What is the difference between injection and infusion?

Infusion vs injection

Injection and infusion are two different methods of administering medication or fluids into the body. Here’s a comparison between the two:


  • Injection involves the direct introduction of a medication or substance into the body using a syringe and needle.
  • The medication is typically delivered into the muscle (intramuscular injection), under the skin (subcutaneous injection), or into a vein (intravenous injection).
  • Injections are usually performed relatively quickly, delivering the medication in a short period.
  • They are commonly used for administering vaccines, certain medications, and substances that need to be rapidly absorbed or have immediate effects.


  • Infusion involves the slow and controlled administration of fluids, medications, or substances into the body through a vein using an intravenous (IV) line or catheter.
  • The substance is delivered gradually over a period of time, ranging from minutes to hours or even days, depending on the treatment.
  • Infusions are commonly used for hydration, administering medications, blood transfusions, chemotherapy, and other long-term treatments.
  • The rate of infusion can be adjusted to control the flow of the substance and ensure proper absorption and distribution in the body.


  • In summary, injections are quick and deliver the medication directly, while infusions involve a slower and controlled administration over a period of time.
  • The choice between injection and infusion depends on factors such as the medication or substance being administered, the desired rate of delivery, the treatment duration, and the specific needs of the patient.
  • It is important to follow the guidance and recommendations of healthcare professionals regarding the appropriate method of administration for a specific medication or treatment.

Summary Table of Infusion vs injection (Difference between Infusion and Injection)

Sr. No.QuestionInfusion
(Infusion therapy, or intravenous therapy)
1DefinitionWhat is Infusion or infusion shot ?
Infusion definition as a medical term.

An infusion is when fluids, medication, or blood is given through a catheter directly into a vein or intravenously (IV).
What is Injection?

An injection refers to the administration of medication using a needle and syringe.

For example, if you’ve been given a flu shot or a vaccine, it was an injection.
2TypeDirectly into intravenously (IV).  
Other Types include:  
– Epidural
– Intramuscular
– Subcutaneous
What are the Types of Injection given to Patient?

Several types of injections:  

Intramuscularly (IM): An injection is given in the muscle.

Subcutaneously (SC): An injection is given is administered into the fatty tissue.

Intradermally (ID) : This is when injections are administered in the top layer of the skin body.

many more types.
3Reason for useInfusion therapy is also often used because it allows for controlled dosing.

Some types of chemotherapy, for example, need to be dripped slowly into the bloodstream.
Some medications can’t be taken orally because they lose their efficacy when they come into contact with your digestive system.    

Some conditions where the patient needs immediate proper dosing in the bloodstream.  

Heart attack
4Application byThe gravitational force used in Infusion, where bag is hanging on the top.Pressure to injection & needle drug release in bloodstream
5DilutionNormally given with saline solution so, that patient rehydrated or keep hydrated is purpose.Injection is directly given no dilution is required.
6PartsPurell LDPE or PP grades Infusion Bag, IV tubing, Cannula, Drip ChamberPlunger, Needle, Barrel and Needle Cap
7Example1. DEXTROSE-5% W/V + LEVOFLOXACIN-500MG (Infusion in combination)  
2. Normal Saline 0.9% Infusion 500 ml
1. Vaccine shots (Covid-19 Vaccine)
2. leuprolide Acetate Injection
3. Triamcinolone acetonide-40mg Injection
Difference between infusion and injection

Different Parts of Infusion and injection :

infusion vs injection
Difference between Infusion and Injection

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