Wednesday, June 12, 2024

EMS Medication Administration - Intramuscular (IM) Route

EMS providers must understand various aspects of intramuscular (IM) medication administration to ensure patient safety and effective treatment.

Here are the key points they should know:

1. Indications and Contraindications

  • Indications:
    • Rapid medication absorption is needed but IV access is not available or practical.
    • Administration of certain vaccines, antibiotics, epinephrine (for anaphylaxis), analgesics, and sedatives.
  • Contraindications:
    • Allergy to the medication
    • Presence of infection or injury at the injection site
    • Conditions causing poor blood flow to muscles, such as shock

2. Anatomy and Site Selection

  • Common IM Injection Sites:
    • Deltoid Muscle: Suitable for small-volume injections (up to 1 mL).
    • Vastus Lateralis Muscle: Preferred for larger volumes (up to 5 mL), especially in infants and children.
    • Ventrogluteal Muscle: Preferred for larger volumes and irritating medications.
    • Dorsogluteal Muscle: Less preferred due to the risk of sciatic nerve injury.
  • Site Selection Criteria:
    • Volume of medication
    • Age and size of the patient
    • Muscle mass and presence of adipose tissue

3. Preparation and Technique

  • Medication Preparation:
    • Check the medication for correct name, dose, and expiration date.
    • Use aseptic technique to draw up the medication.
  • Injection Technique:
    • Clean the injection site with an antiseptic wipe.
    • Use a quick, dart-like motion to insert the needle at a 90-degree angle.
    • Aspirate slightly to ensure the needle is not in a blood vessel (optional and based on local protocols).
    • Inject the medication slowly and steadily.
    • Withdraw the needle and apply pressure to the site to prevent bleeding.

4. Needle Selection

  • Needle Length: Typically ranges from 1 to 1.5 inches for adults and 5/8 to 1 inch for children.
  • Needle Gauge: Usually 22 to 25 gauge, depending on the viscosity of the medication and the muscle mass.

5. Medication Administration

  • Dosage and Volume:
    • Adhere to the recommended dosage and maximum volume for each injection site.
    • For adults: Deltoid (up to 1 mL), Vastus Lateralis (up to 5 mL), Ventrogluteal (up to 3 mL).
  • Rate of Administration: Inject the medication slowly to reduce discomfort.

6. Complications and Management

  • Pain and Discomfort: Techniques to minimize pain include ensuring the muscle is relaxed, using a quick insertion, and administering the medication slowly.
  • Bleeding and Hematoma: Applying pressure post-injection can prevent these.
  • Infection: Using aseptic technique and proper site selection helps prevent infection.
  • Nerve Injury: Correct site selection and needle length are crucial to avoid nerve damage, particularly in the dorsogluteal site.

7. Special Considerations

  • Patient Age and Size: Adjust needle size and injection site based on the patient's age, muscle mass, and adipose tissue.
  • Medication Properties: Some medications may cause irritation or require specific injection techniques.
  • Patient Positioning: Position the patient comfortably to ensure muscle relaxation and reduce the risk of complications.

8. Training and Proficiency

  • Simulation Training: Regular practice using simulation models to maintain proficiency in IM injection techniques.
  • Continuing Education: Staying updated on best practices, new medications, and techniques.

9. Legal and Ethical Considerations

  • Scope of Practice: Adhering to legal scope of practice for their certification level and local regulations.
  • Informed Consent: Obtain informed consent from the patient or guardian whenever possible.
  • Documentation: Accurate documentation of medication name, dose, route, site of injection, time of administration, and any adverse reactions.


Effective IM medication administration requires EMS providers to combine theoretical knowledge with practical skills.

Continuous training, adherence to protocols, and understanding the indications, techniques, and potential complications are essential for safe and effective patient care.

Further Reading:

Alexander, M. & Belle, R. (2017) Advanced EMT: A Clinical Reasoning Approach (2nd Ed). Hoboken, New Jersey: Pearson Education

Bledsoe, B. E., Cherry, R. A. & Porter, R. S (2023) Paramedic Care: Principles and Practice (6th Ed) Boston, Massachusetts: Pearson

Bledsoe, B. E. & Clayden, D. (2018) Prehospital Emergency Pharmacology (8th Ed). Pearson.

Guy, J. S. (2019) Pharmacology for the Prehospital Professional (2nd Ed) Burlington, Massachusetts: Jones & Bartlett Learning.

Mistovich, J. J. & Karren, K. J. (2014) Prehospital Emergency Care (11th Ed). Hoboken, New Jersey: Pearson Education

Peate, I. & Sawyer, S (2024) Fundamentals of Applied Pathophysiology for Paramedics. Hoboken, New Jersey:  Wiley Blackwell

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