Pharmacology - Article
Pharmacology (in Greek: pharmacon (Ï†Î¬ÏÎ¼Î±ÎºÎ¿Î½) meaning drug, and logos (Î»ÏŒÎ³Î¿Ï‚) meaning science) is the study of how chemical substances interact with living systems. If substances have medicinal properties, they are considered pharmaceuticals. The field encompasses drug composition and properties, interactions, toxicology, therapy, and medical applications and antipathogenic capabilities. The science is considered to have been invented by Arab physicians in Baghdad during the Golden Age of Islam; pharmacopoeias were penned in Arabic as early as the 7th century (Amin A. Khairallah: Outline of Arabic Contributions to Medicine: Chapter X, Chemistry and Pharmacy. 1946, ).
Development of medication is a vital concern to medicine, but also has strong economical and political implications. To protect the consumer and prevent abuse, many governments regulate the manufacture, sale, and administration of medication. In the United States, the main body that regulates pharmaceuticals is the Food and Drug Administration and they enforce standards set by the United States Pharmacopoeia.
Pharmacology as a science is practiced by pharmacologists. Subdisciplines are clinical pharmacology (the medical field of medication effects on humans), neuro- and psychopharmacology (effects of medication on behavior and nervous system functioning), and theoretical pharmacology.
The study of medicinal chemicals requires intimate knowledge of the biological system affected. With the knowledge of cell biology and biochemistry increasing, the field of pharmacology has also changed substantially. It has become possible, through molecular analysis of receptors, to design chemicals that act on specific cellular signalling or metabolic pathways by affecting sites directly on cell-surface receptors (which modulate and mediate cellular signalling pathways controlling cellular function).
A chemical has, from the pharmacological point-of-view, various properties. Pharmacokinetics describes its behaviour in the body - particularly in the blood (e.g. its half-life and volume of distribution), and pharmacodynamics relates its behaviour in the blood to its effects (desired effects or toxic side-effects).
When describing the pharmacokinetic properties of a chemical, pharmacologists are often interested in ADME:
- Absorption - How is the medication absorbed (through the skin, the intestine, the oral mucosa)?
- Distribution - How does it spread through the organism?
- Metabolism - Is the medication converted chemically inside the body, and into which substances. Are these active? Could they be toxic?
- Excretion - How is the medication eliminated (through the bile, urine, breath, skin)?
Medication is said to have a narrow or wide therapeutic index or therapeutic window. This describes the ratio of desired effect to toxic effect. A compound with a narrow therapeutic index (close to one) exerts its desired effect at a dose close to its toxic dose. A compound with a wide therapeutic index (greater than five) exerts its desired effect at a dose substantially below its toxic dose. Those with a narrow margin are more difficult to dose and administer, and may require therapeutic drug monitoring (examples are warfarin, some antiepileptics, aminoglycoside antibiotics). Most anti-cancer drugs have a narrow therapeutic margin: toxic side-effects are almost always encountered at doses used to kill tumours.
Drugs used as medicines
A medication is a licensed drug taken to cure or reduce symptoms of an illness or medical condition. Medications are generally divided into two groups -- over the counter (OTC) medications, which are available in pharmacies and supermarkets without special restrictions, and Prescription only medicines (POM), which must be prescribed by a physician. Most OTC medication is generally considered to be safe enough that most persons will not hurt themselves accidentally by taking it as instructed. Many countries, such as the UK have a third category of pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist. However, the precise distinction between OTC and prescription depends on the legal jurisdiction. Medications are typically produced by pharmaceutical companies and are often patented. Those that are not patented are called generic drugs.
The study of pharmacology is typically offered as an advanced degree program, but a few institutions have it available as an undergraduate major or concentration that enables graduates to be entry-level lab technicians in the field of drug design and discovery. The following universities offer the major:
- Duke University
- Massachusetts College of Pharmacy and Health Sciences
- Purdue University
- SUNY Buffalo
- University of California, Santa Barbara
- University of Michigan
- University of the Sciences in Philadelphia
- University of Wisconsin-Madison
- Drug design
- Enzyme inhibitors
- List of withdrawn drugs
- Medicare Part D - the new prescription drug plan in the U.S.
- Medicinal chemistry
- Neuropsychopharmacology - The detailed comprehensive study of mind, brain and drugs.
- Neuropharmacology - The Molecular and Behavior study of Disease and Drugs in the Nervous System
- Nicholas Culpeper - 17th Century English Physician who translated and used 'pharmacological texts'.
- Pharmaceutical company
- Placebo (origins of technical term)
- Psychopharmacology - medication for mental conditions