12.3: Preparing Unit-Dose Packaged Medications
By the end of this section, you will be able to:
- Discuss the guidelines for withdrawing medications from a vial
- Identify how to withdraw medications from a glass ampule
- Recognize how to use prefilled cartridges for medication administration
- Discuss the guidelines for safely reconstituting powdered medication
- Explain the guidelines for mixing medications in one syringe
Parenteral medications may be supplied in a variety of packages, such as vials, glass ampules, and prefilled cartridges. Sometimes, the medication will come prepared, ready for the nurse to administer. Other times, it may be necessary for the nurse to withdraw a dose of medication from a vial, add a liquid to a powdered medication to form a solution that may be suitable for the parenteral route, or mix multiple medications in the same syringe prior to administration. Each of these preparations requires specific guidelines to be followed when preparing the medication. This section will provide you with the knowledge needed to demonstrate appropriate preparation of unit-dosed medications for parenteral administration.
Withdrawing Medications from a Vial
Withdrawing medications from a vial is a common procedure for the nurse to perform. A vial is a glass or plastic container with a rubber stopper on top that contains a liquid medication (Figure 12.18). To prepare for the task, the nurse should gather the medication vial, syringe , needle (if not already packaged with the syringe), and an alcohol swab. Perform hand hygiene and ensure the work surface is clean. Examine the vial to verify the correct medication, concentration (if applicable), and the expiration date of the vial. If the vial is out of date, discard the vial according to the agency’s policy and obtain a new vial.
To prepare the vial, remove the plastic cap from the vial if it is the first time the vial is being accessed. Use an alcohol swab to clean the rubber top. While the rubber top is drying, prepare the syringe. Remove the syringe and needle from the package, using caution to touch only the nonsterile surfaces. Attach the needle to the end of the syringe using aseptic technique. Once assembled, pull the plunger back to equal the amount of the medication to be administered, leaving the cap of the needle on during the process. Remove the cap, insert the needle in the center of the rubber top, and insert the air into the vial . Inserting air into the vial will reduce the vacuum effect and allow the medication to be removed from the vial more easily.
Invert the vial and needle, so the needle is pointing upward. Ensure the bevel is below the level of the solution. Pull back the plunger to obtain the correct dose. Remove any air bubbles by gently tapping the syringe. Gently press the plunger upward to expel the air bubbles from the syringe. If many bubbles are present, inject all of the medication back into the vial and slowly withdraw the medication again. Ensure all bubbles are removed and the correct dose is obtained, then invert the vial and syringe so the needle is pointing downward. Remove the needle from the vial and engage the needle safety device.
While recapping needles is generally discouraged because of the risk of needlestick injuries and potential exposure to bloodborne pathogens, there may be times when recapping the needle is necessary, such as if the needle is built into the syringe. If recapping is necessary, there are several guidelines to follow to minimize the risk of an accidental needlestick injury:
- Use a one-handed technique: Keep one hand behind your back or at your side away from the needle during the recapping process.
- Maintain visual contact: Keep your eyes on the needle while recapping to ensure you can control the process.
- Use a scoop technique: Place the cap on the countertop. Hold the barrel of the syringe with your dominant hand and use a scooping motion to insert the needle into the cap. When the needle is covered by the cap, tip the needle and cap upward and use your nondominant hand to click the cap securely on the needle. Another option is to press the needle and cap on a hard surface such as wall to click the cap onto the needle. During the process, use aseptic technique to avoid contaminating the needle and exposed plunger.
- Use mechanical devices: If available, use mechanical devices designed for recapping needles safely. These devices often have mechanisms to hold and secure the needle cap without requiring direct manual contact.
See the competency checklist for Withdrawing Medication from a Vial. You can find the checklists on the Student resources tab of your book page on openstax.org.
Single-Dose Vials
Single-dose vial s are approved to be used one time for one patient. They do not contain antimicrobial preservatives; hence, harmful bacteria may grow in the vial and infect the patient if it is reused. Therefore, it is important to discard the vial after every use, even if there is unused medication left in the vial after removing the required dose. Single-dose vials are preferred over multidose vial s, when possible, to reduce the risk of contamination.
Single-dose vials may come in a variety of sizes; therefore, it is important to always check the medication label to determine if the vial is single-dose, rather than relying on the volume of the vial. If the vial says single-dose and it has already been accessed or the medication has expired, dispose of the vial according to the agency’s policy and obtain a new vial. In general, the rule of “when in doubt, throw it out” is a good one to follow here.
Multidose Vials
Multidose vials contain more than one dose of medication. Vials are labeled for multiuse or single use. The manufacturer adds antimicrobial preservation to multidose vials. This helps prevent bacterial growth if safe injection practices are followed. This preservative, however, may not be effective against viruses. Multidose vials should be dedicated to a single patient, when possible. If the multidose vial enters the patient’s room, it should be used only for that patient to prevent inadvertent contamination. Otherwise, the multidose vial should be kept in the medication preparation area at all times. New needles and syringes should be used for every injection, even if the multidose vial is used for only one patient. Do not leave needles in vials for subsequent medication withdrawals. If barcode administration is used, the pharmacy will usually supply a sheet of barcodes that may be applied to the syringe and later scanned in the patient’s room, identifying the medication.
When using multidose vials, it is important to note the date when the vial was first accessed by placing a label on the vial with the date, time, and nurse’s initials. This beyond-use date should be calculated according to the agency’s policy, usually twenty-eight days unless the manufacturer specifies differently, and written on the vial. The beyond-use date should never extend past the manufacturer’s expiration date. For expiration dates that display only the month and year, the unopened product is usable until the end of the month unless otherwise noted by the manufacturer. The vial should be discarded if sterility is compromised, the manufacturer’s expiration date has passed, the vial is unlabeled with the date it was first accessed, the beyond-use date has passed, or the solution appears abnormal (e.g., discoloration, floating particles, or cloudy when it should be clear).
Withdrawing Medications from a Glass Ampule
An ampule (Figure 12.19) is a small glass container that holds a single dose of a medication prepared in liquid form. Prior to opening the ampule, gently tap the ampule to move all of the liquid contents to the bottom of the ampule and wipe the scored line with an alcohol swab. To open the glass ampule, place a gauze around the neck of the ampule and snap the neck of the ampule off, at the scored line, away from your body. To withdraw the medication from the ampule, use a blunt fill needle with a filter to prevent glass particles from being drawn up into the syringe with the medication. Replace the filtered needle with a regular needle before administering the medication to the patient. After an ampule is opened, the contents must be used right away and not stored for later use.
See the competency checklist for Withdrawing Medication from a Glass Ampule. You can find the checklists on the Student resources tab of your book page on openstax.org.
Special Considerations
When removing medications from an ampule, it is important to remember that the ampule is made of glass. Therefore, precautions should be taken to avoid cutting yourself. As mentioned in the clinical procedures, it is important to wrap a gauze pad around the neck of the ampule to protect your hands from being cut by the breaking glass. In addition, the glass ampule should always be placed in the sharps container instead of a regular trash can. It is important to be aware of any glass shards that may result from opening the ampule and to ensure all glass is cleaned up properly. If the ampule breaks or does not result in a clean break around the scored line, causing shards of glass, do not use the medication. Carefully clean up, dispose of the glass, and obtain a new ampule. By following these protocols and using a filtered needle, the nurse may avoid drawing glass up into the syringe with the medication. Injecting glass into the patient may cause harmful side effects, including pulmonary thrombi, embolisms, phlebitis, granuloma formation, and inflammation.
Using Prefilled Cartridges
Some medications are packaged in prefilled cartridges. These prefilled cartridges may fall into two categories: injector device s or prefilled syringe s. Prefilled cartridges have many benefits, including enhanced convenience, accuracy, sterility, and safety.
Prefilled cartridges come prepared with the medication premeasured and ready to use, which is much more convenient than having to draw up the medication from a vial or ampule . When a medication is already drawn up and ready to go, injections may be administered more quickly. Prefilled cartridges may be particularly helpful during emergent situations.
Prefilled cartridges may also enhance accuracy, because the manufacturer ensures the cartridges contain the correct amount of medication. It removes the potential for the individual to draw up the wrong amount of medication. This may be particularly helpful when patients need to self-administer the medication and have not been trained to calculate and measure doses.
Sterility is also enhanced when using prefilled cartridges. Prefilled cartridges have a shelf life of approximately two to three years, whereas medications that are drawn up from a vial or ampule typically have a shelf life of approximately twelve hours. Not to mention, there is less risk of contamination if the cartridge is prefilled and ready for the user to administer.
See the competency checklist for Preparing Medication Using a Prefilled Sterile Cartridge. You can find the checklists on the Student resources tab of your book page on openstax.org.
Injector Devices
An injector device (Figure 12.20) is a spring-loaded syringe that delivers a single, preloaded dose of a drug when the device is firmly pressed against the body. These devices can deliver medications through subcutaneous or intramuscular routes. They are easy to self-administer, which may improve patient compliance and reduce anxiety. Some examples of injector devices include epinephrine injections (EPIPEN), insulin pens, diazepam (Valium) auto-injectors, and naloxone ( Narcan ) auto-injectors.
Prefilled Syringes
A prefilled syringe (Figure 12.21) is a disposable syringe that is supplied with the necessary amount of the medication to be injected in a single dose. It is designed to simplify the process of medication administration by eliminating the need for healthcare professionals or patients to manually draw up the medication from a vial into a syringe before injection. By using a prefilled syringe, the risk of vial contamination or improper technique of preparing the medication is reduced, as well as reducing medication waste. In many cases, the prefilled syringe contains a Luer-lock that allows the needle to be twisted in place and then the medication is ready to administer immediately. If there is an air bubble present in the prefilled syringe, gently tap the syringe until the bubbles rise to the top of the syringe and slowly push the plunger up to expel the bubbles, using caution not to expel any of the medication. However, do not remove the air bubble found in enoxaparin (Lovenox) prefilled syringes, as this bubble is needed to help push the medication into the body. After administration, both the needle and the syringe must be discarded because reusing either component may transmit diseases. Some examples of medications that come in prefilled syringes include enoxaparin, propofol (Diprivan), fentanyl, hydromorphone (Dilaudid), and labetalol.
Prefilled syringes may also come packaged for use in a single-dose cartridge system, which loads a specific prefilled cartridge into a plastic holder for easy administration. This system reduces waste by reusing the plastic holder instead of requiring the medication to be withdrawn with a syringe and needle. When using the reusable plastic holder, it is important to wipe the holder down between uses with an appropriate antiseptic cleanser. If withdrawing medication from the single-dose cartridge system with a needle and syringe, do not inject air into the prefilled syringe because the pressure in the prefilled syringe will increase, forcing the rubber stopper and medication to be expelled from the prefilled syringe.
Guidelines for Reconstituting Powdered Medication
Some medications are unstable when supplied in a liquid form; therefore, they are packaged in a powdered form. Prior to administering these medications via the parenteral route, the nurse must reconstitute the powder (solute), or make it into liquid again, with a diluent (solvent) to create a liquid solution. It is important for the nurse to know how to properly reconstitute these medications to ensure that safe medication administration practices are followed.
Selection of Diluent
A diluent is the liquid used to dilute a powdered medication into a liquid form. Sterile solutions must be used when reconstituting parenteral medications. The type of diluent used varies according to the medication. Typically, parenteral medications are diluted with sterile water or sterile normal saline. The type and amount of diluent to be used should be identified in the medication package insert, in the medication label, or the electronic medication administration record (eMAR). If in doubt, consult the pharmacy or a medication reference guide to confirm.
Safety Considerations
When reconstituting powdered medications, it is important to locate the manufacturer’s directions for reconstituting, typically found on the vial or package insert. Within the manufacturer’s directions, there should be clear instructions regarding which diluent to use, as well as the volume of liquid needed to reconstitute the medication. The label should also identify proper storage for the medication after mixing, including the length of time the medication can be stored after reconstitution. To correctly calculate the dose, it is important to note the strength or concentration of the medication after it has been reconstituted. If in doubt or if any of the necessary information cannot be found, consult the pharmacy or a medication reference guide. Reconstitution instructions must always be verified and never be assumed.
The nurse is preparing to administer IV acyclovir to a patient. After retrieving the vial, the nurse notes that the medication is in a powdered form. Recognizing that the powdered medication must be turned into a solution before administering the medication via the IV route, the nurse analyzes the cues to determine whether the medication needs to be reconstituted. The nurse considers common diluents used for reconstituting medications and hypothesizes that sterile water or normal saline may be required; however, the nurse examines the medication label to determine which diluent to use. After reading the medication label, the nurse notes that the instructions read, “Inject 20 mL sterile water for injection into vial.” The nurse takes action by reconstituting the powdered medication with 20 mL of sterile water.
After a medication has been reconstituted, it is best practice for the individual who prepared the medication to administer the medication. Should the individual preparing the medication not use the appropriate type or amount of diluent , the nurse who administered the medication may be held responsible should a medication error occur because of improper reconstitution . If the individual who prepared the medication is not the person administering the medication, best practice is to label the syringe with the type and amount of diluent used, as well as the expiration date of the diluent, and the time in which the medication must be used after being reconstituted.
Special consideration should be given to hazardous medications, such as chemotherapeutics or other cytotoxic drugs. When reconstituting hazardous medications, the procedure must take place inside a chemical fume hood or other containment device to provide safety in the event the powdered medication is released into the air. In addition to using a containment device, personal protective equipment (PPE) should also be worn to protect the individual preparing the medication from accidental exposure. Due to the required safety precautions, hazardous medications must always be reconstituted by trained professionals in the pharmacy.
Procedural Steps for Reconstituting Powdered Medication
Gather the necessary supplies: diluent, medication vial , needle , alcohol swab, and syringe large enough to hold the volume of the diluent. Check expiration dates on the diluent and medication vials. If expired, discard vials according to agency policy and obtain new vials. After performing hand hygiene, remove the plastic caps from the vials, clean the rubber stoppers with an alcohol swab, and allow the alcohol to dry. Then the nurse assembles the needle and syringe.
Inject air into the diluent vial, equivalent to the volume of diluent required. Invert the vial and needle so the needle is pointing up with the bevel below the level of solution inside the vial. Then withdraw the required amount of diluent and remove the syringe and needle from the vial. If there is more diluent in the vial than required, only remove the required volume, and dispose of the remaining diluent according to the agency’s policy. Invert the vial and needle so the needle is facing upward, tap the syringe so air bubbles move to the top. Gently depress the plunger to remove all air bubbles. Inject the diluent into the medication vial. Gently roll the medication vial between your hands until the powder is dissolved, inspecting the vial to ensure all particles are dissolved. Invert the vial and needle so the needle is facing upward and withdraw the required amount of solution. If there is more solution in the vial than required, only remove the required volume, and dispose of the remaining solution according to the agency’s policy. Invert the vial and needle so the needle is facing downward and remove the needle and syringe from the vial. Gently remove all air bubbles as described and engage the needle safety device.
See the competency checklist for Reconstituting Powdered Medication. You can find the checklists on the Student resources tab of your book page on openstax.org.
Dual-Compartment Vial System
Some medications come prepared with the powdered medication and the diluent in the same package; however, they are separated in different compartments until they are ready for use (Figure 12.22). One example of a medication that comes prepared in a dual-compartment vial system is methylprednisolone sodium succinate (Solu-Medrol). To reconstitute the medication, simply press down on the plastic activator. This will displace the rubber stopper and allow the diluent into the lower compartment with the powdered medication. Gently swirl the vial (do not shake) to mix the solution. Ensure no particles are remaining before drawing up the medication. Remove the circular plastic covering on top of the plastic activator to reveal the rubber stopper and withdraw the medication according to the procedure for withdrawing medications from a vial.
Guidelines for Mixing Medications in One Syringe
Some medications must be mixed from two vials or from a vial and an ampule . Other times, the nurse may mix medications to avoid the need for multiple injections. When mixing medications in one syringe , it is essential to first ensure compatibility of the medications. Consideration should also be given to ensure the volume of the mixed medications is appropriate for the injection site. Special consideration must be given when mixing insulins. It is important to follow the guidelines for mixing medications into one syringe to ensure patient safety, comply with aseptic technique, and prevent contamination of the contents.
See the competency checklist for Mixing Medications from Two Vials in One Syringe. You can find the checklists on the Student resources tab of your book page on openstax.org.
Compatibility
It is important to ensure the medications are compatible before mixing medications into one syringe. Compatibility is the ability to administer two or more medications together without them interacting with one another. Incompatible medications drawn up or mixed together may alter the chemical makeup or effects of either medication. After being combined, the medications may have reduced effects or become inactive, harmful chemical reactions may occur, toxicity of the medications may be increased, or microparticles may be created and injected into the body. Compatibility of the medications must be assessed before administering the medications. To do so, the nurse may use an electronic medication interaction checker, look up the medications in a medication reference guide, or use a compatibility chart often provided by the organization (Figure 12.23) for quick access to commonly used medications. If uncertain about whether medications are compatible, consult a pharmacist.
Nurse:
Mike, RN
Clinical setting:
Inpatient psychiatric unit
Years in practice:
5
Facility location:
Southeastern United States
I was recently asked to float to an inpatient psychiatric unit. During the float assignment, a patient on the unit became very aggressive. My first action was to implement nonpharmacological and verbal de-escalation techniques but they were not effective. The prescribing provider had ordered diphenhydramine (Benadryl) 50 mg, haloperidol (Haldol) 5 mg, and lorazepam (Ativan) 2 mg IM times one dose. Reading the order, I understood that the three different medications were ordered via the IM route. I was concerned about giving all three medications at one time. After speaking with other professional personnel on the unit, I learned this combination of medications is widely used in the behavioral health setting and is known as a B-52 cocktail. So, I considered whether the medications could be combined into one syringe to avoid having to give the patient three injections. Therefore, I opened the electronic medication interaction checker, entered all three medications into the system, and concluded that all three medications were compatible. My next step was to calculate the total amount of the medications and ensure that the total volume did not exceed the maximum volume for an IM injection. Finally, I drew up the medications into one syringe and administered them to the patient in a single injection.
Volume Limits for Different Routes
When mixing medications into one syringe, it is important to consider the overall amount of fluid to be injected. This is particularly important when administering medications via the intradermal (ID) , subcutaneous (SQ) , and intramuscular (IM) routes. Injecting too much volume may be difficult for the body to absorb, cause increased pain for the patient, and result in adverse events at the injection site. The maximum volume for ID injections is 0.5 mL or less. Typically, the maximum volume for SQ injections is about 1.5 mL; however, volumes of 2 mL to 3 mL may be tolerated when injected into the abdomen. The maximum volume for IM injections is between 1 mL and 3 mL, though this can depend on the injection site. Children can withstand less volume via the IM route, with no more than 1 mL of fluid injected into the ventrogluteal muscles and no more than 3 mL injected into the vastus lateralis (1 mL in infants) (Table 12.1).
| Route | Typical Maximum Volume |
|---|---|
| Intradermal |
|
| Subcutaneous |
|
| Intramuscular |
|
Mixing Medications from Vial and Ampule
When mixing medications from a vial and an ampule , withdraw the medication from the vial first, followed by the ampule. Determine the amount of medication to be removed from the vial, the amount to be removed from the ampule, and the total volume that should be administered. Follow the guidelines for removing medication from a vial, remove the needle from the syringe using the scoop or hands-free method, add a filtered needle, and then proceed with removing the medication from the ampule. Use caution not to remove more than the exact required dose from the ampule. Remove the filtered needle and replace it with an appropriate-sized needle according to the route of administration.
Mixing Insulins
Some insulins, such as intermediate-acting insulin and short- or rapid-acting insulins, may be mixed together in a single syringe so the individual will require only one injection. Mixing insulins is sometimes needed to help control an individual’s blood sugar throughout the day, because the insulins have varying onsets. Insulin glargine (Lantus) and insulin detemir (Levemir) may never be mixed in the same syringe with each other or other insulins because doing so may alter the onset of the insulins, making it difficult to control the patient’s blood sugar. It is important to follow proper sequencing for mixing insulins to prevent contaminating the insulin vials, which may adversely affect the onset of the medications.
Procedural Sequence for Mixing Insulins
When mixing insulins, obtain the two types of insulin, an insulin syringe large enough to hold the volume of both insulins combined, and alcohol swabs. To prepare the vials, gently roll the intermediate-acting insulin (cloudy vial) between your hands. Wipe the top of each insulin vial with an alcohol swab and allow the alcohol to dry. Inject air equal to the required units of the intermediate-acting insulin into the cloudy insulin vial. Remove the syringe and needle from the intermediate-acting vial. Inject air equal to the required units of short- or rapid-acting insulin into the clear vial of insulin. With the needle in the clear vial, invert the vial and syringe so the needle is pointed up. Ensure that the bevel of the needle is below the level of solution and slowly pull down on the plunger until the desired units of clear insulin are withdrawn into the syringe. Gently tap on the syringe to remove any air bubbles. If there is a large quantity of air bubbles, the insulin may be inserted back into the vial and the process repeated. Gently push up on the plunger to remove the air bubbles from the syringe. If any air bubbles are left in the syringe, the patient will receive less than the intended dose of insulin.
After the correct dose of clear insulin has been withdrawn and there are no air bubbles present, remove the needle from the clear insulin vial . Push the needle into the cloudy insulin vial and invert the bottle upside down with the needle pointed up. Slowly pull down the plunger until the total number of cloudy units are obtained (Figure 12.24). Be cautious that you have the correct number of units because the cloudy insulin has mixed with the clear insulin upon withdrawing the medication from the vial and cannot be pushed back into the vial. If too much cloudy insulin is withdrawn from the vial, discard the dose and start the procedure over.
See the competency checklist for Procedural Sequence for Mixing Insulins. You can find the checklists on the Student resources tab of your book page on openstax.org.