine
Anticholinergic
Motion sickness
Dry mouth, drowsiness
Apply patch behind ear, avoid alcohol
Tiotropium
Anticholinergic
COPD
Dry mouth
Teach inhaler technique
Atropine
Anticholinergic
Bradycardia, pre-op to dry secretions
Tachycardia, dry mouth
Monitor HR, avoid in glaucoma
Dicyclomine
Anticholinergic
IBS
Dry mouth, blurred vision
Avoid driving, monitor bowel function