Pharmaceutical
Dosage Modules
Power Point
Presentation
Instructions• Be sure to work through the problems
before attempting to watch the lecture
tapes.
• After working through the problems as
much as you can, watch the tapes for the
necessary steps needed to solve the
problems correctly. • Remember practice makes perfect when
working dosage problems
Good Luck with the Modules!!!
Dr. R. R. Espinosa, R.Ph., Pharm. D.
Pharmacology Dosage Modules I-V
Dosage Modules
• Module #1 Dimensional Analysis
• Module #2 Basic Dosage Calculations
• Module #3 Reconstitution
• Module #4 Basic IV Dosage Calculations
• Module #5 Advanced Intravenous Calculations
Pharmaceutical Dosage
Module 1 : Dimensional Analysis
Dimensional Analysis
• Given Quantity: the beginning point of the problem
• Conversion Factors- Equivalents necessary to convert between systems of measurement and to allow unwanted units to be cancelled from the problem
Dimensional Analysis
• Unit Path: the series of conversions necessary to achieve the Wanted Quantity
• Wanted Quantity: the answer to the problem
Converting Within and Between
Systems of Measurement
System of Measurement
• Household: tsp, gtt, T, c
• Apothecary: gr, dr, oz
• Metric: ml, mg, g, l
Conversion Problems
• 350 mg =_______g
• 0.016 g =_______mg
• 0.16 kg =_______lb
• 8 mg = _______gr
• 0.07 mg =______mcg
• 500 ml = _______L
• 45 gr = _______mg
Conversion Problems
• issgr =_________g
• xx drams =_____ml
• 75 ml =________oz
• vss oz =_______ml
• 9 g =__________gr
• 102 lb =_______kg
• 3 tsp =________ml
Conversions problems• 3 ml =_________Minims
• 4 drams =______oz
• iv gr =_________mg
• 25 L = ______ml
• 1/300 gr =______mg
• 200ml =________tsp
• 6 tsp =_________T
Answers to problems Not covered on lecture tape
• 4drams=0.67oz
• 4 gr=240mg
• 25L=25000ml
• 200ml=40tsp
• 6tsp=2T
Pharmaceutical Dosage
Module 2: Basic Dosage Calculations
Dosage Calculations
The doctor orders a patient to receive Daypro 1200mg q am and pm. The stock supply is 600mg/tab. How many tablets will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage Calculations
The doctor orders a patient to receive Daypro 1200mg q am and pm. The stock supply is 600mg/tab. How many tablets will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage calculations
A patient is to receive Doxycycline 5 gr po qid for infection. The stock supply is 100mg/caps. How many capsules will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage calculations
A patient is to receive Doxycycline 5 gr po qid for infection. The stock supply is 100mg/caps. How many capsules will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage Calculations
Patient is to receive 0.5 g of Zocor q hs for cholesterol. The stock supply is 20mg/tab. How many tablets will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage Calculations
MD orders the client to have 1/8 gr of Estratab qod. The stock supply is 1.25 mg tablet. How many tablets will the patient receive for the correct dose?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Dosage Calculations
Patient is to receive 70 mg IM stat of Solu-Medrol. The stock supply is 125mg/2ml. How many ml’s is the patient going to receive for the correct dose?
– Given Quantity -Dose on Hand
– Wanted Quantity -Answer
Dosage Calculations Dr orders Trimox 0.5 g q 6 h for infection.
The stock supply is 250mg/5ml. The total volume is 100ml. How many ml’s will the patient receive for the correct dose? How may teaspoonfuls will the patient receive for each dose?– Given Quantity -Dose on Hand– Wanted Quantity -Answer
Dosage Calculations Patient is to receive Atropine 0.2mg Sub Q
stat, then 0.15 mg every 6 hours as needed. The stock supply is 400mcg/ml. How many ml’s will the patient receive for the first dose? How many ml’s will the patient receive on each subsequent dose?– Given Quantity -Dose on Hand– Wanted Quantity -Answer
Dosage Calculations Patient is to receive Gentamicin ¼ gr IV q
4 h for infection. The stock supply is 15mg/ml. How many ml’s will the patient receive for the correct dose? How often is this medication given? What is the route of administration?
-Given Quantity -Dose on Hand
-Wanted Quantity -Answer
Pharmaceutical Dosage
Module 3: Reconstitution
Reconstitution The doctor orders Ancef 750mg IM q 8 h. The stock supply is a 1.0 g vial of powdered Ancef.
Directions say to reconstitute with 2.5 ml of water to produce a total volume of 3 ml.
• How many ml’s will you give to the patient for the correct dose?
• How many mg’s will the patient receive for the correct dose in 24 hours(1 day)?
• How many grams will the patient receive in 24 hours?
Reconstitution The doctor orders Ancef 750mg IM q 8 h. The stock supply is a 1.0 g vial of powdered Ancef.
Directions say to reconstitute with 2.5 ml of water to produce a total volume of 3 ml.
• How many ml’s will you give to the patient for the correct dose?
• How many mg’s will the patient receive for the correct dose in 24 hours(1 day)?
• How many grams will the patient receive in 24 hours?
Reconstitution
Patient is to receive 3 g of Ampicillin to be added to a 1000ml D-5-W IV q 8 h. The stock supply is a 10,000mg Ampicillin vial. Directions say to reconstitute with 9.8 ml of NS to yield 500mg/ml.
• How many ml’s of Ampicillin will you add to the IV bag for the correct dose?
Reconstitution
Patient is to receive 3 g of Ampicillin to be added to a 1000ml D-5-W IV q 8 h. The stock supply is a 10,000mg Ampicillin vial. Directions say to reconstitute with 9.8 ml of NS to yield 500mg/ml.
• How many ml’s of Ampicillin will you add to the IV bag for the correct dose?
Reconstitution
Patient is to receive Nafcillin 5 gr IM q 6 hours for infection. The stock supply is a 2 g vial. The directions say to add 6.6 ml of sterile water to yield 250mg/ml. The total volume in the vial is 8ml.
• How many ml’s will the patient receive for the correct dose?
• How often is the patient receiving the medication?
Reconstitution Suprax 0.4g po q d for 12 days is order
for a patient for infection. The stock supply is a 2 g bottled powder. The directions says to reconstitute with 69 ml of water. This will provide 100mg/ml.
• How many ml’s will the patient receive for one dose?
• What would be the total ml’s for the entire dose?
Reconstitution Client is to receive Cephalexin 2 g IV
qid for infection. The stock supply is a 2 gram vial. Directions say to add 5ml of sterile water for injection, this will yield a concentration of 160mg/ml.
• How may ml’s will the patient receive for the correct dose?
• How often is the patient to receive this dose?
Reconstitution MD orders Timentin 8 gr IV tid.
Timentin is available in a 3.1g powder. Directions say to use 13 ml of sterile water for injection. The concentration will be approximately 200mg/ml.
• How many ml’s will be administered for the correct dose?
Pharmaceutical Dosage
Module 4: Basic IV Dosage Calculations
Calculating Intravenous Flow Rates
Electronic
vs.
Manual Infusion Devise
Electronic
• IV flow rate pump delivers volume in ml/hr
• Nurses responsibility to program the pump
• Amount of fluid/over period of time
Manual
• IV flow rate must be determined in gtts/min
• Nurses responsibility to count the number of drips that drop in a minute into the drip chamber
• The IV tubing provides the drop factor, which is calibrated in drops/ml
Basic IV Calculations
A client on an infusion pump is to receive an antibiotic in 50 ml 0.9% NS over 30 minutes. What is the flow rate in ml per hour?
– Given Quantity
– Wanted Quantity
– Answer
Medication involving Intravenous pump
A client on an infusion pump is to receive 500ml of R/L in 12 hours. What is the flow rate in ml per hour?
– Given Quantity
– Wanted Quantity
– Answer
Medication involving Intravenous pump
The doctor orders 100ml of D-5-W to infuse in 20 minutes q 4 hours. What is the flow rate in ml/hr?
– Given Quantity
– Wanted Quantity
– Answer
Medication Problem Involving a Drop Factor
The doctor orders 150 ml of D5W to be infused over 45 minutes q 4 hours. The drop factor is 20 gtts per ml. What is the flow rate in drops per minute?– Given Quantity– Wanted Quantity– Drop factor– Answer
Basic IV Calculations The doctor orders 250 ml of D-5-W IV q
3 hours. The drop factor is 20 gtts/ml. What is the flow rate in gtts/min? What is the flow rate in ml/hr?– Given Quantity– Wanted Quantity– Drop Factor– Answer
Pharmaceutical Dosage
Module 5: Advanced Intravenous
Calculations
The MD orders 10,000 units of Penicillin to be added to the IVPB of 100ml of NS to infuse in 45 minutes every 6 hours. Stock supply is a vial containing 2,000,000 units of Penicillin. Directions says to reconstitute with 9.8 ml to yield a 10 ml total volume. The drop factor for the IVPB is 15 gtts/ml.
• How many ml’s of penicillin will you add to the IVPB for the correct dose?
• What is flow rate in gtts per min for the IVPB? • What is the flow rate in ml per hour?
The MD orders 10,000 units of Penicillin to be added to the IVPB of 100ml of NS to infuse in 45 minutes every 6 hours. The stock supply is a vial containing 2,000,000 units of Penicillin. Directions says to reconstitute with 9.8 ml to yield a 10 ml total volume. The drop factor for the IVPB is 15 gtts/ml.
• How many ml’s of penicillin will you add to the IVPB for the correct dose?
• What is the flow rate in gtts per min for the IVPB?
• What is the flow rate in ml per hour?
Advanced Intravenous Calculations
Dopamine 2mcg/kg/min is order for a patient. The pharmacy sends an IV bag labeled: Dopamine 400mg/ 250 ml D5W. The client weighs 150 lbs.
-What is the flow rate in ml’s per hour?
– Given Quantity -Dose on Hand
– Wanted Quantity -Answer
Advanced Intravenous Calculations
MD orders Nipride 3mcg/kg/min. The pharmacy sends a bag labeled: Nipride 50mg/ 250 ml of NS. The drop factor is 15 gtts/ml. The patient weighs 110 lbs.
-Calculate the ml/hr to set the IV pump? -What is the flow rate in gtts/min?
– Given Quantity -Dose on Hand– Wanted Quantity -Answer
Advanced Intravenous Calculations
Dobutamine 500mg in 250 ml D5W to infuse at 10mcg/kg/min. The client weighs 250 lbs.
-What is the flow rate in ml/hr? -What is the flow rate in drops/minute with a drop factor of 60 gtts/ml?
– Given Quantity -Dose on Hand
– Wanted Quantity -Answer
Conclusion
• I hope this has helped you achieve yours goals of understanding different types of dosage calculations that you will encounter in this class and on into your careers.
• Good Luck, Allied Health Science Faculty