One method of classifying drugs is based on the form in which they are prepared (liquid or solid).
Systems of measurement
Medical assistants must be familiar with the measurement of drug dosage. Three systems of measure are used in the United States for prescribing and administering medication: the metric system, the apothecaries' system, and the household system. Each has units of weight, volume, and length.
The most commonly used, most accurate, and easiest to use of all the measuring systems. The metric system is used for most scientific and medical measurements, and all pharmaceutical companies now use the metric system for labeling medications.The basic metric units of measurement are the gram, liter, and meter. Prefixes added to the words gram, liter, and meter indicate smaller or larger units in the system.
The basic metric unit of weight (for solids).
The basic metric unit of volume (for liquids).
The basic metric unit of length.
Cubic centimeter (cc)
The amount of space occupied by 1 milliliter: 1 mL = 1 cc.
An older and less accurate measuring system than the metric system. The basic unit of weight in the apothecaries' system is the grain (gr), derived from the weight of a large grain of wheat. The remaining units of increasing weight are the scruple (scr), dram (dr, ), ounce (oz, ), and pound (lb). The pound, which equals 12 apothecaries' ounces, is not generally used in the administration of medication.
More complicated and less accurate for administering liquid medication than the other systems. The only household units of measurement used in the administration of medication are based on volume. The basic unit of liquid volume in the household system is the drop (gt, plural gtt). One drop is approximately equal to 0.06 mL in the metric system and 1 minim in the apothecaries' system. The remaining units, in order of increasing volume, are the teaspoon, tablespoon, ounce, teacup, and glass or cup.
Lists approximate, not exact, equivalents between systems. Check the chart several times, and place a ruler under the applicable line to be sure that you are reading it correctly.
Calculating drug doses
On occasion, it is necessary to calculate drug doses when the drug is not available in the exact amount the physician has prescribed. Drug doses can be calculated with either the ratio method or the fraction method.
"Seven rights" of drug administration
Never deviate from these seven principles: right patient, right drug, right dose, right time, right route, right technique, right documentation.
Always check the name on the order, then ask the patient to tell you his or her name.
Read the drug label before you take the container off the shelf, before you administer the drug, and before you put the container back on the shelf. Make sure to check the expiration date, and never use a drug that has passed this date.
Compare the dose on the order with the dose you prepare.
If a drug must be taken after a meal, make sure that the patient has eaten recently.
Make sure that the route you are preparing to use matches the route the doctor ordered.
Always use the proper administrative technique.
Document the procedure immediately after administering the drug. Include the date, time, drug name, dose, administration route, patient reaction, education of the patient about the drug, and your initials.
Route of administration
Medication may be administered by numerous routes, including oral, sublingual, buccal, inhalation, topical, rectal, urethral, vaginal, parenteral (intramuscular, subcutaneous, intradermal, or intravenous), ophthalmic, and otic.
The drug is given by mouth in either a solid form (tablet, capsule, or powder) or a liquid form (water-based solution, suspension, or alcohol solution). The drug is absorbed into the bloodstream through the lining of the stomach and intestine. This method is easy, safe, and economical, but drug absorption is slow and may be affected by the presence of food. Some medications may also cause nausea or stomach discomfort.
The medication must be placed under the tongue until it dissolves. This method is faster than the oral method.
The medication is placed in the mouth and absorbed in the buccal area. The patient should not chew or swallow the medication.
The medication is given in the form of gases, sprays, or aerosol mists (fluid droplets). The respiratory tract absorbs medication more rapidly than any other mucous membrane. One inhalation medication that should be kept in every medical practice is oxygen.
Used in treating skin disorders. The medication is applied directly to affected areas of the skin. Topical medications come in the form of sprays, creams, lotions, ointments, transdermal patches, and compresses.
Transdermal drug delivery (TDD)
A method of applying a drug to unbroken skin. The drug is absorbed continuously through the skin and enters the bloodstream. It is used particularly for the administration of nicotine, nitroglycerin, and scopolamine. To promote adhesion to the skin, the patch should be applied to a clean, dry area without hair.
Useful if the patient is nauseated, vomiting, or unconscious. The best time to administer a rectal drug is after a bowel movement or the elimination of an enema. A suppository must be inserted about 2 inches above the internal anal sphincter.
A liter or more of a solution of medication in warm water is introduced as a douche into the vagina under low pressure. Other forms of medication are inserted into the vagina with an applicator.
Medication is given outside the gastrointestinal tract. A common parenteral route is by injection. Drugs that are injected are absorbed more rapidly and completed than most other routes. The disadvantages of the parenteral route are that all equipment must be sterile; that the method is often expensive, painful, and awkward for patients to administer themselves; and that there is a danger of injecting a drug incorrectly into a vein, which could cause serious harm or even death.
Given into the dermal layer of the skin. A very short needle of small gauge is used. The angle of insertion is 15 degrees, nearly parallel to the skin. Absorption is slow. Only a small amount of medication may be injected (0.01 to 0.2 cc). The anterior forearm is the most common area for injection. The gauge is usually 25 to 27. When an intradermal injection is correctly administered, a small wheal is raised on the skin.
Subcutaneous (SC) injection
Given into the layer of fatty tissue that lies just below the skin. The most common sites for SC injections are the upper lateral part of the arm, anterior thigh, upper back, and abdomen. The needle length varies from to inch, and the gauge ranges from 23 to 25. The needle should be inserted at a 45-degree angle to the skin. Drugs given subcutaneously must be isotonic, nonviscous, water-soluble, and nonirritating. The amount of drug injected through the SC route should not exceed 1 mL.
Intramuscular (IM) injection
Given deep into a muscle. Muscles can absorb a greater amount of fluid without discomfort to the patient, and IM injections are preferred for substances that can irritate the skin. The most common muscles used for this method of injection are the deltoid, gluteus medius, and vastus lateralis. The needle should be 1 to 3 inches in length or sometimes longer. The gauge of the needle ranges between 18 and 23. The angle of insertion is 90 degrees. Dosage may vary from 0.5 to 5 mL.
Intravenous (IV) injection
Given directly into a vein. IV injection is usually used in an emergency situation for an immediate effect. The disadvantage is that painful infection may result. Rotation of the sites is necessary if injections are given repeatedly. Needles are 1 to inch in length. The gauges are usually between 20 and 21.
The insertion into a vein of a tube or a needle through which fluids are slowly added to the bloodstream over a period of time. It is also called infusion. The IV drip should not be confused with IV injection.
Drugs are placed into the patient's eye.
Drugs are placed into the patient's ear.
Consists of several parts: hub, hilt, shaft, lumen, point, and bevel.
The inside diameter of the needle. A larger gauge indicates a smaller diameter. The common range for administering medication is between 18 and 27 gauge.
Ranges between of an inch and 3 inches.
Used for inserting fluids into the body. It is usually made of plastic. A syringe consists of three parts: barrel, flange (rim), and plunger.
Available in 2-, 2.5-, 3-, and 5-cc sizes. They are commonly used to administer IM injections.
Designed for an insulin injection. It is calibrated in units (U); 100 U = 1 mL. The most commonly used size is the 100 U syringe (with a capacity of 100 units), divided into increments of 2 units. Syringes are also available in 40 U and 80 U sizes.
Has a capacity of 1 cc. The calibrations are divided into tenths (0.1) and hundredths (0.01) of a cubic centimeter.
Known as a cartridge. It is a sterile, disposable syringe. Needle units are packaged by the manufacturer with a single dose of medication inside, ready to administer.
A small, sealed glass container that holds a single dose of medication.
A closed glass container with a rubber stopper protected by a soft metal cap. There are two types: single- and multiple-dose.
Located at the top of the arm on the upper, outer surface. It is a good site for a small amount of medication. The deltoid is commonly used for injections of tetanus boosters in adults, rabies vaccine after exposure, and vitamin B12. Major blood vessels and nerves in the upper arm are located in the posterior portion of the arm. A 23-gauge, 1-inch needle is most frequently used for the injections in the deltoid muscle. A 25-gauge, inch needle is used for a small arm.
Gluteus medius muscle
Most commonly used for deep IM injections, for injections of viscous medications (antibiotics), and for injections of irritating drugs. This site should not be used in infants.
A directive issued by a physician/licensed prescriber telling a nurse or another health-care worker which drug to administer. These orders should be written down so that there is little chance of error. In an emergency situation, when there is no time to give written instructions, the order should be written down and signed by the prescriber within 24 hours. Orders are written on the physician's order sheet in a patient's chart.
Used to write medication orders for outpatients.
Medication order components
The patient's full name, date of the order, name of the drug preceded by the abbreviation Rx, dosage, route of administration, time and frequency, prescriber's signature (without which the medication order is not legal), number of refills and quantity (preceded by the word repetatur), and the prescriber's DEA number on all prescriptions for controlled substances.
Specifies that a drug be administered until a discontinuation order is written or until a specified termination date is reached.
Outlines a specific condition for which the drug is to be administered. These orders are frequently used in critical care units, where the patient's condition changes rapidly, and in long-term care facilities.
Specifies that a drug be given only when the patient needs it, such as for pain or before an operation or diagnostic procedure. (PRN stands for pro re nata, roughly "for a circumstance that has come to be" or "as the situation requires.")
A single order that is administered immediately, written usually for emergencies.
In setting up medication to be administered, be sure to observe the "seven rights" of drug administration. Get information from the Kardex, medication record, or medicine cart, and concentrate on nothing but the task at hand. Do not engage in a conversation with someone else while you are trying to prepare and administer the medication.
Clean up by washing your hands, and try not to touch the drugs at all. Never give a pill that has fallen on the floor. Keep unit doses sealed until you are ready to give them.
After you have calculated the correct dose, you may find that you need only half or a quarter of a tablet. If you need to divide a tablet, use a pill cutter or a knife to make a quick, clean break. If you have to touch the pill to break it, use a tissue. Never open the tablet package until you administer the medication to the patient. If you need tablets from a bottle, pour them into the medicine cup without touching them. Sometimes tablets must be crushed or capsules opened.
Remove the cap and place it upside down to prevent contamination. Hold the bottle so that the label is against the palm of your hand in order to prevent medication from running down the side of the bottle and damaging the label. Place the medication cup on a stable, flat surface at eye level to ensure accuracy. Do not hold the cup at eye level because you might tip the cup as you pour.
A card-filing system that serves as a quick reference to the needs of a patient. Each card is folded once and lists up-to-date information about medications, treatments, and care. All information is written in pencil, so it can be erased and updated.
Used to record the patient's name, room and bed number, name of the drug, dose, route, and time at which the drug is to be given. One medicine card is written for each type of drug the patient is to receive; the information is copied over from the Kardex file.
Medication administration record (MAR)
A convenient way to document all the drugs administered to a patient every day, especially if there are several drugs given at different times. If the drug is to be given regularly, a complete schedule is written for all administration times. Each time a dose is administered, the health-care worker checks off the time at which it was given and initials the entry.
Patient chart or medical record
All events related to the treatment of a patient, including the administration of medications, need to be recorded in the patient's chart as a permanent record of care received. When medication is administered, you must record the drug's name, the strength and amount, the route, the times at which it is given, and the initials and signature of the health-care worker who administered it.
The process of rendering a person immune to a disease.
Produced by the administration of vaccines or other forms of immunization.
Made from dead or harmless infectious agents. They trigger the body's immune response to manufacture antibodies against the particular disease-causing agent.
There are two types of rabies immunizing products. Rabies vaccines induce an active immune response that includes the production of neutralizing antibodies. Rabies immune globulins (RIGs) provide rapid, passive immune protection that persists for only a short time (a half-life of approximately 21 days).
Exposure to rabies
Rabies can be transmitted only when the virus is introduced into open cuts or wounds in skin or mucous membranes. Two categories of exposure (bite and nonbite) should be considered.
Any penetration of the skin by teeth constitutes a bite exposure. Bites to the face and hands carry the highest risk, but the site of the bite should not influence the decision to begin treatment.
Scratches, abrasions, open wounds, or mucous membranes contaminated with saliva or other potentially infectious material (such as brain tissue) from a rabid animal constitute nonbite exposure. If the material containing the virus is dry, the virus can be considered noninfectious.
Studies conducted in the United States by the CDC have shown that a regimen of one dose of HRIG and five doses of HDCV over a 28-day period are safe and induce an excellent antibody response in all recipients.
The schedule of the HDCV vaccinations is
•first dose as soon as possible after exposure
•second dose 3 days after the first
•third dose 7 days after the first
•fourth dose 14 days after the first
•fifth dose 28 days after the first
Hepatitis A vaccine
Should be stored and shipped at temperatures ranging from 35.6°F (2°C) to 46.4°F (8°C) and should not be frozen. The vaccine should be administered intramuscularly into the deltoid muscle. A needle length appropriate for the patient's age and size should be used.
Hepatitis B vaccine
The vaccination schedule used most often for adults and children is three muscular injections, the second and third administered 1 and 6 months after the first, respectively.
In June of 2006, the FDA licensed the first vaccine developed to prevent cancer and other diseases in women that are caused by certain types of the genital human papillomavirus (HPV). This vaccine (trade name Gardasil) protects against four HPV types (6, 11, 16, and 18) that are responsible for cervical cancer and 90 percent of genital warts. It is recommended for females between the ages of 9 and 26 years.
Causes both endemic and epidemic disease, principally meningitis and meningococcemia. As a result of the control of Haemophilus influenzae type B infections (which can result in meningitis), Neisseria meningitidis has become the leading cause of bacterial meningitis in children and young adults in the United States.
Routine vaccination with the quadrivalent meningococcal polysaccharide vaccine is not recommended because of its relative ineffectiveness in children younger than 2 years of age (among whom risk for endemic disease is highest) and its relatively short duration of protection. However, the polysaccharide meningococcal vaccine is useful for controlling serogroup C meningococcal outbreaks.
Indications for use
In general, the use of polysaccharide meningococcal vaccine should be restricted to persons 2 years of age or older; however, children as young as 3 months of age may be vaccinated to elicit short-term protection against serogroup A meningococcal disease (two doses administered 3 months apart should be considered for children 3 to 18 months of age).
Primary vaccination, for both adults and children, is administered subcutaneously as a single 0.5 mL dose. The vaccine can be administered at the same time as other vaccines but at a different anatomical site (i.e., deltoid muscle or buttocks).
Pneumococcal polysaccharide vaccine
Administer pneumococcal vaccine to children who are at risk and to adolescents who have chronic illnesses associated with increased risk for pneumococcal disease or its complications. Use adolescents' visits to providers to ensure that the vaccine has been administered to persons for whom it is indicated: one dose of 0.5 mL, IM or SC.
In May of 2006, the FDA licensed a new vaccine to reduce older patients' risk of shingles, which is a painful skin rash, often with blisters, that is also called "herpes zoster." It is caused by the varicella zoster virus, the same virus that causes chickenpox. This vaccine (trade name Zostavax) has been shown to prevent shingles in about 50 percent of patients who are age 60 or older, and can also reduce the pain associated with shingles.
Tuberculin skin test
Several methods are used. The most common is the Mantoux test.
Administered by means of an intradermal needle and syringe. It must be read within 48 to 78 hours. The amount of solution that is injected is 0.1 mL. A short needle with a gauge of 26 to 27 is used.
Mantoux tuberculin skin test results
Induration of less than 5 mm is considered a negative reaction. According to the American Lung Association, induration of 5 mm or more is considered a positive reaction for infants, children, adults who have had close contact with active tuberculosis, persons with known or suspected HIV infection, and persons whose immune systems are suppressed.
An area of hardened tissue afer a tuberculin test.