Intravenous route of drug administration

Intravenous route of drug administration

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Intravenous route of drug administration (IV)

Some medications must be given by an intravenous (IV) injection or infusion. This means they’re sent directly into your vein using a needle or tube. In fact, the term “intravenous” means “into the vein.”

The IV administration provides immediate access of the drug to the systemic circulation, resulting in the rapid onset of drug action. Depending on the rate of drug administration, IV injections could be a bolus or an infusion. A bolus means the drug is injected into the vein over a short period of time. A bolus is used to administer a relatively small volume and is often written as IV push (IVP).

An infusion refers to the introduction of larger volumes (100–1000 mL) of the drug over a longer period of time. A continuous infusion is used to administer a large volume of drug at a constant rate. Intermittent infusions are used to administer a relatively small volume of drug over a specified amount of time at specified intervals.

IV infusion can be administered through peripheral veins, typically in the forearm or the peripherally inserted central catheter. The commonly administered IV infusion products include Lactated Ringers Injection USP; Sodium Chloride Injection USP (0.9%), which replenish fluids and electrolytes; and Dextrose Injection USP (5%), which provides fluid plus nutrition; and various combinations of dextrose and saline. Other solutions of essential amino acids or lipid emulsions are also used as infusions.

Uses of IV medications

IV medication is often used because it helps control the medication dosing. For instance, in some situations, people must receive medication very quickly. This includes emergencies, like a heart attack, stroke, or poisoning. In these instances, taking pills or liquids by mouth may not be fast enough to get these drugs into the bloodstream. IV administration, on the other hand, quickly sends a medication directly into the bloodstream.

Other times, medications may need to be given slowly but constantly. IV administration can also be a controlled way to give drugs over time.

Certain drugs may be given by IV administration because if you took them orally (by mouth), enzymes in your stomach or liver would break them down. This would prevent the drugs from working well when they’re finally sent to your bloodstream. Therefore, these drugs would be much more effective if sent directly into your bloodstream by IV administration.


Intravenous medications can deliver an immediate, fast-acting therapeutic effect, which is important in emergent situations such as cardiac arrest or narcotic overdose. They are useful to manage pain and nausea by quickly achieving therapeutic levels, and they are more consistently and completely absorbed compared with medications given by other routes of injection.

Doses of short-acting medication can be titrated according to patient responses to drug therapy. Medication can be prepared quickly and given over a shorter period of time compared to the IV piggyback route.

Minimal dilution is required for some medications, which is desirable for patient’s own fluid restrictions.

There is minimal or no discomfort for the patient in comparison to SC and IM injections.

They provide an alternative to the oral route for drugs that may not be absorbed by the GI tract, and they are ideal for patients with GI dysfunction or malabsorption, and patients who are NPO (nothing by mouth) or unconscious.


IV direct route provides a more accurate dose of medication because none is left in the intravenous tubing.


Once an intravenous medication is delivered, it cannot be retrieved. When giving IV medications, there is very little opportunity to stop an injection if an adverse reaction or error occurs. IV medications, if given too quickly or incorrectly, can cause significant harm or death.

Any toxic or adverse reaction will occur immediately and may be exacerbated by a rapidly injected medication.

Extravasation of certain medications into surrounding tissues can cause sloughing, nerve damage, and scarring.

Not all medications can be given via the direct IV route.

There is a high risk for infusion reactions, mild to severe, because most IV medications peak rapidly (i.e., they have a quick onset of effect). A hypersensitivity reaction can occur immediately or be delayed, and requires supportive measures.

Route for administering medications may damage surrounding tissues. There is an increased risk of phlebitis with highly concentrated medication, especially with small peripheral veins or a short venous access device.

Possible side effects

While IV medication use is generally safe, it can cause both mild and dangerous side effects. Medications given intravenously act on your body very quickly, so side effects, allergic reactions, and other effects can happen fast.


Infection can occur at the injection site. To help prevent infection, the administration process must be done carefully using sterile (germ-free) equipment. An infection from the injection site can also travel into your bloodstream. This can cause a severe infection throughout your body.

Infection symptoms can include fever and chills, as well as redness or discoloration, pain, and swelling at the injection site. If you have any symptoms of infection, call your doctor right away.

Damage to veins and injection site

A vein can be damaged during injection or by the use of an IV catheter line. This can cause infiltration. When this occurs, medication leaks into surrounding tissue instead of going into your bloodstream. Infiltration can cause tissue damage.

IV administration can also cause phlebitis, or inflammation of your veins. A 2019 research review found that phlebitis occurred in 31 percent of patients. Symptoms of both infiltration and phlebitis include warmth, pain, and swelling at the injection site. Call your doctor right away if you have any of these symptoms.

Air embolism

If air gets into the syringe or the IV medication bag and the line runs dry, air bubbles can enter your vein. These air bubbles can then travel to your heart or lungs and block your blood flow. An air embolism can cause severe health concerns, such as heart attack or stroke.

Blood clots

IV therapy can cause blood clots to form. Clots can block important veins and cause health concerns such as tissue damage or even death. Deep vein thrombosis is one type of dangerous blood clot that IV treatment can cause.

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