Medication Routes

Overview of Medication Administration & Route Selection

  • Course Information:
    • Course Title: PNCR 102: Math & Pharmacology Medication Routes
    • Schedule: Week 2 – Summer 2026 (May 27, 2026)
    • Instructors: Professor LeGros and DiCicco
  • Key Determinants of Route Selection:
    • Patient condition and physiological state
    • Drug properties (chemical makeup, acid sensitivity, solubility)
    • Onset speed requirements (emergency vs. maintenance therapy)
  • Special Population Considerations:
    • Pediatric Patients: Require adjusted routes and precise delivery techniques due to swallowing ability, developmental capacity, and distinct physiological absorption rates.
    • Older Adults: Require tailored route selection due to changes in swallowing ability, altered GI tract absorption, and age-related physiological declines.
  • Fundamental Patient Assessment Questions Prior to Administration:
    • Can the patient swallow safely?
    • Is the patient currently experiencing nausea or vomiting?
    • Is the patient fully conscious and alert?
    • Does the patient have known allergies to specific drug delivery agents, vehicles, or bases?
  • Speed Hierarchy & NCLEX Pharmacology Tips:
    • Absorption Speed Ranking: IV>IM>SubQ>IDIV > IM > SubQ > ID
    • Intravenous (IV): Offers the absolute fastest onset of action as medication enters the vascular system directly.
    • Sublingual (SL): Placed beneath the tongue to bypass first-pass liver metabolism completely.
    • Transdermal: Applied as a patch to deliver slow, continuous, and steady systemic absorption.
    • Intramuscular (IM): Absorbs significantly faster than subcutaneous tissue due to high muscle vascularity.
    • Rectal (PR): Highly effective alternative route for unconscious, non-compliant, or severely vomiting patients.

Summary Table of Medication Routes

  • Enteral Routes:
    • Oral (PO): Swallowed and absorbed through the gastrointestinal tract (e.g., Tablets, capsules).
    • Sublingual (SL): Placed under the tongue for rapid capillary absorption (e.g., Nitroglycerin).
    • Buccal: Placed between the cheek and gum to dissolve across mucous membranes (e.g., Buccal pain medication).
    • Rectal (PR): Inserted directly into the rectum; bypasses upper GI tract (e.g., Suppositories).
  • Parenteral Routes:
    • Intravenous (IV): Injected directly into a vein; fastest possible absorption (e.g., IV antibiotics).
    • Intramuscular (IM): Injected into vascularized muscle tissue for rapid absorption (e.g., Vaccines, pain medications).
    • Subcutaneous (SC / SubQ): Injected into adipose/fatty tissue beneath the skin; slower absorption (e.g., Insulin, heparin).
    • Intradermal (ID): Injected directly into the dermis layer of skin; utilized for diagnostic testing (e.g., TB test, allergy testing).
  • Topical Routes:
    • Topical / Dermal: Applied directly onto the skin surface primarily for localized effect (e.g., Antibiotic creams, corticosteroid ointments).
    • Transdermal: Absorbed through intact skin via a continuous-release patch for systemic delivery (e.g., Nicotine patch, fentanyl patch).
  • Inhalation Route:
    • Inhalation: Inhaled directly into the lungs as a gas, aerosol mist, or fine powder (e.g., Albuterol MDI, nebulized treatments).
  • Mucosal Routes:
    • Nasal: Administered directly into the nasal passages (e.g., Nasal spray).
    • Ophthalmic: Administered into the eye structures (e.g., Eye drops).
    • Otic: Administered into the external ear canal (e.g., Ear drops).
    • Vaginal (PV): Inserted directly into the vagina (e.g., Vaginal cream, vaginal tablet).

Enteral Route Pharmacodynamics & Terminology

  • Principles of Enteral Administration:
    • Enteral administration involves any medication introduced into and absorbed through the gastrointestinal (GI) tract.
    • Represents the most frequent and preferred route of delivery whenever patients can safely tolerate oral intake.
    • Requires pre-administration assessment of patient swallowing ability, GI motility, and NPO (nothing by mouth) status.
  • Key Vocabulary Definitions:
    • Buccal: Administration route where medication is placed between the cheek and gum to dissolve and absorb directly across oral mucous membranes.
    • Buffered: Tablet formulation containing added antacids to neutralize stomach acid and prevent gastric irritation.
    • Delayed Action / Enteric-Coated: Specialized coating preventing tablet dissolution within the acidic stomach environment; medication dissolves and releases in the small intestine instead.
    • Enema: Liquid solution administered rectally to deliver medication, soften stool, or perform bowel cleansing.
    • Mortar and Pestle: Clinical equipment utilized to crush solid tablets into a fine powder when patients cannot swallow solid forms.
    • Sublingual: Medication placed directly underneath the tongue.
    • Timed-Release: Formulation engineered to release active drug continuously and gradually over an extended time period.

Enteral Formulations & Clinical Administration Protocols

  • Solid Oral Formulations:
    • Tablets & Capsules: The most common solid enteral vehicles.
    • Scored Tablets: Manufactured with a center score line allowing them to be split evenly for dosage adjustments. Only split tablets along the designated score. Unscored tablets, enteric-coated tablets, and extended-release tablets must NEVER be split.
    • Standard Capsules: Gelatin-coated shells containing powder or liquid. Certain standard capsules may be opened and mixed with food only after verifying with a pharmacist.
    • Extended-Release / Timed-Release Capsules: Formulated for gradual absorption over hours. Must NEVER be crushed, chewed, or opened unless explicitly directed by a pharmacist.
  • Liquid Oral Formulations:
    • Solutions: Active medication is evenly dissolved throughout the liquid; requires no shaking prior to administration.
    • Suspensions: Solid drug particles are suspended in liquid and settle over time; MUST be shaken thoroughly before measuring to ensure accurate dosing.
    • Syrups: Medication dissolved in a concentrated, highly sweetened liquid base to improve palatability, particularly in pediatric care.
    • Elixirs: Contain alcohol (ETOH\text{ETOH}) and water to dissolve medication and improve taste. Must be kept tightly capped. Absolute contraindications include pediatric patients, diabetic patients, and patients with a history of alcoholism.
    • Emulsions: Liquid mixtures containing fats or oils suspended in water.
    • Powders: Finely ground medications requiring reconstitution with a specific diluent prior to administration according to precise manufacturer instructions.
  • Specialized Oral Delivery Devices & Techniques:
    • Oral Syringes:
    • Provide precise liquid volume delivery for patients unable to drink from standard med cups.
    • Physical Safety Feature: Completely incompatible with IV tubing, ports, or injection needles.
    • Indications: Infants, young children, neurologically impaired patients, dysphagic patients, and micro-dose volumes.
    • Administration Technique: Inject medication slowly and gently into the side of the mouth (buccal pocket). NEVER squirt directly toward the back of the throat due to high aspiration risk. Allow swallowing between small increments. Position infants in a semi-reclined position.
    • Safety Precaution: Store and label oral syringes separately from parenteral equipment.
    • Sublingual & Buccal Techniques:
    • Sublingual (SL): Placed under the tongue. Highly vascularized capillary bed yields rapid absorption straight into systemic circulation, avoiding the hepatic first-pass effect (e.g., Sublingual Nitroglycerin for acute angina).
    • Buccal: Troches or lozenges placed between cheek and gum to dissolve slowly. Patient must not chew, crush, or swallow the troche.
    • Gastric & Nasogastric (NG) Tube Administration:
    • Liquid enteral medications are preferred for NG tube delivery.
    • Always verify correct tube placement prior to introducing any substance.
    • Flush the tube with water both BEFORE and AFTER medication administration to maintain patency.
    • Always consult a pharmacist before attempting to crush solid tablets or open capsule contents.

Oral Route Evaluation & Clinical Contraindications

  • Advantages of the Oral Route (PO):
    • Preferred administration method whenever clinically feasible.
    • Non-Invasive: Requires no needles, vascular catheters, or sterile procedures; minimizes patient pain and infection risks.
    • Well Tolerated: High familiarity increases patient compliance and comfort.
    • Minimal Equipment: Requires basic, inexpensive supplies (medication cup, water).
    • Highly Cost-Effective: Significantly cheaper than parenteral equipment and sterile setups.
  • Disadvantages of the Oral Route (PO):
    • Slower Absorption: Must undergo GI tract transport and absorption; onset of action is significantly delayed compared to parenteral options.
    • Aspiration Risk: High danger of choking or aspiration pneumonia in patients with dysphagia, altered consciousness, or impaired gag reflexes.
    • Gastric Acid Degradation: Stomach acids destroy vulnerable drug structures (e.g., Insulin cannot be administered orally due to gastric inactivation).
    • Patient Dependency: Requires an alert, cooperative, and physically capable patient.
    • Food & GI Interactions: Gastric contents and food presence unpredictably alter drug absorption rates and therapeutic effectiveness.
  • Absolute & Relative Contraindications for Oral Administration:
    • Active Nausea & Vomiting: Inability to retain fluids; switch to PR, IV, or IM routes.
    • Dysphagia / Swallowing Impairment: Severe aspiration risk.
    • Acid-Inactivated Medications: Requiring parenteral routes (e.g., SubQ Insulin).
    • Unconscious or Unresponsive Patient: Absolute contraindication due to inability to protect the airway. Never administer oral medications to an unconscious patient.
    • Pre-Administration Protocol: Always assess level of consciousness (LOC), presence of a gag reflex, and swallowing capability before giving PO medications.

Rectal Medication Administration

  • Clinical Indications:
    • Indicated when the oral route is completely compromised due to intractable vomiting, patient unconsciousness, or strict NPO orders.
  • Formulations & Clinical Protocols:
    • Rectal Suppositories: Formulated in a solid cocoa butter or glycerin base that melts at internal body temperature. Avoid excessive handling prior to administration, as body heat from hands will melt the suppository prematurely.
    • Enemas: Liquid solutions introduced rectally to administer drugs, soften impacted stool, or cleanse the lower bowel. Delivered using a lubricated applicator tip.
    • Rectal Ointments & Suspensions: Applied directly using specialized rectal applicators for systemic absorption or local rectal tissue treatment.

Parenteral Administration Protocols & Technical Specifications

  • Parenteral Overview:
    • Completely bypasses the gastrointestinal tract by injecting drugs directly into vascular systems or bodily tissues.
    • Demands strict aseptic technique and precise anatomical knowledge.
  • Speed Hierarchy:
    • IV>IM>SubQ>IDIV > IM > SubQ > ID
  • Intravenous (IV) Administration:
    • Injection directly into a vein.
    • Provides instantaneous drug delivery and the fastest onset of action (e.g., IV antibiotic therapy).
  • Intramuscular (IM) Administration:
    • Direct injection into vascularized skeletal muscle tissue for rapid systemic absorption.
    • Indications: Antibiotic delivery, acute pain management, immunizations/vaccines, and Vitamin B12 replacement.
    • Equipment & Technical Specifications:
    • Needle Length: 1 to 2 inches1\text{ to }2\text{ inches} (selected based on patient tissue depth and site).
    • Needle Gauge: 20 to 23 gauge20\text{ to }23\text{ gauge}.
    • Angle of Insertion: 90∘90^\circ (perpendicular to the skin surface).
    • Injection Technique: Z-track method is recommended for all IM injections to prevent medication leakage back into subcutaneous tissue and avoid localized tissue irritation.
    • Anatomical Sites & Volume Limits:
    • Deltoid Muscle: Located in the upper arm. Small muscle mass; strictly limited to needle lengths no longer than 1 inch1\text{ inch} and maximum injection volumes of 1 mL1\,mL. Primary site for adult vaccinations (e.g., influenza vaccine).
    • Vastus Lateralis Muscle: Located on the anterolateral outer thigh. Preferred injection site for infants and toddlers; also used in adults when other sites are unavailable. Accommodates volume capacity up to 2–3 mL2\text{--}3\,mL.
    • Ventrogluteal Muscle: Preferred IM injection site for adult patients. Deep muscle mass situated safely away from major blood vessels and nerve trunks. Accommodates volume capacity up to 2.5\text{--}3\,mL$.\n- Subcutaneous (SubQ / SC) Administration:\n - Injection into the adipose (fatty) layer located directly beneath the dermis.\n - Slower absorption rate than IM due to lesser vascularity of fat tissue; ideal for sustained, slow drug release.\n - Key Medications: Insulin and Heparin (both demand precise dosage verification and systematic site management).\n - Anatomical Injection Sites: Fleshy outer region of upper arms, abdomen (at least 2\text{ inches} away from the umbilicus/navel), and outer anterior thighs.\n - Site Rotation: Crucial to prevent tissue lipodystrophy and ensure uniform drug absorption.\n - Equipment & Technical Specifications:\n - Needle Length: 5/8\text{ inch}.\n - Needle Gauge: 25\text{ to }27\text{ gauge}.\n - Angle of Insertion: 45^\circforlean/thinpatients;for lean/thin patients;90^\circ for patients with abundant subcutaneous tissue.\n - Post-Injection Rule: NEVER massage the injection site following insulin administration.\n- Intradermal (ID) Administration:\n - Injection delivered into the dermal skin layer located right beneath the epidermis.\n - Diagnostic Indications: Mantoux Tuberculin (TB) skin testing and allergy testing.\n - Anatomical Sites: Inner aspect of the forearm or upper back tissue.\n - Technical Specifications:\n - Angle of Insertion: 10^\circ\text{ to }15^\circ.\n - Aspiration: Do NOT aspirate for blood.\n - Expected Outcome: Correct placement produces a visible localized skin elevation known as a wheal or bleb.\n\n# Topical & Transdermal Formulations\n\n- Topical Formulations (Local vs. Systemic Effects):\n - Ointment: Petroleum-based preparation ensuring prolonged skin contact. Creates an occlusive barrier; does not absorb directly into skin layers.\n - Cream: Water-based preparation that absorbs into the skin surface and disappears. Less occlusive and cosmetically preferable.\n - Gel: Semisolid suspension that liquefies upon skin contact. Frequently used for anti-inflammatory or topical antimicrobial administration.\n - Liniment (Salve): Semisolid preparation designed to induce mild localized skin irritation to enhance blood flow to underlying tissues (used for joint stiffness and muscle aches).\n - Lotion: Water-based liquid or semisolid vehicle. Spreads smoothly across wide surface areas and dries rapidly.\n - Plaster: Adhesive material backed with paper, linen, or moleskin applied to skin for sustained localized contact.\n- Transdermal Patches:\n - Delivers medication continuously across intact skin into systemic circulation at a controlled rate over extended timeframes (12\text{ to }72\text{ hours}).\n - Therapeutic Indications: Chronic pain control (e.g., Fentanyl patch), nicotine cessation therapy (e.g., Nicotine patch), prophylactic angina prevention (e.g., Nitroglycerin patch), and continuous hormone therapy (e.g., Estrogen or contraceptive patches).\n - Clinical Advantages: Simple application and removal; yields continuous, even blood concentrations over sustained durations (12\text{ to }72\text{ hours}).\n - Disadvantages & Hazards: Reduced adhesion from diaphoresis or bathing; extreme risk of systemic overdose if multiple patches are active simultaneously; severe poisoning hazard to children and pets if improperly discarded.\n - Nursing Protocols for Patches:\n - Document date, time, and nurse initials directly onto the outer surface of the new patch.\n - Always locate and REMOVE the old transdermal patch BEFORE applying a new one to prevent lethal double-dosing.\n - Safe Disposal: Fold the adhesive sides of the used patch firmly together and dispose of in an appropriate container.\n\n# Mucosal Medication Administration Protocols\n\n- Ophthalmic Administration Protocol:\n - Used for localized eye pathologies (infections, glaucoma, dry eye syndrome).\n - Aseptic Safety: Wear clean gloves. Never touch the dropper tip directly to the eye structures to prevent severe cross-contamination.\n - Patient Positioning: Direct the patient to look upward during instillation.\n - Sequence Rule: Always instil ophthalmic drops BEFORE applying eye ointments.\n - Delivery Types:\n - Eye Drops: Lubricate structures and treat ocular conditions via rapid mucosal absorption.\n - Eye Ointments: Thickened therapeutic preparations applied along the inner border of the lower eyelid conjunctival sac.\n - Ocular Inserts: Flexible, transparent membrane units placed in the eye to release drug continuously.\n- Otic Administration Protocol:\n - Used for localized ear pathologies (otitis externa, ear pain, cerumen impaction).\n - Age-Dependent Pinna Positioning Rules:\n - Adults and Children Older Than 3\text{ Years}: Pull the pinna UP and BACK to straighten the external auditory canal.\n - Children Younger Than 3\text{ Years}: Pull the pinna DOWN and BACK to align the ear canal.\n - Temperature Precaution: Warm otic drops to room temperature prior to instillation. Instilling cold otic drops induces severe vertigo, nausea, and discomfort.\n - Post-Administration Nursing Care:\n - Instruct the patient to keep the treated ear facing upward toward the ceiling following instillation to allow fluid drainage down the canal.\n - Never pack a cotton ball tightly into the ear canal. If ordered, place a cotton ball loosely at the outermost canal opening only (Procedure Box 10.3).\n- Vaginal Administration Protocol:\n - Indicated for local gynecological treatment (fungal/bacterial infections, mucosal hormone deficiency, localized contraception).\n - Frequently self-administered by patients at home.\n - Positioning: Place the patient in the lithotomy position (supine with knees flexed and legs separated) or lying on the left side.\n - Patient Dignity & Comfort: Ensure complete room privacy and maintain patient draping. Have the patient void/empty the bladder prior to administration to maximize comfort and reduce expulsion risk.\n - Technique: Apply water-soluble lubricant to the applicator tip before insertion (Procedure Box 10.4).\n- Nasal Administration Protocol:\n - Indicated for seasonal allergic rhinitis, asthma, acute sinus congestion, and inflammation.\n - Formats: Metered nasal spray pump bottles, pressurized inhalers, or liquid droppers.\n - Sequential Administration Steps:\n 1. Direct the patient to gently blow their nose to clear all nasal mucosa.\n 2. Administer the ordered dosage into the prescribed nostril(s).\n 3. Instruct the patient to tilt their head back to facilitate distribution and absorption across the nasal mucosa.\n 4. Provide tissues to the patient.\n 5. Thoroughly rinse liquid droppers after administration. NEVER rinse nasal spray pump bottles, as water contamination alters calibrated dose delivery (Procedure Box 10.5).\n\n# Respiratory Inhalation Therapy & Devices\n\n- Principles of Inhalation Delivery:\n - Delivers medication directly into the respiratory bronchial tree, providing rapid local therapeutic action and prompt systemic absorption across the vast pulmonary capillary bed.\n- Specific Pathological Indications:\n - Asthma: Inhaled short-acting bronchodilators (e.g., Albuterol) and inhaled corticosteroids are administered to reverse bronchospasm and reduce airway inflammation during acute attacks and chronic management.\n - Cystic Fibrosis: Inhaled mucolytic agents thin and liquefy tenacious bronchial mucus secretions to prevent infectious complications and maintain lung function.\n - Sleep Apnea: Continuous Positive Airway Pressure (CPAP) therapy forces ambient air pressure into respiratory passages to prevent upper airway collapse during sleep.\n- Inhalation Delivery Devices:\n - Nasal Cannula & Oxygen Masks: Administer supplemental oxygen or nebulized agents; ideal for patients unable to perform active breathing maneuvers. Select masks when elevated oxygen concentrations are required.\n - CPAP Machines: Deliver continuous pressurized air/oxygen into the respiratory tract to prevent hypopnea and apneic pauses.\n - Metered-Dose Inhalers (MDIs):\n - Compact, pressurized handheld delivery devices dispensing a measured drug actuation.\n - Essential Patient Teaching: Shake the MDI canister vigorously prior to use. Instruct patient to exhale completely, place mouthpiece in mouth, depress canister while inhaling slowly and deeply, and hold their breath for 10\text{ seconds}$$ to ensure optimal deep pulmonary deposition (Procedure Box 10.6).
    • Nebulizers:
    • Power-driven machines converting liquid drug solutions into a continuous, fine breathable mist.
    • Indicated for young pediatric patients, elderly patients, or patients experiencing severe acute dyspnea who cannot coordinate MDI breathing cycles (Procedure Box 10.7).

Standard Reference Citations

  • Watkins, C. J., & Blades, C. L. (2025). Pharmacology clear & simple: A guide to medication classifications and dosage calculations (5th ed.). F.A. Davis Company.
  • Assessment Technologies Institute. (2023). PN pharmacology for nursing review module (9th ed.). Assessment Technologies Institute, LLC.