DRUG COMPUTATIONS

10 GOLDEN RULES FOR ADMINISTERING DRUG SAFELY

(from Nursing 88, Vol. 18, August 1988)

1. Administer the right drug.2. Administer the right drug to the right patient.3. Administer the right dose. 4. Administer the right drug by the right route.5. Administer the right drug at the right time

6. Document each drug you administer.

7. Teach your patient about the drugs he is receiving.

8. Take a complete patient drug history. (There is a risk of adverse drug reactions when a number of drugs are taken or when patient is taking alcoholic drinks.)

9. Find out if the patient has any drug allergies.

10. Be aware of potential drug- drug or drug- food interactions.

EXERCISE 1

1. Convert 250mg to g ......

2. Convert 0.5g to mg .......

3. Convert 250 mcg to mg .......

4. Convert 50ml to litres ...........

5. Convert 0.125g to mg ...........

EXERCISE 21. 500mg is prescribed, tablets are 250mg each:

how many tablets will you give? ..........2. 50mg is prescribed, tablets are 12.5mg each:

how many tablets will you give ? ..........3. 1mg prescribed, tablets are 500micrograms:

how many tablets will you give? ..........4. 625mg prescribed, tablets are 1.25g each: how

many tablets will you give ? ..........5. 3 tablets each contain 250mg. What is the total

dose in milligrams? ..........

EXERCISE 3

1. Drug available as 10mg/ml: prescription is for 20mg, how many ml will be given ? ......

2. Drug available as 10mg/2ml: prescription is for 5mg, how many ml will be given ? ......

3. Drug available as 20mg/5ml: prescription is for 40mg, how many ml will be given ? ......

4. Drug available as 10mg/ml: how many mg will there be in 3ml ? ......

5. Drug available as 20mg/5ml: how many mg will be in 7.5ml ? ......

EXERCISE 4Find the drop rate for these questions:1. If a patient requires 250ml in 6 hours what is the flow rate (give your

answer to two decimal places)2. If a patient requires 1000ml in 12 hours what is the flow rate (give

your answer to two decimal places) 3. If a patient is to be given 500ml by IVI using a controller with a drip

factor of 20drops/ml over 6hours, what would you set the drip rate to (round to the nearest whole number)

4. If a patient is to be given 750ml by IVI using a controller with a drip factor of 20drops/ml over 12 hours, what would you set the drip rate to (round to the nearest whole number)

5. A patient is to be given 1000 ml by IVI using a controller with a drip factor of 15 drops/ml. The infusion starts at 8.00am and every four hours the patient is given a 1hr rest. If the drip rate was set at 25 drops per minute, how much liquid would be left at 3.00pm ?

EXERCISE 5

1.Ordered: Trilafon 24 mg po bid. Available: Trilafon concentrate labeled 16 mg/5 ml.How many ml will you administer?

2. Ordered: SoluMedrol 100 mg IM q8hAvailable: Vial 1 ml in size labeled 125 mg SoluMedrol/3 mlHow many ml will you administer?What size syringe is best to administer this dose?

3. Ordered: Ampicillin 400 mg IM q6hAvailable: Vial with powder. Label reads: For IM injection, add 3.5 ml diluent (read accompaning circular). Resulting solution contains 250 mg Ampicillin per ml. Use solution within one hour.How many ml will you administer?

4. The physician orders Lasix 20 mg IV stat for a child weighing 34 lbs. The pediatric handbook states that 1 mg/kg is a safe initial dose. Should you give this dose?

5. Ordered: Infuse 2 L of Lactated Ringers solution in 24 hours. The administration set has 12 gtts/ml. How many gtts/min will you administer the IV?

COMPUTE THE FOLLOWING PROBLEMS:1. Administer Ampicillin oral suspension 50 mg

p.o. For 7 days. Stock: 125 mg/5 ml in 30 ml bottle.a. How many ml/dose will you administer?b. How many bottles of the medication will you request?

2. Administer Atrophine Sulfate 0.3 mg IM on call to O.R. Stock: 500 mcg/1ml ampulea. How many ml will you inject?

3. The dr. orders 20 mg IM of a drug for a patient. The drug is available in a 10 mL vial which contains 50mg of drug. Howm many milliliters will be needed to supply the dose of 20 mg?

4. The physician orders 3000 mL of D5W IV over 24-hour period. If the IV set is calibrated to deliver 15 drops per milliliter, how many drops must be administered per minute?

5. At exactly 8 o'clock in the morning, the doctor orders a drug to be administered in three doses at four-hour interval. What time would you administer the last dose?

Interpret the following:e.g. Atenolol 25mg OD= Give 25 mg Atenolol once a day

1. Diphenhydramine (Benadryl) 25 mg q4h po

2. Elixir Acetaminophen (Elixir Tylenol) 20 gtts pc and hs po

3. Demerol 100 mg IM stat

4. Paracetamol 1 amp IV stat then prn for fever

5. Tetrahydrozoline Hcl 0.05% sol'n 2 gtts OD TID

-END-

Answers

EXERCISE 1

1. 0.25g

2. 500mg

3. 0.25mg

4. 0.05 l

5. 125mg

EXERCISE 2

1. 2 tablets

2. 4 tablets

3. 2 tablets

4. 1/2 tablet

5.750mg

EXERCISE 3

1. 2ml

2. 1ml

3. 10ml

4. 30mg

5. 30mg

EXERCISE 4

1. 41.67ml/hr

2. 83.33ml/hr

3. 28 drops/min

4. 21drops/min

5. 400ml

EXERCISE 5

1. 7.5 ml

2. 2.4 ml and 3 cc syringe

3. 5.6 ml

4. No. The dose is not safe for the child

5. 16-17 gtts/min

EXERCISE 6

1. a. 2 ml b. 1 ml

2. 0.6 ml

3. 4 ml

4. 31 gtts/min

5. 4 pm

EXERCISE 7

1. Give diphenhydramine (benadryl) 25 milligrams every 4 hours per orem/ by mouth.

2. Give Elixir 20 drops after meals and during hours of sleep by mouth

3. Give Demerol 100 milligrams intramuscular immediately4. Give Paracetamol 1 ampule intravenous immediately

then as necessary for fever5. Tetrahydrozoline Hcl 0.05% sol'n 2 drops right eye three

times a day