Drug Dosage Calculations

The patient is to receive epoetin 8,000 units subcut 3 times per week for the duration of his chemotherapy. The medication is available in a vial labeled 40,000 units/mL. The ordered dose of 8,000 units is contained in 0.2 mL. The oncology nurse is teaching the patient how to administer the subcut injection. The patient prepares the ordered dose and shows the following to the nurse: Which of the following is the best response by the nurse?

0.2

The nurse is to draw up medication for a subcutaneous injection. Which of the following is the most appropriate needle size to choose?

25G 5/8" is the standard size for subcutaneous injection. A longer needle would be used for injections deep into the muscle, or for large patients.

Read the below labels. Which medication can be administered via the enteral route? Select all that apply.

Amoxicillin Powder for Oral Suspension Vibramycin for Oral Suspension

Which of the following abbreviations are associated with time-released medications? Select all that apply.

CR (controlled-release), Contin (continuous-release), SA (sustained-action), and SR (sustained-release) are all associated with time-released medications. Labels may also include ER, XR, or XL (all meaning extended-release) or TR (time-release).

Which of the following statements is true of a 3 mL syringe?

Each short calibration line measures 0.1 mL.

Which of the following are parenteral routes? Select all that apply.

Intravenous (IV), intramuscular (IM), intradermal (ID), and subcutaneous (subcut) are all parenteral routes. Rectal (PR) is an enteral route.

When measuring a liquid medication in a medicine cup, the nurse should read the fluid level at the meniscus. To accurately read the meniscus, the fluid level is read:

It is important to read the fluid measurement at the meniscus level or horizontal center of the fluid. Liquids curve up at the edge of the medicine cup, and reading the fluid level at the edge of the cup is not accurate. Using the metric and household calibrations is not an accurate reading of the meniscus.

Some drugs are supplied in units of measurement that do not convert to any other unit of measurement:

Parenteral penicillin is measured in units. The "unit" measurement expresses the biological activity or potency of the drug and is the standard measurement for penicillin. Heparin is measured in units. Administration of heparin is covered separately. Insulin is measured in units. Administration of insulin is covered separately. Some electrolytes (such as potassium) are measured in milliequivalents (mEq).

Which type of drug should be placed under the tongue?

Sublingual drugs should be placed under the tongue. Buccal drugs should be placed between the gum and the inner lining of the cheek. Parenteral refers to the administration of drugs that are injected directly into the body. Inhalants are drugs that are inhaled.

The nurse must administer 0.35 mL of medication. Which syringe would the nurse choose to accurately measure this dose?

The 1 mL syringe is the only syringe that measures hundredths of a milliliter.

Which of the following syringes measures in ounces? Select all that apply.

The 20, 30, and 50 mL syringes are calibrated in milliliters and ounces.

Select the statement that best describes the use of an ampule in the administration of medications.

The ampule is used to administer a single dose of medication. The ampule does not have space available to add any medication. Once the top is snapped off, any remaining medication cannot be saved. The ampule is always a single-dose container.

Which part of a syringe holds the medication?

The barrel of the syringe holds the medication. The needle includes the bevel (sharp slanted end), the hollow cylinder of the needle, and the hub (where it attaches to the syringe). The plunger fills and empties the syringe.

Which is the last date that an opened vial can be used? It is written on the drug label by the pharmacist or the nurse who opens a multi-dose vial.

The beyond-use date is the last date that an opened vial can be used. It is written on the drug label by the pharmacist or the nurse who opens the multi-dose vial.

The nurse is reading the Desmopressin Acetate drug label. Select the statement(s) that apply to the drug label. Select all that apply.

The drug label indicates desmopressin is to be administered parenterally (intravenously or subcutaneously). The IM route is not an approved route of administration for this drug. The dosage strength of 4 mcg/mL is the only dosage strength listed on the drug label. The vial contains 1 mL of desmopressin.

The nurse chooses needle length based on: Select all that apply.

The length of the needle is chosen based on the route of administration, injection site, and size of the patient. The properties of the medication do not affect the choice of needle length.

The nurse at an allergy clinic is preparing an intradermal (ID) injection for an adult patient. The dose is contained in 0.3 mL. Which syringe and needle is the correct choice for this injection?

The nurse can choose either a 1 mL or 3 mL syringe as each will measure 0.3 mL accurately. The correct needle choice is a 26G 1/2" needle. This is a short needle with a small gauge. It is the standard ID needle.

The nurse has an order to administer Midazolam 10 mg IM stat. The pharmacy sends the following vial of midazolam. Select the statement(s) that are correct. Select all that apply.

The nurse can use 25 mg per 5 mL or 5 mg per mL as the dosage strength. Midazolam may be administered via the IM route. The midazolam is contained in a multi-dose vial so several doses may be administered. The unit of measurement in the order is "mg" and the drug is available in "mg," so a conversion is not necessary to solve for the ordered dose.

The prescriber orders Dilantin Oral Suspension 250 mg PO bid. The pharmacy sends a bottle of Dilantin Oral Suspension with a dosage strength of 125 mg/5 mL. How many milliliters should the nurse administer? Enter only the numeral (not the unit of measurement) in your answer

The nurse should administer 10 mL.

The prescriber orders Naprosyn SR 500 mg tablets PO q.12h prn migraine headache. The pharmacy supplies Naprosyn SR 250 mg tablets. How many tablet(s) should the nurse give?

The nurse should give 2 tabs as needed for migraine.

The nurse has the following order and medication in the patient's drawer. How many milliliters of Clemastine Fumarate syrup should the nurse administer?

The nurse will administer 10 mL. The units are the same, so no conversion is needed.

The nurse is to draw up 2.4 mL of medication for an intramuscular (IM) injection. The patient weighs 245 pounds. Which of the following is the best syringe and needle size to choose?

The nurse would choose a 3 mL syringe and the needle size 23G 2". The 3 mL syringe is large enough to hold the medication. The 21G to 23G is recommended for most IM injections and the 2-inch needle length is long enough to reach the IM tissue of a large patient.

A nurse practitioner prescribes Paxil HCl 15 mg PO bid. The pharmacy supplies Paxil 10 mg scored tablets. How many tablets should the nurse instruct the patient to take at each dose?

The patient should take 1.5 tablets at each dose.

How many milliliters of medication are contained in the vial for Zantac? Enter only the numeral (not the unit of measurement) in your answer.

There are 6 mL of medication in the vial of Zantac.

The nurse chooses the needle gauge based on: Select all that apply.

To select a gauge, the nurse considers the viscosity of the medication, the ease of withdrawing the medication, and the recommended needle gauges for various injection sites and routes. Based on this consideration, the nurse chooses the smallest gauge for the comfort of the patient.

When using a prefilled syringe, the nurse:

When using a prefilled syringe, the nurse must calculate the ordered dose and discard any extra medication before administering the dose to the patient. The prefilled syringe has a needle and a plunger. The syringe cartridge needs a plunger.

The nurse is preparing to administer 9 mL of an oral medication. The most appropriate measuring device to accurately measure this dose is a/an:

oral syringe

Which of the following medication forms is a liquid that contains small particles of the drug that cannot be dissolved?

suspension

Which of following medication forms contains the drug in a viscous liquid preparation consisting largely of purified water and sucrose or a sugar substitute for a more pleasant taste?

syrup