Intravenous (IV) therapy
Also known as: intravenous therapy, IV infusion therapy
Intravenous (IV) therapy is the administration of fluids, medications, blood products, or nutrition directly into a vein. It provides immediate absorption and precise control, making it the fastest route for delivering treatment.
Intravenous (IV) therapy delivers fluids, medications, electrolytes, blood products, or nutrition directly into a patient's vein through a catheter. Because the infusion enters the bloodstream immediately, IV administration bypasses absorption barriers entirely — it has essentially 100% bioavailability and the fastest onset of any route, which is why it's the route of choice in emergencies and for drugs that can't survive the digestive tract.
Access can be peripheral, through a short catheter in a vein of the hand or forearm, or central, through a line whose tip rests in a large central vein (such as a PICC or central venous catheter) for long-term therapy, irritant medications, or parenteral nutrition. Infusions may run continuously at a prescribed rate — often controlled by an infusion pump — or be given intermittently, including IV push (bolus) doses. Common IV solutions are classified by tonicity: isotonic (0.9% normal saline, lactated Ringer's), hypotonic, and hypertonic fluids, each chosen to match the patient's fluid and electrolyte needs.
Because the route is so direct, monitoring is critical. Nurses assess IV sites for infiltration (fluid leaking into surrounding tissue), phlebitis (vein inflammation), infection, and air embolism, and they watch for fluid overload — especially in cardiac and renal patients. Site care, tubing changes, and strict aseptic technique are core safety practices.
The NCLEX tests IV therapy within pharmacological and parenteral therapies: expect questions on solution tonicity, infusion rate calculations, complication recognition, and safe use of infusion equipment. Medical assisting exams like the CCMA also cover IV-adjacent skills and equipment safety.
Key takeaways
- IV therapy delivers fluids, drugs, blood products, or nutrition directly into a vein, with immediate onset and complete bioavailability.
- Access may be peripheral (short-term, hand or forearm veins) or central (long-term therapy, irritants, parenteral nutrition).
- IV solutions are classified by tonicity — isotonic, hypotonic, or hypertonic — and matched to the patient's fluid needs.
- Key complications include infiltration, phlebitis, infection, air embolism, and fluid overload.