Preparing Powdered Parenteral Medications

Diluent

The liquid solvent added to a dry medication to dissolve or suspend it.

Reconstitution

The process of preparing a powdered medication involves adding a liquid (diluent) to the powdered medication

Approximate volume after dilution

The total volume of the powder plus the diluent.

• could be after reconstitution

• after adding more diluent to a medication that has already been dissolved or prepared

Institute for Safe Medication Practices (ISMP)
and
American Society of Health-System Pharmacists (ASHP)
medication preparation standard

Recommends that all medications be supplied in unit-dose and ready-to-administer formats whenever possible.

Nurse's primary responsibilities during reconstitution

Accurately interpreting directions, selecting the appropriate type and amount of diluent, and identifying the correct dosage strength for calculating ordered doses.

Total strength on a powdered drug label

The total strength of drug present in the vial.

500 mg per vile

1 gram per vile

It is not part of the dosage strength and is not used in solving drug dosage problems.

Dosage strength on powdered medications

Dosage strength

The strength of the medication and the dosage form.

(225 mg per 1mL)

for powdered medications it will be located on the back. Usually after reconstitution

Displacement volume

The additional volume in a reconstituted mixture that exceeds the volume of solvent added, caused by the space occupied by the powder.

The difference between the volume of diluent added and the final volume after reconstitution.

• Diluent added into a powder vile: 2 mL

• Final volume after reconstitution: 2.2 mL

• Displacement volume: 0.2 mL

this happens because of the powder that is already in the vile

Role of displacement volume in dosage calculations

It is omitted entirely from formulas; calculations must rely strictly on the dosage strength stated on the label or package insert.

Active ingredient

The therapeutic component of a drug formulation that must be distinguished from inactive additives to correctly identify dosage strength.

Two types of reconstitution

Single-strength

• 1 diluent amount

• 1 dosage strength
  
  
  
  

multiple-strength

• several diluent amounts (choice of more dilute or more concentration)

• Each diluent amount has its own dosage strength

CDC labeling requirements for reconstituted multi-dose vials

• Date and time of reconstitution

• Type and amount of diluent added

• dosage strength

• beyond-use date and time (28 days but could differ by manufacturer)

• storage instructions

• nurse's initials.

Nurse documentation for multiple-strength vials

Circling the specific amount of diluent added and the resulting dosage strength directly on the container label.

Storage guidance for reconstituted multi-dose vials

Information located on the drug label or package insert, subject to the policies and procedures of the healthcare facility.

bacteriostatic water

Water that has been treated to inhibit the growth of bacteria; often used as a diluent when reconstituting powdered medications. 

Two-compartment vial (e.g., Mix-O-Vial or Act-O-Vial)

A specialized container holding powder in one chamber and diluent in another separated by a rubber stopper, activated by depressing the stopper to mix.

ADD-Vantage system

An intravenous drug delivery setup where a powdered medication vial connects directly to an IV bag, activated by pulling an internal plug to mix the components.

Effect of diluent volume on drug concentration

An inverse relationship where adding less diluent yields a higher concentration, while adding more diluent yields a more dilute solution.

forms of reconstitution instructions for multi-strength drug label

• narrative

• table

• combined format

Clinical factors determining diluent volume in multiple-strength reconstitution

The ordered medication/dosage, route of administration, needs of the patient, and other individual factors

NEED TO KNOW how to recognize active ingredients in dosage and calc

need to know the different types of med labels showing reconstitution options/instructions

The nurse is preparing to administer IV cefoxitin. Read the electronic medication order, label, and insert. The nurse adds 10 mL of diluent to the vial. How many milliliters of reconstituted medication will the nurse administer?

ORDERED 1.8 g IV ever 8 hrs

10 mL