What Is Pharmacology? - Pharmacology

Pharmacology is the study of chemicals drugs on living tissues and how those chemicals help diagnose, treat, cure, and prevent disease or correct the pathophysiology of living tissues. The term pharmacology is derived from two Greek words: pharmakon, the Greek word for drugs, and logos, the Greek word for science.

Pharmacology has its roots in folklore and tradition that dates back to ancient times when knowledge of the medicinal effects of plants were passed down through generations. By 1240 AD, pharmacology moved from the realm of home remedies to a science where drug standards were established and a measuring system was developed called the apothecary system that was used to measure quantities of drugs. Because drugs can vary in strength and purity, pharmacological standards have been developed that govern the manufacturing and control of drugs.

The United States Pharmacopeia National Formulary is the only official book of drug standards in the United States. If a drug is included in this book it has met the standards of quality, purity, and strength. These drugs can use the letters U.S.P. following the official name of the drug. Accurate dosage and the reliability of the effect the drug will have on a patient is dependent upon the purity and strength of the drug.

Purity is the dilution or mixture of a drug with other materials to give it a form that can be administered. Drugs may vary in the strength of their action. The strength of drugs from plants can depend on where the plant is grown, the age at which the plant is harvested, and how the harvest is preserved. Drug packaging standards determine what information needs to be displayed on packages of drugs.

In addition to these standards, there are a number of important laws that have been enacted to control the sale and distribution of drugs.

1938 FOOD, DRUG AND COSMETIC ACT Before 1938 there was no control over pharmaceuticals.

This changed when a drug company distributed a sulfa drug to treat pediatric patients. The drugs turned out to be a chemical similar to antifreeze. It was highly toxic and killed more than 100 people, including children.

At the urging of the public, the United States Congress passed the 1938 Food, Drug and Cosmetic Act. This act required:

  • Drugs must be proven save for use before they can be sold.
  • Inspections of drug manufacturing facilities.
  • Safe tolerance levels be identified to prevent the patient from being poisoned.
  • Cosmetics and therapeutic devices be controlled.


Until 1952, anyone could distribute drugs. With the passage of the Durham- Humphrey amendment to the Food, Drug and Cosmetic Act of 1938, a group of drugs was defined that could only be purchased if the patient had a prescription from a licensed practitioner.


The Food, Drug and Cosmetic Act of 1938 was amended once more in 1962 with the passage of the Kefauver-Harris Amendment. This amendment tightened controls on drug safety by requiring drug manufacturers to use standard labeling of drug containers. The label lists adverse reactions and contraindications or reasons why the drug should not be used.


By 1970, there was widespread abuse of prescription drugs. In an effort to contain this problem, Congress passed the Comprehensive Drug Abuse Prevent and Control Act. This act categorized controlled substances according to a schedule based on potential for abuse.

  • Schedule I is reserved for the most dangerous substances that have no recognized medicinal use.
  • Schedule II drugs have high abuse potential with accepted medicinal use.
  • Schedule III drugs have high abuse potential with accepted medicinal uses.
  • Schedule IV and V drugs have lower abuse potential with accepted medicinal uses.

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