PharmacologyPharmacology

PharmacologyPharmacology

• The study of drugs and their actions

Reasons For Medication Reasons For Medication UseUse

• Diagnose• Treatment• Curative• Lesson pain• Prevent a disease or condition

Where Do Drugs Come Where Do Drugs Come From?From?

• Plants• Animals• Minerals• Laboratory Chemical combinations• Biotechnology Genetics

PharmacokineticsPharmacokinetics

Definition: • The process a drug goes through upon

entering the body• It involves the processes of absorption,

distribution, biotransformation (metabolism - liver), and excretion

PharmacokineticsPharmacokinetics

Absorption: For a drug to work , it must be absorbed. It is absorbed at the site where it is given. Once a drug reaches the capillaries, it is taken into the bloodstream. The rate of absorption varies depending on the type of drug, amount of the drug, route, and the patient.

Pharmacokinetics Pharmacokinetics ContinuedContinued

Distribution: How the drug gets to its target once it is in the bloodstream. Involves circulation of the blood. Targets are cells in tissue or organs.

PharmacokineticsPharmacokinetics

Metabolism: How a drug is broken down for excretion. Products of breakdown are called metabolites. Metabolites are rendered small, inactive or less active before excretion occurs. Metabolism usually occurs in the liver, however can occur in the kidneys, lungs, blood plasma, or intestinal mucosa.

Pharmacokinetics Pharmacokinetics

Excretion: A drug continues to have an action until it is excreted by the body. Kidneys generally are the excretory route. Drugs can be excreted by saliva, sweat, exhalation, breast milk, or feces (poop).

PharmacodynamicsPharmacodynamics

Definition: Is the study of how a drug acts on targeted cells.

PharmacodynamicsPharmacodynamics

Types of Drug Actions: • Inhibitive or destructive• Protection• Supplementation• Replacement• Physiologic function (increase or

decrease)

PharmacodynamicsPharmacodynamics

Drug Effect or Action Theories:• Agonists- Drug binds to a special receptor

on a target cell and produce the desired effect.

• Antagonists- Drug binds with a special receptor on a target cell and prevent or inhibit a response.

• Non-specific- Neither agonists or antagonists. These drugs gather on a cell’s membrane or go through it and interfere with actual cell function

PharmacodynamicsPharmacodynamics

Timing of Drug Effects: • Onset- time from when a drug is

given to when its effects first occur• Peak Effect- when a drug is at its

maximum effect • Duration- time from when drug

effects begin to when they stop

Routes of Routes of Drug AdministrationDrug Administration

• Buccal(topical)• IM• Inhalation• Intra-articular• Intradermal/dermal• Intrathecal

Topical =‘s any epithelial lined surface. Tongue, rectally, cheek, vagina etc

IV Intracardiac po/PO SC/subq sublingual (topical) topical

Drug PreparationsDrug Preparations

• Forms of:• solid• semi-solid• liquid• gas/vapors

Abbreviations for PO or Abbreviations for PO or Topical AdministrationTopical Administration

• Topical• cream• gtts (ear)• ung (ointment)

• PO• cap• gtts (oral/infants) • soln/sol• susp• tab

Frequency of DrugsFrequency of Drugs

• Abbreviations:• bid• h/hr• prn/PRN• q• qd

• qh• q2h• qid• tid• stat

Administration Administration AbbreviationsAbbreviations

• AD (right ear)• AS• AU• OD• OS• OU• os• aa (of each)

• ad (towards)• RX• c (line over it)• dc/DC• KVO/TKO• npo/NPO• per

Nomenclature (Naming) of Nomenclature (Naming) of DrugsDrugs

• Chemical name: chemical make-up of a drug

• Generic name: nonproprietary name given to a drug by the developer of a drug (acetaminophen, ibuprofen, diphenhydramine)

• Trade or Brand name: Proprietary or patented name of the manufacturer of the drug (Tylenol, Motrin & Advil, Benedryl). Manufacturing processes may differ slightly.

Legal ImplicationsLegal Implications(Federal)(Federal)

• Pure Food and Drug Act -Standards for US marketing• Federal Food, Drug, and Cosmetic Act -Regulations -FDA approval• Controlled Substances Act -Established DEA -Schedule of Controlled Substances: C-I - Marijuana C-IV – Phenobarbital (treat

seizures) C-II - Cocaine C-V – antidiarrheal (low abuse

rate) C-III – anabolic steroids The lower the # the higher the addiction/abuse potential

Legal ImplicationsLegal Implications(State)(State)

• Regulate practice acts for ordering, prescribing, and administration of medications

• As a surgical technologist, we act as an extension of the physician handling drugs under their supervision

Legal ImplicationsLegal Implications(Local)(Local)

• May have specific guidelines for medication administration in the institution you are employed in

Metric SystemMetric System

• Meter = length • Liter = capacity• Gram = weight

Metric PrefixesMetric Prefixes

• Micro-one-millionth; 0.000001• Milli-one-thousandth; 0.001• Centi-one-hundredth; 0.01• Deci-one-tenth; 0.1• Unit-one;1.0• Deka-ten;10.0• Hecto-one-hundred;100.0• Kilo-one thousand;1000.0

Metric EquivalentsMetric Equivalents

• Weight (gram)• 1 gram=1000

milligrams• 1 kilogram=1000

grams• 1 ounce=30 grams• Capacity (liter)• 1 liter=1000

milliliters• 1000 liters=1

kiloliter• 1 liter=1.06 quarts

• 1 quart=0.946 liters• 1 milliliter weighs 1

gram• 1 cubic centimeter

(cc) and 1 milliliter (ml) are equal/same

• 1 liter=1000ml or cc• 1 fl. oz.=30ml or cc• 1 fl. dram=0.125fl.

oz. or 4ml or cc• 1 gallon=3.8 liters

Metric EquivalentsMetric Equivalents

• Length (meter)• 1 meter=1000mm=100cm=1.094

yd• 1 yard=3 ft.=36 in.=0.9144 meters• 1 in.=2.54 cm=25.4mm• 1 micron

(micrometer)=0.001mm=0.000001 meter

Metric AbbreviationsMetric Abbreviations

• Gram-gm• Milligram-mg• Kilogram-kg• Liter-L• Milliliter-ml

• Cubic centimeter-cc

• Meter-M• Millimeter-mm• Centimeter-cm

Temperature MeasuringTemperature Measuring

• Fahrenheit (F)Water freezes at 32°Water boils at 212°• Celsius (C) (centigrade)Water freezes at 0°Water boils at 100°

Converting C° to F° or Converting C° to F° or F° to C°F° to C°

• Fahrenheit to Celsius• 5/9 (F°-32) = C° ( or F -32 x 5 divided by 9

= C)

• Celsius to Fahrenheit• 9/5 (C°)+32 = F° (or C x 9 divided by 5 + 32

=‘s F)

Dosage CalculationsDosage Calculations

• Formula:• D (desired dose) x Q (quantity of dose on

hand)

H (dose on hand) =‘s X X = Amount to give/needed• Example: Give 80mg of a drug from

a 30ml stock bottle labeled “100mg per 1ml

• I know: 1ml=100mg Need to give 80mg• I do not know: Fraction of ml

that=80mg• Common sense: If 1 ml of the

solution = 100mg of the drug, then the amount given must be less than 1ml.

• Formula: D x Q = amt to give H• Solution: 80mg x 1ml=0.8 ml of

sol. 100mg• Proof: 80÷100=0.8 0.8x1=0.8

Standard Dilution Standard Dilution EquationsEquations

• C1 x V1 = C2 x V2• C = concentration in %• V = volume• Problem: Dr. needs 60 ml of ½%

contrast media. How much NACL and how much media do you need to make the required amount when you have 60 ml’s of 1% media?

• First we must convert the % to decimals

• 1/2% = 0.5• 1 divided by 2 = 0.5• You always do this when

converting percentages to decimals

• C1=1/2%=0.5 Concentration 1 (asked for)

• C2=1% = Concentration 2 (given)• V1=60ml Volume 1 (asked for)• V2=x (? volume of saline)

• Formula: C1 x V1 = C2 x V2• 0.5 x 60 =1 x x• 30 = x• So, You add x=30 ml’s of pure saline• Need 60mlof 1% – 30ml’s = 30ml’s of

1% dye solution and add 30ml’s saline to get 60ml of 0.5% dye solution

Standard Dilution Standard Dilution EquationEquation

• Doctor wants ½% lidocaine. You have 25ml of 1% Lidocaine. How do you dilute it to the proper strength?

• C1 (asked) x V1 (given) = C2 (given) x V2 (?)

• ½% x 25 = 1% x x• 12.5= x• 25ml lidocaine – 12.5mlof 1% lidocaine =

12.5ml lidocaine = 12.5ml saline = ½% or 0.5% lidocaine

Calculating mg Dose Calculating mg Dose per kg Body Weightper kg Body Weight

• Normal dose of propofol (an induction drug used by anesthesia) is 2 mg per kg for an adult

• Find initial dose for an adult weighing 150lbs

• Convert lbs. to kg (2.2 lbs. = 1kg)• 150lbs. ÷ 2.2lbs. = 68kg• 68kg x 2mg = 136mg

Calculating Child Calculating Child DosagesDosages

• Clark’s Rule: Standard adult weight=150lbs• Problem: If an adult receives 75mg of

Demerol, what would be an appropriate dose for a child weighing 30lbs?

• Adult dose=75mg• Child weighs 30lbs.• Clark’s rule Standard adult weight =

150lbs.• Common sense: child is smaller, dose will

be less than 75mg

• Formula: Child’s weight x Adult dose = Child’s

dose

Adult weight• Solution:• 30lbs. x 75mg = 15mg of Demerol 150lbs

Mixing MedicationsMixing Medications

• Do not mix drugs unless you know for certain that they are compatible together

• If a compatibility is questioned direct the question to the pharmacist to be certain before mixing

• Mixing drugs that are incompatible can result in decreased or increased efficacy, precipitates/crystallization of the drugs which could cause embolization of the drug in the patient, or death

• Institutional pharmacies keep a compatibility chart in the pharmacy/Some ORs may have them in the room

SummarySummary

• Pharmacokinetics• Pharmacodynami

cs• Actions/Effects• Abbreviations• Nomenclature• Legal implications

• Metric System• Conversions/ Mathematics• Dosage

Calculations• Mixing

Medications