Chapter 14:
As a member of the medical office team, you will work with the physicians and other staff to assist patients with medications. It is likely that you will assist the physicians with prescription orders, medication refills, and patient instruction regarding their medication schedules. In this chapter, you will review the basic principles of pharmacology and drug therapy. The major classifications of drugs will be covered, along with information about ensuring safe and effective use of prescribed medications.
Pharmacology is the study of prescription drugs. As a medical assistant, you must have a basic understanding of commonly prescribed medication. You must be able to effectively use reference books to locate information about medications. Because of the vast array of available drugs, you will use reference material regularly. When administering medication to a patient, you will need to know why it is being used and how it should be administered. In addition, you will need to know the common side effects of the drug.
Several federal agencies control medication development and use. The Food and Drug Administration (FDA) controls the sale of over-the-counter medications (OTCs) as well as prescription drugs. The FDA also controls the development of new drugs and the process of these drugs being approved for distribution. Each drug has a name that corresponds to the chemical makeup of the drug. In addition, each drug is also given a unique generic name. This is the drug’s official name and is not copyrighted by the drug manufacturer. The generic name is not capitalized in printed material. Once a medication is approved, the manufacturer is awarded a copyright for that drug for 17 years. During this time, the original manufacturer is the only company that can sell the medication. The manufacturer assigns each new drug a trade name that is used to market the drug under their company name. Trade names of medications are capitalized. Once the copyright expires, other manufacturers may market the drug. Thus, the drug may have many different trade names but the generic name will not change.
When interviewing your patients, you will initiate and maintain an up-to-date list of the medications that are both prescribed and self-administered. Be sure to ask patients specifically about any pills, herbal remedies, or OTCs that they take regularly. It is common for patients to forget to tell their health care provider about self-administered medications, vitamins, and other remedies; however, these may cause complications or incompatibilities with prescription drugs. The doctor will want to review a comprehensive list of each patient’s current medications.
Production and distribution of controlled substances or narcotics are monitored by the federal government through the Drug Enforcement Administration (DEA). The agency is responsible for regulating the use, storage, and recordkeeping involved with narcotics. The DEA also is involved with enforcement of drug abuse laws and drug abuse prevention. The DEA identifies which drugs are classified as controlled substance. The Controlled Substances Act designates a schedule in which all pertinent drugs are separated into five categories. Based on the schedule to which the drug is assigned there are specifications about how and when the drug can be prescribed. Schedule I drugs have no acceptable medical use and cannot be prescribed. Schedules II through V have limitations on prescriptions that must be followed. Meticulous records must be kept in the office when administering, destroying, and accounting for narcotics. Every physician who prescribes controlled substances must have a federal DEA registration number. Prescriptions are completed in triplicate with copies available to the pharmacist and to government regulators. Controlled substances must be stored in a locked area that is secure and procedures must be in place to track their use. Prescription forms should also be kept in a secured area to prevent access by unauthorized persons. If you work in an office where controlled substances are kept and administered, it is essential that you understand the state and federal laws that govern the storage and use of these drugs.
Drug abuse is also something that you should be aware of, and you should know your role in its prevention. All drugs, not only controlled substances, have the potential for misuse. Drug misuse is the improper administration of drugs that can cause physical dependence. Such dependence can occur with routine OTC medications such as laxatives or antihistamines. Drug abuse is the use of a drug in a manner that leads to physical or psychological dependence. When a person develops a physiological dependence to a substance and stops regular intake of the substance, withdrawal may occur. Symptoms of withdrawal can cause minor discomfort or may be life threatening. Patients with problems with drug abuse or family members who have concerns may seek information about treatment alternatives. You should be aware of treatment centers that patients can be referred to if they are having problems with drug abuse. To avoid drug abuse in the office setting, the medical assistant should monitor phone calls for narcotic refills and document requests in the clinical record.
References for looking up medication information must be available in all medical offices. It is important to know the drug action, use, contraindications, precautions, adverse reactions, usual dosage, and available drug forms. Information is available in package inserts, the Physicians’ Desk Reference, the U.S. Pharmacopeia, and other drug references. Your practice may use an online drug reference system. If you work in a specialty practice, you may want to have patient education material for commonly used drugs. It is likely that drug companies and sales staff can provide you with this material.
There are four main sources of drugs:
Medication uses vary widely. Some common examples are listed in the following table.
| Type of Medication | Clinical Use |
|
Diagnostic |
Used to diagnose a health problem Example: allergy testing |
|
Palliative |
Provides relief from symptoms Example: pain medication |
|
Prophylaxis |
Provides prevention of illness or disease Example: immunizations |
|
Replacement |
Replaces substances needed to maintain health Example: insulin or thyroid replacement |
|
Therapeutic |
Used to treat and cure Example: antibiotics |
As the name implies, all prescription medications require an order from a physician or other licensed practitioner. Prescriptions can be handwritten, computer generated, faxed, or phoned in to a pharmacy. Schedule II controlled substances or narcotics require that the prescription must be handwritten, signed by the physician, and filled at the pharmacy within a certain period of time. It is acceptable for the provider to fax the signed prescription for Schedule II drugs to the pharmacy. Schedule III–V drugs may be communicated to the pharmacy orally, in writing, or via fax, and refilled based on authorization on the prescription up to five times. Each prescription will include the following items:
When your office staff provides a patient with a prescription, the information and date should be noted in the medical record and the medication list should be updated. When the drug is refilled, the date and name of the person confirming the refill should be noted in the record. At each appointment, it is important to review and update the medication list with relevant information.
The oral route is the most convenient and cost-effective method to administer most medications. However, some medications cannot be absorbed by the digestive system or are destroyed by the digestive enzymes. Sometimes patient problems such as nausea or vomiting prevent oral administration of medications. Food may slow or prevent absorption of some medications, so they may need to be given before or between meals. Some medications may be damaging to the digestive system and may need to be enteric coated so that they will not dissolve until they reach the small intestine.
The parenteral route refers to the delivery of medication by injection. Medications can be injected in a variety of ways. The most common ways include intramuscular injections into large muscles of the body and subcutaneous injections into the subcutaneous tissues of the body. Insulin is an example of a subcutaneous injection using a small-gauge needle. Other thicker medications such as penicillin require that a large, deep intramuscular injection be administered. Other forms of injection include intradermal or allergy testing, intraspinal, or intra-articular.
Some drugs are administered by mucous membrane absorption. The routes include the mouth, throat, nose, eyes, rectum, vagina, respiratory tract, and urinary tract. Sublingual administration refers to the absorption of medication from the blood vessels below the tongue. Respiratory inhalation and rectal suppository forms of administration are also included in the mucous membrane category.
Topical absorption includes all methods that use the skin to absorb medication. This includes ointments, creams, lotion, and dermal patches.
Drug distribution refers to the transportation of the medication throughout the body once it is absorbed.
Drug action refers to how the medication works in the body. There are many different methods of drug action, dependant on the type of medication.
Drug metabolism is how the medication is converted for excretion from the body.
Drug excretion is the removal of medication from the body. The most common method of excretion is through the kidneys. The combination of metabolism and excretion of half of the medication dose is called the half-life of the medication. Physicians use the half-life of the drug to calculate the dosage schedule.
Weight: In prescribing medication, the usual adult dose is based on a body weight of 150 pounds. Dosage for children may be based on body weight or on body surface area. Dosage for adults who vary a great deal in weight from the 150-pound average may also need to be adjusted.
Age: Dosage may need to be adjusted for children and the elderly due to differences in metabolism or immaturity of the body systems.
Physiological state: States such as pregnancy will change the safety of administration of medications. It is important to determine any potential harmful effects on the fetus of medication treatment in pregnant women. All medications are rated for their safety in pregnancy. The body distribution of fat to muscle differs between men and women, and this may also change the action of medications in the body.
Time of day: Some medications must be administered at the correct time to get the desired effect.
Pathological issues in the body: Disease processes change the dosage needs of the body. Disease of the kidney and liver will change metabolism and excretion and necessitate a decrease in either dosage strength or frequency.
Immune response: Development of antibodies to the medication may cause an allergic reaction to the medication if given again. The most severe reaction is anaphylactic shock, which is a medical emergency.
Psychological factors: Mental attitude may make a difference in how the medication works for the patient. For years, health care providers have given placebos, which contain no active ingredients. The placebo effect refers to the fact that if the patient believes a medication will be helpful, it may be effective even if what is administered is a placebo.
Tolerance: Over a period of time, patients may develop a lack of responsiveness to medications taken regularly.
Accumulation: This occurs if the medication is not adequately excreted from the body prior to another dosage being given. It can happen due to too-frequent dosing or to problems with metabolism and excretion.
Idiosyncrasy: Sometimes a medication will have an effect that is not expected or contradictory to what is expected.
Drug interactions: These may occur when patients take two or more medications. Such interactions may be beneficial or detrimental. If the effect is antagonistic, one of the medications shortens or decreases the intensity of the other. Synergism is when one drug increases or lengthens the action of the other. This can be a negative or positive effect. Potentiation is when one drug increases the action of the other.
Drugs can be classified by several different methods and some medications will be part of more than one category. Drugs may be classified by their action in the body or by the body system that they affect. The following table comprises examples of classification by drug action.
| Classification | Action | Example |
| Adrenergic | Constricts lumen of a vessel | Epinephrine |
| Anesthetic | Brings about inability to feel pain | Lidocaine |
| Antianxiety | Reduces anxiety | Ativan |
| Antibiotic | Kills pathogens | Amoxicillin |
| Anticoagulant | Decreases the clotting time | Coumadin |
| Antidepressant | Decreases depression | Zoloft |
| Antihistamine | Counteracts histamines | Zyrtec |
| Antihypertensive | Decreases blood pressure | Lopressor |
| Anti-inflammatory | Decreases inflammation | Advil |
| Anti-tussive | Decreases cough | Robitussin |
| Bronchodilator | Relaxes smooth muscle of respiratory system | Proventil |
| Cathartic | Irritates lining of the bowel | Dulcolax |
| Decongestant | Relieves congestion | Sudafed |
| Diuretic | Inhibits reabsorption of sodium, chloride, and water | Lasix |
| Hypnotic | Induces sleep | Dalmane |
| Hormone replacement | Replaces deficient hormones | Synthroid |
| Narcotic | Decreases central nervous system activity | Demerol |
Patients also must be given information about any medications that are prescribed for treatment of a medical condition. Patients should be given both verbal and written instructions about the name of their medications, the actions of the medication, the correct route of drug administration, as well as the time schedule and correct dosing. It is very important that patients be aware of side effects so they can be alert for signs and symptoms that they need to report back to your office. A list of commonly prescribed medications and information on each is available at rxlist.com.