Medication Administration: Intramuscular Injections - Acute care
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ALERT
Intramuscular (IM) injections have been associated with adverse effects and pain, and this route of medication injection should be used as a last resort. Consider contacting the practitioner for an alternative, preferred route of medication administration.
Take steps to avoid interruptions and distractions when getting medications ready.
OVERVIEW
The IM injection route deposits medication into deep muscle tissue, which has a rich blood supply, allowing medication to be absorbed faster than it would be by the subcutaneous route. This rich blood supply, however, increases the risk for injecting drugs directly into blood vessels. Any factor that interferes with local tissue blood flow affects the rate and extent of drug absorption.
An IM injection may require a longer and larger-gauge needle to penetrate deep muscle tissue. The needle is inserted at a 90-degree angle; this varies from the angle used for subcutaneous and intradermal injections (Figure 1).undefined#ref2">2,5 The appropriate needle length is determined by the patient’s weight and age and the amount of adipose tissue in the chosen injection site.2,7 The needle must be long enough to reach the muscle tissue, but not too long to present the risk of hitting underlying neurovascular structures or bone.2
IM injections should be administered so that the needle is perpendicular to the patient’s body or as close to a 90-degree angle as possible.2 IM injection sites should also be rotated to decrease the risk for hypertrophy. When possible, IM injections should be avoided in muscles that are emaciated or atrophied because these muscles absorb medication poorly.5
Aspiration before injection and slow injection of the medication are not supported by research for vaccine administration.2 The vastus lateralis and deltoid muscle are the only two sites recommended for vaccine administration because these sites do not contain large vessels that are within reach of the needle.2 For all other medications, there is no evidence to either support or abandon the practice of aspiration before administration. More research is needed to investigate the practice of aspiration before administering an IM injection with medications other than vaccines.8 The recommended route and site for each vaccine is included in the manufacturer’s instructions for use.2
Muscle tissue is less sensitive than subcutaneous tissue to irritating and viscous medications. Small muscles absorb small volumes. For a well-developed adult, no more than 3 ml of medication should be administered in a single IM injection because the muscle tissue does not absorb it well in larger volumes.5 For smaller adults or those with less muscle mass, the volume injected may need to be adjusted. There may be exceptions for specific medications. Refer to the organization’s formulary.
The Z-track method can be used (except with infant vaccination where skin is compressed) provided that the overlying tissue can be displaced. This technique, pulling the skin laterally before injection, prevents medication leakage into subcutaneous tissue, seals medication in the muscle, and minimizes irritation.5 To use the Z-track method in an adult, the appropriate-size needle is attached to the syringe, and an IM site is selected. The overlying skin and subcutaneous tissues are pulled to the side with the ulnar side of the nondominant hand. The skin is held in this position until the injection has been administered. After cleansing the site, the needle is injected deep into the muscle and the medication is injected slowly. After the needle is withdrawn, the skin is released. The displacement of the skin and muscle layer closes off the needle track when the skin is released (Figure 2).
Injection Sites
For IM injections, the nurse selects a site that is free of pain, infection, necrosis, bruising, and abrasions. The location of underlying bones, nerves, and blood vessels and the volume of medication to be administered are also considered. Because of the sciatic nerve location, the dorsogluteal muscle is not recommended as an injection site. If a needle hits the sciatic nerve, the patient may experience partial or permanent paralysis of the leg.5 The rectus femoris is no longer considered a safe injection site because of the risk of damage to the descending branch of the lateral circumflex femoral artery and the muscle branch of the femoral nerve to the vastus lateralis.6
Ventrogluteal Site
The ventrogluteal site involves the gluteus medius and minimus muscles and is a safe injection site for adults and children.5 This site provides the greatest thickness of gluteal muscle, is free of penetrating nerves and blood vessels, and has a narrower layer of fat. The ventrogluteal muscle is the preferred and safest site for all adults, children, and infants for medications with larger volumes that may be more viscous and irritating.5 The ventrogluteal site should be used with caution in infants.1 It is recommended that only an experienced pediatric health care team member use this site.
To locate the ventrogluteal site, the heel of the hand is placed over the greater trochanter of the patient’s hip with the wrist almost perpendicular to the femur. The right hand is used for the left hip, and the left hand for the right hip. The thumb is pointed toward the patient’s groin, with the index finger pointing to the anterior superior iliac spine, and the middle finger is extended back along the iliac crest toward the buttock. The index finger, the middle finger, and the iliac crest form a V-shaped triangle. The injection site is the center of the triangle (Figure 3). To relax this site, the patient lies on the side or back, flexing the knee and hip.
Vastus Lateralis Muscle
The vastus lateralis muscle is another injection site used in adults. The muscle is thick and well developed and is located on the anterior lateral aspect of the thigh. It extends, in an adult, from a handbreadth above the knee to a handbreadth below the greater trochanter of the femur (Figure 4). The middle third of the muscle is used for injection. To help relax the muscle, the patient is asked to lie flat, supine, with the knee slightly flexed and foot externally rotated or to assume a sitting position.
Deltoid Muscle
Although the deltoid site is easily accessible, the muscle is not well developed in many adults. There is potential for injury because the axillary, radial, brachial, and ulnar nerves and the brachial artery lie within the upper arm under the triceps and along the humerus (Figure 5A) (Figure 5B). This site is used for small medication volumes (2 ml or less)5 and for administration of routine immunizations in children older than 3 years with acceptable muscle mass and development and when other sites are inaccessible because of dressings or casts.2
The deltoid muscle is located by fully exposing the patient’s upper arm and shoulder and asking the patient to relax the arm at the side or by supporting the patient’s arm and flexing the elbow. Next, the lower edge of the acromion process, which forms the base of a triangle in line with the midpoint of the lateral aspect of the upper arm, is palpated. The nurse measures 2 to 3 finger widths4 down from the acromion process and visualizes a triangle, with the base at the acromion process and the apex pointing toward the elbow. The injection site is found in the center of the triangle (Figure 5A).
To avoid shoulder injury related to vaccine administration, the nurse should always sit to inject into the arm of a seated patient to ensure that the angle of the needle is correct. If the patient’s shirt cannot be removed, the sleeve should be rolled up so that landmarks can be visualized and used appropriately.4
Rarely, an adverse reaction occurs after immunizations. Reactions may include anaphylaxis, anaphylactic shock, and neurologic deficits.9 Vaccine adverse event reporting is monitored by the Centers for Disease Control and Prevention.
If the patient expresses concern regarding the accuracy of a medication, the medication should not be given. The concern should be explored, the practitioner notified, and the order verified.
SUPPLIES
See Supplies tab at the top of the page.
EDUCATION
Give developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, preferred learning style, and overall neurologic and psychosocial state.
Explain the procedure for an IM injection, including the purpose of the injection and the reason for using the IM route.
Explain the risks related to the procedure, including hematoma formation, nerve injury, and allergic reaction to the medication.
Teach the patient about the potential side effects of the medication.
If the patient requires regular injections, teach the patient and a family member on injection techniques and the importance of rotating sites to decrease the risk for hypertrophy.
Have the patient perform several return demonstrations of medication preparation to validate learning.
Teach the patient and a family member to observe injection sites for complications and to report complications to the practitioner immediately.
Teach the patient and a family member to observe for effectiveness of the medication and adverse reactions and to report ineffectiveness of the medication and adverse reactions to the practitioner.
Encourage questions and answer them as they arise.
ASSESSMENT AND PREPARATION
Assessment
Clean hands and don appropriate personal protective equipment (PPE) based on the risk of exposure to bodily fluids or infection precautions.
Introduce yourself to the patient.
Verify the correct patient using two identifiers.
Determine if the patient has specific contraindications to receiving IM injections and notify the practitioner as needed. Assess for factors such as muscle atrophy, reduced blood flow, skin condition, and circulatory shock.
Assess the patient’s symptoms before initiating medication therapy.
Assess the patient’s knowledge regarding the medication to be received.
Assess the patient’s history of allergies, including any drug allergies, type of allergens, and normal allergic reaction.
Review the patient’s previous verbal and nonverbal responses to injections.
Assess baseline vital signs and the patient’s medical and medication history.
Preparation
Verify the practitioner’s order.
Verify the patient’s actual admission weight in kilograms. Reweigh the patient if appropriate.3 Do not use stated, estimated, or last documented weight.3
Review medication reference information pertinent to the medication’s action, purpose, onset of action and peak action, normal dose, and common side effects and implications.
Get the medication, check against the practitioner’s order, verify the expiration date, and check that the medication and container are clean and intact.
Do not use any medication that is cloudy or precipitated unless such is indicated by its manufacturer as being safe.
Assemble appropriate-size needles, syringes, and other administration supplies.
PROCEDURE
Clean hands and don appropriate personal protective equipment (PPE) based on the risk of exposure to bodily fluids or infection precautions.
Verify the correct patient using two identifiers.
Explain the procedure and ensure that the patient agrees to treatment.
Check accuracy and completeness of the medication administration record (MAR) with the practitioner’s original order.
Check the rights of medication safety.
Label all medications and solutions. The only exceptions are medications that are still in their original container or medications that are given immediately by the person who prepared them.4
Medications or other solutions in unlabeled containers are unidentifiable. Errors, sometimes tragic, have resulted from medications and other solutions removed from their original containers and placed into unlabeled containers. This unsafe practice neglects basic principles of medication management safety, yet has been routine in many organizations.4
Take the medication to the patient at the right time according to the rights of medication safety.
Provide privacy for the patient.
Compare the patient’s name and one other identifier (e.g., organization identification number) with the MAR. Ask for the patient’s name as an additional identifier.
Rationale: This identification comparison and verification comply with The Joint Commission requirements to improve medication safety. In most acute care settings, the patient’s name and identification number on the identification band and the MAR are used to correctly identify patients.4
Compare the medication label with the MAR one final time at the patient’s bedside.
Keep a sheet or gown draped over body parts not requiring exposure.
Select the appropriate site for injection based on the patient’s age, muscle tissue mass, and medication volume and viscosity.
Inspect the skin surface over sites for bruises, inflammation, or edema.
Rationale: Injection sites should be free of abnormalities that interfere with drug absorption (e.g., bruising, signs associated with infection).
Note the integrity and size of the muscle. Palpate for tenderness or hardness and avoid hardened areas. If the patient receives frequent injections, rotate sites.
Rationale: Sites used repeatedly become hardened from lipohypertrophy (increased growth in fatty tissue).
Assist the patient to a comfortable position that is appropriate for the chosen injection site (e.g., sitting, or lying flat, on side, or prone).
Rationale: A comfortable position reduces strain on the muscle and minimizes injection discomfort.
Locate the injection site again using anatomic landmarks. The ventrogluteal site is a safe injection site for adults and children receiving irritating or viscous solutions and is the site of choice for administering IM injections to adults.5 In addition, this site provides the greatest thickness of gluteal muscle, is free of penetrating nerves and blood vessels, and has a narrower layer of fat.5
Rationale: Injection into the correct anatomic site prevents injury to nerves, bone, and blood vessels.
The dorsogluteal site is not recommended because of proximity to the sciatic nerve.5
Clean the site with alcohol or an antiseptic swab. Allow the skin to dry completely. Optional: Use a vapocoolant spray (e.g., ethyl chloride) for pain relief just before injection.
Rationale: A vapocoolant spray decreases pain at the injection site.
Hold a clean swab or dry gauze between the third and fourth fingers of the nondominant hand.
Rationale: The swab or gauze remains readily accessible for use when withdrawing the needle.
Remove the needle cap by pulling it straight off.
Rationale: Pulling the cap straight off prevents the needle from touching the sides of the cap, thus preventing contamination.
Hold the syringe between the thumb and forefinger of the dominant hand as if holding a dart, palm down.
Rationale: A quick, smooth injection requires proper manipulation of the syringe parts.
With your nondominant hand, pull the skin taut.
Administer the injection using the Z-track method, if appropriate.
Position the ulnar side of the nondominant hand just below the site and pull the skin laterally. Hold this position until the medication is injected.
With the dominant hand, inject the needle quickly into the muscle at a 90-degree angle using a steady and smooth motion.5
Rationale: The Z-track technique creates a zigzag path through tissues that seals the needle track to avoid tracking medication. A quick, dart-like injection reduces discomfort. Z-track injections may be used for all IM injections.5
After the needle pierces the skin, use the thumb and forefinger of the nondominant hand to hold the syringe barrel while still pulling on the skin. Move the dominant hand to the end of the plunger. Avoid moving the syringe.
Rationale: Smooth manipulation of the syringe reduces discomfort from needle movement. Skin remains pulled until after the medication is injected to ensure Z-track administration.
Optional: If the patient’s muscle mass is small, grasp the body of the muscle between the thumb and forefingers of the nondominant hand while still pulling the skin laterally.
Rationale: Grasping the muscle body helps to ensure that the medication reaches the muscle mass.
Per the organization’s practice, pull back on the plunger. If no blood appears, inject the medication. If blood appears in the syringe, remove the needle, discard the medication, obtain a new syringe, and try again.
Rationale: Aspiration of blood into the syringe indicates possible placement into a vein.
Rationale: There is no definitive research to recommend eliminating aspiration other than for vaccination and toxoids.5
Smoothly, quickly, and steadily withdraw the needle and release the skin. Apply a dry cotton ball or gauze with light pressure for several seconds over the site.
If not using the Z-track method, follow these steps for injection.
With the dominant hand, inject the needle quickly into the muscle at a 90-degree angle using a steady and smooth motion.5
After the needle pierces the skin, use the thumb and forefinger of the nondominant hand to hold the syringe barrel while still pulling on the skin. Move the dominant hand to the end of the plunger. Avoid moving the syringe.
Optional: If the patient’s muscle mass is small, grasp the body of the muscle between the thumb and forefingers of the nondominant hand.
Rationale: Grasping the muscle body helps to ensure that the medication reaches the muscle mass.
Per the organization’s practice, pull back on the plunger. If no blood appears, inject the medication. If blood appears in the syringe, remove the needle, discard the medication, obtain a new syringe, and try again.
Rationale: Aspiration of blood into the syringe indicates possible placement into a vein.
Rationale: There is no definitive research to recommend eliminating aspiration other than for vaccination and toxoids.5
Smoothly, quickly, and steadily withdraw the needle. Apply a dry cotton ball or gauze with light pressure for several seconds over the site.
Apply gentle pressure to the site; do not massage. Assess the site and apply a bandage if needed.
Rationale: Massage damages underlying tissue.
Assist the patient to a comfortable position.
Stay with the patient for several minutes and observe for any allergic reactions.
Dyspnea, wheezing, and circulatory collapse are signs of severe anaphylactic reaction.
Discard the uncapped needle (or needle enclosed in a safety shield) and the attached syringe into a puncture-proof and leakproof receptacle.
Rationale: Discarding the uncapped needle helps prevent injury to the patient and staff. Recapping needles increases the risk for a needlestick injury.7
Discard supplies, remove PPE, and clean hands.
Document the procedure in the patient’s record.
MONITORING AND CARE
Return to the patient’s room at an appropriate time to assess the injection site.
Report profuse bleeding, hematoma, loss of function, and signs and symptoms of infection.
Watch the patient for adverse and allergic reactions to the medication. If a reaction occurs, follow the organization’s practice for emergency response.
Report rash, seizures, and difficulty breathing.
Assess, treat, and reassess pain.
EXPECTED OUTCOMES
Medication is administered according to the rights of medication safety.
Patient experiences no pain or only mild burning at injection site.
Patient achieves desired effect of medication with no adverse reactions, signs of allergies, or undesired effects.
Patient demonstrates acceptable level of comfort after injection.
Patient explains purpose, dosage, and effects of medication.
UNEXPECTED OUTCOMES
Medication is not administered according to the rights of medication safety.
Patient complains of localized pain, bleeding, or continued burning at injection site, indicating potential injury to nerve or vessels.
Medication is administered in subcutaneous tissue.
Patient displays adverse reaction to the medication, with signs of urticaria, eczema, pruritus, wheezing, or dyspnea.
Other adverse effects occur: hematoma or abscess; infection; fibrosis of the muscle, tissue damage because of patient movement during injection; glass particles injected into muscle as a result of not using a filter needle; permanent damage to sciatic nerve resulting in paralysis, fibrosis, or abscess.
Patient experiences unmanaged pain.
DOCUMENTATION
Medication name, dose, route, site, time, and date of administration (with MAR correctly signed)
Patient’s response to medication, including any adverse reactions
Unexpected outcomes and related interventions
Education
Comfort assessment and any interventions performed
Patient’s weight in kilograms
PEDIATRIC CONSIDERATIONS
Children can be very anxious or fearful of needles. Assistance is sometimes necessary to hold and properly position the child. Distraction, such as blowing bubbles and applying pressure at the injection site before giving the injection, may help alleviate the child’s anxiety.
If possible, a topical analgesic should be applied to the injection site with sufficient time allowed for peak action before the IM injection. A vapocoolant spray (e.g., ethyl chloride) may also be used just before injection to decrease pain. Collaboration with the practitioner helps determines which methods will help best reduce pain before injection.
The vastus lateralis muscle is the preferred site for administration of immunizations to newborns, infants, toddlers, and children up to 3 years old.2,5 The deltoid muscle is the acceptable site for administration of routine immunizations in children 3 to 18 years old who have acceptable muscle mass and development.2,5
Applying a colorful adhesive bandage or sticker to the injection site should be considered.
OLDER ADULT CONSIDERATIONS
Older adult patients may have decreased muscle mass, which reduces drug absorption from IM injections.
Older adults may have loss of muscle tone and strength that impairs mobility, placing them at high risk for falls as a result of guarding an injection site.
Anderson, C.E., Herring, R.A. (2022). Chapter 20: Pediatric nursing interventions and skills. In M.J. Hockenberry, C.C. Rodgers, D. Wilson (Eds.), Wong’s essentials of pediatric nursing (11th ed., pp. 551-618). St. Louis: Elsevier.
Institute for Safe Medication Practices (ISMP). (2024). 2024-2025 Targeted medication safety best practices for hospitals. Retrieved June 1, from https://www.ismp.org/guidelines/best-practices-hospitals
Lilley, L.L., Rainforth Collins, S., Snyder, J.S. (2023). Chapter 9: Photo atlas of drug administration. In Pharmacology and the nursing process (10th ed., pp. 102-134). St. Louis: Elsevier.
Nakajima, Y. and others. (2020). Anatomically safe sites for intramuscular injections: A cross-sectional study on young adults and cadavers with a focus on the thigh. Human Vaccines & Immunotherapeutics, 16(1), 189-196. doi:10.1080/21645515.2019.1646576
Sepah, Y. and others. (2017). Aspiration in injections: Should we continue or abandon the practice? (version 3, peer review, 2 approved). F1000Research, 3, 157. doi:10.12688/f1000research.1113.3
Wodi, A.P., Shimabukuro, T. (2021). Chapter 4: Vaccine safety. In E. Hall and others (Eds.), Epidemiology and prevention of vaccine-preventable diseases (14th ed., pp. 43-52). Centers for Disease Control and Prevention (CDC). Washington, DC: Public Health Foundation. Retrieved June 1, 2024, from https://www.cdc.gov/vaccines/pubs/pinkbook/safety.html
U.S. Food and Drug Administration (FDA). (2021). Safely using sharps (needles and syringes) at home, at work and on travel. Retrieved June 1, 2024, from
