12.1 Injection and Vaccine Administration Technique

12.1 Injection and Vaccine Administration Technique

Exam Focus: "Medication administration" is a distinct subcategory of the Pharmacy Practice blueprint, and the syllabus specifies "skills required for safe and effective administration of vaccines and medications by injection in selected populations." Items test site, needle, dose, and the immediate management of a reaction.

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Authority and Preparation

Injection administration by pharmacists is authorised under provincial legislation, and every province requires documented injection training and current cardiopulmonary resuscitation certification before a pharmacist may inject. The permitted list of injectable products, the minimum patient age, and the requirement for a prescription vary between provinces, so verify local authority rather than assuming a national rule.

Before any injection:

1. Confirm identity, indication, and informed consent, and screen for contraindications and precautions.
2. Review allergy history, current anticoagulation, immunosuppression, pregnancy, and prior reactions.
3. Confirm that epinephrine and an emergency response plan are immediately available.
4. Check the product name, concentration, expiry, appearance, and, where relevant, the diluent.
5. Perform hand hygiene. Gloves are not routinely required for immunization unless the administrator has open skin lesions or contact with blood is anticipated.

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Route, Site, and Needle Selection

Site selection:

• Deltoid — the standard intramuscular site for anyone aged 1 year and older. Locate it by finding the acromion process and injecting into the thickest part of the muscle, roughly two to three finger widths below it, above the level of the axilla. Injecting too high risks shoulder injury related to vaccine administration, a preventable and well-recognised complication.
• Vastus lateralis — the anterolateral thigh, the intramuscular site for infants under 1 year and the site of choice for emergency epinephrine at any age.
• Ventrogluteal — used for larger volumes and viscous depot preparations.
• Subcutaneous sites — the fatty tissue of the posterolateral upper arm, the abdomen avoiding a 5 cm radius around the umbilicus, and the anterior thigh.

Do not aspirate before an intramuscular injection. There are no large blood vessels at the recommended sites, aspiration prolongs the procedure and increases pain, and current Canadian immunization guidance advises against it.

When more than one vaccine is given at the same visit, use separate sites at least 2.5 cm apart, or separate limbs, and record which product went where.

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Technique and Comfort

Position the patient seated with the limb relaxed; a tense muscle makes injection more painful. Clean the site with alcohol only if visibly soiled, and allow it to dry fully — injecting through wet alcohol stings and can inactivate live vaccines.

Insert smoothly and briskly, inject at a steady rate, withdraw, and apply gentle pressure without massage. Pain-reduction techniques with real evidence include the rapid injection without aspiration described above, giving the most painful product last, breastfeeding or sucrose for infants, topical anaesthetic where time permits, distraction, and having the patient sit rather than lie down for adults.

Sharps safety: activate the safety device immediately, never recap, and dispose directly into an approved puncture-resistant sharps container at the point of use. A needlestick injury requires immediate washing, reporting, and post-exposure risk assessment for hepatitis B, hepatitis C, and human immunodeficiency virus.

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Managing Immediate Adverse Events

Distinguishing syncope from anaphylaxis is a favourite examination point: syncope is common, immediate, and resolves when the patient lies down; anaphylaxis involves skin, respiratory, or cardiovascular compromise and worsens without treatment. When genuinely uncertain, treat as anaphylaxis, because epinephrine given to a person who has fainted causes little harm and withholding it in anaphylaxis is life-threatening.

Epinephrine dosing: 0.01 mg/kg of the 1 mg/mL (1:1000) solution intramuscularly into the anterolateral thigh, to a maximum of 0.5 mg in adults and 0.3 mg in children, repeatable every 5 to 15 minutes. Confirm the concentration on the ampoule before drawing up; the 0.1 mg/mL (1:10,000) presentation is for intravenous use in cardiac arrest and is not interchangeable.

Observe every patient for 15 minutes after immunization, extended to 30 minutes for those with a history of anaphylaxis, significant needle anxiety, or a prior post-immunization reaction.

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Cold Chain

Vaccines and many biologics are stored at +2 to +8 degrees Celsius.

• Use a purpose-built vaccine refrigerator with a continuously recording thermometer, not a domestic bar fridge or a food refrigerator.
• Record minimum and maximum temperatures at least twice daily and document the readings.
• Keep vaccines in the middle of the fridge away from walls, vents, and the door; use water bottles to stabilise temperature.
• On a temperature excursion, quarantine the affected stock, label it "do not use", and contact the public health authority or manufacturer for a viability assessment. Do not destroy or administer it on your own judgement.
• Freezing is not reversible. Adjuvanted and aluminium-containing vaccines are destroyed by freezing even if they later thaw and appear normal.
• Transport in a validated cooler with a temperature monitor and a barrier that prevents direct contact with ice packs.