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Sources for Medications and Therapeutic Drugs

Medical Drug Sources

Therapeutic or pharmaceutical drugs are commonly called medications, medicine, pills, or just "drugs". There are many sources of drugs and many resources are readily available to help identify, dispense, and administer medications competently, safely, and in accordance with the law. Whenever healthcare professionals join the workforce in a medical office, free-standing clinic, or hospital, they are faced with the fact that part of the everyday job routine is to deal with drugs. 


The subject of pharmacology was known as Materia Medica until 1890 when the current term began to come into use. Pharmacology is defined as the study of drugs and their actions. The sub-sciences of pharmacology and their specific fields of study are as follows:

Pharmacognosy: The recognition, quality, purity, and identification of drugs.
Pharmacy: The preparation, stability, preservation, and storage of pharmaceutical preparations.
Posology: Dosage or amount of drugs to be administered.
Pharmacodynamics: The response of living tissue to chemical stimulation in the absence of disease. This almost exclusively deals with research and development.
Pharmacotherapeutics: The action of drugs on living tissue in the presence of disease; treatment of the sick.
Toxicology: The study of toxic or poisonous effects of substances.


There are several sources from which medications are derived. Drugs are derived from the following four main sources:

  • Plant sources: Obtained from plant parts or products. Seeds, stem, roots, leaves, resin, and other parts yield these drugs. Examples include digitalis and opium.
  • Animal sources: Glandular products from animals are used, such as insulin and thyroid.
  • Mineral sources: Some drugs are prepared from minerals, for example, potassium, chloride, and lithium carbonate (an antipsychotic).
  • Synthetic sources: Laboratories duplicate natural processes. Frequently this can eliminate side effects and increase the potency of the drug. Examples include barbiturates, sulfonamides, and aspirin.

Brand Name and Generic Name of a Drug:

When a drug is developed and marketed, it is assigned a specific name that is patented by the pharmaceutical company that has manufactured it. This is called the trade or brand name of the drug, and is the exclusive property of the manufacturer. After a patent has expired (drug patents run 17 years,) other companies (any number of companies!) may manufacture and sell the drug either under different brand names or under a drug's generic name. These exact copies of the original drug are then called generic drugs. The generic name is often descriptive of the chemical composition or class of the drug. Generic names are established by the U.S. Adopted Name Council (USAN,) and the generic USAN name is identical to the United States Pharmacopeia or National Formulary name.

References and Official Books on Drugs:

Fortunately, there are many resources available to medical staff to learn about most medications available on today’s market, however, beware of certain resources on the Internet bearing on the matter! Always make sure when consulting the Internet that you know who the publisher of the website is before you use it, and always check out the general purpose is of the site. It will not hurt to always take the extra step and double check any information retrieved! That protects you and the patient.


One very reliable reference to learn about medications is the Physician’s Desk Reference (PDR). It is the most widely used professional drug handbook. However, it is really a drug reference intended for use by physicians. It only contains information supplied by the pharmaceutical companies, offers no comparisons among drugs, and only lists FDA-approved indications; therefore it is not a one hundred percent complete reference.


A references that is easier to read and use is the U.S. Pharmacopeia/Dispensing Information
(USP/DI), which consists of three volumes:
Volume 1: Drug Information for the Health Care Professional
Volume 2: Advice for the Patient
Volume 3: Approved Drug Products and Legal Requirements


The American Hospital Formulary Service (AHFS) Drug Information, and the Compendium of Drug Therapy are also excellent reference books.


The United States Pharmacopeia and National Formulary (USP-NF) provides standards for drugs of therapeutic usefulness and pharmaceutical necessity. It provides tests for identity, quality, strength, and purity.

medical assistant writesRemember! Remember: all these references are routinely updated, and usually include the medication’s classification, brand and generic name, as well as their organic and chemical names, and list sided effects, precautions and warnings, contraindications, routes, and dosages.

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