General Pharmacology

The 7 core medications an EMT can carry/administer

An EMT carries or administers seven core medications; depending on local protocol, the national scope of practice also allows oral over-the-counter pain and fever relievers such as acetaminophen or ibuprofen. The table below lists each one with its purpose and the route by which it is given.

Table 18.1The 7 core medications an EMT can carry/administer

Activated charcoal is also carried in some systems as an optional medication for certain poisonings. It is system-dependent, not universal.

Aspirin, oral glucose, oxygen & naloxone

Aspirin reduces the blood's ability to clot. During a myocardial infarction (MI) it limits the damage that the clot would otherwise cause, and it has been proven to reduce mortality significantly. It is contraindicated in a patient with an aspirin allergy or gastrointestinal (GI) bleeding.

Oral glucose treats altered mental status caused by low blood sugar in a diabetic patient who is conscious and able to swallow. It is applied as a gel between the cheek and the gum and is absorbed through the digestive tract.

Oxygen treats hypoxia or the risk of hypoxia. Treat it as you would any other medication: it is given when there is a good reason to give it and withheld when there is not.

Naloxone reverses a narcotic overdose, including the loss of consciousness and the respiratory failure or arrest that come with it, and it is one of the few true antidotes in medicine. It is given by injection or as an atomized mist into the nose. Naloxone does nothing if no narcotic was taken, and the intranasal form will not work if the nasal membranes are damaged or blocked.

Medications EMTs assist patients with (their own prescription)

Beyond the medications you carry, there are several that you may help a patient take from the patient's own prescription. In every case, confirm that the medication belongs to the patient and not to a bystander or a family member.

Bronchodilator inhalers, such as albuterol and levalbuterol, are prescribed for asthma, emphysema and bronchitis. Their side effects are an increased heart rate (HR) and jitteriness. Assisting with one requires medical direction.

Nitroglycerin (Nitrostat) is prescribed for recurrent chest pain. It comes as a pill that dissolves under the tongue or as a spray applied under the tongue, and it is never swallowed. It is contraindicated when the patient has recently taken an erectile dysfunction (ED) medication such as Viagra or Cialis, because the combination risks a dangerous drop in blood pressure (BP). Its side effect is a drop in blood pressure; if that happens, lay the patient flat.

Epinephrine auto-injectors (EpiPen, Auvi-Q) are prescribed for anaphylaxis and are injected intramuscularly (IM) into the thigh. Their side effects are an increased heart rate and an increased blood pressure.

Force protection medications, such as an atropine auto-injector for a responder's own treatment in a chemical weapons scenario, are carried in some systems and not in others.

How asthma and anaphylaxis medications actually work

Understanding what a medication does at the level of the receptor explains why it is chosen. The table below compares the pathophysiology of asthma and anaphylaxis with the action of the medication used for each.

Table 18.2How asthma and anaphylaxis medications actually work

The comparison shows why epinephrine is the drug of choice in anaphylaxis: alone among these agents it acts on alpha and beta receptors at once, so it treats the circulatory collapse and the airway narrowing together. Albuterol, acting almost only on beta2 receptors, opens the airway with limited effect on the heart.

General pharmacology concepts

Every drug has three names. The chemical name is the technical description of the molecule. The generic name is written in lowercase, as in albuterol. The trade or brand name is capitalized, as in Ventolin HFA. All drugs are catalogued in the U.S. Pharmacopoeia (USP).

Four terms describe when and how a drug acts. An indication is a condition for which the drug is appropriate. A contraindication is a condition in which the drug is not appropriate or could be harmful. A side effect is any action of the drug other than the intended one, and an untoward effect is a side effect that is harmful.

Medications come in many forms: a compressed powder or tablet, a parenteral liquid for injection, an enteral liquid taken by mouth, a vaporized or nebulized liquid, a gel, a suspension, a fine powder for inhalation, a gas for inhalation, and a sublingual spray.

Medication authorization & the Five Rights

Authorization to give a medication comes from medical direction in one of two forms. Off-line medical direction consists of pre-written standing orders, and no live contact with a physician is needed. On-line medical direction is live verbal permission given by phone or radio. When you receive an on-line order, use the "echo technique" and repeat the order back to the physician, which reduces errors.

Before administering any medication, confirm the Five Rights:

1. Right patient
2. Right time
3. Right medication
4. Right dose
5. Right route

Always check the expiration date first as well, and document the administration fully and promptly afterward.

Routes of administration

The route by which a drug enters the body determines how fast it acts and what can interfere with it. The table below sets out the routes and what you need to know about each.

Table 18.3Routes of administration

A swallowed drug is the safest and the slowest, because it must be digested before it can act. The sublingual route is faster than swallowing, but it depends on circulation and is impaired in shock. Inhaled drugs, whether aerosol or gas, are absorbed through the alveoli. The intranasal route can rival the speed of an injection, but it will not work if the nasal mucosa is damaged. The intravenous (IV) route is fast and precise; it is beyond the EMT scope, although EMTs may assist. An intramuscular (IM) injection is fast but affected by poor circulation, and it is typically given with a needle; subcutaneous absorption is slightly slower than IM. An intraosseous (IO) injection goes into the bone marrow and reaches the central circulation nearly as fast as an IV. The endotracheal route is an advanced life support (ALS) measure used as a last resort, because absorption is unpredictable.

Pharmacodynamics differ with the patient. Smaller and lighter patients, which is to say pediatric patients, need less medication for the same effect, and geriatric patients often have difficulty eliminating medications. The Broselow tape helps estimate correct pediatric dosing and equipment sizing. After any medication, reassess the patient immediately and repeatedly, and document the name, dose, exact route, time given and the effects you noted.

Common medication categories & herbal agents

Much of what you learn about a patient's history comes from the medications in the home, so you need to recognize the common categories. The table below gives each category, its purpose and examples.

Table 18.4Common medication categories & herbal agents

Two points deserve emphasis. Daily maintenance respiratory medications such as beclomethasone and Advair should never be used to reverse an acute attack. And ask about herbal agents specifically, naming examples such as gingko, St. John's wort, garlic, hawthorn, kava kava and valerian root. Patients often do not think to mention them, but several have real interactions with prescribed drugs.

Assisting with IV therapy

IV therapy is an ALS-level procedure. The EMT assists with it but does not perform the insertion. There are two methods: a saline or heparin lock, which is a capped port with no fluid bag, and a traditional IV bag with an administration set. The administration set consists of a drip chamber, a flow regulator, a drug or needle port and an extension set. The drip chamber comes in two sizes: a micro drip, which delivers 60 drops/mL and is used for pediatric patients, and a macro drip, which delivers 10–15 drops/mL and is used for shock and trauma.

Several problems can arise with a running IV. If it is not flowing at all, look for a constricting band left on the arm, a closed flow regulator or kinked tubing. If it is flowing too slowly, check the patient's positioning and whether the bag is held high enough. A "runaway IV" is one flowing too fast, which is dangerous, especially in children. An infiltrated IV is one in which the needle has punctured through or out of the vein; stop the flow and report or discontinue it according to protocol.