Clinical pharmacology

The medical field of medication effects on humans

Neuropharmacology

Effects of medication on nervous system functioning.

Psychopharmacology

Effects of medication on the brain; observing changed behaviors of the body

and read the effect of drugs on the brain.

Pharmacogenetics

Clinical testing of genetic variation that gives rise to differing response to drugs.

Pharmacogenomics

Application of genomic technologies to new drug discovery and further characterization of older drugs.

Pharmacoepidemiology

Study of effects of drugs in large numbers of people

Toxicology

Study of harmful or toxic effects of drugs

Theoretical Pharmacology

Study of metrics in Pharmacology

Posology

How medicines are dosed

It also depends upon various factors like age, climate, weight, sex etc

Pharmacognosy

A branch of pharmacology dealing especially with the composition, use, and development of medicinal substances of biological origin and especially medicinal substances obtained from plants also known as deriving medicines from plants

Behavioral Pharmacology

Is the study of the effects of drugs on behavior. It includes preclinical and in vivo research, such as small animal and rodent testing used to evaluate behavioral responses to novel drug treatment.

Environmental Pharmacology

Environmental pharmacology is a new discipline. Focus is being given to understand Gene???environment interaction, drug-environment interaction and toxin-environment interaction. There is a close collaboration between the Environmental science and Medical community in addressing these issues. It is recognised that healthcare can itself be a cause of Environmental damage as well as its remediation. Human health and ecolology is intimately related. Demand for more pharmaceutical products is destroying countless species of animals and plants, placing the public at risk. The entry of chemicals and drugs into the Aquatic ecosystem is a more serious concern today. In addition, the production of some Illegal drugs pollutes drinking water supply by releasing carcinogens. The pharmaceutical industry is encouraged to pay greater attention to the environmental impact of its products. More and more biodegradability of drugs are needed. It means environment friendly drugs could be designed. General standards for discharge of environment pollutants is implemented strictly and environmental impact assessment is checked frequently by health and other concerned regulators. Today, in Environmental Pharmacology , the topics which are covered includes Pharmacoenvironmentology and Ecopharmacology which is all about the study of Pharmaceuticals and personal care products in the environment.

The study of 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 signaling or metabolic pathways by affecting sites directly on cell-surface receptors (which modulate and mediate cellular signaling pathways controlling cellular function).

A chemical has, from the pharmacological point-of-view, various properties. Pharmacokinetics describes the effect of the body on the chemical (e.g. half-life and volume of distribution), and pharmacodynamics describes the chemical's effect on the body (desired or toxic).

When describing the pharmacokinetic properties of a chemical, pharmacologists are often interested in LADME :

• Liberation - disintegration (for solid oral forms {breaking down into smaller particles}), dispersal and dissolution

• 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 tumors.

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. In the European Union, the main body that regulates pharmaceuticals is the EMEA and they enforce standards set by the European Pharmacopoeia.

The metabolic stability and the reactivity of a library of candidate drug compounds have to be assessed for drug metabolism and toxicological studies. Many methods have been proposed for quantitative predictions in drug metabolism; one example of a recent computational method is SPORCalc . If the chemical structure of a medicinal compound is altered slightly, this could slightly or dramatically alter the medicinal properties of the compound depending on the level of alteration as it relates to the structural composition of the substrate or receptor site on which it exerts its medicinal effect, a concept referred to as the structural activity relationship (SAR). This means that when a useful activity has been identified, chemists will make many similar compounds called analogues, in an attempt to maximize the desired medicinal effect(s) of the compound. This development phase can take anywhere from a few years to a decade or more and is very expensive.

These new analogues need to be developed. It needs to be determined how safe the medicine is for human consumption, its stability in the human body and the best form for delivery to the desired organ system, like tablet or aerosol. After extensive testing, which can take up to 6 years, the new medicine is ready for marketing and selling.

As a result of the long time required to develop analogues and test a new medicine and the fact that of every 5000 potential new medicines typically only one will ever reach the open market, this is an expensive way of doing things, costing millions of dollars. To recoup this outlay pharmaceutical companies may do a number of things:

• Carefully research the demand for their potential new product before spending an outlay of company funds.

• Obtain a patent on the new medicine preventing other companies from producing that medicine for a certain allocation of time.

In the United States, the Food and Drug Administration (FDA) is responsible for creating guidelines for the approval and use of drugs. The FDA requires that all approved drugs fulfill two requirements:

1. The drug must be found to be effective against the disease for which it is seeking approval.
2. The drug must meet safety criteria by being subject to extensive animal and controlled human testing.

Gaining FDA approval usually takes several years to attain. Testing done on animals must be extensive and must include several species to help in the evaluation of both the effectiveness and toxicity of the drug. The dosage of any drug approved for use is intended to fall within a range in which the drug produces a therapeutic effect or desired outcome.

The safety and effectiveness of prescription drugs in the U.S. is regulated by the federal Prescription Drug Marketing Act of 1987 .

The Medicines and Healthcare products Regulatory Agency (MHRA) has a similar role in the UK.

The study of pharmacology is offered in many universities worldwide in programs that differ from pharmacy programs. Students of pharmacology are trained as researchers, studying the effects of substances in order to better understand the mechanisms which might lead to new drug discoveries for example. Whereas a pharmacy student will eventually work in a pharmacy dispensing medications or some other position focused on the patient, a pharmacologist will typically work within a laboratory setting.

• Certain safety factor

• Cosmeceuticals

• Crude drugs

• Drug design

• Drug metabolism

• Drug Discovery Hit to Lead

• Enzyme inhibitors

• Pharmaceutical formulation

• Herbalism

• International Union of Basic and Clinical Pharmacology

• List of abbreviations used in medical prescriptions

• List of pharmaceutical companies

• List of withdrawn drugs

• Medicare Part D - the new prescription drug plan in the U.S.

• Medication

• Medicinal chemistry

• Medical School

• Neuropharmacology - The Molecular and Behavior study of Disease and Drugs in the Nervous System

• Neuropsychopharmacology - The detailed comprehensive study of mind, brain and drugs.

• Nicholas Culpeper - 17th century English Physician who translated and used 'pharmacological texts'.

• Pharmaceutical company

• Pharmacognosy

• Pharmacopoeia

• Pharmacotherapy

• Pharmakeia

• Pharmakos

• Placebo (origins of technical term)

• Prescription drug

• Prescription Drug Marketing Act (PDMA)

• Psychopharmacology - medication for mental conditions

• Traditional Chinese Medicine

• Pharmaceuticals and personal care products in the environment

• British Pharmacological Society .

• Pharmaceutical company profiles at NNDB .

• International Conference on Harmonisation .

• US Pharmacopeia .

• International Union of Basic and Clinical Pharmacology .

• IUPHAR Committee on Receptor Nomenclature and Drug Classification .