Key Takeaways

  • Ventrogluteal is the preferred IM injection site for adults
  • Do not aspirate for heparin or insulin subcutaneous injections
  • Infiltration presents as cool, pale, swollen IV site; phlebitis presents as warm, red, tender
  • Never crush enteric-coated, extended-release, or sublingual medications
  • IV complications require immediate intervention—know the signs and appropriate responses
Last updated: January 2026

Routes of Administration

Understanding different medication routes is essential for safe and effective drug delivery. Each route has specific advantages, disadvantages, and nursing considerations within the LPN/VN scope of practice.

Oral Route (PO)

Most common route—convenient, economical, and generally safe.

AdvantagesDisadvantages
Non-invasiveSlower onset
ConvenientVariable absorption
EconomicalAffected by GI function
Self-administration possibleFirst-pass metabolism

Nursing Considerations:

  • Assess swallowing ability before administration
  • Follow instructions for timing with food
  • Do not crush enteric-coated or extended-release medications
  • Provide adequate fluids (120-240 mL) unless fluid restricted
  • For sublingual medications: place under tongue, no water until dissolved

Parenteral Routes

Parenteral medications bypass the GI tract and are administered by injection.

Subcutaneous (SUBQ)

Injection into fatty tissue beneath the dermis

SiteMaximum VolumeNeedle Size
Outer upper arm1 mL25-27 gauge, 3/8-5/8 inch
Anterior thigh1 mL25-27 gauge, 3/8-5/8 inch
Abdomen (2 inches from umbilicus)1 mL25-27 gauge, 3/8-5/8 inch

Technique:

  • Pinch skin for thin patients; do not pinch for average/obese
  • Insert at 45-90 degree angle depending on tissue depth
  • Do NOT aspirate for heparin or insulin
  • Rotate injection sites

Intramuscular (IM)

Injection into muscle tissue for faster absorption

SiteMaximum VolumeNeedle SizeLandmark
Ventrogluteal (preferred)3 mL22-25 gauge, 1-1.5 inchIliac crest, greater trochanter
Vastus Lateralis3 mL22-25 gauge, 1-1.5 inchOuter middle third of thigh
Deltoid1 mL23-25 gauge, 5/8-1 inch2-3 finger widths below acromion
Dorsogluteal (least preferred)3 mL21-23 gauge, 1.5-2 inchUpper outer quadrant

Technique:

  • Use Z-track for irritating medications
  • Spread skin taut
  • Insert at 90-degree angle
  • Aspirate except for immunizations (CDC guidelines)
  • Inject slowly (10 seconds per mL)

Intradermal (ID)

Injection into dermis, just below epidermis

  • Used for TB skin test (Mantoux), allergy testing
  • Volume: 0.1-0.5 mL
  • Needle: 26-27 gauge, 3/8 inch
  • Site: Inner forearm or upper back
  • Angle: 5-15 degrees, bevel up
  • Should form a small bleb (wheal)

Intravenous (IV) Route

Fastest onset; medication enters bloodstream directly

LPN/VN IV Responsibilities (varies by state):

  • Monitoring IV infusions
  • Adding medications to existing IV (some states)
  • IV push medications (additional training required in most states)
  • Discontinuing peripheral IVs
  • Site assessment and documentation

IV Complications:

ComplicationSigns/SymptomsIntervention
InfiltrationCool, pale, swollen, painful siteStop infusion, elevate, apply warm compress
ExtravasationSame as infiltration + tissue damageStop immediately, antidote if available, notify MD
PhlebitisRed, warm, tender, swollen along veinStop infusion, apply warm compress, may need new site
InfectionErythema, drainage, feverStop infusion, culture site, notify MD
Air EmbolismSudden dyspnea, chest pain, hypotensionClamp line, left Trendelenburg position, O2, call for help
Fluid OverloadCrackles, JVD, edema, dyspneaSlow rate, elevate HOB, O2, notify MD

Topical Routes

RouteExamplesNursing Considerations
TransdermalPatches (nitroglycerin, fentanyl)Rotate sites, wear gloves, remove old patch first
OphthalmicEye drops, ointmentsPull lower lid down, apply to conjunctival sac
OticEar dropsWarm to body temp; adults: pull pinna up and back
NasalSprays, dropsHave patient blow nose first, insert tip slightly
InhaledMDI, nebulizer, DPITeach proper technique, spacer use, rinse mouth after steroids
RectalSuppositories, enemasLeft Sims' position, insert beyond sphincter
VaginalSuppositories, creamsLithotomy position, provide privacy

Medication Administration Techniques

Crushing Medications:

  • NEVER crush: enteric-coated, extended-release, sublingual, buccal
  • Check reference if unsure
  • Crush separately to avoid interactions
  • Mix with small amount of soft food if approved

Giving Medications via Feeding Tube:

  • Verify tube placement first
  • Use liquid forms when available
  • Flush with 30 mL water before and after
  • Give each medication separately with flushes between
  • Check for drug-food interactions
Test Your Knowledge

Which intramuscular injection site is preferred for adults?

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B
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D
Test Your Knowledge

An LPN/VN observes that an IV site is cool, pale, and swollen. The patient reports discomfort at the site. What is the most likely complication?

A
B
C
D
Test Your Knowledge

When administering a subcutaneous injection of heparin, what should the LPN/VN do?

A
B
C
D