Principles of Pharmacology

Principles of Pharmacology

Introduction

• Medications are a crucial part of emergency intervention.

• They can effectively reduce pain and enhance the patient's overall condition.

• However, improper or incompetent administration can have dire outcomes, including fatality.

How Medications Work

• Pharmacology: The study of drugs.

• Medication: A substance that:

  • Prevents or treats disease

  • Relieves pain

• Pharmacodynamics: How the medication affects the body.

• Agonist: Stimulates receptors.

• Antagonist: Blocks receptors from other medications or chemicals.

• Dose: The amount of medication given.

• Action: The expected therapeutic effect on the body.

• Pharmacokinetics: How the body affects the medication.

  • Onset of action

  • Duration

  • Elimination

  • Peak

• Factors Affecting Medication:

  • Route of administration

  • Shock

• Indications: Reasons or conditions for use.

• Contraindications: Harmful effects.

  • Absolute

  • Relative

• Adverse Effects Unintended effects

• Untoward Effects

Medication Names

• Generic Name: Simple, nonproprietary name (e.g., ibuprofen).

• Trade Name: Manufacturer's brand name (e.g., Tylenol).

• A drug can have multiple trade names.

• Types:

  • Prescription medications

  • Over-the-counter (OTC) medications

  • Recreational drugs

  • Herbal remedies

  • Enhancement drugs

  • Vitamin supplements

  • Alternative medicines

Routes of Administration

• Enteral: Enters through the digestive system.

• Parenteral: Enters by other means.

• Absorption: Medication travels through tissues to the bloodstream.

• Common Routes:

  • Per rectum (PR)

  • Oral or per os (PO)

  • Intravenous (IV)

  • Intraosseous (IO)

  • Subcutaneous (SC)

  • Intramuscular (IM)

  • Inhalation

  • Sublingual (SL)

  • Transcutaneous (transdermal)

  • Intranasal (IN), via mucosal atomizer device

Medication Forms

• Form dictates the route of administration.

• The manufacturer chooses the form to ensure:

  • Proper route

  • Timing of release

  • Effects on target organs

Tablets and Capsules

• Capsules: Gelatin shells filled with powder or liquid.

• Tablets: Contain medication mixed and compressed with other materials.

Solutions and Suspensions

• Solution: Liquid mixture that doesn't separate.

  • Can be given as IV, IM, or SC injection

• Suspension: Doesn't dissolve well in liquid and will separate.

Metered-Dose Inhalers (MDI)

• Liquids/solids in droplets or particles for inhalation.

• Delivers a consistent amount with each use.

Topical Medications

• Lotions, creams, and ointments.

• Applied to the skin to affect only that area.

  • Lotion: calamine lotion

  • Cream: hydrocortisone cream

  • Ointment: Neosporin ointment

Transcutaneous Medications

• Absorbed through the skin (transdermal).

• Can have systemic effects.

• Can be absorbed by the person administering it.

Gels

• Semiliquid, administered in capsules or tubes.

• Example: Oral glucose for diabetics.

Gases for Inhalation

• Delivered via nonrebreathing mask or nasal cannula.

• Commonly used: Oxygen.

General Steps in Administering Medication

• Administer only with medical control authorization.

• Follow the “rights” of medication administration.

• Medication errors usually happen when these “rights” are not followed.

Medication Administration and the EMT

• Circumstances for administration:

  • Peer-assisted

  • Patient-assisted

  • EMT-administered

• Determined By:

  • State and local protocols

  • Medical control

Oral Medications

• Confirm a patent airway and ability to swallow.

• Instruct the patient to swallow or chew the medication.

Oral Glucose

• A sugar for energy.

• Treats hypoglycemia.

• Given only by mouth and not to unconscious patients.

Aspirin

• Reduces fever, pain, and inflammation.

• Inhibits platelet aggregation.

• Useful in heart attack.

• Contraindications:

  • Hypersensitivity

  • Liver damage

  • Bleeding disorder

  • Asthma

  • Not for children

Sublingual Medications

Advantages

• Easy to advise patients

• Quick absorption

Disadvantages

• Constant evaluation of the airway is needed

• Risk of choking

• Not for uncooperative or unconscious patients

Nitroglycerin

• Relieves angina pain.

• Increases blood flow and relaxes veins.

• Before administering:

  • Check blood pressure.

  • Obtain order to administer.

  • Consider MI if no relief.

  • Avoid with erectile dysfunction medications.

  • May cause mild headache.

Administration

• Tablet: Under the tongue, tingling or burning sensation.

• Spray: On or under the tongue; one spray = one tablet.

• Administration considerations (for both tablet and spray):

  • Wait 5 minutes before repeating.

  • Monitor vital signs.

  • Wear gloves.

  • Follow local protocols.

Intramuscular Medications

Advantages

• Quick, easy access without using a vein

• Stable blood flow to muscles

Disadvantages

• Use of a needle

• Patients may fear pain or injury.

Epinephrine

• Controls fight-or-flight response (sympathomimetic).

• Primary IM medication.

• Increases heart rate and constricts blood vessels.

• Do not give to patients with:

  • Hypertension

  • Hypothermia

  • MI

  • Wheezing

• May be delivered with an auto-injector for anaphylaxis.

Naloxone

• Reverses opioid overdose.

• Considerations:

  • Consult medical direction.

  • Effects may not last as long as opioids; may need repeated doses.

  • Can cause severe withdrawal symptoms.

  • Consider your safety.

Intranasal Medications

• Naloxone is commonly administered intranasally.

Inhalation Medications

Oxygen

• All cells need it to survive.

• Administered via:

  • Nonrebreathing mask

  • Nasal cannula

MDIs and Nebulizers

• Liquid turned into mist or spray.

• Medication delivered to alveoli.

• Fast absorption rate.

• Easy route to access.

• Portable.

Spacer Use

• Avoid spray misdirection.

• Patient sprays into chamber and breathes in and out of mouthpiece.

• Especially useful with young children.

Small-Volume Nebulizers

• Easier to use than MDIs.

• Take longer to deliver medication.

• Require external air or oxygen source.

• More effective in moderate to severe respiratory distress.

• Can be used with CPAP and bag-mask ventilation.

Patient Medications

• Assess patient medications.

• Provides clues to the patient’s condition.

• Guides treatment.

• Useful to the emergency department.

• Do not underestimate the importance of obtaining a thorough medication history.

• Medications are often not taken as prescribed.

• Medications may alter the clinical presentation.

Medication Errors

• Inappropriate medication use that could lead to patient harm.

• Minimize errors by understanding circumstances.

• Ensure the environment does not contribute to errors.

• Response to errors:

  • Provide patient care.

  • Notify medical control.

  • Follow protocols.

  • Document thoroughly, accurately, and honestly.

  • Talk with your partner, supervisor, or medical director.