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Pharmacokinetics Pharmacokinetics Pharmacology Pharmacology Chapter 2 Chapter 2
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Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Jan 03, 2016

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Page 1: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokineticsPharmacokinetics

PharmacologyPharmacology

Chapter 2Chapter 2

Page 2: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

How Does medication Work How Does medication Work in our Bodies?in our Bodies?

Pharmacokinetic ModelPharmacokinetic Model Different cells are targeted to evoke Different cells are targeted to evoke

a desired responsea desired response Via chemical messangers.Via chemical messangers.

Can you name some?Can you name some?

Page 3: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

ReceptorsReceptors Cells communicate through the action of Cells communicate through the action of

chemical messengers chemical messengers ““Target cellTarget cell”-(”-(the cell that responds to the the cell that responds to the

communicationcommunication). ). ReceptorReceptor is a protein molecule on the is a protein molecule on the

surface of or within a cell that recognizes surface of or within a cell that recognizes and binds with specific molecules, thereby and binds with specific molecules, thereby producing some effect within the cell.producing some effect within the cell.

SpecificitySpecificity-- the messenger has the same the messenger has the same receptor structure as the target cell. receptor structure as the target cell.

AffinityAffinity-- the strength by which a the strength by which a messenger binds to a receptor site. messenger binds to a receptor site.

Page 4: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Mechanisms of Drug ActionMechanisms of Drug Action How a drug produces its effects. How a drug produces its effects. AgonistAgonist is a drug that binds to a particular is a drug that binds to a particular

receptor site and triggers the cell’s receptor site and triggers the cell’s response in a manner similar to the action response in a manner similar to the action of the body’s own chemical messenger.of the body’s own chemical messenger.

AntagonistsAntagonists- Drugs that bind to a receptor - Drugs that bind to a receptor site and block action of chemical site and block action of chemical messengersmessengers..

Other drugs Other drugs interact with non specific lipids interact with non specific lipids combine with proteins combine with proteins Use Osmosis -how water is reabsorbed by the Use Osmosis -how water is reabsorbed by the

kidneyskidneys

Page 5: Pharmacokinetics Pharmacology Pharmacology Chapter 2.
Page 6: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokineticsPharmacokinetics The action of drugs in the body over a period of The action of drugs in the body over a period of

time . time . Pharmacokinetic Processes Pharmacokinetic Processes

ADME Scheme of kinetics (Pharmacokinetic ADME Scheme of kinetics (Pharmacokinetic Modeling) Modeling)

AbsorptionAbsorption DistributionDistribution MetabolismMetabolism EliminationElimination

Considerations such as:Considerations such as: Levels of the drug in blood and tissuesLevels of the drug in blood and tissues Overall distribution Overall distribution Reaction of the drugs with other drugsReaction of the drugs with other drugs Patient compliancePatient compliance

Life of the drug that includes bioavailability, Life of the drug that includes bioavailability, half-life, bioequivalencehalf-life, bioequivalence

Page 7: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokinetiPharmacokineticscs

Page 8: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

AbsorptionAbsorption The process whereby a drug enters the The process whereby a drug enters the

circulatory system. circulatory system. Rate depends on ROA, solubility and Rate depends on ROA, solubility and

physical properties. physical properties. Dissolution –the time necessary drug to be Dissolution –the time necessary drug to be

dissolved. dissolved. Rate of dissolution depends on the Rate of dissolution depends on the

chemistry, surface area, and mnf variables.chemistry, surface area, and mnf variables. Primary site of absorption- Small IntestinePrimary site of absorption- Small Intestine GI motility can affect the rate of absorptionGI motility can affect the rate of absorption

Page 9: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

DistributionDistribution The process by which a drug moves The process by which a drug moves

from the blood into other body from the blood into other body fluids and tissues. fluids and tissues.

Factors that affect distributionFactors that affect distribution Binding to Plasma ProteinsBinding to Plasma Proteins Binding to Cellular ConstituentsBinding to Cellular Constituents Blood Brain BarrierBlood Brain Barrier Blood flow is the rateBlood flow is the rate

The distribution is not necessarily The distribution is not necessarily equal throughout the whole bodyequal throughout the whole body

Page 10: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

MetabolismMetabolism The process of converting drugs to The process of converting drugs to

compounds that are useful in the body.compounds that are useful in the body. Factors that can alter metabolismFactors that can alter metabolism

Other medicationsOther medications Disease states, age, geneticsDisease states, age, genetics

Page 11: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

MetabolismMetabolism

Most metabolism takes place Most metabolism takes place in the liverin the liver

Metabolism changes the chemical Metabolism changes the chemical structure of the original drugstructure of the original drug

There are different influences that can There are different influences that can alter metabolism such as age, gender, alter metabolism such as age, gender, genetics, diet, and other chemicals genetics, diet, and other chemicals digesteddigested

Page 12: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

ExcretionExcretion Occurs primarily in the kidney and Occurs primarily in the kidney and

bowel. bowel. Also exhalation, sweat glands, breast Also exhalation, sweat glands, breast

milkmilk ClearanceClearance - rate at which a drug is - rate at which a drug is

eliminated from a specific volume eliminated from a specific volume of blood per unit of time.of blood per unit of time.

Excretion is the last phase of a Excretion is the last phase of a drug’s life in the bodydrug’s life in the body

Page 13: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Important Pharmacokinetic Important Pharmacokinetic ParametersParameters

Safe and effective drug therapy requires that Safe and effective drug therapy requires that drugs be delivered in concentrations that will drugs be delivered in concentrations that will treat the disease without toxicity. treat the disease without toxicity.

BioavailabilityBioavailability how much of the drug how much of the drug administered becomes active in the body.administered becomes active in the body.

First Pass effect-First Pass effect- drugs must first pass through drugs must first pass through the intestines and the liver before reaching the intestines and the liver before reaching target site. target site.

Ceiling effectCeiling effect -Greater doses are given until a -Greater doses are given until a point is reached when no improved clinical point is reached when no improved clinical response occurs and increasing beyond this response occurs and increasing beyond this point can cause side effects, toxicity and point can cause side effects, toxicity and death.death.

Page 14: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokineticsPharmacokineticsDose-Response CurveDose-Response Curve

Page 15: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Therapeutic windowTherapeutic window - optimum - optimum response with the least probability of response with the least probability of toxicity. toxicity.

Therapeutic level/RangeTherapeutic level/Range -amount of -amount of drug in the blood that produces the drug in the blood that produces the desired effect. desired effect.

Duration of ActionDuration of Action -The amount of -The amount of time a drug is at this level time a drug is at this level

Loading doseLoading dose, the amount of drug , the amount of drug needed to bring blood quickly to needed to bring blood quickly to desired response. desired response.

Page 16: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokineticsPharmacokinetics

Therapeutic RangeTherapeutic Range

Page 17: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

PharmacokineticsPharmacokinetics

Duration of ActionDuration of Action

Page 18: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Maintenance DosesMaintenance Doses Given to maintain therapeutic levelsGiven to maintain therapeutic levels

Page 19: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Half LifeHalf Life The time it takes for the body to eliminate half the The time it takes for the body to eliminate half the

drugdrug T1/2T1/2 It takes a drug 5-7 times longer than it’s half life to It takes a drug 5-7 times longer than it’s half life to

be considered removed from the bodybe considered removed from the body 1000mg of Drug a has t ½ of 2 hours1000mg of Drug a has t ½ of 2 hours 12 am Take first dose12 am Take first dose 2am = 500 mg left2am = 500 mg left 4am = 250 mg left4am = 250 mg left 6 am = 125 mg left6 am = 125 mg left 8 am = 62 mg left8 am = 62 mg left 10 am 31 mg left10 am 31 mg left 12pm = 15 mg left12pm = 15 mg left 2 pm = 7 mg left2 pm = 7 mg left 4 pm = drug eliminated4 pm = drug eliminated 14 hours to rid the body of the medications14 hours to rid the body of the medications

Page 20: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Half LifeHalf Life

0

100

200

300

400

500

600

700

800

900

1000

12:00 AM 2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM

Page 21: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

DiscussionDiscussion

How is a drug’s volume of How is a drug’s volume of distribution, clearance, and half-life distribution, clearance, and half-life used in dosing drugs?used in dosing drugs?

Answer:Answer: Volume of distribution is Volume of distribution is important for calculating the loading important for calculating the loading dose, clearance for calculating the dose, clearance for calculating the maintenance dose, and half-life for maintenance dose, and half-life for determining the dosing interval.determining the dosing interval.

Page 22: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

BioequivalenceBioequivalence

This is the comparison between drugs either This is the comparison between drugs either from different manufacturers from different manufacturers or in the same company but from different or in the same company but from different batches of a drugbatches of a drug

Generic drug manufacturers strive Generic drug manufacturers strive to achieve the same equivalence to achieve the same equivalence as brand name manufacturers for as brand name manufacturers for competitioncompetition

Page 23: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Drug EffectsDrug Effects Effects of drugs can be beneficial or Effects of drugs can be beneficial or

detrimental and dangerous. detrimental and dangerous. Site of action-Site of action- location in the body location in the body

where a drug exerts its therapeutic where a drug exerts its therapeutic effect.effect.

Beneficial ResponsesBeneficial Responses Therapeutic EffectTherapeutic Effect

effect-The desired action of a drug in treatment effect-The desired action of a drug in treatment or symptom of a disease.or symptom of a disease.

Local EffectLocal Effect Confined to a specific part of the bodyConfined to a specific part of the body

Systemic EffectSystemic Effect Generalized, all-inclusive effect on entire body Generalized, all-inclusive effect on entire body

Page 24: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Drug EffectsDrug EffectsWhen choosing a drug for a patient, a When choosing a drug for a patient, a healthcare practitioner considers:healthcare practitioner considers:

IndicationsIndicationsdiseases, symptoms, and conditions for diseases, symptoms, and conditions for which the drug is known to be of benefitwhich the drug is known to be of benefit

ContraindicationsContraindicationsconditions for which the drug will not be conditions for which the drug will not be beneficial and may do harmbeneficial and may do harm

Page 25: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Drug EffectsDrug Effects

Side EffectsSide Effects secondary responses to a drug other secondary responses to a drug other than it’s intended effect. than it’s intended effect.

Allergic responsesAllergic responses Drug dependence, addiction, abuse, and Drug dependence, addiction, abuse, and

tolerancetolerance

Page 26: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Harmful ResponsesHarmful Responses An allergic response can be a local or general An allergic response can be a local or general

immune response. immune response. an overreaction to a harmless substance. an overreaction to a harmless substance. Can be mild to severeCan be mild to severe Anaphylactic response- characterized by respiratory Anaphylactic response- characterized by respiratory

distress, vascular collapse and shock. distress, vascular collapse and shock. Idiosyncratic reactionsIdiosyncratic reactions-- unusual or unexpected unusual or unexpected

reactions to a medication. reactions to a medication. Drug dependenceDrug dependence-- physiological and/or physiological and/or

psychological need for a drugpsychological need for a drug AddictionAddiction- A perceived need for a drug - A perceived need for a drug AbuseAbuse –The use of a drug for purposes other than –The use of a drug for purposes other than

prescribed and or in amounts not directed. prescribed and or in amounts not directed. Tolerance Tolerance -Decreased response to the effects of a -Decreased response to the effects of a

drug do to its continued use. drug do to its continued use.

Page 27: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Drug InteractionsDrug Interactions Combined effect of two or more Combined effect of two or more

drugs. drugs. Common Drug relationshipsCommon Drug relationships

AdditionAddition 1 + 1 = 21 + 1 = 2

Antagonism Antagonism 1 + 1 = 1 1 + 1 = 1

PotentiationPotentiation 0 + 1 > 10 + 1 > 1

SynergismSynergism 1 + 1 > 2 1 + 1 > 2

Page 28: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

DiscussionDiscussion

Name a common drug-food Name a common drug-food interaction.interaction.

Answer:Answer: Grapefruit juice can Grapefruit juice can affect drugs for up to a day affect drugs for up to a day following ingestion. following ingestion.

Page 29: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

DiscussionDiscussion

Why is it important for the Why is it important for the pharmacy to have a complete list of pharmacy to have a complete list of all of the prescription drugs, OTC all of the prescription drugs, OTC medications, vitamins, and herbal medications, vitamins, and herbal remedies that a patient is taking?remedies that a patient is taking?

Answer:Answer: Such a list will help Such a list will help healthcare professionals identify healthcare professionals identify potential drug interactions.potential drug interactions.

Page 30: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Factors that Influence Drug Factors that Influence Drug EffectsEffects

AgeAge GenderGender Disease/Medical conditionDisease/Medical condition Other-psychological, genetics, Other-psychological, genetics,

allergies.allergies.

Page 31: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Geriatric PharmacologyGeriatric Pharmacology

Factors that affect the rate of agingFactors that affect the rate of aging GeneticsGenetics NutritionNutrition exerciseexercise injuryinjury diseasedisease environmentenvironment

Geriatric = over 65, Geriatric = over 65, Most elderly patients will take 4 different Most elderly patients will take 4 different

RX’s.RX’s. This increases the chance of adverse This increases the chance of adverse

reactions or drug-drug interactions.reactions or drug-drug interactions.

Page 32: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Physiological Effects of Aging Physiological Effects of Aging on Pharmacokinetic Processon Pharmacokinetic Process

Loss of lean body mass Loss of lean body mass Decrease in % of body waterDecrease in % of body water Increased of body fatIncreased of body fat Absorption- is slowed and a delay in the Absorption- is slowed and a delay in the

onset of drug action occurs.onset of drug action occurs. Distribution - drugs can become more Distribution - drugs can become more

concentrated within the system. Increased concentrated within the system. Increased body fat can slow the excretion of fat body fat can slow the excretion of fat soluble drugs. soluble drugs.

Metabolism-is reduced and there is an Metabolism-is reduced and there is an increase in the duration of drug actionsincrease in the duration of drug actions

Elimination - Reduced blood flow and Elimination - Reduced blood flow and surface area can cause delays in excretion.surface area can cause delays in excretion.

Page 33: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Drug Compliance in the ElderlyDrug Compliance in the Elderly The elderly can easily become confused by The elderly can easily become confused by

their dosing regiments and can have difficulty their dosing regiments and can have difficulty remembering what meds are for what. remembering what meds are for what.

Polypharmacy- multiple drug prescriptions. Polypharmacy- multiple drug prescriptions. Increased side effects, Increased side effects, Forgetting to take prescribed dose Forgetting to take prescribed dose Continuing to take D/C MedsContinuing to take D/C Meds Difficult dosage form Difficult dosage form Small print on drug labelsSmall print on drug labels Look alike pillsLook alike pills

An average of six diseases coexist in older An average of six diseases coexist in older persons.persons.

Page 34: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Pediatric PatientsPediatric Patients Children undergo constant physiologic Children undergo constant physiologic

changes that can affect the ADME changes that can affect the ADME scheme of Kinetics. scheme of Kinetics.

Could cause over or under dosing, Could cause over or under dosing, resulting in failure of therapy, adverse resulting in failure of therapy, adverse reactions and death. reactions and death.

Age and or weight is the least reliable Age and or weight is the least reliable guideline for dosing, guideline for dosing,

BSABSA

Page 35: Pharmacokinetics Pharmacology Pharmacology Chapter 2.
Page 36: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Lets Try it! Lets Try it!

Child weighs 13.9 kg and is 85 cm tallChild weighs 13.9 kg and is 85 cm tall What is the BSA? What is the BSA? 13.9 x 85 = 13.9 x 85 =

1181.51181.5

1181.5/3600 = (hit the = before next step!)1181.5/3600 = (hit the = before next step!) 0.3281944 0.3281944

0.3281944 0.3281944 √ = √ = 0.572 m20.572 m2

Page 37: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Once More with Feeling!Once More with Feeling!

Child weighs 12.2 lb and is 24 inches tallChild weighs 12.2 lb and is 24 inches tall What is the BSA? What is the BSA? 12.2 x 24 = 12.2 x 24 =

292.8292.8

292.8/3131 = (hit the = before next step!)292.8/3131 = (hit the = before next step!) 0.09351640.0935164

0.0935164 √ = 0.0935164 √ = 0.305 m2 0.305 m2

Page 38: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

DiscussionDiscussion

What can the pharmacy What can the pharmacy technician do to help patients technician do to help patients manage their medications manage their medications properly?properly?

Page 39: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Teaching Patients To Teaching Patients To Manage Their MedicationsManage Their Medications

Patients failure to follow drug regimen is Patients failure to follow drug regimen is often caused by a lack of understanding or often caused by a lack of understanding or unclear information. unclear information.

The pharmacy technician can positively The pharmacy technician can positively affect patient compliance by providing affect patient compliance by providing clearly written instructions and aids.clearly written instructions and aids.

Techs are responsible for gathering and Techs are responsible for gathering and maintaining patient information such as maintaining patient information such as medical history and possible allergies to medical history and possible allergies to prevent drug interactions and duplications.prevent drug interactions and duplications.

Obtain information about OTC medications.Obtain information about OTC medications.

Page 40: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Techs should type full , clear Techs should type full , clear directions on the prescription label directions on the prescription label this includes. this includes. Name and strength of medication ( Brand Name and strength of medication ( Brand

and Generic if applicable) and Generic if applicable) Qty ( 1 tablet , 5 ml, 1 teaspoonful) Qty ( 1 tablet , 5 ml, 1 teaspoonful) Route ( po, pr) Route ( po, pr) Time ( tid, qid ) Time ( tid, qid ) Any extra information. ( dx) Unwrap etc) Any extra information. ( dx) Unwrap etc) Axillary labelsAxillary labels 1 qd 1 qd

Take 1 every day?Take 1 every day? Take 1 tablet orally every day. Take 1 tablet orally every day.

NO!!!

Page 41: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Teaching Patients Medication Teaching Patients Medication ManagementManagement

Page 42: Pharmacokinetics Pharmacology Pharmacology Chapter 2.

Teaching Patients Medication Teaching Patients Medication ManagementManagement