7.3 Routes of Administration

Matching Route to Technique

The NCLEX-PN expects you to pick the right site, needle, angle, and volume and to recognize a complication from its description. Onset speed generally runs IV > IM > SUBQ > PO, which explains why the IV route is reserved for emergencies and why oral is preferred when time allows.

Oral (PO) Route

Most common, cheapest, and safest, but with slower, more variable absorption and first-pass metabolism through the liver.

• Assess swallowing ability before giving; aspiration risk is a key NCLEX safety check.
• Provide 120-240 mL fluid unless restricted.
• Sublingual (e.g., nitroglycerin): place under the tongue, no food or water until dissolved.
• Do NOT crush: enteric-coated, extended-/sustained-release (ER/SR/XL), sublingual, or buccal tablets — crushing destroys the delivery system or causes a toxic bolus.
• Use liquid forms when available for feeding-tube administration.

Intradermal (ID)

Used for the TB (Mantoux) test and allergy testing.

Subcutaneous (SUBQ)

Injection into fatty tissue; sites include the abdomen (2 inches from the umbilicus), outer upper arm, and anterior thigh.

• Do NOT aspirate and do NOT massage heparin or insulin sites — both increase bruising/hematoma.
• Rotate within one region for insulin to prevent lipohypertrophy.

Intramuscular (IM)

Faster absorption than SUBQ; site choice depends on muscle mass and volume.

• Use the Z-track technique for irritating/staining drugs (e.g., iron dextran) to seal the medication in muscle.
• Insert at 90 degrees; per current CDC guidance, do not aspirate for vaccines.

Intravenous (IV) Route and Complications

The IV route gives the fastest onset because the drug enters the bloodstream directly. LPN/VN IV duties (state-dependent) include monitoring infusions, site assessment, discontinuing peripheral IVs, and — with added training in many states — IV push and adding meds to existing fluids.

The most-missed distinction is infiltration (cool/pale) versus phlebitis (warm/red) — let the temperature and color decide.

Topical and Other Routes

Feeding tube meds: verify placement, use liquids, flush 30 mL water before, between, and after each drug, and give meds separately to avoid clogging and interactions.

Choosing and Defending the Route

The NCLEX-PN frequently frames route questions as a judgment call: which site, which angle, or what to do when a complication appears. Anchor your reasoning in absorption and safety. The oral route is preferred whenever the patient can swallow and time permits, because it is the least invasive; an aspiration or NPO concern moves you toward a parenteral or feeding-tube route. Among injections, match volume to the site — never force 2 mL into a deltoid that tolerates about 1 mL, and never choose the dorsogluteal site when the ventrogluteal is available and safer.

For IV complications, the response almost always begins with stopping the infusion, then positioning, applying the correct compress, and notifying the prescriber; the only exception worth memorizing is air embolism, where you immediately clamp the line and turn the patient to the left side in Trendelenburg to trap air in the right atrium. Recognizing the cool-and-pale versus warm-and-red distinction, and pairing each complication with its single most important first action, converts a large family of look-alike questions into predictable points and reflects exactly how a careful nurse protects the vein and the patient at the bedside.