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HLT-EMT39-05 · Lesson 10 · 22 clock hours · practice

Alternative Routes: IM, SQ, SL, IN, and Oral Medication Administration

Objective. Students will correctly administer medications via intramuscular, subcutaneous, sublingual, intranasal, and oral routes on task trainers and standardized patient volunteers, using correct site selection, technique, and documentation.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

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Why Alternative Routes Matter in EMS

Intravenous access is the gold standard for rapid drug delivery, but it is not always possible or appropriate. Veins collapse in shock, pediatric patients are difficult to cannulate, and some medications are simply not formulated for IV use. As an EMT or paramedic, you must be proficient in intramuscular (IM), subcutaneous (SQ), sublingual (SL), intranasal (IN), and oral routes so that you can match the route to the patient, the drug, and the situation.

Intramuscular (IM) Injection

IM injections deposit medication directly into muscle tissue, where a rich blood supply allows relatively rapid absorption — typically faster than SQ but slower than IV. Three sites are used in EMS:

Site rotation is required when multiple injections are given. After selecting the site, clean it with an antiseptic swab using an outward circular motion and allow it to dry. Insert the needle at 90 degrees, aspirate briefly per your local protocol, inject smoothly, withdraw, and apply gentle pressure. Do not recap the needle by hand — use a one-handed scoop technique or a safety device, then discard in a sharps container immediately.

Needle selection: Length and gauge must match the patient's muscle mass and the medication's viscosity. Typical adult IM needles range from 1 to 1.5 inches. Using a needle that is too short results in SQ rather than IM delivery, altering absorption.

Subcutaneous (SQ) Injection

SQ injections place medication in the fatty tissue just beneath the skin. Absorption is slower than IM and suitable for medications designed for that profile (such as epinephrine auto-injectors in some protocols). Common sites include the outer upper arm, the abdomen (avoiding 2 inches around the navel), and the outer thigh. Use a shorter needle (typically 5/8 inch) at a 45-degree angle, pinching the skin to lift the subcutaneous layer away from muscle. Volume is limited — generally 0.5 to 1 mL per site.

Sublingual (SL) Administration

Sublingual medications are placed under the tongue, where the mucous membranes and dense vasculature allow rapid absorption directly into the bloodstream, bypassing first-pass hepatic metabolism. Nitroglycerin tablets and sprays are the classic EMS example. Before administering, confirm the patient is conscious, can protect their airway, and has no contraindications. Instruct the patient to lift the tongue, place or spray the medication, and hold it in place without swallowing until it dissolves. Keep the patient seated or supine if hemodynamically unstable. Monitor blood pressure and symptoms closely, as onset is rapid.

Intranasal (IN) Administration

The intranasal route delivers medication through the nasal mucosa using a mucosal atomization device (MAD) that converts liquid to a fine mist. IN delivery is used in EMS for medications such as naloxone, midazolam, and others per local protocol. Absorption depends on the mucosal surface area contacted, so technique matters.

Assembly and technique: Attach the MAD tip to a syringe containing the drawn-up medication. Because the nasal cavity on each side holds a limited volume effectively (generally no more than 1 mL per nostril), larger doses must be split equally between nostrils. Gently insert the MAD tip into one nostril, aim slightly toward the ear on the same side, and compress the plunger briskly to atomize the dose. Repeat in the opposite nostril with the remaining volume. Document volume per nostril and total dose on the patient care report (PCR).

Active epistaxis or heavy nasal secretions reduce absorption; consider an alternate route if the nasal passages are obstructed.

Oral Administration

Oral medications are swallowed and absorbed through the gastrointestinal tract. Onset is slowest of all routes covered here. In EMS, oral medications (such as oral glucose, aspirin, or activated charcoal) are given only to patients who are conscious, alert, and able to swallow safely. Always assess the gag reflex and level of consciousness before proceeding. Position the patient upright or semi-upright to reduce aspiration risk. Provide clear instructions: what to do, how much to take, and whether to chew or swallow. Monitor for adverse reactions.

Universal Safety Rules for All Routes

Key terms10

Intramuscular (IM) injectionDelivery of medication directly into muscle tissue, allowing moderately rapid absorption via local blood supply; administered at a 90-degree angle.
Subcutaneous (SQ) injectionDelivery of medication into the fatty tissue beneath the skin at a 45-degree angle; absorption is slower than IM due to lower vascularity.
Sublingual (SL) administrationPlacement of medication under the tongue, where it is absorbed rapidly through mucous membranes directly into the bloodstream, bypassing first-pass metabolism.
Intranasal (IN) administrationDelivery of atomized medication to the nasal mucosa using a mucosal atomization device; provides reasonably rapid systemic absorption without IV access.
Mucosal atomization device (MAD)A tip attached to a syringe that converts liquid medication into a fine mist, maximizing contact with the nasal mucosa for IN delivery.
Site rotationThe practice of alternating injection sites across administrations to prevent tissue damage, lipodystrophy, or localized irritation.
First-pass metabolismThe process by which orally swallowed drugs are partially broken down in the liver before reaching systemic circulation; bypassed by SL and IN routes.
Six rights of medication administrationA safety checklist — right patient, drug, dose, route, time, and documentation — verified before every medication is given.
Vastus lateralisThe large muscle of the outer thigh; a preferred IM injection site for larger volumes and for pediatric patients whose deltoid mass is insufficient.
Patient care report (PCR)The official written record of assessment, treatment, and medication administration completed by EMS providers for every patient contact.

Worked examples3

1. You are administering naloxone intranasally. Your protocol calls for 2 mg total dose. The concentration available is 2 mg/mL. How many mL will you draw up, and how much goes in each nostril?
  1. Step 1 — Determine total volume needed: Dose ÷ Concentration = Volume. 2 mg ÷ 2 mg/mL = 1 mL total.
  2. Step 2 — Split the dose equally between two nostrils: 1 mL ÷ 2 = 0.5 mL per nostril.
  3. Step 3 — Confirm each nostril receives 0.5 mL, which is within the generally accepted limit of 1 mL per nostril for effective mucosal absorption.
  4. Step 4 — Document: total dose 2 mg, volume per nostril 0.5 mL, route IN, time, and patient response on the PCR.
Answer: Draw up 1 mL total; administer 0.5 mL to each nostril.
2. Your protocol allows epinephrine 0.3 mg SQ for a severe allergic reaction. The concentration is 1 mg/mL. What volume do you inject?
  1. Step 1 — Apply the volume formula: Volume = Dose ÷ Concentration.
  2. Step 2 — Substitute values: 0.3 mg ÷ 1 mg/mL = 0.3 mL.
  3. Step 3 — Confirm this volume is appropriate for a SQ injection (0.3 mL is well within the typical SQ volume limit of 0.5–1 mL).
  4. Step 4 — Select a SQ site, use a short needle at 45 degrees with skin pinched, administer 0.3 mL, document site, time, and patient response.
Answer: Inject 0.3 mL subcutaneously.
3. You need to give an IM medication in a volume of 2.5 mL to an adult patient. You have chosen the vastus lateralis. Is this appropriate, and would you need to split the dose?
  1. Step 1 — Recall IM volume guidelines: the deltoid generally accommodates up to about 1 mL; the vastus lateralis can generally accommodate larger volumes (up to approximately 2–2.5 mL in a well-developed adult, per standard injection references).
  2. Step 2 — Assess the specific patient: for an average adult, 2.5 mL in the vastus lateralis is at the upper limit; for a smaller or pediatric patient it may need to be split.
  3. Step 3 — If the patient's muscle mass supports it, administer the full 2.5 mL in the vastus lateralis at 90 degrees. If splitting is needed, divide equally between two sites and document both.
  4. Step 4 — Document site chosen, volume administered, needle angle, time, and patient response on the PCR.
Answer: For an average adult, the vastus lateralis is appropriate for 2.5 mL; assess muscle mass and split the dose across two sites if the volume exceeds what the tissue can safely absorb.

The math in this lesson1

Learners divide 2 mg by 2 mg/mL for 1 mL total and split 0.5 mL per nostril for intranasal dosing.
7.RP.2
In class: Site-selection drill on injection pad trainers: students practice deltoid, vastus lateralis, and dorsogluteal IM injections, rotating sites per protocol, with instructor checking needle angle and depth at each attempt. · Intranasal atomizer lab: students assemble a mucosal atomization device, draw up a simulated volume, and deliver a split dose to each nostril of a task trainer head, documenting volume per nostril and total dose. · Role-play with standardized patient: student administers a simulated sublingual tablet and oral liquid medication to a fellow student acting as a conscious patient, including consent, instruction, position, monitoring, and documentation on a sample PCR.
Materials: Injection pad trainers, IM needles and syringes, mucosal atomization devices, simulated medications (NS), task trainer head, sublingual tablet placebo, oral liquid simulation, sample PCR forms
Check: Instructor observation checklist for each route (IM, SQ, SL, IN, oral); pass requires correct site, angle, volume, and documentation for each route. Any incorrect site or volume error requires immediate correction and repeat.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Pharmacology and Medication Administration
1. When performing a deltoid IM injection on an adult, the correct needle angle is:
Pharmacology and Medication Administration
2. A patient requires an intranasal medication dose that totals 1.5 mL. How should this volume be distributed?
Pharmacology and Medication Administration
3. Which of the following patients is the BEST candidate for sublingual nitroglycerin?
Pharmacology and Medication Administration
4. The primary advantage of the sublingual route over the oral route is:
EMS Operations and Safety
5. After completing an IM injection, the correct method for handling the used needle is to:
Pharmacology and Medication Administration
6. A subcutaneous injection is administered at which angle?
Pharmacology and Medication Administration
7. When selecting the correct IM site for a 6-month-old infant, which site is preferred and why?
Pharmacology and Medication Administration
8. You are preparing to give oral activated charcoal to a patient. Before administration, your MOST important assessment is to confirm the patient:
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