Medication Math PDF

Medica'on Math Module 4  Systems of Measurement The first system of measurement for drugs was the sat's apothecary a system. In that system, the weight of drugs was measured in grains. I Linear measures included inches, yards, and...

Medica'on Math Module 4  Systems of Measurement The first system of measurement for drugs was the sat's apothecary a system. In that system, the weight of drugs was measured in grains. I Linear measures included inches, yards, and miles. Volume (i.e., the measurement of fluids and liquids) was measured in minims. The metric system currently is the preferred system for drug measurement and calcula@on. It is logical and well organized, based on a basic unit and its mul@ples or submul@ples of 10. It is similar to the U.S. monetary system.  Systems of Measurement Just as the apothecary system has basic units of measure for weight, length, and volume, so does the metric system, as follows: Weight (solids or mass): gram (g). Length: meter (m). Volume (liquid or fluid): liter (L). In addi@on, several prefixes are commonly used in medicine to dis@nguish mul@ples or smaller parts of these units. The four commonly used in drug calcula@on are kilo, cen', Mi mig milli, and micro.  7 106 41103 21102 9 10 y 8 10 10 4 15 1 2 15 1 9 10 I  Conversions The ability to convert one unit of measure to another is vital to ensure that the intended dose of medica@on is administered to the pa@ent. Failure to understand and use unit conversions may lead to overdosing the pa@ent inadvertently or providing the pa@ent with a less than op@mal dose. Most IV medica@ons are supplied as solu@ons expressed as a concentra@ons (e.g., milligrams per milliliter [mg/mL]). Medica@ons are dosed as a mass (e.g., milligrams), and drug doses are oQen determined based on a pa@ent’s weight (e.g., pounds or kilograms). hip 1115.60sec  Millimeters and Cubic Cen'meters The milliliter is a measurement of volume (liquids or fluids in this case) and is equal to 1/1,000 of a liter. The cubic cen@meter is also a measurement of volume, but it is based on the cen@meter, which is equal to 1/100 of a meter. Because 1 cc equals 1 mL, the terms are oQen used interchangeably. For example, you may receive an order to administer 2 mL of morphine sulfate. The same order may be given as 2 cc of morphine sulfate. These two doses are considered equivalent.  Millimeters and Cubic Cen'meters A box with dimensions of 1 cm × 1 cm × 1 cm has a volume of cubic cen@meter. If the box were filled with 1 mL of water at a temperature of 4°C, the water would exactly fill the box. Therefore, the volume is equal to the space that was created.  Kilograms and Pounds The next conversion commonly used to calculate drug dosages is kilograms (kg) to pounds (lb). Note that these units refer to the pa,ent’s weight, not the weight of the drug. Many drug dosages, par@cularly those administered to ½ pediatric pa@ents, are based on the pa@ent’s weight in kilograms to ensure safety from overdose. The equivalent to remember is 1 kg = 2.2 lb. Therefore, to convert weight in pounds to weight in kilograms, divide the number of pounds by 2.2. ¾ EH  502s 2 4 III 12210 154 10 to 22 10 To to g.it f Efo o f  Milligrams, Micrograms, and Grams The next conversion is from milligrams to grams and, in reverse, from grams to milligrams. This process also includes conver@ng milligrams to micrograms and micrograms to milligrams. To use an everyday example, when changing a dollar into coins (e.g., dimes or pennies), the larger unit (dollar) is changed into an equivalent sum in smaller units (dimes or pennies). Therefore, to get the total number of the smaller unit, mul@ply the number of dollars (e.g., 5 dollars) by the number of dimes or pennies per dollar.  Prac'ce Problems Convert grams to milligrams and milligrams to grams. 1. 1 g = ___________ 1000 mg 2. 1,000 mg = __________ 7 g 3. 250 mg = ___________ 0,25 g 4. 400 mg = ___________ g 019 5. 500 mg = ___________ DS g 6. 0.75 g = __________ 350 mg 7. 1.25 g = __________ 1250 mg 8. 10 g = ___________ 10000 mg 9. 2 g = ____________ 2000 mg 10. 2,500 mg = __________ 215 g  Prac'ce Problems Convert milligrams to micrograms and micrograms to milligrams. 1. 1 mg = _____________ 1000 mcg 2. 500 mcg = __________ mg 0,5 3. 250 mcg = __________ 125 mg 4. 400 mg = __________ 400000 mcg 5. 0.2 mg = ___________ 200 mcg 6. 800,000 mcg = ________ 800 mg 7. 800 mg = ____________ 800000 mcg 8. 200 mg = ____________ 200000 mcg 9. 1,000 mcg = __________ 1 mg 10. 200,000 mcg = _______ 200 mg  0125 251  Formulas Formulas are used to solve drug problems or determine dosages for pa@ents. They should be used in conjunc@on with the basic conversions explained previously. Four basic formulas can be used to solve all prehospital pharmacology math problems: a period of 5min IV bolushoreter In push concentrated dose of a drug via a cannula over a period of 30 sec DD v DH DD GTTmin  11 xg.tt m I Ifdg  1- CASE STUDY A 64-year-old woman is enjoying a round of golf when she suddenly steps in a hornets’ nest and is stung mul@ple @mes. Because she is allergic to bee s@ngs, she quickly heads back to the clubhouse and asks for help. A paramedic unit is dispatched. On arrival, the pa@ent is in mild distress, with large hives appearing on her face and neck. Because of her age and the rela@vely mild signs and symptoms at this point, the paramedics avoid epinephrine and choose to administer diphenhydramine (Benadryl) 25 mg IM. 7 Their prefilled syringe reads 50 mg/mL. How many milliliters should they administer? 25 on  Formula 1 Prac'ce Problems O 3mg Remember the steps: cross out like terms and mul'ply across. DD 1. Administer epinephrine (Adrenalin) 1:1,000 0.3 mg Sub- Q. The prefilled syringe reads 1 mg/mL. How many milliliters should you administer? Tpp 2 as 2. Administer furosemide (Lasix) 20 mg IV line. Furosemide is m supplied in a concentra@on of 40 mg/5 mL. How many milliliters should you administer?213ᵗʰ 3. Administer atropine sulfate 0.5 mg rapid IV push. The as prefilled syringe reads 1 mg/10 mL. How many milliliters should you administer?  Formula 1 Prac'ce Problems DD 4. Administer verapamil (Isop@n) 5 mg slow IV push. The prefilled syringe reads 5 mg/2 mL (2.5 mg/mL). How many 2.5542mF milliliters should you administer? 2m 21 21 5. Administer adenosine 12 mg rapid IV push. The prefilled syringe reads 6 mg/2 mL. How many milliliters should you administer? a  2- CASE STUDY Your ALS unit is called out during a snowstorm to akend to an older man who has had the flu since yesterday. His daughter tells you that he has been vomi@ng, has had diarrhea for more than 24 hours, and has not been able to keep any fluids down. Your pa@ent is weak and warm to the touch. He has elevated respiratory and pulse rates but a blood pressure of 88/60 mm Hg. His lung sounds are present bilaterally and clear. Medical direc@on tells you to administer a fluid bolus of 200 mL normal saline over a 20-minute period and then reevaluate the pa@ent and call back. You decide to use a i macrodrip infusion set that delivers 10 gk (drops)/mL. 2 4 1 10 100 got min woomanana oooo  Formula 2 Prac'ce Problems Remember the steps: cross out like terms and mul'ply across. T 1. Administer 60 mL of fluid containing a medica@on over a 10- minute period. Use a microdrip IV infusion set that delivers 60 gk/mL. How many drops per minute should be grr administered? MX 6091192,609ft 3609min 2. Administer 120 mL of Ringer’s lactate as a fluid challenge over a 20-minute period with an IV infusion set that delivers 20 gk/mL. How many drops per minute should be administered? 3. Administer 150 mL of normal saline over a 30-minute period with an IV infusion set that delivers 10 gk/mL. How many drops per minute should be administered?  3001 LI Formula 2 Prac'ce Problems min 4. lougtt Administer 300 mL of Ringer’s lactate over a 30-minute period with an IV infusion set that delivers 10 gk/mL. How many drops per minute should be administered? 5. Administer 1,000 mL of normal saline over a 5-hour period with a macrodrip IV infusion set that delivers 15 gk/mL. How many drops per minute should be administered? 509mF  3- CASE STUDY You are called to respond to the home of the base commander. On arrival, you find a 62-year-old man complaining of heart palpita@ons. You connect the cardiac monitor to find the pa@ent with a narrow-complex supraventricular tachycardia at a rate of 178 beats/min. You have akempted to correct the arrhythmia with vagal maneuvers and adenosine to no avail. Medical direc@on orders you to administer an infusion of procainamide at 20 mg/min. 1 Emi 1 1 2,960964 You have a peripheral IV line in place capable of delivering 60 gk/mL. Your secondary premixed bag of procainamide reads 100 mg/mL. At how many drops per minute should you run the procainamide to administer the proper dose?  Formula 3 Prac'ce Problems 1 9605 Remember the steps: cross out like terms and mul'ply _both across. 1. Administer an epinephrine infusion at 4 mcg/min. Add 1 mg epinephrine to a bag of 250 mL normal saline. Use a microdrip infusion set that delivers 60 gk/mL. What is the drip rate in drops per minute? 2. Administer a procainamide infusion at 3 mg/min. Prepare the infusion by adding 1 g procainamide to a bag of 250 mL normal 9 saline. Use a microdrip infusion set that delivers 60 gk/mL. What is the drip rate in drops per minute? arm 609mm 3221299 3. Administer an epinephrine infusion at 2 mcg/min. Prepare the infusion by adding 1 mg epinephrine to a bag of 500 mL normal saline. What is the drug concentra@on (DH)? What is the drip rate if a microdrip infusion set that delivers 60 gk/mL is used? microdrip Gogrami 4- CASE STUDY You are transpor@ng an older woman with a history of mul@ple cardiac events to the hospital. En route, her blood pressure begins to drop even though her cardiac rhythm shows only sinus tachycardia at a rate of 120 beats/min. You contact medical direc@on and are told to begin a dopamine infusion at 2 mcg/kg per minute and to @trate it un@l her blood pressure is approximately 90 mm Hg systolic. Prepare the infusion by adding 800 mg of dopamine to a 500-mL bag 5 dripÉ of normal saline. The pa@ent weighs 110 lb.using 1 1009daL 009Mt DH 8000,511 1600mg liftoff 3 75914min c  4 shooooooages iodhotillippellhoshoooooo esw aos The End