Pharmacology is the study of drugs, or pharmaceuticals. The pharmacologist studies pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. Pharmacognosy is the study of the characteristics of natural drugs and their sources. Pharmacokinetics pertains to how the body absorbs, metabolizes, distributes, and excretes a drug. Pharmacodynamics relates to a drug's mechanism of action, or how it affects the body. Pharmacotherapeutics addresses the use of drugs to prevent or treat disease. Toxicology is the study of poisons and the toxic effects of drugs, including adverse effects or drug interactions.

Every drug has several names, including chemical, generic, and trade names. Based on its action, a drug can belong to one of many classifications. These data can be found in the Physicians' Desk Reference and other sources of drug information.

Patients can obtain nonprescription (over-thecounter) drugs without a physician's order. For prescription drugs, patients must have a physician's written (or oral) order. For drugs that have been classified as controlled substances because they are potentially dangerous and addictive, extensive regulations apply. The physician must be registered with the Drug Enforcement Administration and follow the legal requirements of the Controlled Substances Act of 1970 to administer, dispense, and prescribe these drugs.

Immunizations usually contain killed or weakened organisms. They are used to provide immunity against specific diseases. Childhood immunizations should follow a recommended schedule. Other immunizations should be given as the need arises.

No matter what type of drug a patient must take, your role as an educator is an important one. You need to teach patients about specific drugs and required safety precautions. When you educate a patient carefully and thoroughly about a drug, you enhance the likelihood of patient compliance and safety.