1. Dr. Order: Give 0.5L of D5W over 4 hours. Calculate flow rate.  

 Solution:

Since the drop factpr (the size of the drops) is not provided in this problem, you should assume that there is a pump available.
The formula to use when pump is available is:

 Flow Rate = Total fluid in ml / Total time in hour

We need to convert 0.5 L into milliliters: From L to ml, multiply by 1000 Therfore 0.5 L = 500 mls
The solution is the followiing:

FR = 500 ml / 4 hrs = 125 ml / hr. That's it!

EZ wasn't it?

2. Dr. Order: Give 1000 ml of D5W between 8 AM and 6 PM. Drop factor is 20 gtt/ml. Calculate flow rate?  

Solution:

Since drop factor is provided, there is NO pump. The formula to use is 

 Flow Rate = (Total fluid in ml x DF) / Time in minutes

FR = (1000 ml  x  20 gtt/ml) / Time in minutes       (between 8 AM and 6 PM  there are 10 hours or 600 minutes)

The formula becomes  FR =   (1000 ml  x  20 gtt/ml) / 600 minutes   .... FR = 33 gtt / min
 

3. Give gr ii ss aspirin to a patient. How many mg of aspirin do you give?

Solution: The desired dose is gr ii ss. It is given in GRAINS in this problem. But the answer should be in mg.
Obviously one must convert gr to mg. Gr ii ss means 2.5 (ii = 2 and ss = half)
1 grain = 60 - 65 mg therefore 2.5 gr = (2 x 60) + 30 = 150 mg.

The answer is 150 mg.


4. Dr. order: Give 50 mg Cardizem (dilitiazem HCL). 30 mg Dilitiazem HCL tablets are available.
How many tablets do you give? What do you do?     

Answer:    You cannot accurately give 30 mg out of a 50 mg tablet (+ the tablet is not said to be scored).
Inform the caregiver who prescribed the drug about the situation.

5. Dr. order: Give 30 mg/kg of cefaclor (Ceclor) to a patient weighing 60 kg. How many mg of Ceclor will the patient receive?

Answer: The patient will receive 30 mg of cefaclor for every kg of body weight. Since he/she weighs 60 kg, the patient will receive
60 x 30 = 180 mg of cefaclor

6. Dr. order: Give 40 mg/kg of cefaclor (Ceclor) to a patient weighing 44 pounds. The correct dose of Cefaclor is
  
Answer:  The first step to solving this problem is to convert 44 lbs into kg.
(FROM POUNDS to KG DIVIDE by 2.2)  1 kg = 2.2 lbs.

44 / 2.2 = 20 kg
Now the problem becomes as easy as the preceding one. Simply multiply 20 x 40 = 800 mg

7. A 3 feet tall child weighing 50 lbs is prescribed 10 mg / m² of a drug BID. Using the BSA method. How many mg of drug wil the child receive?
  
Answer:    The drug is prescribed per rm² consequently it is necessary to know the body surface area of this child. Knowing the height and the weight of this child allows us to find his/her BSA. Using a nomogram we found the child BSA to be 0.72 m². (Click here for a copy of a BSA nomogram)
 
Since according to the problem the child should receive 10 mg / m2. We should multiply 10 x 0.72. The answer i s 7.2 mg

8. Give drug A to a 2'3" child weighing 30 lbs. The usual dosage for adult of this particular drug is 200 mg.
How many milligrams should be given to the child? (Use BSA method)

 Answer:   Again we need to calculate the BSA of the child using the same method used before. 2'3" (2 feet 3 inches = ( 2 x 12 ) + 3 = 27 inches. Using the nomogram, we find that the BSA of this child is 0.44 m2.

The formula to use when you know the body surface area of a child and the usual dose to adult is:

Child dose = adult dose x (Child BSA / Adult BSA) 
NB. Adult BSA in average is 1.73 m2.

Therefore Child Dose = 200 mg x (0.44 / 1.73) = 50.86 or 51 mg.

9. Give 250 mg of drug A. Drug A available as 500 mg scored tablets. Dose?

Answer:   Dosage = D/H = 250 / 500 = 1/2.

Give half tablet. It's OK because the tablets are scored.

10. Give 20 units of U-100 R insulin. Drug available as U-500 R insulin? How many units of U-500 R insulin should the patient receive?
The problem is that the desired drug is U-100 R insulin and the available drug is U-500 R insulin. Although it is the same type of insulin, the strength (concentration) is different.

The formula to use is Dosage = D/H where D dis 20 units of U-100 and H is U-500 
Dosage = 20 units U-100 / U 500 = 20 x 1/5     ..... 100 / 500 = 1/5
20 x 1/5 = 20/5 = 4 units. 

4 units of U-500 R insulin is same as 20 units of U-100 R  insulin