2. Respiratory Pharmacology RC 195 Dan Farrell Dan Farrell

3. Goal of Respiratory Care: Airway Maintenance

4. Two ways to name a drug: Brand (Trade) name and Generic Name Always know a drug by both names!

5. Respiratory Pharmacology Calculations

6. Definitions Solute – material to be dissolved Solute – material to be dissolved  Usually the actual drug Solvent – the dissolving or diluting medium Solvent – the dissolving or diluting medium  Almost always is water!

7. Handy Conversions 1 ml = 1 cc 1 ml = 1 cc 1 gm = 1000mg 1 gm = 1000mg 1 gm H2O = 1 ml H2O 1 gm H2O = 1 ml H2O 1 lbs = 454 gms 1 kg = 2.2 lbs

8. 3 Ways to Express Drug Strength

9. “X” mg/ml Tells how many milligrams of drug (solute) are in each ml of solution (solvent) Tells how many milligrams of drug (solute) are in each ml of solution (solvent) 10 mg/ml = 10 milligrams of drug in each ml of solution 10 mg/ml = 10 milligrams of drug in each ml of solution Best form to use for most calculations! Best form to use for most calculations!

10. % Solution “X” grams of solute (drug) in each 100 ml of solvent (solution) “X” grams of solute (drug) in each 100 ml of solvent (solution) 1% solution = 1 gram of solute (drug) in each 100 ml of solvent (solution) 1% solution = 1 gram of solute (drug) in each 100 ml of solvent (solution)  Is also the same strength as 10 mg/ml since 1% = 1gm/100ml = 1000mg/100 ml = 10 mg/ml

11. Dilution Ratio 1 gram solute (drug) per “X” grams (or ml) of solvent (solution) 1 gram solute (drug) per “X” grams (or ml) of solvent (solution)  1:100 = 1 grams of drug (solute) per 100 grams of solvent (or ml of solution)  1:100 = 1000mg/100 ml = 10 mg/ml

12. 10 mg/ml, 1% and 1:100 are all the same strength just expressed 3 different ways

13. Conversions: mg/ml to % solution Move decimal point 1 place to the left! Move decimal point 1 place to the left! 10 mg/ml = 10 mg/ml = 1% 1% 75 mg/ml = 75 mg/ml = 7.5% 7.5%

14. Conversions: % solution to mg/ml Move decimal point 1 place to the right! Move decimal point 1 place to the right! 2% = 2% = 20 mg/ml 20 mg/ml.5% =.5% = 5mg/ml 5mg/ml 7.5% = 7.5% = 75 mg/ml 75 mg/ml

15. Conversions: Dilution Ratio to % Solution Convert to mg/ml and then move decimal point 1 place to the left! Convert to mg/ml and then move decimal point 1 place to the left! 1: 1000 = 1 gram per 1000 grams = 1000mg/1000 ml (why?) = 1: 1000 = 1 gram per 1000 grams = 1000mg/1000 ml (why?) = 1 mg/ml =.1 % 1 mg/ml =.1 %

16. Conversions: mg/ml or % solution to a dilution ratio If in mg/ml, first change to % solution, then express the % solution by its definition and then divide it out If in mg/ml, first change to % solution, then express the % solution by its definition and then divide it out Crystal clear, isn’t it!?!?!? Crystal clear, isn’t it!?!?!? 20 mg/ml = 2% solution 20 mg/ml = 2% solution By definition, a 2% solution is 2 grams of solute (drug) in every 100 grams of solvent (solution) or 2: 100 By definition, a 2% solution is 2 grams of solute (drug) in every 100 grams of solvent (solution) or 2: 100 By dividing it out, you get the true dilution ratio: By dividing it out, you get the true dilution ratio: 2:100 is 1:50 dilution ratio 2:100 is 1:50 dilution ratio

17. Calculations To determine how many mg of drug are in “X” ml of solution, or to determine how many ml of solution contain “X”mg of drug, use: To determine how many mg of drug are in “X” ml of solution, or to determine how many ml of solution contain “X”mg of drug, use: mg/ml (available) = mg/ml (desired) mg/ml (available) = mg/ml (desired) where mg/ml (available) is the strength of the drug. Solve for the desired variable on the right side (“desired”) side of the equation where mg/ml (available) is the strength of the drug. Solve for the desired variable on the right side (“desired”) side of the equation

18. Calculation Example: How many ml of 1% Isoetharine (Bronkosol) are needed to give the patient 2.5 mg of drug? Convert 1% to mg/ml and use the equation Convert 1% to mg/ml and use the equation mg/ml (available) = mg/ml (desired) mg/ml (available) = mg/ml (desired) 1% = 10 mg/ml, so 1% = 10 mg/ml, so 10 mg/ml = 2.5 mg/”X” ml 10 mg/ml = 2.5 mg/”X” ml  Using algebra, solve for “X” X =.25 ml X =.25 ml

19. Thus, to give a patient 2.5 mg of 1% Isoetharine (Bronkosol), you would need to administer.25 ml of 1% Isoetharine (Bronkosol)

20. Calculation Example: How much drug does a patient get if you administer.5 ml of.5% Albuterol (Proventil)? Convert.5% to mg/ml and use the equation Convert.5% to mg/ml and use the equation mg/ml (available) = mg/ml (desired) mg/ml (available) = mg/ml (desired).5% = 5 mg/ml, so.5% = 5 mg/ml, so 5 mg/ml = “X” mg/.5 ml 5 mg/ml = “X” mg/.5 ml  Use algebra and solve for X X = 2.5 mg X = 2.5 mg

21. Thus, if a patient receives.5 ml of.5% Albuterol (Proventil), he receives 2.5 mg of Albuterol (Proventil)!

22. Calculations: Diluting a Solution Use formula, V¹C¹ = V²C², where: Use formula, V¹C¹ = V²C², where: V¹ = Volume of desired solution V¹ = Volume of desired solution C¹ = Concentration (strength) of desired C¹ = Concentration (strength) of desired solution solution V² = Volume of available solution to be V² = Volume of available solution to be drawn up and diluted drawn up and diluted C² = Concentration (strength) of available C² = Concentration (strength) of available solution solution

23. Calculation Example Give 15 ml of 2.5% Sodium Bicarb. You have 20 ml of 7.5% available. Give 15 ml of 2.5% Sodium Bicarb. You have 20 ml of 7.5% available. Don’t be misled by the amount of solution available! It’s not part of the equation! Don’t be misled by the amount of solution available! It’s not part of the equation! V¹ = 15 ml V¹ = 15 ml C¹ = 2.5% C¹ = 2.5% V² = X (what you are solving for – how much of the available solution you are going to use) V² = X (what you are solving for – how much of the available solution you are going to use) C² = 7.5% C² = 7.5%

24. V¹C¹ = V²C² 15 ml (2.5%) = “X” ml (7.5%) 15 ml (2.5%) = “X” ml (7.5%) 15ml (2.5%)/7.5% = “X” ml 15ml (2.5%)/7.5% = “X” ml “X”ml = 5 ml =V² “X”ml = 5 ml =V² Take 5 ml of the 7.5% solution and add enough water to end up with 15 ml of solution Take 5 ml of the 7.5% solution and add enough water to end up with 15 ml of solution Adding 10 ml of water to 5 ml of 7.5% solution will yield 15 ml of 2.5% solution! Adding 10 ml of water to 5 ml of 7.5% solution will yield 15 ml of 2.5% solution!

25. Calculation Example Give 8 ml of 50% ETOH. You have 12 ml of 80 % ETOH available. Give 8 ml of 50% ETOH. You have 12 ml of 80 % ETOH available. V¹ = 8 ml V¹ = 8 ml C¹ = 50 % C¹ = 50 % V² = X (the amount of 80% ETOH to be used for dilution) V² = X (the amount of 80% ETOH to be used for dilution) C² = 80% C² = 80%

26. V¹C¹ = V²C² 8 ml (50%) = “X” ml (80%) 8 ml (50%) = “X” ml (80%) 8 ml (50%)/80% = “X” ml 8 ml (50%)/80% = “X” ml “X” ml = 5 ml = V² “X” ml = 5 ml = V² Take 5 ml of 80% ETOH and add enough water to end up with 8 ml of solution Take 5 ml of 80% ETOH and add enough water to end up with 8 ml of solution Adding 3 ml of water to 5 ml of 80 ETOH will yield 8 ml of 50% ETOH! Adding 3 ml of water to 5 ml of 80 ETOH will yield 8 ml of 50% ETOH!

27. Let’s get the hell out of here and take a break!!