Pharmacology

Definition

Pharmacology is the study of how drugs act on biological systems.

Description

Pharmacology is the science of understanding how drugs act on the body and conversely, how the body acts on drugs. This is not to be confused with pharmacy, which deals with the preparation and dispensing of drugs. Drugs can be defined as chemical compounds with a specific therapeutic function, such as aspirin. Pharmacology focuses on how a drug gets into the body, where in the body the drug acts, and how the body gets rid of a drug. In addition, a pharmacologist will also study the therapeutic potential of a drug, the interaction of a drug with other drugs, and analyze adverse drug reactions, otherwise known as toxicities. There are several subdivisions and sub-disciplines of pharmacology which use the basic principles of pharmacology in different ways.

Pharmacology can be divided into subdivisions based on the body organ being studied. These include, but are not limited to, neuropharmacology, cardiovascular pharmacology, endocrine pharmacology, and chemotherapy. Neuropharmacology deals with the effect of drugs on the nervous system, which includes the brain, spinal cord, and nerves. Neuropharmacology includes the study of drugs of abuse such as heroin and also drugs used to treat nervous system disorders such as L-dopa, which is given to Parkinson's disease patients. Cardiovascular pharmacology focuses on drugs that modify the heart and vascular system. Blood pressure medications would be studied under this category. Endocrine pharmacology focuses on the interaction of drugs with various hormones or hormonal systems. Birth control pills would fall under the division of endocrine pharmacology. Lastly, the division of chemotherapy studies the pharmacology of drugs used to treat cancer such as tamoxifen used in breast cancer.

In addition to dividing the field of pharmacology on the basis of the targeted organ system, pharmacology can also be divided into sub-disciplines. These sub-disciplines include, but are not limited to, molecular pharmacology, behavioral pharmacology, and clinical pharmacology. Molecular pharmacology studies the interaction of drugs at the cellular level. This includes studies on the interaction of drugs with protein receptors expressed on the surface of the cell. For example, the asthma drug, albuterol, interacts with beta receptors in the lung to increase airflow. The effect of drugs on behavior is the

basis for the behavioral pharmacology discipline. Behavioral pharmacology includes addiction research which tries to understand why people become addicted to drugs like alcohol. The field of clinical pharmacology focuses more on the therapeutic use of drugs, the interactions of drugs with one another in the body, and the nature of adverse drug reactions.

The various subdivisions and disciplines of pharmacology pursue the discovery and understanding of drugs for the purpose of treating a disease or condition, such as high blood pressure. The basic principles of pharmacokinetics, pharmacodynamics, and efficacy are universal across the various areas of pharmacology. A significant amount of pharmacology research is spent on identifying new drugs to treat disease. In addition, it is important to predict drug toxicities or adverse reactions. This is accomplished by studying the pharmacokinetics of a drug. Pharmacokinetics is basically how drugs get into the body and how they get out. It describes the relationships between drug dosage and drug blood levels, which can be influenced by individual differences in drug absorption, distribution, metabolism, and elimination. This is important because if a drug is eliminated by the kidneys and a patient has damaged kidneys, then the drug could accumulate in the patient to fatal levels. Pharmacokinetic calculations can be used to determine the dose needed to give safe and effective blood levels in this situation. A significant amount of pharmacology research is also spent on understanding how drugs act on the body. This is important to understanding adverse reactions, drug interactions, and also for the design of better drugs. This area is known more specifically as pharmacodynamics. Pharmacodynamics is basically how drugs interact with the body. Many drugs bind to protein receptors on the surface of a cell. Pharmacodynamics strives to understand how tightly a drug binds to its receptor and what happens inside the cell upon drug binding. Lastly, the overall outcome of drugs on the human condition is studied and this is known as efficacy. Efficacy deals with analyzing how well a drug may correct a condition such as arthritis. All three principles, pharmacodynamics, pharmacokinetics, and efficacy, play a pivotal role in pharmacology research.


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