introduction to pharmacology kala

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Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Pharmacologic PrinciplesPharmacologic Principles





DrugDrug

�� Any chemical that affects the processes of Any chemical that affects the processes of

a living organisma living organism





PharmacologyPharmacology

�� The study or science of drugsThe study or science of drugs




Pharmacologic Principles: Drug NamesPharmacologic Principles: Drug Names

Chemical nameChemical name

�� The drug¶s chemical composition and molecular The drug¶s chemical composition and molecular structurestructure

Generic name (nonproprietary name)Generic name (nonproprietary name)

�� Name given by the United States AdoptedName given by the United States AdoptedName CouncilName Council

Trade name (proprietary name)Trade name (proprietary name)

�� The drug has a registered trademark; useThe drug has a registered trademark; useof the name restricted by the drug¶s owner of the name restricted by the drug¶s owner (usually the manufacturer)(usually the manufacturer)




Pharmacologic Principles: Drug NamesPharmacologic Principles: Drug Names

Chemical nameChemical name

�� (+/(+/--))--22--(p(p--isobutylphenyl) propionic acidisobutylphenyl) propionic acid

Generic nameGeneric name

�� ibuprofenibuprofen

Trade nameTrade name

�� MotrinMotrin





�� PharmaceuticsPharmaceutics

�� PharmacokineticsPharmacokinetics

�� PharmacodynamicsPharmacodynamics

�� PharmacotherapeuticsPharmacotherapeutics

�� PharmacognosyPharmacognosy





PharmaceuticsPharmaceutics

�� The study of how various drug forms influenceThe study of how various drug forms influence

pharmacokinetic and pharmacodynamic activitiespharmacokinetic and pharmacodynamic activities





PharmacokineticsPharmacokinetics

�� The study of what the body does to the drug:The study of what the body does to the drug:

±± AbsorptionAbsorption

±± DistributionDistribution

±± MetabolismMetabolism

±± ExcretionExcretion





PharmacodynamicsPharmacodynamics

�� The study of what the drug does to the bodyThe study of what the drug does to the body::

±± The mechanism of drug actions in living tissuesThe mechanism of drug actions in living tissues





PharmacotherapeuticsPharmacotherapeutics

�� The use of drugs and the clinical indications for The use of drugs and the clinical indications for

drugs to prevent and treat diseasesdrugs to prevent and treat diseases





PharmacognosyPharmacognosy

�� The study of natural (plant and animal) drug sourcesThe study of natural (plant and animal) drug sources




Drug Absorption of VariousDrug Absorption of Various

Oral PreparationsOral Preparations

Liquids, elixirs, syrupsLiquids, elixirs, syrups FastestFastestSuspension solutionsSuspension solutions

PowdersPowders

CapsulesCapsules

TabletsTablets

Coated tabletsCoated tablets

EntericEnteric--coated tabletscoated tablets SlowestSlowest




Pharmacokinetics: AbsorptionPharmacokinetics: Absorption

�� The rate at which a drug leaves its site of The rate at which a drug leaves its site of administration, and the extent to whichadministration, and the extent to which

absorption occurs.absorption occurs.±± BioavailabilityBioavailability

±± BioequivalentBioequivalent




Pharmacokinetics: AbsorptionPharmacokinetics: AbsorptionFactors That Affect AbsorptionFactors That Affect Absorption

�� Administration route of the drugAdministration route of the drug

�� Food or fluids administered with the drugFood or fluids administered with the drug

�� Dosage formulationDosage formulation

�� Status of the absorptive surfaceStatus of the absorptive surface

�� Rate of blood flow to the small intestineRate of blood flow to the small intestine

�� Acidity of the stomachAcidity of the stomach

�� Status of GI motilityStatus of GI motility





RoutesRoutes

�� A drug¶s route of administration affects the rateA drug¶s route of administration affects the rate

and extent of absorption of that drug.and extent of absorption of that drug.

±± EnteralEnteral

±± ParenteralParenteral

±± TopicalTopical





Enteral RouteEnteral Route

�� Drug is absorbed into the systemic circulationDrug is absorbed into the systemic circulation

through the oral or gastric mucosa, the smallthrough the oral or gastric mucosa, the smallintestine, or rectum.intestine, or rectum.

±± OralOral

±± SublingualSublingual

±± BuccalBuccal

±± RectalRectal




FirstFirst--Pass EffectPass EffectThe metabolism of a drug and its passageThe metabolism of a drug and its passage

from the liver into the circulation.from the liver into the circulation.

�� A drug given via the oral route may be extensivelyA drug given via the oral route may be extensivelymetabolized by the liver before reaching the systemicmetabolized by the liver before reaching the systemiccirculation (high firstcirculation (high first--pass effect).pass effect).

�� The same drugThe same drug²²given IVgiven IV²²bypasses the liver,bypasses the liver,preventing the firstpreventing the first--pass effect from taking place, andpass effect from taking place, and

more drug reaches the circulation.more drug reaches the circulation.




FirstFirst--Pass EffectPass Effect

�� Routes that bypass the liver:Routes that bypass the liver:

±± SublingualSublingual TransdermalTransdermal

±± BuccalBuccal VaginalVaginal

±± Rectal*Rectal* Intramuscular Intramuscular

±± IntravenousIntravenous SubcutaneousSubcutaneous

±± IntranasalIntranasal InhalationInhalation

*Rectal route undergoes a higher degree of first*Rectal route undergoes a higher degree of first--pass effects than the other routes listed.pass effects than the other routes listed.




Pharmacokinetics: AbsorptionPharmacokinetics: AbsorptionParenteral RouteParenteral Route

�� Intravenous*Intravenous*

�� Intramuscular Intramuscular

�� SubcutaneousSubcutaneous

�� IntradermalIntradermal

�� IntrathecalIntrathecal

�� Intraarticular Intraarticular

*Fastest delivery into the blood circulation*Fastest delivery into the blood circulation




Pharmacokinetics: AbsorptionPharmacokinetics: AbsorptionTopical RouteTopical Route

�� Skin (including transdermal patches)Skin (including transdermal patches)

�� EyesEyes

�� EarsEars

�� NoseNose

�� Lungs (inhalation)Lungs (inhalation)

�� VaginaVagina




Pharmacokinetics: DistributionPharmacokinetics: DistributionThe transport of a drug in the body by theThe transport of a drug in the body by the

bloodstream to its site of action.bloodstream to its site of action.

�� ProteinProtein--bindingbinding

�� Water soluble vs. fat solubleWater soluble vs. fat soluble

�� BloodBlood--brain barrier brain barrier

�� Areas of rapid distribution: heart, liver,Areas of rapid distribution: heart, liver,

kidneys, brainkidneys, brain�� Areas of slow distribution: muscle, skin, fatAreas of slow distribution: muscle, skin, fat




Pharmacokinetics: MetabolismPharmacokinetics: Metabolism(also known as Biotransformation)(also known as Biotransformation)

The biologic transformation of a drug intoThe biologic transformation of a drug intoan inactive metabolite, a more solublean inactive metabolite, a more soluble

compound, or a more potent metabolite.compound, or a more potent metabolite.�� Liver (main organ)Liver (main organ)

�� KidneysKidneys

�� LungsLungs�� PlasmaPlasma

�� Intestinal mucosaIntestinal mucosa




Pharmacokinetics: MetabolismPharmacokinetics: Metabolism

Factors that decrease metabolism:Factors that decrease metabolism:

�� Cardiovascular dysfunctionCardiovascular dysfunction

�� Renal insufficiencyRenal insufficiency

�� StarvationStarvation

�� Obstructive jaundiceObstructive jaundice

�� Slow acetylator Slow acetylator

�� Erythromycin or ketoconazole drug therapyErythromycin or ketoconazole drug therapy





Factors that increase metabolism:Factors that increase metabolism:

�� Fast acetylator Fast acetylator

�� BarbituratesBarbiturates

�� Rifampin therapyRifampin therapy





Delayed drug metabolism results in:Delayed drug metabolism results in:

�� Accumulation of drugsAccumulation of drugs

�� Prolonged action of the effects of the drugsProlonged action of the effects of the drugs

Stimulating drug metabolism causes:Stimulating drug metabolism causes:

�� Diminished pharmacologic effectsDiminished pharmacologic effects




Pharmacokinetics: ExcretionPharmacokinetics: Excretion

The elimination of drugs from the bodyThe elimination of drugs from the body

�� Kidneys (main organ)Kidneys (main organ)

�� Liver Liver

�� BowelBowel

±± Biliary excretionBiliary excretion

±± Enterohepatic circulationEnterohepatic circulation




PharmacokineticsPharmacokinetics

Half Half--LifeLife

�� The time it takes for one half of the original amountThe time it takes for one half of the original amount

of a drug in the body to be removed.of a drug in the body to be removed.

�� A measure of the rate at which drugs are removedA measure of the rate at which drugs are removedfrom the body.from the body.





Drug actions:Drug actions:

�� The cellular processes involved in the drug andThe cellular processes involved in the drug and

cell interactioncell interaction

Drug effect:Drug effect:

�� The physiologic reaction of the body to the drugThe physiologic reaction of the body to the drug





OnsetOnset

�� The time it takes for the drug to elicit aThe time it takes for the drug to elicit atherapeutic responsetherapeutic response

PeakPeak

�� The time it takes for a drug to reach its maximumThe time it takes for a drug to reach its maximumtherapeutic responsetherapeutic response

DurationDuration

�� The time a drug concentration is sufficient to elicitThe time a drug concentration is sufficient to elicita therapeutic responsea therapeutic response




Pharmacodynamics:Pharmacodynamics:

Mechanisms of ActionMechanisms of ActionThe ways by which drugs can produceThe ways by which drugs can produce

therapeutic effects:therapeutic effects:

�� Once the drug is at the site of action, it can modifyOnce the drug is at the site of action, it can modifythe rate (increase or decrease) at which the cells or the rate (increase or decrease) at which the cells or tissues function.tissues function.

�� A drug cannot make a cell or tissue perform aA drug cannot make a cell or tissue perform a

function it was not designed to perform.function it was not designed to perform.




Pharmacodynamics:Pharmacodynamics:

Mechanisms of ActionMechanisms of Action�� Receptor interactionReceptor interaction

�� Enzyme interactionEnzyme interaction

�� Nonspecific interactionsNonspecific interactions




Pharmacotherapeutics:Pharmacotherapeutics:

Types of TherapiesTypes of Therapies�� Acute therapyAcute therapy

�� Maintenance therapyMaintenance therapy

�� Supplemental therapySupplemental therapy

�� Palliative therapyPalliative therapy

�� Supportive therapySupportive therapy

�� Prophylactic therapyProphylactic therapy




Pharmacotherapeutics: MonitoringPharmacotherapeutics: Monitoring

�� The effectiveness of the drug therapy mustThe effectiveness of the drug therapy mustbe evaluated.be evaluated.

�� One must be familiar with the drug¶sOne must be familiar with the drug¶s

�� intended therapeutic action (beneficial)intended therapeutic action (beneficial)

�� and the drug¶s unintended but potential sideand the drug¶s unintended but potential side

effects (predictable, adverse drug reactions).effects (predictable, adverse drug reactions).





�� Therapeutic indexTherapeutic index

�� Drug concentrationDrug concentration

�� Patient¶s conditionPatient¶s condition

�� Tolerance and dependenceTolerance and dependence

�� InteractionsInteractions

�� Side effects/adverse drug effectsSide effects/adverse drug effects





Therapeutic IndexTherapeutic Index

�� The ratio between a drug¶s therapeutic benefitsThe ratio between a drug¶s therapeutic benefits

and its toxic effectsand its toxic effects





ToleranceTolerance

�� A decreasing response to repetitive drug dosesA decreasing response to repetitive drug doses





DependenceDependence

�� A physiologic or psychological need for a drugA physiologic or psychological need for a drug





Interactions may occur with other drugs or foodInteractions may occur with other drugs or food

�� Drug interactions: the alteration of action of Drug interactions: the alteration of action of

a drug by:a drug by:

±± Other prescribed drugsOther prescribed drugs

±± Over Over--thethe--counter medicationscounter medications

±± Herbal therapiesHerbal therapies





InteractionsInteractions

�� Additive effectAdditive effect

�� Synergistic effectSynergistic effect

�� Antagonistic effectAntagonistic effect

�� IncompatibilityIncompatibility





Medication MisadventuresMedication Misadventures

Adverse drug eventsAdverse drug events

�� ALL are preventableALL are preventable�� Medication errors that result in patient harmMedication errors that result in patient harm

Adverse drug reactionsAdverse drug reactions

�� Inherent, not preventable event occurring in theInherent, not preventable event occurring in thenormal therapeutic use of a drugnormal therapeutic use of a drug

�� Any reaction that is unexpected, undesirable, andAny reaction that is unexpected, undesirable, andoccurs at doses normally usedoccurs at doses normally used





Some adverse drug reactions are classified asSome adverse drug reactions are classified asside effects.side effects.

�� Expected, wellExpected, well--known reactions that result in littleknown reactions that result in littleor no change in patient managementor no change in patient management

�� Predictable frequencyPredictable frequency

�� The effect¶s intensity and occurrence is related toThe effect¶s intensity and occurrence is related to

the size of the dosethe size of the dose





Adverse Drug ReactionAdverse Drug Reaction

An undesirable response to drug therapyAn undesirable response to drug therapy�� IdiosyncraticIdiosyncratic

�� Hypersensitivity reactionsHypersensitivity reactions

�� Drug interactionsDrug interactions





Iatrogenic ResponsesIatrogenic Responses

Unintentional adverse effects that areUnintentional adverse effects that aretreatmenttreatment--inducedinduced

�� DermatologicDermatologic

�� Renal damageRenal damage

�� Blood dyscrasiasBlood dyscrasias

�� Hepatic toxicityHepatic toxicity





Other DrugOther Drug--Related EffectsRelated Effects

�� TeratogenicTeratogenic

�� MutagenicMutagenic

�� CarcinogenicCarcinogenic

introduction to pharmacology kala

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