How to reconstitute a powdered medication

Many antibiotics and other drugs come as a powder that must be mixed before use. The wrong liquid or volume changes the strength and the dose the patient gets.

What you need

• Powdered drug vial
• Correct diluent
• Syringes and needles
• Alcohol swabs
• Label

Step by step

1. Read the label

   Find the type of diluent, the volume to add and the final strength, for example 1 g in 10 mL. Some drugs list several volumes for different routes. [1]

2. Check the diluent

   Use exactly what the label says, such as sterile water or normal saline. Bacteriostatic diluent is not safe for every drug or for newborns. [1]

3. Add the diluent

   Clean both vial tops with alcohol and let them dry. Draw up the diluent and inject it slowly into the powder vial. [2]

4. Dissolve gently

   Roll or swirl the vial unless the label says to shake. Look for a clear solution with no particles or clumps. [2]

5. Calculate the dose

   Use the new strength to work out the volume to give. Have a second person check if the drug is high-alert or the math is complex. [1]

6. Label a multidose vial

   Write the date, time, strength after mixing, expiry and your initials. Store it as the label directs. [3]

Common errors

• Using the wrong diluent or the wrong volume.
• Calculating the dose from the old strength instead of the mixed one.
• Leaving a mixed multidose vial without a label.

Sources

1. Open RN, Nursing Pharmacology 2e (CC BY 4.0)
2. Open RN, Nursing Skills 2e (Chippewa Valley Technical College) (CC BY 4.0)
3. The Joint Commission, National Patient Safety Goals

Steps adapted from Open RN, Nursing Pharmacology 2e and Open RN, Nursing Skills 2e (Chippewa Valley Technical College), licensed under CC BY 4.0. VMS is not affiliated with these organizations. Updated: 2026-10-11.