© 2006 The McGraw Hill Companies Pharmacology. © 2006 The McGraw Hill Companies Introduction

© 2006 The McGraw Hill Companies

Pharmacology


Introduction

Introduction

• Drugs are chemical agents used in the diagnosis, treatment, and prevention of disease

What is pharmacology?

Why is it important?

Introduction

• Written records of drug use date back to the ancient Egyptians

• Hippocrates wrote extensively about drugs

• During his time, a more scientific approach was used in treating specific diseases with drugs

Introduction

• Subspecialties of Pharmacology

–Pharmacokinetics

–Pharmacodynamics

–Pharmacogenetics

–Pharmacogenomics

Introduction

• Pharmacokinetics is dependent upon the body’s ability to move substances within the body– Active transport– Facilitated diffusion– Passive transport

Pharmacology Basics

• Pharmacokinetics considerations– Molecule size and shape– Solubility in water and lipids– Ability to bind to tissue proteins– Ionization

Solubility Exercise

Introduction

• Pharmacodynamics – Study of the

mechanisms by which specific drug dosages act to produce biochemical or physiological changes

Introduction

• Pharmacodynamics – Drugs may act in four different ways:

• Bind to a receptor site• Change the physical properties of the cell• Chemically combine with other chemicals• Alter a normal metabolic pathway

Introduction

• Pharmacogenetics and pharmacogenomics– Study unique genetic processes linked to

DNA coding and genetics

Pharmacogenosy

• The study of natural drug sources– Plants– Animals– Minerals

• What are some common examples of each drug source?

Pharmacogenosy

– Researchers can now manipulate the molecular structure of substances to create synthetic drugs

Plant Sources of Drugs

• Oldest source of medications

• Drugs may consist of using the entire plant, leaves, roots, bulbs, stems, seeds, buds, or blossoms

Animal Sources of Drugs

• Body fluids or glands from animals can act as sources for drugs

• Hormones• Oils and fats• Enzymes

Mineral Sources of Drugs

• Metallic and nonmetallic minerals provide various inorganic materials

• Occur naturally or are combined to form acids, bases, or salts

Introduction

• Laboratory-produced drug sources – New drugs may be a

more pure form of a naturally occurring drug or they may be a synthetic form

Routes

• Routes of Administration– Enteral Route– Parenteral Route– Topical Route

Introduction

• Subroutes of administration– Ingestion– Injection– Absorption– Inhalation

Route of Administration

• Depends of many factors– Accessibility– Rate of absorption– Deactivation by enzymes or acids– Toxicity to tissues

Drug Absorption

• Drug’s progress from its pharmaceutical dosage form to a biologically available substance

• Several factors affect drug absorption

Factors

1. Solubility

2. Concentration

3. pH

4. Site of absorption

5. Blood supply

6. Bioavailability

RouteOral (PO)

Subcutaneous (SQ)

Topical

Intramuscular (IM)

Rectal (PR)

Sublingual (SL)

Endotracheal (ET)

Inhalation

Intraosseous (IO)

Intavenous (IV)

Rate of AbsorptionSlow

Slow

Moderate

Moderate

Rapid

Rapid

Rapid

Rapid

Immediate

Immediate

Drug Forms

• Usually consist of a powder dissolved in a liquid– Solute: drug– Solvent: liquid in which it is dissolved

• Primary difference between one preparation and another is the solvent

• What is a solution?

Drug Forms

• Liquids

• Solids

• Suppositories

• Inhalants

• Sprays

• Creams/lotions

• Patches

• Lozenges

Liquid Drugs

– Solutions

– Tinctures

– Suspensions

– Spirits

Liquid Drugs

–Emulsions

–Elixirs

–Syrups

Routes of Administration

–Enteral• Orally (PO)

–Parenteral• Intramuscular (IM)

• Subcutaneous (SC or SQ)

• Intravenous (IV)

• Inhalation

Packaging

• Packaging and preparations – Vials

– Ampules

– Self-contained systems or syringes

– Nebules

Solid Drugs

– Administered orally or rectally

• Pills

• Powders

• Capsules

• Tablets

• Suppositories

Inhalants

–Nebulizers

–Metered-dose aerosols

–Turbo inhalers

–Vaporizers

Distribution

• Several factors affect distribution:

• Cardiovascular function

• Regional blood flow

• Drug storage reservoirs

• Physiological barriers

Biotransformation

• Biotransformation has two effects:– It can transform the drug into a more or less

active metabolite– It can make the drug more water soluble (or

less lipid-soluble) to facilitate elimination

Biotransformation

• Can activate metabolites to make the drug active (prodrugs)

• Many processes occur in the liver– First-pass effect– Body detoxifies and disposes of

toxins and excess drug by increasing water solubility

Basics

• Drugs are eliminated in either their original form or as metabolites– Drug excretion is the movement of a drug or

its metabolites from the tissues back into circulation and from secretion into organs of excretion

Elimination

• Can be affected by– Drug half-life– Accumulation– Clearance– Onset, peak, and

duration

Therapeutic Index

• Medication must reach a certain concentration at the target tissue to be effective

• Medication must reach a certain concentration at the target tissue to be effective

Therapeutic index

Therapeutic threshold

Therapeutic Index

• Dose calculation• ED50

• LD50


Receptors

Receptors

• Mechanism of Action: how a drug works– Drug action

– Drug effect

Receptors

• Drug receptors: proteins present on cell membrane to which a drug must bind in order to elicit a desired response

Receptors

• Receptors are classified based on effects – Agonist– Antagonist

• Competitive antagonist• Noncompetitive antagonist

• A drug attached to a receptor site displays affinity

Receptors

• Efficacy: the power of a drug to produce a therapeutic effect– Agonists have affinity and

efficacy– Antagonists have affinity but not

efficacy

• Drug potency: relative amount of drug required to produce the desired response

Receptors

• How do drugs bind to receptor sites?– Ionic bonds– Hydrogen bonds– Hydrophobic bonds– Van der Waals forces– Covalent bonds

Receptors

• Receptor sites– Several drugs may bind to the same receptor

site, thus creating different responses by the cells

– Two main functions• Ligand binding• Message propagation


Neurotransmitters

Neurotransmitters

• The nervous system is the body’s control system, regulating all bodily function via electrical impulses

• What are the two main parts of the central nervous system that drugs can affect?

Neurotransmitters

• Two divisions:– Central Nervous System (CNS)– Peripheral Nervous System (PNS)

Neurotransmitters

NeurotransmittersOrgan Sympathetic stimulation Parasympathetic stimulation

Heart Increased rate, force

Decreased rate, force

Lungs Bronchodilation Bronchoconstriction

Kidneys Decreased output None

Systemic blood vessels

Constricted – dilated –

None

Liver Glucose release Glycogen synthesis

Blood glucose Increased None

Pupils Dilated Constricted

Basal metabolism Increased up to 100%

None

Skeletal muscle Increased strength None

Neurotransmitters

• Nerves of the autonomic nervous system exit the CNS and enter autonomic ganglia

Neurotransmitters

• No connection exists between two nerve cells or a nerve cell and its target organ; instead there is a space called a synapse

• Neurotransmitters are specialized chemicals that conduct impulses between nerve cells or between a nerve cell and an organ

Neurotransmitters

• Neurotransmitters of ANS:– Acetylcholine (Ach)– Norepinephrine (NE)

• Synapses:– Cholinergic synapses: use acetylcholine– Adrenergic synapses: use norepinephrine

Neurotransmitters

• What is the action of an adrenergic drugs?

• What is the action of a cholinergic drug?

Neurotransmitters

• Sympathetic Nervous System– Arises from the thoracic and lumbar

regions of the spinal cord– Results in direct stimulation of adrenal

medulla and release of norepinephrine (noradrenaline) and epinephrine (adrenaline)

Neurotransmitters

• Sympathetic Nervous System– Stimulation ultimately results in release of

norepinephrine from postganglionic nerves– Sympathetic stimulation also results in

release of epinephrine and norepinephrine from the adrenal medulla

– What is/are the chemical mediators of the SNS?

Neurotransmitters

• Types of sympathetic receptors– What is the action of adrenergic receptors?

• Alpha1 (1)

• Alpha2 (2)

• Beta1 (1)

• Beta2 (2)

– Of dopaminergic receptors?

NeurotransmittersReceptor Actions

alpha1 (1) Peripheral vasoconstriction, increased contractile force, decreased rate

alpha2 (2) Peripheral vasoconstriction

beta1 (1) Increased heart rate, contractile force and automaticity

beta2 (2) Peripheral vasodilation, bronchodilation, uterine smooth muscle relaxation

dopaminergic Renal vasodilation and mesenteric vasodilation

Neurotransmitters

• Sympathomimetics: medications that stimulate the sympathetic nervous system

• Sympatholytics: medications that inhibit the sympathetic nervous system

Neurotransmitters

• The Parasympathetic Nervous System– Arises from the brain stem and sacral

segments of the spinal cord– Synapse in parasympathetic ganglia

– What is/are the chemical mediators of the PNS?

Neurotransmitters

• Stimulation of the parasympathetic nervous system results in:– Pupillary constriction

– Secretion by digestive glands

– Increased smooth muscle activity along GI tract

– Bronchoconstriction

– Reduction in heart rate and contractile force

Neurotransmitters

• Parasympatholytics: medications that block the actions of the parasympathetic nervous system

• Parasympathomimetics: medications that stimulate the parasympathetic nervous system


Homeostasis and Balance

Homeostasis and Balance

• Our bodies require constant regulation in order to maintain balance and control


Drug Names and

References

Drug Names and References

• Drug Classification– Prescription (Rx)

– Over-the-counter (OTC)• Herbal


• Drug Names– Official: generally same as generic name

• meperidine hydrochloride, USP

– Chemical: anatomic and molecular structure• Ethyl 1-methyl-4-phenylisonipecotate

hydrochloride


• Drug Names– Generic: abbreviated version of chemical

name• meperidine hydrochloride

– Trade: name based on chemical name or problem used to treat

• Demerol hydrochloride• What is another term for a drug’s trade name?

Sources of Drug Information

• Using multiple sources may provide the best information

• United States Pharmacopia (USP)• National Formulary (NF)• American Hospital Formulary Service• Physician’s Desk Reference (PDR)• Packaging inserts, as required by law


• A process must be approved by the FDA

• Studies take place in four phases– Preclinical testing, research, and development– Clinical research and development– NDA Review– Postmarketing surveillance


• Bringing a drug to market is a process that takes several years and must be approved by the U.S. Food and Drug Administration (FDA)


• Studies take place in four phases– Preclinical testing, research and development– Clinical research and development– NDA Review– Postmarketing surveillance


• New Drug Development

–Phase I

–Phase II

–Phase III

–Phase IV


• New Drug Development – Orphan Drugs

• Drugs not developed or adopted

Unlabeled Uses of Drugs

• FDA only accepts a new drug for the indications in which phase II and III clinical studies have shown it to be effective.

• Indications approved (labeled)• Not approved (unlabeled)


• Unlabeled uses of drugs– FDA recognizes that a drug’s labeling does

not always contain the most current information on usage


Patient Medication Rights


• What are the six “rights” of patient medication administration that ensure safe, proper, and effective administration?


1. Right patient

2. Right medication

3. Right dose

4. Right route

5. Right time

6. Right documentation


Classifying Medications

AHA Classes of Recommendations for Drug Therapies

• Class I

Benefit >>> Risk

– Procedure/treatment or diagnostic test/assessment should be performed/administered

Table 15-7


• Class IIaBenefit >>RiskIt is reasonable to perform procedure/administer treatment or perform diagnostic test/assessment.

Table 15-7


• Class IIbBenefit RiskProcedure/treatment or diagnostic test/assessment may be considered.

Table 15-7


• Class IIIRisk Benefit Procedure/treatment or diagnostic test/assessment should not be performed/administered. It is not helpful and may be harmful.

Table 15-7


• Class Indeterminate– Research is just getting started– Continuing area of research– No recommendation until further research

(e.g., cannot recommend for or against)

Table 15-7


• Classified with other similar medications with the same effects– Body system/disease used to treat– Chemical group– Receptor binding site


What Paramedics Need to Know About Drugs


• Comprehensive drug list based on protocol– Be familiar with AHA Guidelines for

treating cardiac patients– Know local protocol and drugs used in

your region

Need to Know

• Components of a drug

profile

– Names

– Classification

– Mechanism of action

– Indications

– Pharmacokinetics


• Components of a drug profile– Side effects/adverse reactions

– Contraindications

– Dosage

– How supplied

– Special considerations

Need to Know

• Special considerations in drug therapy– Pediatric patients– Geriatric patients– Pregnant and lactating

patients

Need to Know

• Use care administering medications

• Follow the medication order


• Preparation involves selecting the appropriate sized needle and syringe

• No compensation for dead space is necessary when drawing up medications


• Use different needles when reconstituting medication to be drawn up

• Use caution when mixing drugs in one syringe

• ALWAYS use sterile technique

Need to Know

• Medical control– As a paramedic, you operate under the

licensure of a medical director who is responsible for all of your actions

– The medical director determines which drugs you will administer and the routes by which they are given

Need to Know

• Reduce the potential for contamination

• Identify allergies prior to contacting hospital

• Obtain vital signs

• Obtain and confirm/repeat order

• Write the order and the time

Need to Know

• Select the proper medication

• Inspect the medication

• Confirm the order and medication

• Six rights of administration

• Record drug, dose, volume, route, and time, and obtain vital signs and effects


• Storage and handling considerations– USP28-NF23, PF30 (6), p. 2118

• “Storage of Drugs in Emergency Medical Services (EMS) Vehicles”

• Narcotics and controlled substances should be secured according to local protocols


• Legal regulations, standards, and legislation– International controls

• United Nations World Health Organization provides technical assistance and encourages new research for drug use

Need to Know

• Legal regulations, standards, and legislation– Controls in the U.S.

• Testing (animals studies and clinical patient trials)

• Legislative control

Need to Know

• Legal regulations, standards, and legislation– “Truth in labeling”

• Why might “truth in labeling” be important?

Need to Know

• Legal regulations, standards, and legislation– Narcotics

• Harrison Narcotic Act, 1914• Comprehensive Drug Abuse Prevention and Control

Act, 1970

Schedule of Controlled DrugsCategory Examples

Schedule INo recognized medical use;

high abuse potential

Opiates (heroin), hallucinogens (LSD), depressants (methaqualone)

Schedule IIWritten prescriptions required;

no telephone renewals

Opiates (codeine, morphine, meperidine), stimulants (amphetamines), depressants

Schedule IIIPrescriptions rewritten after six months or five refills

Opiates (codeine <1.8 g/dl), stimulants, depressants, anabolic steroids

Schedule IVPrescriptions rewritten after six months or five refills

Opiates (propoxyphene), stimulants, depressants (chloral hydrate)

Schedule VAny nonnarcotic medication, OTC

Small amounts of opiates when uses as antitussives or antidiarrheals

Need to Know

• Legal regulations, standards, and legislation– Controlled Substances Act, 1970

Need to Know

• Legal regulations, standards, and legislation– Canadian drug legislation

• Under direct control of Department of National Health and Welfare

• Food and Drug Act, 1941• Canadian Food and Drugs Act, 1953

Need to Know

• Legal regulations, standards, and legislation– Canadian Narcotic Control Act and Regulations

• Canadian Narcotic Control Act, 1965– Restricts sale, possession, and use of narcotics– Restricts narcotic distribution to authorized personnel

Need to Know

• Legal regulations, standards, and legislation– Drug Standards

• United States Pharmacopeia (USP) is official standard to maintain uniformity

Need to Know

• Important pharmacological terminology

– What is antagonism?

– What is cumulative action?

– What is potentiation?

– What is synergism?

Need to Know


– Contraindications

– Hypersensitivity

– Idiosyncrasy

– Side effects

– Untoward effects

Need to Know


– Bolus

– Indication

– Therapeutic action

– Tolerance

Need to Know


– Depressant

– Habituation

– Refractory

– Stimulant


Pre- and Postmedication Administration

Procedures

Pre- and Postmedication Administration Procedures

• Premedication procedures– Obtain a complete SAMPLE history– Obtain a full set of vital signs– Complete a detailed exam– Contact medical control for authorization

Pre- and Postmedication Administration Procedures

• Postmedication procedures– Document– Obtain a full set of vital signs– Complete a detailed exam– Ongoing assessment

Summary

• In order to deliver exceptional patient care, the paramedic must have a basic understanding of the responsibilities and scope of management prior to administration of any drug


Classifications

Street Secret

• Most drugs within the same class have the same suffix; this name generally only applies to the generic name– Beta blockers: –olol– Antihyperlipidemics: –statin– ACE inhibitors: –pril– Calcium channel blocker: –ipines– Opiods: –ine, –one

Street Secret

• Shortcut for remembering what types of doses cardiac drugs have (works for all ACLS drugs)– If the drug begins with a consonant, it is a

two-part dose for normal administration:• Lidocaine—mg/kg• Cardizem—mg/kg• Procainamide—mg/min

Street Secret

• Shortcut for remembering what types of doses cardiac drugs have (works for all ACLS drugs)– If the drug begins with a vowel, it is a one-part

dose:• Epinephrine—mg• Adenosine—mg• Atropine—mg

– Note: This does not work for drips

Street Secret

• A key to remembering the doses on ACLS drugs is as easy as taking a pulse– The dose for a patient with a pulse is half that

of a patient without a pulse

• Antiarrhythmics• Adenosine

• Amiodarone

• Lidocaine

• Procainamide

ACLS Medications

• Catecholamine-sympathomimetic

• Epinephrine 1:10,000

• Isoproterenol

ACLS Medications

• Inotrope• Digoxin

• Epinephrine 1:10,000

ACLS Medications

• Vasopressors• Dopamine

• Dobutamine

• Epinephrine 1:1 000

• Norepinephrine

• Vasopressin

ACLS Medications

• Calcium channel blockers

• Diltiazem

• Verapamil

ACLS Medications

• Parasympatholytics• Atropine

ACLS Medications

• Mineral/electrolyte• Calcium chloride

• Magnesium sulfate

• Sodium bicarbonate

ACLS Medications

• Endocrine/metabolic enhancing agent

• Vasopressin

ACLS Medications


• Analgesics–Nonsteroidal anti-inflammatory

agents (NSAID)• Ibuprofen

• Ketorolac


• Analgesics–Narcotics

• Butorphanol

• Fentanyl

• Meperdine

• Morphine sulfate

• Nalbuphine


• Analgesics–Other analgesics

• Acetaminophen


• Anaphylaxis–Antianaphylactic agents

• Epinephrine 1:1 000

• Diphenhydramine

• Hydroxyzine


• Anesthetics– Topical anesthetics

• Benzocaine• Cetacaine• Lidocaine topical gel• Procaine• Proparacaine• Tetracaine


• Anesthetics–Local anesthetics

• Procaine

• Proparacaine

• Tetracaine


• Anesthetics–Inhaled agents

• Nitrous oxide


• Antianginal agents–Nitroglycerine

–Nitroprusside


• Anticoagulants– Heparin– Warfarin sodium


• Anticonvulsants–Anticonvulsants

• Fosphenytoin

• Phenobarbital

• Phenytoin


• Anticonvulsants–Benzodiazepine

• Diazepam

• Lorazepam

• Midazolam


• Antiemetics–Droperidol

–Prochlorperazine

–Promethazine–Hydroxyzine


• Antihypertensives–Antihypertensive

• Clonidine

• Diazoxide


• Antihypertensives–ACE Inhibitor (acetylcholinesterase)

• Enalapril


• Antihypertensives–Calcium channel blocker

• Nifedipine


• Antihypertensives–Vasodilator

• Nitroprusside


• Antihypoglycemics–Dextrose

–Glucagon

–Insulin

–Oral glucose paste


• Antiplatelet agents–Acetylsalicylic

acid (ASA) or aspirin


• Antitoxicologics–Anticholinergic

• Atropine


• Antitoxicologics–Antidote

• Cyanide antidote kit

• Methylene blue

• Physostigmine

• Pralidoxime auto injector


• Beta blockers–Esmolol

–Labetalol

–Metoprolol

–Propranolol


• Diuretics–Diuretic

• Mannitol


• Diuretics–Loop diuretics

• Bumetanide

• Furosemide


• Fibrinolytics– Alteplase

– Antithrombin III

– Heparin

– Reteplase

– Tenectplase

– Urokinase


• Gastric decontaminants– Toxicological agents

• Activated charcoal• Ipecac


• Induction agents–Analgesic

• Ketamine


• Induction agents–Barbiturate

• Methohexital

• Thiopental


• Induction agents–Benzodiazepine

• Midazolam


• Induction agents–Hypnotic

• Etomidate


• Induction agents–Opiate

• Fentanyl


• Narcotic and benzodiazepine antagonists–Flumazenil

–Naloxone

–Nalmefene


• Nasal decongestants– Oxymetazoline

nasal – Phenylephrine

nasal


• Neuroleptics–Antipsychotics

• Chlorpromazine

• Haloperidol


• Neuroleptics–Antiemetic

• Droperidol


• Paralytics– Neuromuscular blocking agents (NMBA)

• Depolarizing– Succinylcholine

• Nondepolarizing– Mivacurium– Pancuronium– Vecuronium


• Postpartum agents–Oxytocin


• Respiratory agents–Bronchodilators

• Sympathomimetic (adrenergic)– Beta2 selective

» Albuterol» Isoetharine» Terbutaline



• Sympathomimetic (adrenergic)– Nonselective

» Epinephrine » Epinephrine (inhaled)» EpiPen Autoinjector/EpiPen Jr» Metaproterenol» Racemic epinephrine



• Combination agents– Albuterol/ipratoprium

combination



• Methylxanthine (xanthine) derivative– Aminophylline


• Respiratory agents– Bronchodilators

• Parasympatholytic (anticholinergic)

– Ipratoprium


• Steroids–Dexamethasone

–Hydrocortisone

–Prednisone

–Methylprednisolone sodium succinate


• Tocolytics–Magnesium sulfate

–Terbutaline


• Vasopressors–Adrenergics

–Sympathomimetics

–Catecholamines


• Vitamins and electrolytes– Calcium chloride

– Calcium gluconate

– Magnesium sulfate

– Potassium chloride

– Sodium bicarbonate

– Thiamine

Documents

© 2006 The McGraw Hill Companies Pharmacology. © 2006 The McGraw Hill Companies Introduction