Admixture of Drugs in a Syringe
Combining two drugs in one syringe avoids the discomfort of two injections. Usually, drugs can be mixed in a syringe in one of four ways: They may be combined from two multidose vials (for example, regular and long-acting insulin), from one
multidose vial and one ampule, from two ampules, or from a cartridge-injection system combined with either a multidose vial or an ampule. Such combinations are contraindicated when the drugs aren’t compatible and when combined doses exceed the amount of solution that can be absorbed from a single injection site.
multidose vial and one ampule, from two ampules, or from a cartridge-injection system combined with either a multidose vial or an ampule. Such combinations are contraindicated when the drugs aren’t compatible and when combined doses exceed the amount of solution that can be absorbed from a single injection site.
Equipment
Prescribed medications ▪ patient’s medication record and chart ▪ alcohol pads ▪ sterile syringe and needle ▪ Optional: cartridge-injection system, safety needle, filter needle.
The type and size of the syringe and needle depend on the prescribed medications, the patient’s body build, and the route of administration. Medications that come in prefilled cartridges require a cartridge-injection system. (See Cartridge-injection system.)
Implementation
Verify that the drugs to be administered agree with the patient’s medication record and the doctor’s orders.1
Calculate the dose to be given.
Mixing Drugs from Two Multidose Vials
Using an alcohol pad, wipe the rubber stopper on the first vial to decrease the risk of contaminating the medication as you insert the needle into the vial.
Pull back the syringe plunger until the volume of air drawn into the syringe equals the volume to be withdrawn from the drug vial.
Without inverting the vial, insert the needle into the top of the vial, making sure that the needle’s bevel tip doesn’t touch the solution. Inject the air into the vial and withdraw the needle. This step replaces air in the vial, thus preventing the creation of a partial vacuum on withdrawal of the drug.
With a new needle, repeat the steps above for the second vial. Then, after injecting the air into the second vial, invert the vial, withdraw the prescribed dose, and then withdraw the needle (as shown below).
Wipe the rubber stopper of the first vial again and insert the needle, taking care not to depress the plunger. Invert the vial, withdraw the prescribed dose, and then withdraw the needle.
Change the needle on the syringe, if indicated.
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Equipment
