Preparing parenteral medication: ampoules, vials and reconstitution

What it is

Injectable drugs come in glass ampoules (broken at the neck and used once), in rubber-stoppered vials (single-dose or multidose) or as a powder that must be reconstituted with a diluent. Preparation is done with aseptic technique, in a clean area, with a new needle and syringe for each patient. Ampoules are drawn up with a filter needle so no glass is drawn in; air is injected into vials to equalise the pressure. Whatever is left in an ampoule or a single-dose vial is discarded.

Indications

• IM, SC, ID or IV drugs supplied in an ampoule, a vial or as a powder.
• Mixing two compatible drugs in one syringe when the order and the reference allow it.
• Mixing two compatible insulins (the clear one is drawn up first).

Contraindications and precautions

• Expired or unlabelled medication: do not use it.
• Leftover from an ampoule or a single-dose vial is not saved or pooled: discard it.
• Never leave a needle in a vial stopper for repeated use.
• Prepare close to the time of administration, in a clean area away from sinks.

Equipment

• Medical order and medication.
• Syringes and needles of the right size; a filter needle for ampoules.
• Alcohol swabs and gauze.
• The stated sterile diluent (sterile water or saline) if reconstitution is needed.
• Sharps container, labels and gloves per protocol.

Step by step (and why)

1. Clean your hands and prepare in a clean area — aseptic technique starts before the drug is opened.
2. Compare the label with the order and check expiry and appearance — prevents errors and contamination.
3. Ampoule: tap the liquid down, wrap the neck in gauze and snap it away from your hands — protects against cuts and glass.
4. Draw up from the ampoule with a filter needle, then change it — the filter holds back glass particles.
5. Vial: scrub the stopper, inject air equal to the dose and draw up with the vial inverted — equal pressure makes drawing up easier.
6. Powder: add the diluent type and volume stated on the label — the volume sets the final concentration.
7. Remove air bubbles and check the volume at eye level — air changes the measured dose.
8. Label the syringe if it is not given at once and discard the rest per protocol — prevents mix-ups and reuse.

Complications

• Glass particles in the syringe if no filter needle is used.
• Contamination of the drug from a break in aseptic technique.
• Precipitates when incompatible drugs are mixed.
• Needlestick injury when recapping.
• Wrong dose from air bubbles or reconstitution with the wrong volume.

Next step: when to call for help

• Needlestick or cut during preparation: report it at once per the occupational-exposure protocol.
• Doubt about the diluent, compatibility or stability: ask the pharmacist before preparing.
• Expired or unlabelled medication: do not use it and tell pharmacy.

Test yourself

Think of the answer, then tap the question to see it.

Add to my cards (3)

Connections

← All of nursing

Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.

Sources: Nursing Skills (Open RN), 18.2 Basic Concepts (Administration of Parenteral Medications) (Open RN, Chippewa Valley Technical College (LibreTexts), 2022); Nursing Skills (Open RN), 18.8 Checklists for Parenteral Medication Administration (Open RN, Chippewa Valley Technical College (LibreTexts), 2022); Nursing Skills (Open RN), 5.10 Reconstituted Medication (Open RN, Chippewa Valley Technical College (LibreTexts), 2022); Preventing Unsafe Injection Practices (Centers for Disease Control and Prevention (CDC), 2024).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Send

Representative model, for educational purposes only.