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.