Benefit From Free Dosage
Calculation Practice Problems

Correct Answer : 13.2 mL/hr

Explanation:

Using dimensional analysis, perform the following steps to calculate the infusion rate in milliliters per hour of naloxone (NAL) diluted in normal saline (NS):

1. Identify the prescribed, available, and required medication information

   Prescribed: 2 mcg NAL / kg | hr   Available: 2 mg NAL / 2 mL   Required: mL NAL / hr

2. Identify the final diluted medication volume

   Dilution instructions: infusion bag - medication volume + medication

   OR

   500 mL NS - 2 mL NS + 2 mL NAL = 500 mL diluted NAL or 2 mg NAL / 500 mL

3. Convert the prescription to the infusion rate of NAL in milliliters per hour

   Prescription x diluted medication = mL NAL / hr

   OR

   ( mcg NAL / kg | hr ) ( kg / lb ) ( lb /   )( mg / mcg ) ( mL / mg NAL ) = mL NAL / hr

   OR

   ( 2 mcg NAL / kg / hr ) ( kg / 2.2 lb ) ( 58 lb /   )( mg / 1000 mcg ) ( 500 mL / 2 mg NAL ) = 13.1818 mL NAL / hr

4. Round to one decimal place

   13.1818 mL NAL / hr ≈ 13.2 mL NAL / hr

Educational objective:
To calculate the infusion rate of naloxone diluted in normal saline, the nurse should first identify the prescribed dose (eg, 2 mcg/kg/hr), available medication (eg, 2 mg/2 mL), and diluted volume (eg, 2 mg/500 mL) and then convert to milliliters per hour (eg, 13.2 mL/hr).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the infusion rate in milliliters per hour of naloxone (NAL) diluted in normal saline (NS):

1. Convert the weight to kilograms

   ( kg / 2.2 lb ) ( 58 lb /   ) = 26.3636 kg

2. Calculate the dose in micrograms per hour

   ( 2 mcg NAL / kg | hr ) ( 26.3636 kg /   ) = 52.7272 mcg NAL / hr

3. Convert the prescription to milligrams per hour

   ( 52.7272 mcg NAL / hr ) ( mg / 1000 mcg ) = 0.0527 mg NAL / hr

4. Identify the final diluted medication volume

   Dilution instructions: infusion bag - medication volume + medication

   OR

   500 mL NS - 2 mL NS + 2 mL NAL = 500 mL diluted NAL or 2 mg NAL / 500 mL

5. Convert the prescription to the infusion rate of NAL in milliliters per hour

   Prescribed dose / diluted dose x diluted volume = mL NAL / hr

   OR

   0.0527 mg NAL / 2 mg NAL x 500 mL = 13.1818 mL NAL / hr

6. Round to one decimal place

   13.1818 mL NAL / hr ≈ 13.2 mL NAL / hr

Correct Answer : 6.3 mL/dose

Explanation:

Using dimensional analysis, perform the following steps to calculate the administration volume of pancuronium (PAN) in milliliters per dose:

1. Identify the prescribed, available, and required medication information

   Prescribed: 0.06 mg PAN / kg | dose   Available: 1 mg PAN / mL   Required: mL PAN / dose

2. Convert the prescription to the administration volume of PAN in milliliters per dose

   Prescription x available medication = mL PAN / dose

   OR

   ( mg PAN / kg | dose ) ( kg / lb ) ( lb /   )( mL / mg PAN ) = mL PAN / dose

   OR

   ( 0.06 mg PAN / kg | dose ) ( kg / 2.2 lb ) ( 231 lb /   )( mL / 1 mg PAN ) = 6.3 mL PAN / dose

Educational objective:
To calculate the administration volume of pancuronium, the nurse should first identify the prescribed dose (eg, 0.06 mg/kg/dose) and available medication (eg, 1 mg/mL) and then convert to milliliters per dose (eg, 6.3 mL/dose).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the administration volume of pancuronium (PAN) in milliliters per dose:

1. Convert the weight to kilograms

   ( kg / 2.2 lb ) ( 231 lb /   ) = 105 kg

2. Calculate the prescribed dose in milligrams per dose

   ( 0.06 mg PAN / kg | dose ) ( 105 kg /   ) = 6.3 mg PAN / dose

3. Convert the prescription to the administration volume of PAN in milliliters per dose

   Prescribed dose / available dose x available volume = mL PAN / dose

   OR

   6.3 mg PAN / 1 mg PAN x mL = 6.3 mL PAN / dose

Correct Answer : 5.4 mL/dose

Explanation:

Using dimensional analysis, perform the following steps to calculate the administration volume of alendronate (ALN) in milliliters per dose:

1. Identify the prescribed, available, and required medication information

   Prescribed: 5 mg ALN / dose   Available: 70 mg ALN / 75 mL   Required: mL ALN / dose

2. Convert the prescription to the administration volume of ALN in milliliters per dose

   Prescription x available medication = mL ALN / dose

   OR

   ( mg ALN / dose ) ( mL / mg ALN ) = mL ALN / dose

   OR

   ( 5 mg ALN / dose ) ( 75 mL / 70 mg ALN ) = 5.3571 ... mL ALN / dose

3. Round to one decimal place

   5.3571 ... mL ALN / dose ≈ 5.4 mL ALN / dose

Educational objective:
To calculate the administration volume of alendronate, the nurse should first identify the prescribed dose (eg, 5 mg/dose) and available medication (eg, 70 mg/75 mL) and then convert to milliliters per dose (eg, 5.4 mL/dose).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the administration volume of alendronate (ALN) in milliliters per dose:

1. Convert the prescription to the administration volume of ALN in milliliters per dose

   Prescribed dose / available dose x available volume = mL ALN / dose

   OR

   5 mg ALN / 70 mg ALN x 75 mL = 5.3571 ... mL ALN / dose

2. Round to one decimal place

   5.3571 ... mL ALN / dose ≈ 5.4 mL ALN / dose

Correct Answer : 0.1 mg/kg/dose

Explanation:

Using dimensional analysis, perform the following steps to calculate the prepared dose of hydromorphone (HM) in milligrams per kilogram:

1. Identify the prepared volume, available medication, client's weight, and required units

   Volume: 2.8 mL HM / dose   Available: 1 mg HM / mL   Weight: 61 lb /     Required: mg HM / kg | dose

2. Convert the administration volume to the prepared dose of HM in milligrams per kilogram

   Volume x available medication ÷ weight = mg HM / kg | dose

   OR

   ( mL HM / dose ) ( mg HM / mL ) ( lb / kg ) (   / lb ) = mg HM / kg | dose

   OR

   ( 2.8 mL HM / dose ) ( 1 mg HM / mL ) ( 2.2 lb / kg ) (   / 61 lb ) = 0.1009 ... mg HM / kg | dose

3. Round to one decimal place

   0.1009 ... mg HM / kg | dose ≈ 0.1 mg HM / kg | dose

Educational objective:
To calculate the prepared dose of hydromorphone, the nurse should first identify the administration volume (eg, 2.8 mL/dose),available medication (eg, 1 mg/mL), and client′s weight (61 lb) and then convert to the dose (eg, 0.1 mg/kg/dose).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the prepared dose of hydromorphone (HM) in milligrams per kilogram:

1. Convert the weight to kilograms

   ( kg / 2.2 lb ) ( 61 lb /   ) = 27.7272 kg

2. Convert the administration volume of HM to the prepared dose in milligrams

   Administration volume / available volume x available dose = mg HM / dose

   OR

   2.8 mL HM / mL HM x 1 mg = 2.8 mg HM / dose

3. Convert the prepared dose to the weight-based dose of HM

   ( 2.8 mg HM / dose ) (   / 27.7272 kg ) = 0.1009 ... mg HM / kg | dose

4. Round to one decimal place

   0.1009 ... mg HM / kg | dose ≈ 0.1 mg HM / kg | dose

Correct Answer : 4 mL/dose

Explanation:

Using dimensional analysis, perform the following steps to calculate the total diluted volume in milliliters per dose of lorazepam:

1. Identify the prescribed, available, and required medication information

   Prescribed: 4 mg lorazepam / dose   Available: 2 mg lorazepam / mL   Required: mL lorazepam / dose

2. Convert the prescription to the volume of lorazepam in milliliters per dose

   Prescription x available medication = mL lorazepam / dose

   OR

   ( mg lorazepam / dose ) ( mL / mg lorazepam ) = mL lorazepam / dose

   OR

   ( 4 mg lorazepam / dose ) ( mL / 2 mg lorazepam ) = 2 mL lorazepam / dose

3. Add the dilution volume to the medication for total administration volume

   Concentration: 1 mL diluent per 1 mL lorazepam

   OR

   2 mL lorazepam + 2 mL diluent = 4 mL total solution

Educational objective:
To calculate the total administration volume in milliliters of lorazepam, the nurse should first identify the prescribed dose (eg, 4 mg), available medication (eg, 2 mg/mL), and diluent needed (eg, 1 mL diluent per 1 mL lorazepam) and then calculate the total milliliters per dose (eg, 4 mL/dose).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the total diluted volume in milliliters per dose of lorazepam:

1. Convert the prescription to the volume of lorazepam in milliliters per dose

   Prescribed dose / required concentration x volume = mL lorazepam / dose

   OR

   4 mg lorazepam / 2 mg lorazepam x mL = 2 mL lorazepam / dose

2. Add the dilution volume to the medication

   Concentration: 1 mL diluent per 1 mL lorazepam

   OR

   2 mL lorazepam + 2 mL diluent = 4 mL total solution

Correct Answer : 2.5 mL/dose

Explanation:

Using dimensional analysis, perform the following steps to calculate the administration volume of methadone in milliliters per dose:

1. Identify the prescribed, available, and required medication information

   Prescribed: 0.1 mg methadone / kg | dose   Available: 1 g methadone / 500 mL   Required: mL methadone / dose

2. Convert the prescription of methadone to the volume in milliliters per dose

   Prescription x available concentration = mL methadone / dose

   OR

   ( mg methadone / kg | dose ) ( kg / lb ) ( lb /   ) ( g / mg )( mL / g methadone ) = mL methadone / dose

   OR

   ( 0.1 mg methadone / kg | dose ) ( kg / 2.2 lb ) ( 108 lb /   ) ( g / 1000 mg )( 500 mL / 1 g methadone ) = 2.4545 mL methadone / dose

3. Round to one decimal place

   2.4545 mL methadone / dose ≈ 2.5 mL methadone / dose

Educational objective:
To calculate the administration volume of methadone, the nurse should first identify the prescribed dose (eg, 0.1 mg/kg/dose) and available concentration (eg, 1 g/500 mL) and then convert to milliliters per dose (eg, 2.5 mL/dose).

Alternate Method:

The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.

Using the formula method, perform the following steps to calculate the administration volume of methadone in milliliters per dose:

1. Convert the weight to kilograms

   ( 108 lb /   ) ( kg / 2.2 lb ) = 49.0909 kg

2. Calculate the prescribed dose in milligrams

   ( 0.1 mg methadone / kg | dose ) ( 49.0909 kg /   ) = 4.9090 mg methadone / dose

3. Convert the dose to grams

   ( 4.9090 mg methadone / dose ) ( g / 1000 mg ) = 0.0049 ... g methadone / dose

4. Convert the prescription of methadone to the volume in milliliters per dose

   Prescribed dose / available medication x available volume = mL methadone / dose

   OR

   0.0049 ... g methadone / 1 g methadone x 500 mL = 2.4545 mL methadone / dose

5. Round to one decimal place

   2.4545 mL methadone / dose ≈ 2.5 mL methadone / dose