Preparing Parenteral Medications from Drugs supplied as a Powder(Reconstitution)On the drug label or the package insert will state the diluents to be used and the exact amount tobe added. When adding a solution or diluents to the powder, you will notice that the directionswill state the volume and dose after the solution has been added.

For example, the directions may read to add 1.8 mL of normal saline to a vial and when addedto the powder, the solution contains a total of 2 mL, and after reconstitution the vial contains250 mg/mL. The reconstituted amount is what you would use to solve the dose amount. Inthis case 250 mg/mL is the dosage supply amount you would use to solve this problem.Use the formula method:A patient is to receive Penicillin 200mg IV every 6 hours. The label on the vial reads: add 1.8mL of sterile water diluents. On the label it states, after reconstitution the vial will contains 250mg/mL( the dosage supply amount).Use the formula method to calculate the dose:D X V =AH200 mg X 1 mL = 0.8 mL250 mgYou would prepare 0.8 mL to administer in the IV to your patient.

Practice Problems:

1. Synthroid 150 mcg intravenous is ordered daily. After reconstitution the vial contains a total of 5 mL and there is 100 mcg/mL.Give: _____________

2. Cefazolin sodium 250 mg IV every 8 hours. Reconstitute with 2.5 mL sterile normal saline. After reconstitution the vial contains 225 mg/mL.Give: ____________

3. Ampicillin 250 mg IM every 12 hours is ordered. After reconstitution there is 125 mg/mL.Give: _____________

4. Cefazolin sodium 125 mg IV every 12 hours is ordered. After reconstitution the vial contains 225 mg/mL.

Give: __________

5. Ampicillin 350 mg IM is ordered daily. After reconstitution with 3.5 mL of sterile water, the vial contains a total of 500 mg/mL.Give: ___________

Practice Problems Answers: 1. 1.5 mL2. 1.1 mL3. 2 mL4. 0.56 mL5. 0.7 mL

Reconstitution Practice1. Order: Prostaphlin 500 mg IM q6h

Label reads:

Prostaphlinoxacillin sodium for injection

For IM use add 11.5 mL SterileWater for Injection U.S.P.  Each

1.5 mL of solution contains 250 mgoxacillin.

Give ________ mL

2. Order: Ticar 500 mg IM stat and q8h

Label reads:

Ticarticarcillin disodium

For IV or IM use.  Add 12 mLSterile Water for Injection,

U.S.P.or 1% Lidocaine HCl solution

(withoutepinephrine). Each 2.5 mL of

solution will then contain 1 g ticarcillin.

How many mL would be given?

3. Order: Ancef 225 mg IM q6h

Stock: on the shelf there are three vial sizes of powder: 250 mg, 500 mg, and 1g

RECONSTITUTIONPreparation of Parenteral Solution

For IM injection, IV direct (bolus) injection, or IV infusion, reconstitute with Sterile Water for Injection according to the following table.  SHAKE WELL

Vial size     Amt. diluent     Approx. concentration     Approx. available volume250 mg       2.0 mL             125 mg/mL                    2.0 mL500 mg       2.0 mL             225 mg/mL                    2.2 mL1 gram        2.5 mL             330 mg/mL                    3.0 mL

Stock chosen: _________    Add _____ mL  Give _____ mL

Stock chosen: _________    Add _____ mL  Give _____ mL

4. Order: carbenicillin disodium 1 g IM q6h for an adult

Stock: vial of powder labeled 2 gUse the following label for reconstitution.

For intramuscular use: The 2 g vial should be reconstituted with 4.0 mL of Sterile Water for Injection,  0.5% Lidocaine Hydrochloride (without epinephrine), or Bacteriostatic Water containing 0.9% benzyl alcohol. In order to facilitate reconstitution up to 7.2 mL diluent can be used.

Amount of Diluent to be                  Volume to be Withdrawn for aAdded to the 2 g vial                        1 g Dose

4.0 mL                                                      2.5 mL

5.0 mL                                                      3.0 mL7.2 mL                                                      4.0 mL

The 5 g vial should be reconstituted with 7.0 mL Sterile Water for Injection,  0.5% Lidocaine Hydrochloride (without epinephrine), or Bacteriostatic Water containing 0.9% benzyl alcohol. In order to facilitate reconstitution up to 17 mL diluent can be used.

Amount of Diluent to be                          Volume to be Withdrawn for aAdded to the 5 g vial                               1 g dose

7.0 mL                                                      2.0 mL9.5 mL                                                      2.5 mL12.0 mL                                                    3.0 mL17.0 mL                                                    4.0 mL

After reconstitution, no significant loss of potency occurs for up to 24 hours at room temperature, and for 72 hours if refrigerated.  Any of these unused solution should be discarded.

a. Add _____ mL and give _____ mL b. Add _____ mL and give _____ mL

Key for Reconstitution Problems

1. 3cc 2. 1.3cc3. Stock chosen: 250 mg vial; add 2 mL Sterile Water for Injection; give 1.8 mL    Stock chosen: 500 mg vial; add 2 mL Sterile Water for Injection; give 1 mL4a. Add 4 mL and give 2.5 mL 4b. Add 5 mL and give 3 mL