Drug calculation & Dilution

Drug calculation, Dilution for nurses working in critical care and non critical care set up.

1. Drug calculations and Dilutions Shemil DM WIMS

2. Delivery of the correct medication, dose, and infusion rate and time is essential for safe and therapeutic intravenous (IV) medication administration

3. The first step in determining IV flow-rate calculations is to check the medication label. Compare the label to the medication administration record (MAR) for the correct patient, medication, dose, time, and route. You should perform this comparison a total of three times before you begin the infusion

4. IV medications are diluted in a variety of concentrations and delivered in a variety of dose rates. Be sure to clarify any questionable orders and use only approved abbreviations to avoid dangerous adverse events

5. There are three factors involved in performing calculations for IV medication infusions. If you know two factors, you can calculate the third by using the basic formula:

6. The concentration of medications   is the amount of drug diluted in a given volume of IV solution, usually measured in units, micrograms (mcg), milligrams (mg), or grams (gm ). The dose of the medication  is the amount of drug ordered for infusion over a specific length of time. Doses have varying units of measurement. The length of time is either by the minute or by the hour. If the medication is dosed by weight, the calculation is made using the patient’s weight in kilograms (kg ). The flow rate determines how rapidly the infusion is delivered to the patient. On an infusion pump, the flow rate is set using mL/ hr or drops/ mit

7. volume

8. .   1. Administer Inj.Taxim 350 mg. Available dose of Inj.Taxim is 1g. Here you have to convert the unit available dose to desired dose, And dilute it in 100 ml NS. 1 g = 1 x 1000 mg, 1 g = 1000 mg. Formula, D x V , 350 mg x 100 ml H 1000 mg 35000/1000 = 35 ml. So you will administer 35 ml to the patient.

9. To calculate the hourly rate (ml/ hr ), Dose (in mcg/kg/min) x wt (kg) x drug volume in ml x 60 (min/ hr )  = ml/ hr   drug concentration in mcg Or Dose (in mcg/min) x drug volume in ml x 60 (min/ hr )  = ml/ hr drug concentration in mcg Or Dose (in mg/kg/ hr ) x wt (in Kg) x drug volume in ml  = ml/ hr drug concentration in mg If the dosage calculation is in mg/min or mcg/min add 60 minutes into the formula. If the dosage calculation is in mg/ hr or mg/kg/ hr , remove 60 minutes from the formula. If the dosage calculation does not require wt , remove  wt from the formula.

10. Weight based medication doses measured / minute Formula ml/ hr = body weight x dose x 60 min. Concentration of drug Concentration of Drug = mg x 1000 volume of the solution If you are diluting in 50 ml… Ml/hr = body weight x dose x 3 mg

11. Dose (in mcg/kg/min) x wt (kg) x drug volume in ml x 60 (min/hr)  = ml/hr drug concentration in mcg. Dose x wt x 50 x 60 mg x 1000 50 x 60 = 3000 = 3 1000 1000 So , Dose x wt x3 = ml/hr ( only if the dilution is in 50 ml) mg

12. Drug concentration mg x 1000 = mcg

13.  Administer Dopamine 5 mcg/kg/min. Patient weighs 55kg ). Available is Dopamine 200 mg. Ans. 200 mg = 200000 mcg ( 200 x 1000) 5 x 55 x 50 x 60 = 4.12 ml/hr 200000 2. 5 x 55 x 3 = 4.12 ml/hr 200 (50 ml dilution.)

14. To calculate mcg/kg/min ml/hr x mcg solution X 60 X kg or ml/hr X mg 3 X wt (dilution is in 50 ml) Ml/hr x mg x 1000 = ml/hr x mg 50 x 60 x wt 3 x wt

15. A patient is receiving dopamine 4.12 ml/hr. Find the mcg/kg/mint Ans. 4.12 x 200 = 5 mcg/kg/mint 3 x 55

16. Iv fluid calculation . Drop Factors 1. Microset-60 drops/ml 2. Macroset-20 drops/ml 3.Blood Transfusion set-20drops/ml

17. IV fluid calculation Amount of fluid to be infused X Drop factor Time( hr ) X 60

18. 120 mg/5 ml syrup- 3.5 ml to be given but available dose is 150 mg/5 ml. So how many ml has to be given ?(desired Dose unknown). D X V H D X 5 = 3.5, D = 3.5 ml X 120 mg = 84 mg 120 5 ml 84 mg X 5 ml = 2.8 ml 150 mg

19. Dilutions

20. Inj.Midazolam (1ml) 1 ml= 1 mg direct iv/ im

21. each 1 ml= 50 mcg Inj.Fentanyl (2ml) BOLUS INFUSION Fenta (2ml) + Ns(8ml)= 10 ml= 100 mcg 1ml=10 mcg 6 ml (300 mcg) +24 ml Ns=30 ml=300mcg 1 ml=10 mcg

22. Morphine(1 ml) e ach 1 ml = 15 mg( iv,im ) BOLUS INFUSION Morphine(1 ml)+ Ns(9ml)=10 ml=15mg 1 ml=1.5 mg or Morphine(1 ml)+ Ns(14ml)=15 ml=15mg 1 ml=1 mg Morphine(1 ml)+ Ns(14ml)=15 ml=15mg 1 ml=1 mg

23. NTG( 5 ml/25mg) e ach 1 ml = 5 mg(iv) BOLUS INFUSION NTG (5ml)+Ns(45ml)=50 ml=25 mg 1ml=0.5 mg

24. Dopamine ( 5 ml/200mg) e ach 1 ml = 40 mg ,iv (Consider pt’s wt ) INFUSION Dopamine(5 ml)+ Ns(45ml)=50 ml=200 mg 1 ml= 4 mg

25. Calcium Gluconate (10 ml) BOLUS INFUSION Calcium gluconate (10 ml)+ Ns(10 ml) slow iv

26. Sodium bicarbonate (25ml/75 mg) BOLUS INFUSION Direct IV

27. Adrenalin (1ml/1mg) BOLUS INFUSION Adrenalin(4 ml)+ Ns(46ml)=50 ml=4 mg 1 ml=0.08 mg

28. Atropine(1 ml/0.6mg or 0.5mg) BOLUS INFUSION Direct iv/ im

29. Cordarone(3ml/150mg) e ach 1 ml = 50mg BOLUS INFUSION Cordarone (6ml)+ 5 D (44 ml)=50 ml=300 mg 1 ml=6 mg

30. Noradrenalin(2ml/4mg) e ach 1 ml = 2 mg BOLUS INFUSION Noradrenalin(2ml)+Ns(48ml)=50 ml=4mg 1ml=0.08mg

31. Vassopressin (1ml/20 units) BOLUS INFUSION Vassopressin (1ml)+Ns(19 ml)=20 ml 1ml= 1 unit

32. Epsolin (2ml/100mg) e ach 1 ml = 50 mg BOLUS INFUSION Dilute in 100 ml Ns +slow iv

33. Dobutamin (250 mg) BOLUS INFUSION Dobutamin 250 mg + Ns(50 ml)=50 ml=250mg 1 ml=5mg

34. Octride (1ml/50mg/100 mg) 100 mg 50 mg Octride (5ml)+Ns(45 ml)=50 ml=500 mg 1ml= 10 mg Octride (10ml)+Ns(40 ml)=50 ml=500 mg 1ml= 10 mg

35. Atracurium (2.5ml/25mg) each 1 ml=10 BOLUS INFUSION Atracurium (5 ml) + Ns(45 ml)=50 ml=50mg 1 ml=1 mg

36. Adenosin (2ml/6 mg) each 1 ml=3 mg BOLUS INFUSION Direct iv + 20 ml Ns flush

37. Levosimendan (12.5mg) BOLUS INFUSION Levosimendan 12.5mg + 5 D (50 ml)=12.5 mg 1 ml=0.25 mg.

38. Lasix (2ml/20 mg) BOLUS INFUSION Lasix(4ml)+Ns(36ml)=40ml=40 mg 1ml=1 mg

39. Insulin(40 units) 1 ml=40 units BOLUS INFUSION Insulin (1ml)+Ns(39 ml)=40 ml=40 units 1ml= 1 unit