Types of Injections:

Hypodermal or subcutaneous injection: medicines when introduced into the subcutaneous tissue or areolar tissue (just below the skin), it is called hypodermic or subcutaneous injection.

Hypospray: the hypospray permits drugs to be sprayed through the skin without a needle. Pressure of about 125 pounds is created in a device, which forces the drug into the tissues without pain and without a visible mark.

Infusions: When a large quantity of medicines are to be introduced into the body, it is called infusion. Usually these are given intravenously or subcutaneously.

Intradermal: Medicines when introduced into the dermis (under the epidermis), it is called intradermal injection.

Intramuscular Injection: medicines when injected into the muscle, it is called intramuscular injection.

Intraosseous Injection: when drugs or fluids are introduced into the peritoneal cavity, it is called intraperitoneal injection.

Intraperitoneal Injection: medicines when introduced into the bone marrow, then it is called intraperitoneal injection.

Intrapinal or intrathecal Injections:
medicines when introduced into spinal cavity, it is called intraspinal or intrathecal injections.

Intravenous and intra-arterial Injection:
medicines and fluids when introduced into a vein, it is called intravenous injection and when introduced into the arteries is called intra-arterial injection.

Venesection or Cut down: opening a vein and introducing a tube or wide-bore needle and introducing medicines  and fluids or taking out blood is called venepuncture or venesection. This is done in emergencies.

Transfusions: it is the introduction of whole blood or plasma into vein or artery to supply actual volume of blood or to introduce constituents as clotting factors or antibodies which are different in the client.

Purpose of Injections:

1. To get a rapid and systematic effect of the drug. Drugs given by mouth take time for their absorption, hence comes the delay.

2. To provide the needed effect even when the client is unconscious, unable to swallow due to neurological or surgical alternations affecting the throat and mouth or when the client is not cooperative.

3. Assures that the total dosage will be administered and the same will be absorbed for the systemic actions of the drug. When taken by mouth the absorption may not be complete due to many reasons.

4. Provides the only means of administration for medications that cannot be given orally.

Some medication are rendered ineffective in the gastrointestinal tract by the action of the digestive juices. E.g. insulin.

Some are not retained in the intestine for a sufficient period for its absorption due to diarrhea, vomiting or gastric suction.

When the medicines are poorly absorbed from the G.I. tract.

When the drug is toxic and irritating to the gastrointestinal mucosa.

5. To obtain a local effect at the sight of the injection:

Local anaesthetics as xylocaine and novocaine.

Diagnostic purpose as in Shick test, tuberculin test etc.

To test allergic conditions of the drugs. E.g. Penicillin, serums etc.

To treat local conditions, e.g. hydrocortisone injection into joint cavity.

6. To restore blood volume by replacing the fluid, e.g. in shock conditions.

7. To give nourishment when it cannot be taken by mouth.


Factors that Favor Absorption:

1. Blood supply to the area: fluids injected into the blood stream will act quicker than any other methods used. When the fluids are deposited in an area where there is abundant blood supply (e.g. muscles), they are more quickly absorbed than the fluids deposited in an area with less blood supply (e.g. subcutaneous tissue).

2. The composition of the fluid injected (solubility and diffusibility of the fluid): the fluids that are isotonic or nearly isotonic with the blood are most easily absorbed.

3. Application of heat: heat dilates the blood vessels and the dilated capillaries become more permeable and their capacity for absorption is greatly increased. Therefore, the heat applied over the site of the injection or raising the temperature of the solution increases the rate of absorption.

4. Massage: massage stimulates the local blood supply and increases the rate of absorption.

5. Circulation time of the blood:
absorption of medicines and fluids injected to the body will be diminished in a person who has venous congestion (oedema), or who has neurogenic, cardiogenic or vasogenic shock.

6. Physical conditions:
the local disease conditions of the skin and underlying tissues such as skin-lesions, inflammations, excoriations, indurations (fibrosis) etc., delays the absorption of the drug.

7. Addictions of the substance that tend to breakdown the natural resistance of the tissues can increase the rate of absorption, e.g. hyaluronidase.


Complications of Injections:

1. Allergic reactions: certain drugs e.g. penicillin, sera etc., can produce allergic reactions in the client. It can be prevented by a test dose.

2. Infections: infections may be introduced through the careless handling and improper sterilization of syringes, needles and the fluids used for injections. It can lead to abscess formation and sloughing of the tissues.

3. Pyrogenic reactions (producing fever): for example, the clients getting intravenous fluids may develop fever due to the pyrogens present in the fluids.

4. Tissue trauma:

Repeated injections on the same spot can lead to induration of the skin, scar formation etc.

Injury to the periosteum.

Injury to the nerves, e.g. injury to the sciatic nerve due to faulty intragluteal injections.

Injury to the walls of the blood vessels.

5. Psychic trauma especially in children.

6. Pain.

7. Accidental intravascular injections.

8. Foot drop, persistent paralysis of the limbs etc., due to the nerve injury.

9. Air embolism due to the introduction of air into the blood vessels.

10. Overdose and underdose of the medication.

11. Errors in the administration of medicines.

12. Circulatory overload when large quantities of fluids are introduced into the body within short time.

13. Serum hepatitis : infectious hepatitis have been attributed to improperly disinfected syringes and needles. Inoculation of 0.0004 ml of the infected blood may transmit the serum hepatitis.


Drugs and Fluids/Administered:

The following are some drugs given by needle injections classified according to their action.

Preventive action: antitoxins, toxoids, vaccines, antibiotics.

Diagnostic aids: dyes and histamines.

Remedial action: antibiotics, specifies. E.g. quinine for malaria.

Palliative action: narcotics, sedatives, local anaesthetics, general anaesthetics.

Substitution: hormones, minerals and vitamins, fluids.

The commonly used solutions for intravenous therapy are as follows:

5% glucose (dextrose): each 100 ml contains 5 grams dextrose.

10% glucose: each 100 ml contains 10 grams dextrose.

25% glucose: each 100 ml contains 25 grams dextrose.

50% glucose: each 100 ml contains 50 grams of dextrose.

5% glucose saline: each 100 ml contains 5 grams glucose and 0.9 grams sodium chloride.

Normal saline: each 100 ml contains 0.9 gram sodium chloride.

Paediatric glucose saline: each 100 ml contains 2.5 grams dextrose and 0.45 grams sodium chloride.

Sodium lactate solution: each 100 ml contains 1.866 grams sodium R lactate.

Ringer’s solution.

Hartmann’s solution.


Safety Measures:

Five Rights of Medicine Administration:

1. Right client.
2. Right drug.
3. Right dosage.
4. Right time.
5. Right route.


1. Sterile syringes and needles.

2. Freshly distilled and sterile water for injections.

3. Drugs used for injection should be sterile.

4. Handling the drugs and equipment used for injections with aseptic technique, e.g. washing hands before touching the equipment; not touching and contaminating the syringes and needles etc.

5. Cleaning of the injection site with antiseptics to reduce the number of bacteria present in the skin.
6. Protecting the injections and the equipment during the transportation of the injections to the client e.g. the needle is covered with a protector.

Selection of the Site for Injection:

The selection of site depends upon:

Route ordered by the physician.

The quantity of medication to be given.

The muscular development and the condition of the client.

The characteristic of the medication to be given.

Knowledge of the anatomical location of nerves.

Expected action of the drug.

In order to prevent tissue tauma, rotation of the site and skilful techniques are necessary.

Manual and Technical Skills

The nurse should select equipment appropriate for therapy.
The nurse should develop skills in giving the injection properly according to the route ordered.
She should select the site quickly and accurately.
She should be able to prepare the medications as desired.


The parenteral route refers to medications that are given by injection or infusion. It means giving therapeutic agents outside the alimentary tract. It is the forcing of fluid into cavity, a blood vessel or a body tissue through a hollow tube or needle. Advanced injection techniques consist of injecting medications into artery, the peritoneum, heart tissue, the spinal canal and bones.

Medications given by parenteral route are absorbed more rapidly and completely than medications given by other routes.

Administration of Injections – Types of Injections, purpose of injections, complication of injections, drugs and fluids administered and Safety measures.

Administration of injection, types, purpose and safety measures