Introduction to respiratory care pharmacology

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CHAPTER 1

Introduction to respiratory care pharmacology

Key terms and definitions

Acute respiratory distress syndrome (ARDS)

Respiratory disorder characterized by respiratory insufficiency that may occur as a result of trauma, pneumonia, oxygen toxicity, gram-negative sepsis, and systemic inflammatory response.

Aerosolized agents

Group of aerosol drugs for pulmonary applications that includes adrenergic, anticholinergic, mucoactive, corticosteroid, antiasthmatic, and antiinfective agents and surfactants instilled directly into the trachea.

Airway resistance (Raw)

Measure of the impedance to ventilation caused by the movement of gas through the airway.

Brand name

See Trade name.

Chemical name

Name indicating the chemical structure of a drug.

Chronic obstructive pulmonary disease (COPD)

Disease process characterized by airflow limitation that is not fully reversible, is usually progressive, and is associated with an abnormal inflammatory response of the lung to noxious particles or gases. Diseases that cause airflow limitation include chronic bronchitis, emphysema, asthma, and bronchiectasis.

Code name

Name assigned by a manufacturer to an experimental chemical that shows potential as a drug. An example is aerosol SCH 1000, which was the code name for ipratropium bromide, a parasympatholytic bronchodilator (see Chapter 7).

Cystic fibrosis (CF)

Inherited disease of the exocrine glands, affecting the pancreas, respiratory system, and apocrine glands. Symptoms usually begin in infancy and are characterized by increased electrolytes in the sweat, chronic respiratory infection, and pancreatic insufficiency.

Drug administration

Method by which a drug is made available to the body.

Generic name

Name assigned to a chemical by the United States Adopted Name (USAN) Council when the chemical appears to have therapeutic use and the manufacturer wishes to market the drug.

Nonproprietary name

Name of a drug other than its trademarked name.

Official name

In the event that an experimental drug becomes fully approved for general use and is admitted to the United States Pharmacopeia–National Formulary (USP-NF), the generic name becomes the official name.

Orphan drug

Drug or biologic product for the diagnosis or treatment of a rare disease (affecting fewer than 200,000 persons in the United States).

Pharmacodynamics

Mechanisms of drug action by which a drug molecule causes its effect in the body.

Pharmacogenetics

Study of the interrelationship of genetic differences and drug effects.

Pharmacognosy

Identification of sources of drugs, from plants and animals.

Pharmacokinetics

Time course and disposition of a drug in the body, based on its absorption, distribution, metabolism, and elimination.

Pharmacology

Study of drugs (chemicals), including their origin, properties, and interactions with living organisms.

Pharmacy

Preparation and dispensing of drugs.

Pneumocystis carinii (jiroveci)

Organism causing Pneumocystis pneumonia in humans, seen in immunosuppressed individuals such as those infected with human immunodeficiency virus (HIV).

Prescription

Written order for a drug, along with any specific instructions for compounding, dispensing, and taking the drug. This order may be written by a physician, osteopath, dentist, veterinarian, and others but not by chiropractors or opticians.

Pseudomonas aeruginosa

Gram-negative organism, primarily a nosocomial pathogen. It causes urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia, bone and joint infections, gastrointestinal infections, and various systemic infections, particularly in patients with severe burns and in patients who are immunosuppressed (e.g., patients with cancer or acquired immunodeficiency syndrome [AIDS]).

Respiratory care pharmacology

Application of pharmacology to the treatment of pulmonary disorders and, more broadly, critical care. Chapter 1 introduces and defines basic concepts and selected background information useful in the pharmacologic treatment of respiratory disease and critical care patients.

Respiratory syncytial virus (RSV)

Virus that causes the formation of syncytial masses in cells. This leads to inflammation of the bronchioles, which may cause respiratory distress in young infants.

Therapeutics

Art of treating disease with drugs.

Toxicology

Study of toxic substances and their pharmacologic actions, including antidotes and poison control.

Trade name

Brand name, or proprietary name, given by a particular manufacturer.

Pharmacology and the study of drugs

The many complex functions of the human organism are regulated by chemical agents. Chemicals interact with an organism to alter its function, providing methods of diagnosis, treatment, or prevention of disease. Such chemicals are termed drugs. A drug is any chemical that alters the organism’s functions or processes. Examples include oxygen, alcohol, lysergic acid diethylamide (LSD), heparin, epinephrine, and vitamins. The study of drugs (chemicals), including their origin, properties, and interactions with living organisms, is the subject of pharmacology.

Pharmacology can be subdivided into the following more specialized topics:

The principles of drug action from dose administration to effect and clearance from the body are the subject of processes known as drug administration, pharmacokinetics, and pharmacodynamics. These processes are defined and presented in detail in Chapter 2. Table 1-1 summarizes key developments in the regulation of drugs in the United States.

TABLE 1-1

Legislation Affecting Drugs

1906 First Food and Drugs Act is passed by Congress; the United States Pharmacopeia (USP) and the National Formulary (NF) were given official status
1914 Harrison Narcotic Act is passed to control the importation, sale, and distribution of opium and its derivatives as well as other narcotic analgesics
1938 Food, Drug, and Cosmetic Act becomes law. This is the current Federal Food, Drug, and Cosmetic Act to protect the public health and to protect physicians from irresponsible drug manufacturers. This act is enforced by the Food and Drug Administration (FDA)
1952 Durham-Humphrey Amendment defines the drugs that may be sold by the pharmacist only on prescription
1962 Kefauver-Harris Amendment is passed as an amendment to the Food, Drug, and Cosmetic Act of 1938. This law requires proof of the safety and efficacy of all drugs introduced since 1938. Drugs in use before that time have not been reviewed but are under study
1970 Controlled Substances Act becomes effective; this act lists requirements for the control, sale, and dispensation of narcotics and dangerous drugs. Five schedules of controlled substances have been defined. Schedule I to Schedule V generally define drugs of decreasing potential for abuse, increasing medical use, and decreasing physical dependence. Examples of each schedule are as follows:
Schedule I All nonresearch use is illegal; examples—heroin, marijuana, LSD, peyote, and mescaline
Schedule II: No telephone prescriptions, no refills; examples—opium, morphine, certain barbiturates, amphetamines
Schedule III: Prescription must be rewritten after 6 months or five refills; examples—certain opioid doses, anabolic steroids, and some barbiturates
Schedule IV: Prescription must be rewritten after 6 months or five refills; penalties for illegal possession differ from those for Schedule III drugs; examples—phenobarbital, barbital, chloral hydrate, meprobamate (Equanil, Miltown), and zolpidem (Ambien)
Schedule V: As for any nonopioid prescription drug; examples—narcotics containing nonnarcotics in mixture form, such as cough preparations or Lomotil (diphenoxylate [narcotic; 2.5 mg] and atropine sulfate [nonnarcotic])
Orphan Drug Amendments of 1983 Provides incentives for the development of drugs that treat diseases that affect fewer than 200,000 patients in the United States
Drug Price Competition and Patent Restoration Act of 1984 Abbreviated new drug application for generic medication. Allows the patent to be extended for up to 5 years owing to loss of marketing because of FDA reviews
Prescription Drug User Fee Act of 1992 Reauthorized in 2007. User fees are paid for certain new drug applications by manufacturers
Dietary Supplement Health and Education Act of 1994 Established standards of dietary supplements. Specific ingredient and nutrition labels must be included on each package
Bioterrorism Act of 2002 More stringent control on biologic agents and toxins
Food and Drug Administration Amendments Act of 2007 FDA has greater authority over drug labeling, marketing, and advertising. Makes clinical trial information more visible to the public

For more information, access the FDA website at www.fda.gov.

Naming drugs

A manufacturer of a drug or pharmacologic agent must complete numerous steps set forth by the U.S. Food and Drug Administration (FDA). Along the way, each agent picks up various labels rather than a single name. An agent that becomes officially approved for general clinical use in the United States will have accumulated at least five different names, as follows:

• Chemical name: The name indicating the drug’s chemical structure.

• Code name: A name assigned by a manufacturer to an experimental chemical that shows potential as a drug. An example is aerosol SCH 1000, which was the code name for ipratropium bromide, a parasympatholytic bronchodilator (see Chapter 7).

• Generic name: The name assigned to a chemical by the United States Adopted Name (USAN) Council when the chemical appears to have therapeutic use and the manufacturer wishes to market the drug. Instead of a numeric or alphanumeric code, as in the code name, this name often is loosely based on the drug’s chemical structure. For example, isoproterenol has an isopropyl group attached to the terminal nitrogen on the amino side chain, whereas metaproterenol is the same chemical structure as isoproterenol except that a dihydroxy attachment on the catechol nucleus is now in the so-called meta position (carbon-3,5 instead of carbon-3,4). The generic name is also known as the nonproprietary name, in contrast to the brand name.

• Official name: In the event that an experimental drug becomes fully approved for general use and is admitted to the United States Pharmacopeia–National Formulary (USP-NF), the generic name becomes the official name. Because an officially approved drug may be marketed by many manufacturers under different names, it is recommended that clinicians use the official name, which is nonproprietary, and not brand names.

• Trade name: This is the brand name, or proprietary name, given by a particular manufacturer. For example, the generic drug named albuterol is currently marketed by Schering-Plough as Proventil-HFA, by GlaxoSmithKline as Ventolin-HFA, and by Teva as Proair HFA.

Following is an example of the various names for the drug zafirlukast, an agent intended to control asthma: