Emt Pharmacology

This deck introduces the core pharmacology concepts that every emergency medical technician needs to know. The cards walk you through essential terminology, such as what "indication" and "contraindication" mean, how generic and trade drug names differ, and what phrases like "onset of action" and "duration of action" describe. You'll also practice identifying common routes of administration, from sublingual and inhaled medications to injections and oral doses, along with the foundational "six rights" of safe medication administration in the field.

It's designed for EMT students working through a basic pharmacology module, whether you're preparing for a classroom exam, a certification test, or just building a strong foundation for clinical rotations. Because the material is term-heavy, the cards work well as a quick way to check your understanding of definitions before you move on to applying these concepts to specific medications and patient scenarios.

Since pharmacology leans heavily on precise vocabulary, try spacing your review sessions out over several days rather than cramming everything at once. A helpful approach is to group related cards together in your mind, for example pairing each route of administration with the situations in which it is typically used, so the terms stick as part of a larger mental picture rather than as isolated words.

Pharmacology in emergency medical services begins with a clear framework for safe medication use. EMTs follow the "six rights" of medication administration: the right patient, right medication, right dose, right route, right time, and right documentation. Every medication decision must be tied to an indication, the specific condition or situation for which a drug is appropriate, and weighed against any contraindications, which are circumstances in which the drug must be withheld. EMTs also distinguish between routine side effects, which are unintended but typically mild responses at normal dosing, and untoward effects, which are unexpected or dangerous reactions that demand immediate reassessment.

Every drug has a generic name, the official non-proprietary chemical designation such as acetylsalicylic acid, and a trade or brand name given by the manufacturer, such as Bayer. EMTs should recognize both. Pharmacologic understanding also requires distinguishing agonists, which bind to a receptor and activate it to produce a response, from antagonists, which bind to a receptor and block it without activating one. Naloxone, for example, is an opioid antagonist that reverses opioid effects by competing for those receptors.

Medication administration in the field is governed by medical direction. Standing orders, sometimes called offline medical direction, are pre-approved protocols that allow treatment without real-time physician contact, while online medical direction involves direct communication with a physician at the time of care. Before any medication is given or assisted, the EMT must ask about drug allergies, often documented as NKDA (no known drug allergies), to avoid triggering an allergic or anaphylactic reaction. Orders written PRN mean the medication is to be given as needed, and EMTs must always document the time, dose, route, and patient response.

The route of administration is the pathway by which a drug enters the body, and it directly influences how quickly and completely the medication works. In EMS, the most common routes include oral (PO), in which the drug is swallowed; sublingual, where it is placed under the tongue for absorption through the mucosal lining; intramuscular (IM) injection into muscle; inhalation or nebulization into the lungs; and rectal (PR) administration. Each route has trade-offs between speed of absorption, reliability, and patient cooperation.

Two timing concepts govern how drugs behave once given. Onset of action is the interval between administration and the start of the drug's effect, while duration of action is the total length of time the drug remains effective. A medication with a rapid onset but short duration, such as inhaled albuterol, may need to be repeated, whereas a drug with a longer duration may require fewer doses. The EMT must also understand a drug's mechanism of action, that is, how it produces its effect at the cellular or molecular level, because this underlies both the expected therapeutic response and potential adverse reactions.

Two delivery devices are particularly important in prehospital care. An auto-injector is a spring-loaded syringe that delivers a premeasured dose, often through clothing, making it ideal for emergency use by laypeople or rescuers. A metered-dose inhaler (MDI) is a handheld canister that releases a measured aerosolized dose into the lungs, often paired with a spacer to improve delivery for patients who struggle with coordination. Understanding both the route and the delivery device helps the EMT coach the patient effectively and recognize when technique is undermining the medication's effect.

Oxygen is classified as a medication and is the most frequently administered drug in EMS. Its primary indication is suspected or confirmed hypoxia or hypoxemia, and it has very few contraindications; oxygen should not be withheld from a patient who needs it. EMTs are trained to recognize signs of hypoxia, including cyanosis, altered mental status, tachypnea, and tachycardia, and to use pulse oximetry to guide therapy. An SpO2 reading below approximately 94% generally indicates the need for supplemental oxygen, although local protocols may set slightly different thresholds.

The choice of delivery device depends on the concentration of oxygen required and the patient's breathing effort. A nasal cannula delivers roughly 24 to 44 percent oxygen at flow rates of 1 to 6 L/min and is appropriate for patients who need only mild supplementation. A non-rebreather mask provides approximately 90 to 100 percent oxygen at 10 to 15 L/min, with flow kept high enough to keep the reservoir bag inflated between breaths. A Venturi mask allows precise, controlled oxygen percentages for patients who need a specific concentration. For patients who are not breathing adequately on their own, a bag-valve mask (BVM) is used with oxygen flowing at 15 L/min or higher, often through a reservoir, to deliver ventilatory support along with high-concentration oxygen.

While oxygen is safe for nearly all EMS patients, EMTs must be aware of special considerations. In some patients with chronic obstructive pulmonary disease (COPD), high-flow oxygen can blunt the hypoxic respiratory drive, but this should never delay oxygen delivery in a patient with acute hypoxia. Humidified oxygen is sometimes preferred during prolonged transports to prevent drying of the mucous membranes and to improve patient comfort. Overall, oxygen remains a mainstay of prehospital care because it is both highly effective and extremely safe when used appropriately.

Within their standing protocols, EMTs may administer a limited set of medications directly. Oral glucose, supplied as a gel such as Glutose or Insta-Glucose, is indicated for suspected hypoglycemia in a conscious patient who can swallow and protect the airway. The typical adult dose is one tube containing roughly 15 to 25 g of glucose, administered buccally between the cheek and gum for rapid mucosal absorption and reduced aspiration risk. A blood glucose level below approximately 60 to 70 mg/dL generally defines hypoglycemia in adults, and EMTs should look for altered mental status, diaphoresis, tachycardia, weakness, and confusion. Oral glucose must never be given to an unconscious patient or to anyone who cannot protect the airway; instead, the EMT should secure the airway and arrange transport, with intravenous dextrose provided by ALS if available.

Activated charcoal is used for certain oral poisonings and overdoses, although it has become less common in modern protocols because of limited prehospital benefit. The standard adult dose is approximately 25 to 50 g, around 1 g/kg, mixed as a black, gritty slurry and given by mouth. Its mechanism of action is adsorption of certain toxins in the gastrointestinal tract, preventing their systemic absorption. Activated charcoal is most effective when given within about an hour of ingestion and only when the patient is awake, alert, and able to protect the airway. It is contraindicated in patients with altered mental status, in those who have ingested acids, alkalis, or hydrocarbons, and for substances it does not bind well, such as iron, lithium, and alcohols. Aspiration of the slurry can cause aspiration pneumonitis, and medical direction is typically required before administration.

Aspirin, generically acetylsalicylic acid (ASA), is administered for suspected acute coronary syndrome (ACS) and cardiac chest pain. The standard adult dose is 160 to 325 mg given as chewable, non-enteric-coated tablets, commonly four 81 mg baby aspirins, because chewing increases surface area and accelerates absorption. Aspirin is an NSAID with antiplatelet properties; by inhibiting platelet aggregation, it limits clot propagation in coronary arteries and reduces mortality when given early in suspected myocardial infarction. Contraindications include a known aspirin allergy and active gastrointestinal bleeding or a bleeding disorder. Aspirin is not given by EMTs for suspected stroke because of the risk of hemorrhage, and it is generally avoided in children because of the risk of Reye's syndrome. Aspirin fits into the traditional MONA mnemonic, Morphine, Oxygen, Nitroglycerin, Aspirin, used for early cardiac chest pain care, though morphine administration falls outside the EMT scope.

For certain prescribed medications, the EMT's role is to assist the patient in self-administration rather than to give the drug directly. Before doing so, the EMT must confirm that the medication is prescribed to that patient, that it is the correct drug for the current symptoms, and that it has not expired. The three classic patient-assist medications are sublingual nitroglycerin for chest pain, an epinephrine auto-injector for anaphylaxis, and a metered-dose inhaler (MDI) such as albuterol for bronchospasm.

Nitroglycerin is indicated for suspected cardiac chest pain or angina in a patient with a prescription and adequate blood pressure. The typical dose is 0.4 mg, delivered as one sublingual tablet or spray, repeated up to three times at five-minute intervals per protocol. Its mechanism is vasodilation, particularly of venous vessels, reducing cardiac preload and myocardial oxygen demand while dilating coronary arteries. Blood pressure must be reassessed before each dose, and nitroglycerin is withheld if the systolic pressure is generally below 100 to 110 mmHg, depending on protocol. Other contraindications include recent use of a phosphodiesterase inhibitor such as sildenafil within 24 to 48 hours, suspected right ventricular or inferior wall infarction, head injury, or increased intracranial pressure, because the combination can cause severe, profound hypotension. Common side effects include headache, dizziness, flushing, and hypotension, so patients should be seated or supine after administration. Nitroglycerin tablets must be stored in their original dark glass container, away from light, heat, and moisture, and a burning or tingling sensation under the tongue indicates the tablet is still potent.

Epinephrine auto-injectors such as EpiPen, Auvi-Q, and Adrenaclick are first-line, time-critical treatments for anaphylaxis. The adult dose is 0.3 mg intramuscular and the pediatric dose (EpiPen Jr) is 0.15 mg, delivered to the lateral mid-thigh and held in place for about 3 to 10 seconds. Most devices can be used through light clothing. Epinephrine is a sympathomimetic adrenergic agonist that produces vasoconstriction, bronchodilation, and increased cardiac output, reversing the airway swelling, bronchospasm, and hypotension of anaphylaxis. Because delay increases the risk of airway obstruction and cardiovascular collapse, there are no absolute contraindications in true anaphylaxis. Common side effects include tachycardia, anxiety, tremors, and palpitations. Effects are short-lived, typically 10 to 20 minutes, so a second dose may be needed if symptoms persist or recur, after which the EMT continues monitoring the ABCs and transports promptly. The used auto-injector should accompany the patient to the hospital, with the time of administration documented.

Albuterol delivered via metered-dose inhaler or nebulizer is indicated for bronchospasm and wheezing associated with asthma or COPD. The typical MDI dose is 1 to 2 puffs, about 90 mcg per puff, repeated per protocol, often every 5 to 20 minutes. As a short-acting beta-2 agonist, albuterol relaxes bronchial smooth muscle to produce bronchodilation, with an onset of action of roughly 5 minutes. The EMT should coach the patient to exhale fully, seal the lips around the mouthpiece, inhale deeply while pressing the canister, and hold the breath for about 10 seconds; shaking the canister first ensures the medication is evenly mixed. A spacer can improve delivery for patients with poor coordination. Side effects include tachycardia, tremors, nervousness, and palpitations. Albuterol should not be assisted without a patient prescription or explicit protocol authorization.

Naloxone is a pure opioid receptor antagonist that reverses opioid overdose by displacing opioids from their receptors, restoring respiratory drive and level of consciousness. It is most commonly administered by EMT-Basics via the intranasal route; for example, Narcan Nasal Spray delivers 4 mg per spray, typically one spray per nostril, and naloxone can also be given intramuscularly, including via auto-injector devices such as Evzio. The indication for naloxone is suspected opioid overdose with respiratory depression, classically marked by pinpoint pupils (miosis), decreased level of consciousness, and slow or absent breathing.

The priority in any suspected opioid overdose is airway and ventilatory support, because naloxone does not replace the need for oxygenation. The EMT should provide bag-valve-mask ventilation as needed while preparing to administer naloxone. Intranasal naloxone typically takes effect within 2 to 5 minutes. Because naloxone's duration of action is shorter than that of many opioids, particularly long-acting ones such as methadone, re-sedation can occur, and repeat doses along with continued ventilatory support may be required.

Naloxone has minimal contraindications; the only notable one is rare hypersensitivity. It is considered very safe even when given to a patient whose overdose turns out not to be opioid-related. In opioid-dependent patients, however, the sudden reversal can precipitate acute withdrawal, producing agitation, nausea, vomiting, or combativeness as consciousness returns. EMTs should anticipate this response, continue to manage the airway, and transport the patient for further evaluation. Naloxone has no effect on overdoses from benzodiazepines, stimulants, or other non-opioid agents.

Beyond the medications EMTs administer or assist with, they routinely encounter patients taking drugs for chronic conditions. Recognizing these medications, and understanding their purposes and risks, helps the EMT anticipate complications, identify interactions, and communicate effectively with receiving facilities. Cardiovascular medications are especially common in older adults. Beta blockers such as metoprolol and atenolol treat hypertension, angina, and arrhythmias by blocking beta-adrenergic receptors, but in trauma or shock they can blunt the tachycardic response the EMT might otherwise rely on as an early warning sign. ACE inhibitors like lisinopril and enalapril treat hypertension and heart failure by causing vasodilation, and a persistent dry cough, or rarely angioedema, is a classic side effect. Statins such as atorvastatin and simvastatin lower LDL cholesterol to reduce long-term cardiovascular risk but rarely cause acute issues in the field.

Anticoagulants and antiplatelet agents are critical history-taking items because they dramatically increase bleeding risk after trauma. Warfarin, apixaban, and rivaroxaban inhibit parts of the clotting cascade, while clopidogrel and similar drugs block platelet aggregation, often after coronary stent placement. Head trauma in a patient on these medications raises serious concern for intracranial hemorrhage. Diabetic medications pose the opposite risk: insulin and oral hypoglycemics such as metformin or glipizide can cause hypoglycemia when food intake or activity does not match the dose. Diuretics like furosemide (Lasix) reduce fluid volume in heart failure, hypertension, and pulmonary edema, but chronic use may produce hypokalemia and volume depletion.

Respiratory medications include chronic bronchodilator inhalers such as ipratropium and tiotropium, which maintain airway patency in asthma and COPD by relaxing bronchial smooth muscle. Neurologic and psychiatric drugs are also common. Anticonvulsants like phenytoin and levetiracetam prevent seizures, while benzodiazepines such as diazepam and alprazolam treat anxiety, seizures, and insomnia as central nervous system depressants, with significant respiratory depression risk when combined with opioids. Antihistamines such as diphenhydramine block histamine receptors to relieve allergic symptoms, and corticosteroids like prednisone reduce inflammation in asthma, COPD, allergic reactions, and autoimmune disease. Tricyclic antidepressant overdose is a serious toxicologic emergency causing cardiac dysrhythmias and seizures, while antipsychotics such as risperidone and haloperidol manage psychotic symptoms and severe agitation by blocking dopamine receptors. Finally, erectile dysfunction medications such as sildenafil are highly relevant because they potentiate nitrate-induced hypotension, making nitroglycerin administration dangerous if the patient has used them within roughly 24 to 48 hours.