Principles of Pharmacology for Emergency Medical Technicians
Unit Summary and National EMS Education Standard Competencies
This chapter introduces the fundamental principles of pharmacology relevant to Emergency Medical Technicians (EMTs). Upon completion, students will grasp the significance and characteristics of general pharmacology, and will be proficient in identifying, describing, and demonstrating the procedures for assisting patients with and administering medications carried by EMTs.
The National EMS Education Standard Competencies specifically address pharmacology, emphasizing the EMT's application of foundational knowledge regarding medications they may assist with or administer during emergencies. This includes:
Medication Safety (pp. 461–463)
Kinds of Medications Used During an Emergency (pp. 464–475)
Regarding Medication Administration, competencies cover:
Self-administer Medication (pp. 463–464)
Peer-administer Medication (pp. 463–464)
Assist/Administer Medications to a Patient (pp. 463–464)
Key aspects of Emergency Medications that EMTs must understand include:
Names (p. 456)
Effects (pp. 455–456)
Actions (p. 455)
Indications (p. 456)
Contraindications (p. 456)
Complications (p. 456)
Routes of Administration (pp. 456–458)
Side Effects (p. 456)
Interactions (pp. 465–466, 475–476)
Dosages for Administered Medications (pp. 455, 462, 465–466)
Knowledge and Skills Objectives
Knowledge Objectives Guide
Define Terms: Understand pharmacodynamics, intended effects, indications, side effects, unintended effects, and untoward effects (pp. 455–456).
Medication Contraindications: Explain what they are and provide an example (p. 456).
Medication Names: Differentiate between generic and trade names, providing an example for each (p. 456).
Routes of Administration: Distinguish between enteral and parenteral routes (p. 456).
Specific Routes: Describe rectal, oral, intravenous, intraosseous, subcutaneous, intramuscular, inhalation, sublingual, and transcutaneous routes, including their absorption rates (pp. 457–458).
Medication Forms: Explain solid, liquid, and gas forms, their routes of administration, and provide examples (pp. 459–461).
"Six Rights" of Administration: List and explain each of the "six rights" and their relevance to EMS (pp. 461–463).
Medical Control: Explain the differences between direct orders (online) and standing orders (offline) and the role of medical control (p. 463).
Administration Circumstances: Discuss peer-assisted, patient-assisted, and EMT-administered medication scenarios (pp. 463–464).
EMT Medications: Know the generic and trade names, actions, indications, contraindications, routes, side effects, interactions, and doses for emergency medications an EMT may administer, as per state protocols and local medical direction (pp. 463–475).
Special Populations: Describe medication administration considerations for pediatric, geriatric, and pregnant patients (pp. 464, 472–473).
Auto-injector Steps: State the steps for dispensing medications using an auto-injector (p. 471).
Patient Assessment: Explain why determining a patient's prescription and OTC medications is critical during an emergency (pp. 475–476).
Medication Errors: State the steps to take if a medication error occurs (p. 477).
Skills Objectives Guide
Application of "Six Rights": Apply the six rights of medication administration (pp. 461–463).
Oral Medication: Demonstrate how to administer oral medication to a patient (pp. 464, 467–468).
Aspirin Administration: Demonstrate how to administer aspirin to a patient with chest pain (p. 468).
Oral Glucose Administration: Demonstrate how to administer oral glucose to a patient with hypoglycemia (p. 468).
Sublingual Assistance: Demonstrate how to assist a patient with sublingual medication administration (p. 468).
Auto-injector Administration: Demonstrate how to administer a medication by auto-injector (p. 471).
Intranasal Administration: Demonstrate how to administer an intranasal medication (pp. 471–472).
Introduction to Pharmacology for EMTs
Medications are a pivotal intervention available to EMTs. When utilized appropriately, they can effectively alleviate pain and significantly improve a patient's condition. Conversely, the unsafe or incompetent administration of medications carries severe risks for the patient, potentially resulting in death.
As an EMT, your responsibilities regarding medications will include:
Directly administering medications.
Assisting patients in self-administering their own medications.
Inquiring about patients' medication use and any known allergies.
Accurately reporting patients' medication information to hospital personnel.
How Medications Work: Medical Definitions
Understanding Key Pharmacological Terms
Pharmacology: This is the scientific study of drugs, encompassing their ingredients, preparation methods, various uses, and their specific actions on the human body.
Medication: A substance specifically used to treat or prevent a disease, or to relieve a patient's pain.
Pharmacodynamics: This term describes the dynamic process by which a medication influences the body. Medications can either enhance (increase) or suppress (decrease) a normal bodily function.
Agonist: A medication classified as an agonist operates by stimulating specific receptors within the body.
Antagonist: In contrast, an antagonist medication binds to a receptor site and subsequently blocks other medications or naturally occurring chemicals from attaching to that site.
Dose: Refers to the precise amount of medication that is administered. The appropriate dose is determined by several factors, including the patient's weight, age, and the desired therapeutic action of the medication.
Action: This term defines the intended therapeutic effect that a particular medication is expected to have on the body.
Indications: These are the specific reasons or conditions for which a given medication is deemed appropriate and should be administered.
Contraindications: A contraindication exists when a medication should not be given because it would either cause harm to the patient or produce no positive effect.
Absolute Contraindications: These are conditions under which the medication should never be given.
Relative Contraindications: These are situations where the potential benefits of administering the drug might outweigh the associated risks.
Side Effects: These are any effects of a medication other than the primary desired therapeutic actions.
Unintended Effects: These are undesirable effects, but they typically pose little to no significant risk to the patient.
Untoward Effects: These are effects that are inherently harmful or potentially dangerous to the patient's well-being.
Medication Names
Generic Name: This is a simple, clear, nonproprietary name given to a drug. Generic names are generally not capitalized. For example, the generic name for Tylenol is acetaminophen.
Trade Name (Brand Name): This is the specific brand name a manufacturer assigns to a drug. Trade names always begin with a capital letter. For example, Tylenol, Lasix. It is common for a single generic drug to be marketed under multiple trade names.
Prescription Drugs: These are medications available only through pharmacists and require a physician's written order.
Over-the-Counter (OTC) Drugs: These medications can be purchased directly by consumers without a prescription.
Other Kinds of Drugs: This category includes recreational drugs (e.g., heroin, cocaine), herbal remedies, enhancement drugs, and vitamin supplements. It is crucial to remember that any substance a patient takes can be pharmacologically active and exert an effect. Therefore, EMTs must inquire about all medications or drugs a patient is taking.
Routes of Administration
Medications traverse body tissues to reach the bloodstream through a process called absorption.
Enteral Medications
These medications enter the body via the digestive system. They are often available in pill or liquid form, such as cough medicine. Medications administered this way typically absorb slowly and are less commonly used in acute emergency settings due to their delayed onset of action.
Parenteral Medications
These medications enter the body through means other than the digestive system. They are frequently in liquid form and administered via needles or syringes. Parenteral routes result in quicker absorption and offer a more predictable and measurable physiological response.
Common Routes of Administration and Absorption
Per Rectum (PR): Administered "by rectum." This route is easy to use and provides reliable absorption, particularly useful for pediatric patients or those who are nauseated or vomiting.
Oral (PO): Administered "by mouth." Medications travel through the digestive system. Absorption via this route can take as long as hour.
Intravenous (IV) Injection: Administered "into the vein." This is the fastest method of drug delivery as it goes directly into the bloodstream, but it cannot be used for all medications.
Intraosseous (IO) Injection: Administered "into the bone." Medications reach the bloodstream through the bone marrow. This route requires drilling a needle into the outer layer of the bone, typically used in critical emergencies when IV access is not possible.
Subcutaneous (SC) Injection: Administered "beneath the skin." The injection is given into the fatty tissue located between the skin and muscle. Absorption is generally slower than IM.
Intramuscular (IM) Injection: Administered "into the muscle." This route usually results in quick absorption due to good blood flow in muscular tissue. However, not all medications can be given via the IM route. Examples include the EpiPen auto-injector and the Mark-1 auto-injector.
Inhalation: Medications are breathed into the lungs and are quickly absorbed into the bloodstream through the vast surface area of the alveoli. Forms include aerosols, fine powders, and sprays.
Sublingual (SL): Administered "under the tongue." The medication enters the bloodstream within minutes through the rich vascular network of the oral mucosa beneath the tongue. A common example is nitroglycerin tablets.
Transcutaneous (Transdermal): Administered "through the skin." Medications are applied as a patch to the skin's surface and are designed for a longer-lasting effect compared to many other routes. Examples include nicotine patches and nitroglycerin patches.
Intranasal (IN): A relatively new method of medication delivery. The medication is delivered into the nostril as an aerosolized liquid, pushed through a device called a mucosal atomizer device (MAD). This route allows for quick absorption. Examples include the flu vaccine and naloxone.
Medication Forms
The physical form of a medication typically dictates its route of administration. Manufacturers select specific forms to ensure the proper route, optimal timing of the medication's release into the bloodstream, and effective targeting of specific organs or body systems.
Tablets and Capsules: Most orally administered medications are either in tablet or capsule form. Capsules are gelatin shells filled with powdered or liquid medication. Tablets are compressed mixtures of medication and other materials.
Solutions and Suspensions:
Solution: A liquid mixture where one or more substances are completely dissolved and cannot be separated by simple means (e.g., filtering). Solutions can be administered by almost any route (oral, IV, IM, SC). Oral solutions are absorbed relatively quickly because the medication is already dissolved.
Suspension: A mixture of finely ground particles evenly distributed throughout a liquid. Unlike solutions, these particles do not dissolve and will separate if left to stand or filtered. It is critical to shake or swirl a suspension thoroughly before administration to ensure even distribution of the medication.
Metered-Dose Inhalers (MDIs): These devices deliver liquids or solids broken into tiny droplets or particles directly into the lungs when inhaled. A spray canister directs the substance through the mouth and provides a consistent, measured amount of medication with each use. MDIs are commonly used for respiratory conditions such as asthma or emphysema.
Topical Medications: This category includes lotions, creams, and ointments. They are applied to the skin's surface and are primarily intended to affect only the localized area where they are applied.
Transcutaneous Medications (Transdermal): Also absorbed through the skin, but unlike topical medications, transcutaneous preparations usually have systemic (whole-body) effects. Examples include nitroglycerin paste or patches. EMTs must exercise caution as they can also absorb these medications through skin contact.
Gels: Gels are semiliquid medications administered in capsules or through plastic tubes. An example is oral glucose, used for patients with diabetes.
Gases for Inhalation: These medications are typically delivered via a nonrebreathing mask or nasal cannula. Oxygen is the most frequently administered medication in gas form outside of operating rooms.
General Steps in Administering Medication: The "Six Rights"
Medications should only be administered under the explicit authorization of either online (direct) or offline (standing) medical direction.
To ensure patient safety and prevent medication errors, EMTs must meticulously follow the "six rights" of medication administration:
Right Patient: Always verify that the individual receiving the medication is indeed the patient for whom it is prescribed.
Right Medication: Confirm the correct medication and ensure it matches the prescription or protocol.
Right Dose: Double-check the appropriate form and exact dose of the medication.
Right Route: Verify the correct pathway for administration (e.g., oral, sublingual, intramuscular).
Right Time: Inspect the medication's expiration date and assess its overall condition (e.g., clarity of solution, intact packaging).
Right Documentation: Accurately and thoroughly document your actions, including the medication given, time, dose, route, and the patient's response to the medication.
It is imperative to understand that medication errors are almost invariably a result of failing to adhere to one or more of these "six rights."
Medication Administration and the EMT
Over time, EMTs have been granted increasing responsibility concerning medication administration. However, most departments operate with strict guidelines dictating when an EMT is permitted to administer specific medications.
Medication administration circumstances involving EMTs fall into three main categories:
Peer-Assisted Medication: This occurs when you administer medication to yourself or your partner. An example might be administering an antidote following exposure to a toxic agent.
Patient-Assisted Medication: In this scenario, you assist the patient in administering their own prescribed medication. Common examples include helping a patient use an epinephrine auto-injector, take nitroglycerin, or operate a metered-dose inhaler.
EMT-Administered Medication: This is when the EMT directly administers the medication to the patient. This is often necessary when the patient is severely confused or unable to understand the need for the medication. Examples of EMT-administered medications include oxygen, oral glucose, and aspirin.
An EMT's scope of practice regarding medication administration is strictly determined by medical control, state guidelines, and local protocols. It is essential to refer to your local standards for a comprehensive listing of how and when EMTs in your system can administer medications.
Medications Used by EMTs
Oral Medications
Considerations:
Advantages: Ease of access is a primary benefit.
Disadvantages: The digestive tract's absorption can be easily influenced by food, stress, and underlying illnesses.
Activated Charcoal:
Action: Primarily used for poisonings involving oral ingestions. Activated charcoal works by a process called adsorption, where it binds the ingested drug to its surface, thereby reducing the amount of medication absorbed by the body.
Form/Administration: Frequently suspended with sorbitol, a sugar that acts as a laxative, which helps move the charcoal-bound medication quickly through the digestive system. It is administered by mouth and can be unappealing to patients; therefore, using a covered container and a straw is recommended. Note that it can stain clothing.
Contraindications: Should not be given to patients with an altered level of consciousness due to the significant risk of aspiration. It is also contraindicated if the patient has ingested an acid, an alkali, or a petroleum product, as it may be ineffective or hinder treatment.
Oral Glucose:
Action: Glucose is a vital sugar that cells use for energy, especially crucial for brain cell function. Oral glucose is administered to counteract the effects of hypoglycemia (extremely low blood glucose levels).
Form/Administration: An EMT can administer glucose only by mouth. It is available as a gel designed to be spread on the mucous membranes between the cheek and gum, or as glucose tablets.
Contraindications: Never administer oral medications, including oral glucose, to an unconscious patient or to one who is unable to swallow or protect their airway.
Aspirin:
Action: Aspirin effectively reduces fever, pain, and inflammation. Most critically, it inhibits platelet aggregation (clumping), making it extremely useful during a suspected heart attack to prevent further clot formation.
Contraindications: Patients with hypersensitivity to aspirin, preexisting liver damage, bleeding disorders, or asthma. Aspirin should generally not be given to children due to the risk of Reye's syndrome.
Sublingual Medications
Considerations:
Advantages: This route is easy to use with awake and alert patients by advising them to place a pill under their tongue. Absorption is relatively quick.
Disadvantages: Any medication placed in the mouth necessitates constant evaluation of the patient's airway. It should not be used if the patient is uncooperative or unconscious.
Nitroglycerin:
Action: Many cardiac patients carry fast-acting nitroglycerin to alleviate angina pain. Nitroglycerin increases blood flow by relieving spasms and dilates (relaxes) the muscles of the coronary arteries and veins. It also relaxes veins throughout the body, leading to less blood returning to the heart, which decreases the heart's workload and lowers blood pressure.
Pre-Administration: Before administering nitroglycerin, check the patient's blood pressure. If the systolic blood pressure is less than , nitroglycerin can have harmful effects, potentially causing a dangerous drop in blood pressure. Even patients with adequate blood pressure should sit or lie down with their head elevated before taking this medication to prevent fainting. If a significant drop in blood pressure occurs and the patient feels dizzy or sick, have them lie down promptly. Always obtain a medical order or follow local protocols for administration.
Interactions: Nitroglycerin can have potentially fatal interactions with erectile dysfunction (ED) medications if taken within the past hours. These include sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra). It's important to remember that ED drugs may be used by both men and women.
Administration by Tablet: Place the tablet under the tongue, where it will dissolve. The patient should experience a slight tingling or burning sensation, indicating potency. Tablets should be stored in their original glass container with the cap screwed on tightly to protect potency.
Administration by Metered-Dose Spray: This method deposits medication on or under the tongue. One spray is typically equivalent to one tablet.
Protocols: Always know and follow your local protocols concerning nitroglycerin administration.
Intramuscular Medications
Considerations:
Advantages: Provides quick and easy access to the circulatory system without the need for placing a needle within a vein. Blood flow to the muscles is relatively stable, even in severe illness or injury.
Disadvantages: Involves the use of a needle and can cause subsequent pain.
Epinephrine (Adrenaline):
Action: Also known as adrenaline, epinephrine is a hormone released by the body during sudden stress. It is the main hormone controlling the body's fight-or-flight response and is a sympathomimetic (mimicking the sympathetic nervous system).
Effects: Increases heart rate, constricts blood vessels (leading to increased blood pressure), and dilates passages in the lungs.
Indications: Should only be given to patients experiencing a life-threatening allergic reaction (anaphylaxis).
Administration: Epinephrine may be dispensed from an auto-injector, which automatically delivers a preset amount of the medication (usually ). Some services may not permit EMTs to carry epinephrine but may allow them to assist patients in administering their own prescribed epinephrine.
Intranasal Medications
Naloxone:
Action: Used specifically to reverse the profound effects of an opioid overdose by displacing opioids from their receptors.
Administration: The most common technique for naloxone administration in the prehospital setting is via the intranasal route. The EMT should place the atomizer in one nostril, pointing it upward and slightly outward. A half dose ( maximum) should be administered into each nostril.
Inhalation Medications
Oxygen:
Action: Oxygen is by far the most commonly administered medication in the prehospital setting. All cells, particularly those in the heart and brain, require adequate oxygen to function properly and survive.
Administration: Generally administered via a nonrebreathing mask at to or via a nasal cannula at to . If the patient is not breathing, artificial ventilations must be provided using a bag-valve mask (BVM) at .
Safety: Ensure that there are absolutely no open flames, lit cigarettes, or sparks in the area where oxygen is being administered due to the risk of combustion.
Metered-Dose Inhalers (MDIs) and Nebulizers:
Action: These devices are used to administer liquid medications that have been transformed into a fine mist by a flow of air or oxygen. The medication is atomized, breathed into the lungs, and delivered directly to the alveoli.
Advantages: A fast and relatively easy route to access the respiratory system.
Disadvantages: Requires the patient to be cooperative and able to control their breathing effectively. Cannot be used for unconscious patients.
MDI Administration: MDI use often requires a significant amount of coordination, which can be particularly difficult for a person experiencing trouble breathing. To mitigate this, a spacer (adapter) can be used to prevent spray misdirection. A spacer fits over the inhaler like a sleeve, with an opening for the inhaler at one end and a mouthpiece on the other. The patient sprays the prescribed dose into the chamber and then breathes in and out of the mouthpiece until the mist is completely inhaled.
Rescue Inhalers: Only fast-acting rescue inhalers, such as albuterol (Proventil or Ventolin), will be effective during an acute attack of shortness of breath.
Patient Medications
Patient assessment must always include thoroughly inquiring about all medications the patient is currently taking. This information is vital as it provides crucial clues to the patient's current condition, helps to guide your treatment decisions, and is extremely useful to the emergency department physician upon arrival. Knowing a patient's medication regimen can also help you identify a chronic or underlying medical condition when the patient is unable to relate their full medical history.
It is imperative to discover what prescription medications the patient takes and to transport either the actual medications or an accurate list of them with you to the emergency department. Additionally, always ask about any nonprescription drugs, including over-the-counter (OTC) medications, herbal remedies, or any illegal drugs or substances the patient may be using.
Medication Errors
A medication error is defined as any inappropriate use of a medication that has the potential to lead to patient harm.
Preventing Errors
To minimize the risk of medication errors, ensure that the environment is conducive to safe practice:
Ensure lighting is sufficient.
Organize all equipment efficiently.
Limit distractions as much as possible.
Consider using a "cheat sheet" or checklist to help remember all crucial steps in medication administration.
Steps to Take if a Medication Error Occurs
If a medication error inadvertently takes place, follow these critical steps:
Patient Care: Rapidly provide any appropriate patient care that is required to address the consequences of the error.
Medical Control Notification: Notify medical control as quickly as possible to report the incident and receive guidance.
Local Protocols: Follow your local protocols meticulously regarding medication errors and incident reporting.
Documentation: Document the incident thoroughly, accurately, and honestly. Include all details of the error and the patient's response.
Supervisor/Medical Director Discussion: Talk with your supervisor or medical director. This represents a crucial opportunity both to learn from the error and to identify areas for improvement within your quality improvement processes.
Enhancements and General Teaching Considerations
Readings and Preparations
Review all instructional materials, including "Emergency Care and Transportation of the Sick and Injured, Eleventh Edition, Chapter 11," and all related presentation support materials.
Support Materials
Lecture PowerPoint presentation
Case Study PowerPoint presentation
Equipment necessary to perform the psychomotor skills presented in this chapter
Samples of medications an EMT might encounter in a home setting (e.g., medication inserts, labels, OTC bottles/boxes, old prescription bottles with patient names blocked out)
Samples of medications carried by the local EMS agency
Enhancements
Direct students to visit Navigate 2 for additional resources.
Contact a local pharmacist to obtain current literature and package inserts for medications approved for EMTs to administer or assist in administering. Use these materials to emphasize the potency and potential hazards of these medications to students.
Content Connections
Inform students that as they progress through other lessons, they will be better able to apply their basic knowledge of pharmacology to specific medical conditions such as heart disease, hypertension, and diabetes.
Cultural Considerations
Discuss various cultural attitudes toward medications. Be mindful that some cultures may not advocate taking medicine for pain and might utilize alternative illness treatments that differ from conventional norms. Additionally, certain cultures and religions may have specific dietary requirements that conflict with particular types and forms of medications (e.g., those made from animal products).
Teaching Tips
Avoid assuming that all students possess even the most basic understanding of medications; accurate knowledge can vary widely.
Consider projecting a prescription label and an OTC medication label. Conduct a short pretest to assess students' ability to comprehend the information on these labels.
Unit Activities
Writing Assignments: Assign each student a fictional "patient" with a medical history that includes medication use. Ask students to research which medication(s) patients with such conditions might be taking (encouraging both generic and trade names) and what the medication does in the body. Limit assignments to common conditions and no more than two medications.
Student Presentations: Have pairs of students discuss barriers to medication compliance and their possible consequences. They should also propose solutions to this issue. Common barriers include:
The patient forgets medication guidelines.
The patient doesn't understand the label (e.g., inability to read, language barrier, poor vision).
The patient cannot access the medication (e.g., unable to open the bottle, confined to bed).
The patient cannot afford the medication.
Group Activities: Assign each group one medication from the EMT medications chart (Table ). If possible, provide actual samples. Groups should present facts about the medication, create a scenario demonstrating its use, and perform a skit for the class. Encourage role-playing realistic parts, such as the patient, EMT, and family members.
Medical Terminology Review: Provide a few paragraphs written from the perspective of a fictional patient, describing their medication and its effects in everyday language. For example: "I'm taking this pill for my arthritis pain. It helps ease the pain and also reduces swelling in my joints. I'm supposed to take one pill in the morning and one at night. I have to be careful that I don't get an upset stomach when I take this medication, because the doctor told me it could cause ulcers. The doctor said that if I'm going to be drinking any alcohol that I shouldn't take the pill that day. Also, if I have any itching or vomiting, I should stop taking the medicine right away. The doctor also said that it might make me a little sleepy, but that it's okay if that happens." Students should then identify the indications, untoward effects, side effects, dosage, contraindications, and intended effects using the terminology presented in the chapter. Consider providing a word list to guide students.
"You Are the Provider" Case Study
This is a progressive case study designed to foster critical thinking skills.
Instructor Directions:
Direct students to read the "You Are the Provider" scenario found throughout Chapter 11.
Assign students to partners or groups to review the discussion questions at the end of the scenario and prepare responses. Facilitate a class dialogue based on these questions and the Patient Care Report.
Alternatively, use this as an individual activity, having students submit their comments on separate paper.