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newSchoolWorks.com › VoTechWorks › Health & Personal Services › Veterinary Technology / Vet Assistant › Veterinary Nursing: Patient Care Fundamentals › Lesson 6
HLT-VET42-03 · Lesson 6 · 28 clock hours · lab

Medication Administration: Oral, Subcutaneous, and Intramuscular Routes

Objective. Students will prepare and administer medications by oral, subcutaneous, and intramuscular routes on simulation models, verifying the five rights of medication administration and documenting each dose accurately in a mock medical record.

⚠ 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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Medication Administration: Oral, Subcutaneous, and Intramuscular Routes

Safe medication administration is one of the most important responsibilities of a veterinary assistant or veterinary technician. Every time you give a drug, you must protect the patient from harm. This lesson covers the preparation and administration of medications by the oral (PO), subcutaneous (SQ or SC), and intramuscular (IM) routes on small-animal patients.

The Five Rights of Medication Administration

Before giving any medication, verify all five rights:

1. Right patient — Confirm the patient's name and ID against the medical record or cage card.

2. Right drug — Read the label completely; never assume. Look-alike or sound-alike drug names cause errors.

3. Right dose — Confirm the calculated dose matches the order. Recheck your math.

4. Right route — Oral, SQ, and IM are not interchangeable for every drug. The route affects absorption and safety.

5. Right time — Give medications at the scheduled interval. Document immediately after administration, never before.

These five rights apply to every administration event without exception.

Reading a Veterinary Prescription Label

A dispensed drug label includes the patient name, owner name, drug name, concentration, dose instructions, route, frequency, quantity dispensed, refills, prescribing veterinarian, and dispensing pharmacy or clinic. Always reconcile the label with the medical record order before drawing up or dispensing.

Dose Calculation

Most veterinary doses are weight-based and expressed in milligrams per kilogram (mg/kg). The basic calculation sequence is:

1. Convert body weight to kilograms if needed (pounds ÷ 2.2 = kg).

2. Multiply the ordered dose (mg/kg) by the patient's weight in kg to get the required dose in mg.

3. Divide the dose in mg by the drug's concentration (mg/mL) to find the volume to draw up in mL.

Always double-check your work before drawing up the syringe. A dose calculation error greater than 10% is a significant safety event.

Syringe and Needle Selection

Choose the syringe size closest to — but not smaller than — the volume you need to draw. Using a syringe that is too large reduces accuracy. Common sizes used in small-animal practice include 1 mL, 3 mL, and 6 mL.

Needle gauge is inversely related to needle diameter: a higher gauge number means a thinner needle. Thinner needles cause less tissue trauma and are preferred for SQ injections in small patients. Needle length must be sufficient to reach the target tissue.

Oral Medication Administration

Tablets and capsules (pilling): Gently extend the patient's head upward, open the mouth by pressing the upper lips over the upper teeth with your thumb and forefinger, place the pill as far back on the tongue as possible, then close the mouth and gently hold it shut while stroking the throat or blowing lightly on the nose to encourage swallowing. A pill popper (pill gun) helps keep your fingers away from teeth and is especially useful in cats. Always confirm the patient swallows; some patients will hold a pill and spit it out.

Liquid oral medications: Draw the correct volume into a dosing syringe. Insert the tip gently into the side of the mouth, behind the canine teeth, and deposit the liquid slowly so the patient can swallow without aspirating. Never administer liquid rapidly or directly into the back of the throat.

Subcutaneous Injection Technique

The subcutaneous space — between the skin and the underlying muscle — is a common and relatively low-risk injection site. Preferred sites in dogs and cats include the loose skin over the dorsal neck (scruff) and along the dorsal and lateral trunk.

Technique:

1. Put on gloves and prepare PPE.

2. Draw up the correct volume; confirm no air bubbles.

3. Tent the skin by grasping a fold of loose skin and lifting gently.

4. Insert the needle at approximately a 45-degree angle into the tent, bevel up.

5. Aspirate briefly; if blood appears, withdraw and start over at a new site.

6. Inject slowly, release the skin tent, then withdraw the needle smoothly.

7. Apply gentle pressure if needed; do not massage forcefully.

Rotate injection sites for patients receiving repeated SQ medications (e.g., insulin) to prevent tissue damage.

Intramuscular Injection Technique

IM injections deliver medication directly into muscle, producing faster absorption than SQ. Common sites in small animals include:

Technique:

1. Identify landmarks carefully; avoid nerves and blood vessels.

2. Insert the needle at a 90-degree angle to the muscle surface.

3. Aspirate before injecting. If blood is seen, withdraw, replace the needle, and reposition.

4. Inject slowly and steadily.

5. Withdraw smoothly and apply gentle pressure.

Volume limits for IM injections in small patients are small; large volumes can cause pain and tissue damage. Follow practice guidelines and drug reference recommendations.

Documentation on the Medication Administration Record (MAR)

Document every dose immediately after administration — never in advance. Record the date, time, drug name, dose administered, route, site used, and your initials. Omissions or pre-signing create medical and legal risk and constitute a documentation error. If a dose is not given, document the reason.

Safety Points

Key terms8

Five RightsA safety checklist confirmed before every medication administration: right patient, right drug, right dose, right route, and right time.
Subcutaneous (SQ/SC)The tissue layer beneath the skin and above the muscle; a common injection route for small-animal patients because it is relatively low-risk and well tolerated.
Intramuscular (IM)An injection route that deposits medication directly into muscle tissue, providing faster absorption than subcutaneous administration.
ConcentrationThe amount of drug dissolved in a given volume of solution, typically expressed as milligrams per milliliter (mg/mL); used to calculate the volume to draw up.
Medication Administration Record (MAR)The legal document used to record each medication given to a patient, including drug, dose, route, site, time, and the initials of the person who administered it.
AspirationThe act of pulling back the syringe plunger before injecting to check for blood, confirming the needle tip is not inside a blood vessel.
GaugeA numerical measure of needle diameter; higher gauge numbers indicate a thinner (smaller diameter) needle.
Pill popper (pill gun)A plastic device used to place a tablet or capsule at the back of a patient's tongue without putting fingers inside the mouth, reducing the risk of a bite injury.

Worked examples4

1. A dog weighs 33 lb. The veterinarian orders a drug at 5 mg/kg SQ. The drug is supplied at a concentration of 25 mg/mL. What volume do you draw up?
  1. Convert weight to kg: 33 lb ÷ 2.2 = 15 kg
  2. Calculate required dose in mg: 15 kg × 5 mg/kg = 75 mg
  3. Calculate volume: 75 mg ÷ 25 mg/mL = 3.0 mL
Answer: Draw up 3.0 mL.
2. A cat weighs 4.4 lb. The order is for 2.5 mg/kg of a drug supplied at 10 mg/mL. What volume do you draw up?
  1. Convert weight to kg: 4.4 lb ÷ 2.2 = 2 kg
  2. Calculate required dose in mg: 2 kg × 2.5 mg/kg = 5 mg
  3. Calculate volume: 5 mg ÷ 10 mg/mL = 0.5 mL
Answer: Draw up 0.5 mL.
3. A dog weighs 22 lb. The order calls for 10 mg/kg of a drug concentrated at 50 mg/mL. What volume is needed?
  1. Convert weight to kg: 22 lb ÷ 2.2 = 10 kg
  2. Calculate required dose in mg: 10 kg × 10 mg/kg = 100 mg
  3. Calculate volume: 100 mg ÷ 50 mg/mL = 2.0 mL
Answer: Draw up 2.0 mL.
4. A patient requires 0.1 mg/kg of a drug supplied at 0.5 mg/mL. The patient weighs 6.6 lb. What volume do you draw up?
  1. Convert weight to kg: 6.6 lb ÷ 2.2 = 3 kg
  2. Calculate required dose in mg: 3 kg × 0.1 mg/kg = 0.3 mg
  3. Calculate volume: 0.3 mg ÷ 0.5 mg/mL = 0.6 mL
Answer: Draw up 0.6 mL.

The math in this lesson2

Learners convert 33 lb to 15 kg, find a 75 mg dose at 5 mg/kg, and draw 3.0 mL at 25 mg/mL.
7.RP.2N-Q.1
Brush up in the math halls at newSchoolWorks.com:
In class: Lecture on the five rights (right patient, drug, dose, route, time), reading a veterinary prescription label, calculating a dose using weight-based math (mg/kg), and drawing up a correct volume in a syringe; students solve 10 practice calculation problems with faculty review. · Simulation lab: students practice pilling a cat using a pill popper and liquid oral medication administration using a dosing syringe on feline mannequins; then perform subcutaneous injection technique using saline on injection pads, rotating sites correctly. · Intramuscular injection station: faculty demonstrate epaxial muscle and semimembranosus/semitendinosus site landmarks on a canine mannequin; students practice injection technique on pads and document each administration on a mock MAR (medication administration record).
Materials: Syringes (1 mL, 3 mL, 6 mL), needles (various gauges), injection training pads, saline (for practice), pill poppers, dosing syringes, mock MAR forms, drug calculation worksheet, veterinary drug reference (Plumb's Veterinary Drug Handbook or equivalent), PPE
Check: Faculty-observed skills check: student verbally states all five rights before each administration, draws up the correct volume (within 0.1 mL of target), selects correct site, and documents on MAR without omissions; any dose calculation error greater than 10% is an automatic retest.

Practice check8

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

Pharmacy and Pharmacology
1. Before administering any medication, a veterinary assistant verifies the five rights. Which of the following is NOT one of the five rights?
Patient Care and Nursing
2. A veterinary assistant is about to give a subcutaneous injection and aspirates the syringe. A flash of blood appears in the hub. What is the correct next action?
Pharmacy and Pharmacology
3. A 10-kg dog requires a drug at 4 mg/kg. The drug concentration is 20 mg/mL. What volume should be drawn up?
Patient Care and Nursing
4. Which needle gauge would be most appropriate for a subcutaneous injection in a small cat to minimize tissue trauma?
Patient Care and Nursing
5. When performing an intramuscular injection in the semimembranosus/semitendinosus site of a dog, at what angle should the needle be inserted relative to the muscle surface?
Medical Records and Documentation
6. A veterinary assistant completes a medication administration and then realizes they forgot to document it on the MAR. What should they do?
Patient Care and Nursing
7. When administering liquid oral medication to a cat using a dosing syringe, where should the tip of the syringe be placed?
Patient Care and Nursing
8. A patient receiving daily subcutaneous insulin injections develops localized thickening at the injection site. What practice would best prevent this complication?
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