IV Drug Administration

Drug Calculations – Syringe Pump and Infus Pump

Drug Calculation Assessment

• SECTION 1: Units & Equivalences• SECTION 2: Calculating dose as volume• SECTION 3: Drug Strengths & Stated

Concentrations• SECTION 4: Duration of Infusion – Stated

rate (dose per min) & Infusion rate (mL/hr)• SECTION 5: Infusion Rate Calculations

SECTION 1: Units & Equivalences

1 Kg = 1,000 g

1 g = 1,000 mg

1 mg = 1,000 micrograms

1 L = 1,000 mL

Converting from One Unit to Another

• To convert from a larger unit to a smaller unit, multiply by 1000 or move the decimal point three places to the right

• To convert from a smaller unit to a larger unit, divide by 1000 or move the decimal point three places to the left

Tangga Ukuran Berat

Units & Equivalences

Convert 0.25 mg into micrograms

Convert 600 micrograms to mg

Answers

0.25 × 1000 or move decimal point three places to the RIGHT = 250 micrograms

600 ÷ 1000 or move the decimal point three places to the LEFT

= 0.6 mg

SECTION 2: Calculating Dose as Volume

What you WANT X what it is INWhat you have GOT

= the volume you want to administer

What we WANT

Furosemide 250mg/10mL

Furosemide Time

0700-0900

1200-1400

Dose200mg

RouteIV

Start Date18.05.07

End Date

1600-1800

2200-2400

Other Time

Signature of Doctor

P.Rescriber

What we have GOT

What it is IN

A patient is prescribed 200mg of Furosemide I.V. The ampoules available contain 250mg in 10mL. What volume containing the drug do you need to administer?

Answer

What you WANT X what it is INWhat you have GOT

200 mg250 mg × 10 mL

= 8 mL

SECTION 3: Drug Strengths & Stated Concentrations

What you HAVE (mg)CONCENTRATION (mg/mL)

= How much fluid is required (Volume)

Aciclovir Time

0700-0900

1200-1400

Dose250mg

RouteIV

Start Date18.05.07

End Date

1600-1800

2200-2400

Other Time

Signature of Doctor

Additional Comments

P.Rescriber

Final Concentration 5mg/mL

A patient is prescribed 250mg of Aciclovir I.V. Aciclovir has to be initially reconstituted with water for injection, then added to a bag of compatible infusion fluid, giving a final concentration of 5mg/mL. How much infusion fluid should be used dilute the reconstituted Aciclovir to achieve this final concentration?

What we HAVE

CONCENTRATION

Answer

What you HAVE (mg)CONCENTRATION (mg/mL)

250mg5mg/mL

= 50 mL

A 1% (w/v) solution means that in every 100mL of solution you will find 1g of drug. Therefore, how many g of Glucose would there be in 500mL of 5% Glucose?

Glucose 5%500ml

Answer• A 1% (w/v) solution means that in every

100mL of solution you will find 1g of drug.100mL = 1g

Therefore a 5% w/v must mean that 100mL = 5gMultiply each side by 5500mL = 25g

1:10,000 strength means that in every 10,000ml of solution you will find 1g of Adrenaline. Therefore, how many mg of Adrenaline would there be in 10mL of 1:10,000 Adrenaline?

Answer

• 1:10,000 means that 1g of adrenaline is dissolved in 10,000mL.

1g = 10,000mL1000mg = 10,000mLDivide both sides by 10001mg = 10mL

SECTION 4: Duration of Infusion Stated rate (dose per min)

Infusion rate (mL/hr)

Stated Rate – dose per min

Dose (mg) = TimeRate (mg/min)

Furosemide must be administered at a rate no faster than 4mg/minute. How many minutes would it take to give 200mg of this drug?

Furosemide Time

0700-0900

1200-1400

Dose200mg

RouteIV

Start Date18.05.07

End Date

1600-1800

2200-2400

Other Time

Signature of Doctor

Additional Comments

P.Rescriber

Rate of 4mg/minute

Furosemide 250mg/10mL

Rate(mg/min)

DOSE(mg)

Answer

Dose (mg) = TimeRate (mg/min)

200mg4mg/min

= 50 minutes

Infusion rate – mL/hr

Volume (mL) = Rate (mL/min)Time (Min)

X 60 = Rate (mL/Hr)

* Tip if rate is in hours omit “X 60”

Omeprazole 40mg/100mL

Omeprazole (Losec ®) 40mg is diluted in 100mL of compatible infusion fluid. This infusion has to be given over 20 minutes. What rate should you set the infusion pump at, in ml/hr, to deliver this dose?

Answer

Volume (mL) = Time (mL/hr) x 60Rate (hr)

100ml 20 mins x 60= 300mL/hr

Acetylcysteine 7.5g/1000mL

Acetylcysteine (Parvolex ®) 7.5g is diluted in 1000mL of compatible infusion fluid. This infusion has to be given over 16 hours. What rate should you set the infusion pump at, in ml/hr, to deliver this dose?

Answer

Dose (mL) = Time (mL/hr)Rate (hr)

100016= 62.5 mL/hr

SECTION 5: Infusion Rate Calculations

What you WANT x 60 (60 mins per hr) What you have GOT X what it is IN

= the volume you want to administer

Glyceryl Trinitrate Time

0700-0900

1200-1400

Dose25 micrograms/minute

RouteIV

Start Date18.05.07

End Date

1600-1800

2200-2400

Other Time

Signature of Doctor

Additional Comments

P.Rescriber

Continuous Infusion

You are required to give a patient Glyceryl Trinitrate as a continuous I.V infusion at 25 micrograms/minute. You have prepared a 50mg in 50mL infusion. What rate should you set the infusion pump at, in ml/hr, to deliver this dose?

What we WANT Glyceryl

Trinitrate 50mg/50mL

What we have GOT

What its IN

60 mins per hr

Answer What you WANT x 60 (60 mins per hr) What you have GOT X what it is IN

25 micrograms/min x 60 = 1500 micrograms/hr 1500 ÷ 1000

= 1.5 mg

1.5 mg x 50mL50 mg= 1.5 mL/hr

Any Questions?

Assessment time……