General Pharmacology

Chapter 16Chapter 16

Drugs are chemicals used to diagnose, treat, and prevent

disease.

Medication Forms Used by the EMT-Basic

Compressed powders or tablets (e.g., nitroglycerin)

Liquids for injection (e.g., epinephrine)

Gels (e.g., glucose)

Suspensions (e.g., activated charcoal)

Fine powder for inhalation

Gases (e.g., oxygen)

Aerosol or spray (e.g., nitroglycerin)

Names of Drugs

Chemical States its chemical composition and molecular

structure

Generic Usually suggested by the manufacturer

Official As listed in the U.S. Pharmacopeia

Brand The trade or proprietary name

Medication NamesGeneric Name listed in the U.S.

Pharmacopoeia Name assigned to drug before

it becomes officially listed Usually a simple form of the

chemical name

Trade Brand name manufacturer

uses in marketing the drug

Medication TermsIndications Most common uses of the

drug

Contraindications Situations in which a drug

should not be used May cause harm to the

patient May have no effect in

improving the patient's condition

Medication Terms

Dose How much of the drug should be given

Administration Route by which the medication is

administered

Actions Desired effects a drug has on the

patient/body systems

Medication Terms

Side effects Actions of a drug

other than those desired

DoseMetric Conversions

Kilograms Grams Milligrams Micrograms

1 kg 1000 g

1 g 1000 mg

1 mg 1000 g

DoseMetric Conversions

Liters Milliliters

1 L 1000 mL

0.5 L 500 mL

0.1 L 100 mL

0.01 L 10 mL

0.001 L 1 mL 1 L1000 mL

Legal

Knowing and obeying the laws and regulations governing medications and their administration is an important part of an EMT’s career.

These include federal, state, and agency regulations.

Federal

Pure Food & Drug Act of 1906

Harrison Narcotic Act of 1914

Federal Food, Drug, & CosmeticAct of 1938

Comprehensive Drug AbusePrevention & Control Act of 1970

State vs. Local Standards

They vary widely.

Always consult local protocols and with medical direction for guidance in securing and distributing controlledsubstances.

New Drug Development

Components of a Drug Profile

Name Generic, trade

Classification

Mechanism ofAction

Indications

Pharmacokinetics

Side Effects/adverse reactions

Routes ofAdministration

Contraindications

Dosage

How Supplied

SpecialConsiderations

Providing Patient Care Using Medications

Have current medication referencesavailable.

Take careful drug histories including: Name, strength, dose of prescribed medications Over-the-counter drugs Vitamins Herbal medications Allergies

Providing Patient Care Using Medications

Evaluate the patient’s compliance, dosage, and adverse reactions.

Consult with medical direction as needed.

Seven “Rights” of Medication Administration

Right medication

Right dosage

Right time

Right route

Right patient

Right documentation

Right to refuse

De-Mystifying Pharmacology

Drugs do not do anything new. They can only alter functions that are

already occurring in the body.Replace a function, enhance a function or

interrupt a function

Drugs will always leave residual effects.Even selective-site drugs!

Albuterol and muscle tremors

De-mystifying Pharmacology

Drugs usually have to bind to something before anything can occur.Antacids bind to receptors in the stomachMorphine binds to euphoria receptors,

nausea and vessel control receptors in the brain

Pediatric Considerations

Dosages must be administered based on body weight.

Patient may have difficulty with inhalation. Consider spacer or extension tubing

Patient may be reluctant to take medication. Enlist patient/parent cooperation

Geriatric Considerations

Patient may take several medications. Prone to adverse effects, drug interactions,

inadvertent overdose

When possible, transport all medications to hospital with patient. May help hospital staff diagnose and manage

patient condition

Absorption RatesOral

Subcutaneous

Topical

Intramuscular

Sublingual

Rectal

Endotracheal, Inhalation, IO, IV

Intracardiac

Reassessment Strategies

After drug administration, reassess patient for: Therapeutic effects Side effects Noticeable changes in patient condition

Document time of administration

Document times of ongoing assessments Vital signs Changes in patient condition Therapeutic or side effects

Cells talk to each other

Three distinct languagesNervous system

neurotransmittersEndocrine system

hormones Immune system

cytokines

In disease, all systems are affected

The three systems can’t exist without each otherThe actions of one impact the actions of the othersI.e., stress (nervous system) disrupts endocrine system which may respond with glucocorticoid production = suppressed immune response

Drug Classifications

Drugs are classified 3 different ways:By body systemBy the action of the agentsBy the drug’s mechanism of action

Drug Class ExamplesNitroglycerin Body system: “Cardiac drug” Action of the agent: “Anti-anginal” Mechanism of action: “Vasodilator”

Indications for nitroglycerin Cardiac chest pain Pulmonary edema Hypertensive crisis

Which drug class best describes this drug?

Medications Carried on the EMS Unit Activated Charcoal

Used for toxic ingestion

Binds to certain poisons

Prevents absorption

Not all brands are the same. Some bind much more poison. Consult medical direction about the brand to use

Medications Carried on the EMS Unit Oral Glucose

Used for altered mental status, suspected hypoglycemia

Absorbed in the oral mucosa

Provides needed glucose for patient with low blood sugar

Medications Carried on the EMS Unit Oxygen

Increases oxygen delivery to blood

Essential treatment for hypoxia and hypoperfusion

% of delivered oxygen (dose) determined by flow rates and delivery device

Medications carried on the EMS unit Epinephrine

Used to treat severe allergic reaction

Blocks release of histamine

Increases vascular resistance to maintain blood pressure

Epinephrine AbsorptionWhat is the concentration and dosing time for subcutaneous and IV epinephrine? SQ - 1:1000 with repeat doses every 3-5 minutes

Why is there a need for 2 different concentrations? Epinephrine is a short-lived drug and will break down

quickly SQ absorption is significantly slower than IV A higher concentration of the drug will assure that

enough of the active drug will still be available after it is absorbed

Medications carried on the EMS unitAspirin

ActionProduces analgesia Reduces inflammation and fever by

inhibiting the production of prostoglandinsDecreases platelet aggregation

Aspirin

For cardiac chest pain

Usual dose81 mg x 3 or 4 (243 – 324 mg) pochewable

New Info!New England Journal of Medicine, 3/05

Men 50 y/o or more (no clinical evidence of coronary disease).

ASA - Risk of MI 44% less

No significant effect on risk of stroke and no effect on mortality from cardiovascular causes

Women 65 y/o or more (no history of cardiovascular disease)ASA - No significant effect on risk of MI or risk of death from cardiovascular causesBUT 24% reduction in risk of ischemic stroke and 17% reduction in stroke risk overall

Conclusion of study

• Women < 65 y/o• Reasonable to avoid prescribing low-dose

aspirin (75-100mg) as a preventative measure for coronary disease

• Rx for stroke – left to pt and Dr

Drugs carried on the EMS unit

Activated CharcoalTo treat poison ingestionActs externally to the surface of the bowel

to adsorb toxins from the mucosa Increases drug diffusion rate from plasma into

GI tract for absorption

Medications EMT-Basic May Assist Prescribed Inhalers

Used to treat bronchoconstriction

Prescribed by patient’s physician

Administration is approved by medical direction and/or by local protocol.

May be carried in the ambulance in some EMS systems

AlbuterolCauses bronchodilation by acting on B-2

receptors (B-agonist)

Atrovent (Ipratroprium)Causes bronchodilation by inhibiting

acetylcholine at receptor sites on bronchial smooth muscle

Medications EMT-Basic May Assist Nitroglycerin

Used to treat ischemic chest pain

Dilates vessels to improve circulation through the coronary arteries

Decreases the workload of the heart by dilating peripheral vessels

Administered under the tongue by tablet or spray

Nitroglycerin

How does the drug come packaged?As a tablet, spray, ointment, liquid (IV)

Nitroglycerin forms and absorption ratesSL: 1-3 minutesOintment/transdermal: 30 minutes IV: immediate!

SummaryMedications play a critical role in EMS.

Care must be taken to assess patients to identify the need for medication.

Be familiar with the indications, contraindications, and side effects of administered medications.

Always contact medical direction and/or follow local protocols.

Remember the “rights” of medication administration.