General Pharmacology

• General pharmacology is closely linked to multiple areas of emergency medical care, including respiration, cardiac function, diabetes, allergic reactions, poisoning, and response to terrorism.

• Understanding pharmacology is essential for managing respiratory and cardiac emergencies, as well as for treating diabetic crises, allergic reactions, and overdose situations.

• Knowledge from related chapters enhances your ability to apply pharmacological principles in a variety of emergency scenarios, ensuring comprehensive patient care.

Standards

• Principles of Pharmacology: You need to understand how drugs interact with the body, including pharmacokinetics (how drugs are absorbed, distributed, metabolized, and excreted) and pharmacodynamics (how drugs produce their effects).

• Medication Administration: Safe and effective medication administration requires knowledge of drug dosages, routes of administration (oral, intravenous, intramuscular, etc.), and the importance of the "five rights": right patient, right drug, right dose, right route, and right time.

• Emergency Medications: In emergency situations, certain medications (such as epinephrine, naloxone, and atropine) are used to treat life-threatening conditions. You must be familiar with their indications, mechanisms of action, and potential side effects.

Competency

• EMTs are trained to assist with or administer specific emergency medications, which typically include oxygen, oral glucose, activated charcoal, aspirin, epinephrine auto-injectors, and sometimes naloxone.

• Each medication has specific indications, contraindications, dosages, and routes of administration that you must know to ensure safe and effective patient care.

• Understanding the effects and potential side effects of these medications is essential for monitoring patient response and recognizing adverse reactions during emergency situations.

Core Concepts

• EMTs are authorized to carry and administer certain medications, which typically include oxygen, oral glucose, activated charcoal, aspirin, and epinephrine auto-injectors.

• EMTs may assist patients in taking their own prescribed medications, such as nitroglycerin, inhalers, or epinephrine, when indicated and with proper medical direction.

• Key considerations when administering any medication include confirming the right patient, right medication, right dose, right route, and right time, as well as checking for contraindications and potential side effects.

• Medical direction plays a crucial role in medication administration, providing protocols and real-time guidance to ensure safe and appropriate use of medications.

• EMTs may assist with IV therapy by preparing equipment, maintaining sterile technique, and monitoring the patient, but typically do not initiate IV lines unless specifically trained and authorized.

Learning Objectives

• Pharmacology involves understanding drug names, effects, and safe administration. You need to distinguish between chemical, generic, and trade names of drugs, and assess both the patient and the situation to determine when a medication is indicated or contraindicated.

• Anticipate and recognize drug effects. Before administering a drug, anticipate its desired effects and possible side effects, and be able to identify these effects—both beneficial and adverse—after administration.

• Clinical judgment and medical authorization are essential. Use clinical judgment when giving medications, and understand the two types of medical authorization available to EMTs: offline (standing orders/protocols) and online (direct communication with medical control).

• Medication safety protocols must be followed. Always check expiration dates and adhere to the Five Rights of medication administration: right patient, right medication, right dose, right route, and right time.

• Routes of drug administration vary. Know the different routes (oral, inhalation, intramuscular, sublingual, etc.) and examples of medications for each.

• Pharmacodynamics influence medication decisions. Understand how a drug’s effects on the body (pharmacodynamics) impact your decisions about administration.

• Reassessment and documentation are required after giving medication. Monitor the patient’s response and document all relevant details after administration.

• EMTs carry and administer specific medications. Common medications include albuterol (inhaled bronchodilator), aspirin, epinephrine, naloxone, nitroglycerin, oral glucose, and oxygen. EMTs may also administer acetaminophen, activated charcoal, diphenhydramine, glucagon, nitrous oxide, and ondansetron.

• Know the actions and indications for each medication. Understand why each medication is given, its effects, and the appropriate route of administration.

• Be familiar with both generic and trade names. Recognize the names of medications you carry and those prescribed to patients you may assist.

• Patients may take a variety of prescribed and herbal medications. Be aware of common categories of prescribed drugs, the role of medical direction in assisting with these, and the actions and reasons for use of common herbal agents.

• Albuterol and epinephrine are key in treating anaphylaxis and asthma. Both medications help correct the underlying pathophysiology of these conditions.

• EMTs assist with intravenous (IV) therapy. Know the parts and supplies for IV therapy, the steps for preparing IV fluids and tubing, and how to troubleshoot issues with IV flow.

• EMTs may assist with additional IV-related tasks as directed. Be prepared to help with other tasks during IV therapy if requested.

Key Terms

• Pharmacology is the study of drugs, including their sources, characteristics, and effects on the body.

• As an EMT, you are responsible for administering medications in emergencies, which requires critical decision-making and attention to detail to avoid causing harm.

• Medications can be lifesaving but must be given correctly; improper administration can be dangerous.

• You need to understand key terminology, principles, and rules related to pharmacology, including the different forms and names of medications, their indications (when to use them), contraindications (when not to use them), and possible side effects.

• EMTs carry certain medications and may assist patients with prescribed medications under medical direction.

• The terms "medications" and "drugs" are used interchangeably in EMS, but "medications" is preferred when communicating with the public to avoid confusion with illegal substances.

• Good judgment and proper decision-making are essential tools when administering medications.

General Information about Medications

• Every drug has three main names: the chemical name (used by scientists/manufacturers), the generic name (a general, non-brand name), and one or more trade (brand) names (assigned by manufacturers).

• The U.S. Pharmacopoeia (USP) lists drugs by their generic names, which are not specific to any manufacturer.

• Chemical names and formulas are technical and used primarily by professionals; for example, epinephrine’s chemical formula is .

• Trade (brand) names are capitalized in print (e.g., Ventolin® HFA), while generic names are not (e.g., albuterol, the generic name for Ventolin® HFA).

• Examples illustrate the naming system: EpiPen® is a trade name for an epinephrine autoinjector; epinephrine is the generic name, and its chemical name is more complex and technical.

What You Need to Know When Giving a Medication

• Every drug has indications—specific signs, symptoms, or circumstances that make it appropriate to administer the drug (e.g., nitroglycerin is indicated for chest pain or pressure).

• Drugs also have contraindications—situations where the drug should not be given because it may be harmful (e.g., nitroglycerin is contraindicated in patients with low blood pressure or those who have recently taken Viagra due to risk of dangerous interactions).

• Side effects are actions of a drug other than the intended effect; some are predictable (like nitroglycerin causing a drop in blood pressure), and if not considered, can lead to harmful outcomes.

• Untoward effects are unexpected and potentially harmful reactions that can occur in addition to the desired effect.

• Medications come in various forms and routes of administration, including:

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

  • Parenteral liquids (injections, bypassing the GI tract, e.g., epinephrine autoinjector)

  • Enteral liquids (taken orally, using the GI tract, e.g., cough syrup)

  • Vaporized liquids (e.g., nebulizer treatments)

  • Gels (e.g., oral glucose paste)

  • Suspensions (e.g., activated charcoal in water)

  • Fine powders for inhalation (e.g., inhalers)

  • Gases for inhalation (e.g., oxygen)

  • Sublingual sprays (e.g., nitroglycerin spray)

Medication Safety and Clinical Judgment

• Administering medications is a critical responsibility because incorrect administration can cause serious harm to patients.

• Thorough patient assessment is essential before giving any medication to ensure it is appropriate for the specific patient and situation.

• Distractions and multitasking are common in emergency settings, but when administering medication, you must focus solely on the task to avoid errors.

• Understanding the medication is crucial; if you are unsure about any aspect, consult reliable resources or seek guidance rather than guessing.

• Medical direction should be consulted as needed for permission or assistance with medication administration.

• Once a medication is given, it cannot be undone, so careful judgment and clear thinking are necessary to ensure patient safety.

Medication Authorization

• Medication administration by EMTs requires authorization from a medical director, which can be at the service, regional, or state level.

• Two types of medical direction exist: off-line and on-line. Off-line medical direction involves following written protocols or standing orders without direct communication with a physician. On-line medical direction requires direct verbal communication with a physician or designee to obtain permission for medication administration.

• The echo technique is recommended during on-line medical direction: you repeat the physician’s order back to them, and they confirm its accuracy, which helps prevent medication errors.

• Clarification should always be sought if there is any confusion during on-line medical direction to ensure safe and accurate medication administration.

The Five Rights

• Always confirm and document the medication order before administration, ensuring the medication is not expired.

• Apply the "five rights" to medication administration: right patient, right time, right medication, right dose, and right route.

• After giving the medication, promptly and thoroughly document the administration.

Routes of Administration

• The route of administration is the pathway used to deliver medication into your body and bloodstream, affecting how quickly and effectively the medication works.

• Oral (swallowed) medications are safe and easy to administer but act slowly because they must be digested; examples include chewable aspirin and diphenhydramine (Benadryl®).

• Sublingual (under the tongue) medications dissolve and are absorbed quickly through the mouth’s vascular tissue, acting faster than oral medications; an example is nitroglycerin (Nitro®), but absorption can be limited if circulation is poor.

• Inhaled medications are breathed into the lungs and absorbed through the alveoli, providing rapid effects; examples include oxygen and albuterol/ipratropium (DuoNeb®).

• Intranasal medications are sprayed into the nostrils and absorbed through nasal capillaries, offering effects similar in speed and strength to injections for certain drugs; naloxone (Narcan®) is a common example.

• Intramuscular (IM) injections deliver medication directly into muscle tissue for rapid absorption, but effectiveness can decrease with poor circulation; epinephrine (EpiPen®) is a typical IM medication.

• Subcutaneous injections place medication under the skin, resulting in slower absorption than IM injections; insulin is commonly given this way.

• Intravenous (IV) administration (beyond EMT scope) injects medication directly into a vein for immediate effect; atropine is an example.

• Intraosseous (IO) administration involves injecting medication into bone marrow, allowing rapid entry into the bloodstream, similar to IV; used in emergencies for drugs like epinephrine.

• Endotracheal (ET) administration sprays medication into a tube in the trachea for lung absorption, but absorption is unpredictable and this route is typically a last resort; epinephrine can be given this way.

• The choice of route impacts the speed, effectiveness, and potential complications of medication delivery, with each route suited to specific situations and medications.

Pharmacodynamic Considerations

• Pharmacodynamics examines how medications affect the body, emphasizing the importance of understanding the specific effects of each drug before administration.

• Patient-specific factors, such as age and weight, significantly influence medication response; for example, pediatric patients typically require lower doses, while older adults may experience prolonged effects due to slower medication elimination.

• Tools like the Broselow™ tape assist in determining appropriate pediatric medication dosages and medical device sizing by using length-based measurements, ensuring safer and more accurate care for children.

Reassessment and Documentation

• Reassess your patient after administering any medication by starting the assessment process again to identify any changes, including improvements, deteriorations, or unintended effects.

• Reassessment should be immediate and repeated frequently, especially for medications that require time to take effect.

• Accurate documentation is essential and must include the medication name (with correct spelling), dose, specific route of administration (e.g., "injected into the right upper thigh"), time of administration, and any observed effects.

• Clear records are crucial for continuity of care, as hospital staff rely on this information to safely continue the patient's treatment plan.

Medications EMTs Can Administer

• Medications you can administer or assist with are determined by your state and local EMS protocols, not by your certification alone.

• Common medications EMTs may administer include acetaminophen, aspirin, diphenhydramine, epinephrine, intramuscular glucagon, inhaled bronchodilators, inhaled nitrous oxide, naloxone, ondansetron, nitroglycerin, oral glucose, and oxygen.

• Some EMS systems may allow EMTs to administer additional medications beyond this list, depending on local protocols.

• You may be authorized to carry and administer certain medications, while for others (such as patient-prescribed medications), you are trained to assist the patient in taking them if needed.

• Administration of any medication by an EMT is under the delegated authority of the EMS system or Medical Director, and may require on-line (real-time) or off-line (standing orders) medical direction as specified by local protocols.

• It is essential to know and follow your local protocols regarding which medications you can administer, how you can administer them, and under what circumstances.

Common Medications Administered by EMTs

• Bronchodilators relax smooth muscles in the lower airways, improving airflow and easing breathing for patients with asthma or COPD.

• Inhaled bronchodilators act directly on airway muscles, minimizing systemic side effects compared to injected epinephrine, which can cause increased blood pressure and tachycardia.

• Common inhaled bronchodilators include albuterol (Ventolin® HFA, Proventil®, Volmax®), levalbuterol (Xopenex®), ipratropium bromide (Atrovent®), and combination products like albuterol with ipratropium bromide (Combivent®, DuoNeb®).

• Inhalers deliver medication as an aerosol directly into the airway; spacers can be attached to inhalers to help patients inhale the medication more effectively and comfortably.

• Emergency Medical Technicians (EMTs) may assist patients with their prescribed inhalers or administer bronchodilators using a small volume nebulizer powered by oxygen, which provides medication over several minutes and is often more effective than inhalers.

• Albuterol and albuterol/ipratropium bromide combinations are the most commonly administered inhaled bronchodilators by EMS providers.

• Administration of inhaled bronchodilators should always follow the specific protocols of the EMS system.

Think Like an EMT

• Aspirin is a critical medication in EMS for patients with chest pain of suspected cardiac origin, as it reduces the blood’s ability to clot and helps prevent further heart damage during a heart attack.

• The standard EMS dose of aspirin is 162–324 mg (two to four 81 mg chewable tablets), and patients are instructed to chew and swallow the tablets to speed absorption.

• Aspirin administration can significantly reduce the chance of death in heart attack patients, making it an essential intervention when myocardial infarction is suspected.

• Contraindications for aspirin include allergies and gastrointestinal bleeding, as these conditions can be worsened by the medication; always adhere to local protocols for administration.

• For asthma patients with a prescribed albuterol inhaler, you are permitted to assist with its use if protocols allow, even if ALS is only a few minutes away, as timely intervention can be critical.

Think Like an EMT

• Epinephrine is the primary treatment for severe allergic reactions (anaphylaxis), rapidly reversing life-threatening airway and circulatory changes by constricting blood vessels and relaxing airway passages (bronchodilation). It is administered intramuscularly, preferably into the lateral thigh, due to its large muscle mass and minimal risk to underlying structures.

• Epinephrine autoinjectors (e.g., EpiPen®, Adrenaclick®, Auvi-Q®) are commonly used by patients at risk for anaphylaxis, and EMTs may assist with their use or administer epinephrine from a vial, depending on local protocols. Side effects include increased heart rate and jitteriness.

• Medications for asthma and anaphylaxis act on the sympathetic nervous system, affecting alpha and beta receptors to produce effects such as increased heart rate, blood vessel constriction, and airway dilation.

• Naloxone (Narcan®) is an antidote for narcotic overdose, quickly reversing respiratory depression caused by opioids. It can be administered by injection or as a nasal spray, but is only effective if opioids are present in the system.

• Nitroglycerin is used to treat chest pain of cardiac origin by dilating coronary vessels, improving blood flow to the heart muscle. It is administered sublingually (tablet or spray) and should not be swallowed. EMTs may assist patients with their prescribed nitroglycerin if protocols allow, but must ensure the medication belongs to the patient, check for recent use of erectile dysfunction drugs (which can cause dangerous interactions), and confirm systolic blood pressure is above 90–100 mmHg to avoid hypotension.

• Oral glucose is given to conscious patients with altered mental status and a history of diabetes who are suspected of having low blood sugar, typically as a gel placed between the cheek and gum or under the tongue for rapid absorption.

Point of View: Patient

• Oxygen is a medication used to treat hypoxia (low oxygen levels) or the risk of hypoxia; it is commonly administered by EMTs in various medical and traumatic situations.

• Oxygen is also used as a propellant for nebulized bronchodilators and is always administered with nitrous oxide, highlighting its role in supporting other emergency treatments.

• Recent research indicates that excessive oxygen can be harmful, so you should only administer oxygen when there is a clear medical reason, such as a low pulse oximeter reading, rather than giving it routinely to all patients.

• Oxygen should be regarded and managed like any other medication, meaning you must consider both its benefits and potential risks before administration.

Other Medications Administered by EMTs

• Acetaminophen is used for pain relief (analgesic) and fever reduction (antipyretic), administered orally in pill or liquid form; dosing for children is based on weight, and it should be avoided in patients with liver disease.

• Activated charcoal is used to treat certain poisonings or overdoses by adsorbing toxins in the digestive tract, preventing their absorption; it is administered as a slurry and only for specific cases as per protocol.

• Diphenhydramine (Benadryl) is an antihistamine used for allergy symptoms and as part of emergency treatment for severe allergic reactions (anaphylaxis); it can cause drowsiness and may be administered orally, intramuscularly, or intravenously depending on protocols.

• Force protection medications like atropine and pralidoxime (in autoinjectors such as the Mark 1 kit) are carried for self-administration by responders exposed to nerve agents or chemical weapons, with use determined by local guidelines.

• Glucagon treats hypoglycemia in diabetic patients with altered mental status who cannot take oral glucose; it raises blood glucose by stimulating liver glucose production and is administered as a nasal spray (3 mg powder) or intramuscular injection (1 mg reconstituted from powder).

• Nitrous oxide ("laughing gas") is used for acute pain management, delivered as a self-administered gas mixture with oxygen (never more than 50% nitrous oxide); contraindications include hypoxia, low blood pressure, inability to self-administer, suspected pneumothorax, bowel obstruction, severe COPD, and altered mental status.

• Ondansetron (Zofran) is used to treat nausea and vomiting by blocking certain body chemicals; commonly administered as oral disintegrating tablets (ODTs) placed under the tongue, and may also be given intravenously by advanced providers.

Medications Patients Often Take

• Medications a patient is taking can indicate underlying medical conditions or contribute to current symptoms if misused or interacted with other drugs. For example, antihypertensives and antidiabetics may be clues to chronic conditions, while drugs like phenytoin, codeine, or propranolol can affect mental status.

• Some medications for chronic conditions should not be used for acute emergencies. For instance, beclomethasone and Advair are for daily respiratory management, not for treating acute attacks or sudden breathing difficulties.

• Having access to reliable drug information resources is essential. Pocket guides or smartphone apps help quickly identify medications, their categories, and common uses, aiding communication with medical direction and hospital staff.

• The primary goal in identifying patient medications is to report them accurately, not to diagnose in the field. Comprehensive medication knowledge improves patient care and communication.

• Ten common medication categories encountered in patient care include:

  • Analgesics (pain relief): e.g., acetaminophen, ibuprofen, morphine, oxycodone.

  • Antidysrhythmics (heart rhythm disorders): e.g., digoxin, metoprolol, propranolol.

  • Antiseizure drugs: e.g., carbamazepine, phenytoin, valproic acid.

  • Antihypertensives (blood pressure control): e.g., amlodipine, captopril, nifedipine.

  • Antidiabetics (blood sugar control): e.g., glimepiride, metformin, insulin.

  • Antidepressants: e.g., amitriptyline, fluoxetine, sertraline.

  • Opioid use disorder medications: e.g., buprenorphine/naloxone, methadone, naloxone.

  • Congestive heart failure agents: e.g., furosemide, metoprolol, enalapril.

  • Blood thinners (anticoagulants and antiplatelets): e.g., apixaban, rivaroxaban, aspirin, clopidogrel.

  • Bronchodilators (asthma/COPD): e.g., albuterol, ipratropium, Advair.

• Herbal agents are commonly used but often unreported by patients. Examples include:

  • Gingko biloba (dementia, circulation)

  • St. John’s wort (depression)

  • Echinacea (cold prevention)

  • Garlic (cholesterol)

  • Ginger root (nausea)

  • Saw palmetto (prostate)

  • Hawthorn (heart failure)

  • Evening primrose oil (PMS)

  • Feverfew (migraine)

  • Kava kava (anxiety)

  • Valerian root (insomnia)

• Herbal agents can have significant effects and interact with prescription or over-the-counter medications, so they should be documented.

• After administering any medication, reassess the patient’s condition and vital signs, and document the response to the intervention. For example, note improvements in symptoms or changes in vital signs after treatment.

Assisting with IV Therapy

• IV therapy involves inserting a catheter into a vein to administer fluids, blood, or medications directly into the patient’s circulation.

• Fluids and medications can be administered via two main methods: a heparin or saline lock (used when only medication or future IV access is needed, without continuous fluid administration) and a traditional IV bag (used for ongoing fluid and medication delivery).

• A saline or heparin lock consists of a catheter with a cap or lock containing a port for medication administration, but no attached IV bag.

• The traditional IV administration set includes a fluid bag and clear plastic tubing with three key components:

  • The drip chamber (micro drip for minimal flow, where 60 small drops = 1 mL; macro drip for higher flow, where 10–15 large drops = 1 mL).

  • The flow regulator (controls the rate of fluid flow by being pushed up or down).

  • The drug or needle port (allows for medication injection into the IV line).

• An extension set may be used to add extra tubing length, making patient handling easier and reducing the risk of accidental IV removal.

• EMTs may assist in setting up the IV administration set, even though paramedics or AEMTs typically insert the IV catheter.

SCAN 18-1

• During cardiac arrest, raising the patient's arm after injecting medication into the IV can enhance the effectiveness of the drug.

• You may be asked to hold up the patient’s arm for a few minutes during this process to facilitate better medication delivery.

Maintaining an IV

• IV flow can be interrupted by several factors, including a constricting band left on the arm, a closed flow regulator or clamp, kinked tubing, tubing caught under the patient or equipment, or improper positioning of the IV or the patient’s arm.

• IV flow often depends on gravity, so the IV bag must be positioned well above the IV site and the patient’s heart to ensure proper flow.

• Insufficient IV flow can lead to blood clotting in the catheter, which is prevented by maintaining an adequate "keep vein open" (KVO) rate—typically about 30 drops per minute for a micro drip set and 10 drops per minute for a macro drip set.

• If the drip chamber is overfilled, clamp the tubing, invert the chamber, and pump fluid back into the bag to correct the issue.

• A "runaway IV" occurs when the flow rate is too fast, risking fluid overload, especially in infants and children; the rate must be adjusted to the proper setting.

• An infiltrated IV means fluid is entering surrounding tissues instead of the vein, often due to the needle puncturing through or pulling out of the vein. This can cause swelling and pain at the site and is especially dangerous with high-concentration medications, which can damage tissue.

• If infiltration is suspected, the IV must be stopped and discontinued according to protocol, or the issue should be reported immediately if you are not authorized to act.

• Assisting with IV setup and maintenance can save valuable time during emergency care and transport.