Because there are thousands of drugs and hundreds of facts about each one, taking responsibility for drug administration can seem overwhelming. One way that you can enhance your understanding of the principles of drug administration is to associate, ask, and predict during the critical thinking process. For example, associate each drug with general information you may already know about the drug or drug class. Ask yourself why a drug is administered by a certain route and why it is given multiple times throughout the day rather than only once. Learn to predict a drug’s actions, uses, adverse effects, and possible drug interactions based on your knowledge of the drug’s mechanism of action. As you apply these principles to drug administration, you’ll begin to intuitively know which facts you need to make rational clinical decisions.
Prescriptions for patients in hospitals and other institutions are typically written by a physician, physician assistant, or nurse practitioner on a form called the physician’s order sheet or they’re directly input into a computerized system with an electronic signature. Drugs are prescribed based not only on their specific mechanisms of action but also on the patient’s profile, which commonly includes age, ethnicity, gender, pregnancy status, smoking and drinking habits, and use of other drugs.
“Rights” of Drug Administration
Always keep in mind the following “rights” of drug administration: the right drug, right time, right dose, right patient, right route, right preparation and administration, and right documentation.
RIGHT DRUG
Many drugs have different concentrations, similar spellings, and several generic forms. Before administering any drug, compare the exact spelling and concentration of the prescribed drug that appears on the label with the information contained in the medication administration record or drug profile. Regardless of which drug distribution system your facility uses, you should read the drug label and compare it with the medication administration record at least three times:
RIGHT TIME
Various factors can affect the time that a drug is administered, such as the timing of meals and other drugs, scheduled diagnostic tests, standardized times used by the institution, and factors that may alter the consistency of blood levels and drug absorption. Before administering any p.r.n. drug, check the patient’s chart to ensure that no one else has already administered it and that the specified time interval has passed. Also, document administration of a p.r.n. drug immediately.
RIGHT DOSE
Whenever you’re dispensing an unfamiliar drug or are in doubt about a dosage, check the prescribed dose against the range specified in a reliable reference. Be sure to consider any reasons for a dosage adjustment that may apply to your particular patient. Also, make sure you’re familiar with the standard abbreviations your institution uses for writing prescriptions.
RIGHT PATIENT
Always compare the name of the patient on the medication record with the name on the patient’s identification bracelet. When using a unit dose system, compare the name on the drug profile with that on the identification bracelet.
RIGHT ROUTE
Each drug prescription should specify the administration route. If the administration route is missing from the prescription, consult the prescriber before giving the drug. Never substitute one route for another unless you obtain a prescription for the change.
RIGHT PREPARATION AND ADMINISTRATION
For drugs that must be mixed, poured, or measured, be sure to maintain aseptic technique. Follow any specific directions included by the manufacturer regarding diluent amount and type and the use of filters, if needed. Clearly label any drug that you’ve reconstituted with the patient’s name, the strength or dose, the date and time that you prepared the drug, the amount and type of diluent that you used, the expiration date, and your initials.
RIGHT DOCUMENTATION
It’s crucial that documentation of drug administration appears on the right patient’s medical record. Sometimes two patients on the same nursing unit may have the same last name, and even the same first initial. Documentation done in haste may cause the wrong medical record to be pulled. This could result in an apparent medication error as it would appear from the documentation—the patient who was supposed to get a drug did not and the patient who was not supposed to get the drug did. Always double-check the patient’s full name and one other identifying factor such as the patient’s age or prescriber name before documenting drug administration on the patient’s medical record.
Administration Routes
Drugs may be administered by a variety of routes and dosage forms. A particular route may be chosen for convenience or to maximize drug concentration at the site of action, to minimize drug absorption elsewhere, to prolong drug absorption, or to avoid first-pass metabolism.
Different dosage forms of the same drug may have different drug absorption rates, times of onset, and durations of action. For example, nitroglycerin is a coronary vasodilator that may be administered by the buccal, I.V., oral, sublingual, or translingual route, or as a topical ointment or patch. The buccal, I.V., and sublingual forms of nitroglycerin provide a rapid onset of action, whereas the ointment, oral, and patch forms have a slower onset and a prolonged duration of action.
Drug administration routes include the enteral, parenteral, and transcutaneous routes.
ENTERAL
The enteral route consists of oral, gastric or nasogastric, and rectal administration. Drugs administered enterally enter the blood circulation by way of the GI tract. This route is considered the most natural and convenient route as well as the safest. As a result, most drugs are taken enterally, usually to provide systemic effects.
Oral
Gastric or Nasogastric
Drugs administered through a gastrostomy or nasogastric tube enter the stomach directly, bypassing the mouth and esophagus. They’re usually administered in liquid form because an intact tablet or capsule could cause an obstruction in a gastric or nasogastric tube. Sometimes, a tablet may be crushed, or a capsule opened for gastric or nasogastric administration; however, doing so will affect the drug’s release. You may need to consult a pharmacist to determine which tablets can be crushed or capsules opened.
Rectal
Some enteral drugs are administered rectally—as ointments, solutions, or suppositories—to provide either local or systemic effects. When inserted into the rectum, suppositories soften, melt, or dissolve, releasing the drug contained inside them. The rectal route may be preferred for drugs that are destroyed or inactivated by the gastric or intestinal environment or that irritate the stomach. It also may be indicated when the oral route is contraindicated because of difficulty swallowing or vomiting. The drawbacks of rectal administration include inconvenience, noncompliance, and incomplete or irregular drug absorption.
PARENTERAL
In parenteral drug administration, a drug enters the circulatory system through an injection rather than through GI absorption. This administration route is chosen when rapid drug action is desired; when the patient is uncooperative, unconscious, or unable to accept medication by the oral route; or when a drug is ineffective by other routes. Drugs may be injected into the arteries, joints, muscles, spinal column, and veins. However, the most common parenteral routes are the intradermal (I.D.), intramuscular (I.M.), intravenous (I.V.), and subcutaneous (SubQ) routes. Drugs administered parenterally may be mixed in either a solution or a suspension; those mixed in a solution typically act more rapidly than those mixed in a suspension. Parenteral administration has several disadvantages: The drug can’t be removed, or the dosage reduced once it has been injected, and injections typically are more expensive to administer than other dosage forms because they require strict sterility.
Intradermal
Common sites for intradermal injection are the arm and the back. Because only about 0.1 ml may be administered intradermally, this route is rarely used except in diagnostic and test procedures, such as screening for allergic reactions.
Intramuscular
I.M. injections are administered deep into the anterolateral aspect of the thigh (vastus lateralis), the dorsogluteal muscle (gluteus maximus), the upper arm (deltoid), or the ventrogluteal muscle (gluteus medius). I.M. injections typically provide sustained drug action. This route is commonly chosen for drugs that irritate the subcutaneous tissue. The drug should be injected as far as possible from major nerves and blood vessels.
Intravenous
In I.V. drug administration, an aqueous solution is injected directly into the vein—typically of the forearm. Drugs may be administered as a single, small-volume injection or as a slow, large-volume infusion. Because drugs injected I.V. don’t encounter absorption barriers, this route produces the most rapid drug action, making it vital in emergency situations. Except for I.V. fat emulsions used as nutritional supplements, oleaginous preparations aren’t usually administered by this route because of the risk of fat embolism.
Subcutaneous
The subcutaneous route may be used to inject small volumes of medication, usually 1 ml or less. Subcutaneous injections typically are given below the skin in the abdominal area, lateral area of the anterior thigh, lateral lumbar area, or posterior surface of the upper arm. Injection sites should be rotated to minimize tissue irritation if the patient receives frequent subcutaneous injections—as, for example, in a patient who takes insulin.
TRANSCUTANEOUS
In transcutaneous administration, a drug crosses the skin layers from either the outside (dermal) or the inside (mucocutaneous). This route includes inhalation, nasal, ophthalmic, otic, sublingual, topical, and vaginal administration.
Inhalation
Some drugs may be inhaled nasally or orally to produce a local effect on the respiratory tract or a systemic effect. Although drugs given by inhalation avoid first-pass hepatic metabolism, the lungs can also serve as an area of first-pass metabolism by providing respiratory conversion to more water-soluble compounds.
Nasal
Nasal solutions and suspensions are applied directly to the nasal mucosa for decreased systemic absorption and enhanced local penetration. These drugs are usually used to reduce the inflammation typically associated with perennial or seasonal rhinitis but may also be used for other purposes such as to elicit a systemic response.
Ophthalmic
Ophthalmic ointments and solutions are applied directly to the conjunctiva or cornea for enhanced local penetration and decreased systemic absorption. Ophthalmic solutions pose a greater risk of drug loss through the nasolacrimal duct into the nasopharynx than ophthalmic ointments do.
Otic
Otic solutions are instilled directly into the external auditory canal for decreased systemic absorption and local penetration. These drugs, which include anesthetics, antibiotics, and anti-inflammatory drugs, usually require occlusion of the ear canal with cotton after instillation.
Sublingual
In sublingual administration, tablets are placed under the tongue and allowed to dissolve. Nitroglycerin is commonly administered by this route, which allows rapid drug absorption and action. The sublingual route also avoids first-pass metabolism.
Topical
Topical drugs—including creams, lotions, pastes, and ointments—are applied directly to the skin. Transdermal delivery systems, usually in the form of a disk or an adhesive patch, are among the latest developments in topical drug administration. Because they provide slow drug release, these systems are typically used to avoid first-pass metabolism and ensure prolonged duration of action.
Vaginal
Vaginal creams, suppositories, and troches are inserted into the vagina for slow, localized absorption. Body pH that differs from blood pH causes drug trapping or reabsorption, which delays drug excretion through the renal tubules. Vaginal secretions are alkaline, with a pH of 3.4 to 4.2, whereas blood has a pH of 7.35 to 7.45.