A drug interaction is a situation in which a substance affects the activity of a drug A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own. Typically, interaction between drugs come to mind (drug-drug interaction). However, interactions may also exist between drugs & foods (drug-food interactions), as well as drugs & herbs (drug-herb interactions). These may occur out of accidental misuse or due to lack of knowledge about the active ingredients An active ingredient , is the substance in a pharmaceutical drug or a pesticide that is biologically active. Terms in similar use include: active pharmaceutical ingredient (API) and bulk active in medicine, or in pesticide formulations active substance may be used. Some medications and pesticide products may contain more than one active ingredient involved in the relevant substances.[1]
Generally speaking, drug interactions are to be avoided, due to the possibility of poor or unexpected outcomes. However, drug interactions have been deliberately used, such as co-administering probenecid Probenecid is a uricosuric drug that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia with penicillin Penicillin is a group of antibiotics derived from Penicillium fungi. Penicillin antibiotics are historically significant because they are the first drugs that were effective against many previously serious diseases such as syphilis and Staphylococcus infections. Penicillins are still widely used today, though many types of bacteria are now prior to mass production of penicillin. Because penicillin was difficult to manufacture, it was worthwhile to find a way to reduce the amount required. Probenecid retards the excretion of penicillin, so a dose of penicillin persists longer when taken with it, and it allowed patients to take less penicillin over a course of therapy.
A contemporary example of a drug interaction used as an advantage is the co-administration of carbidopa US FDA:link with levodopa L-DOPA is a naturally-occurring dietary supplement and psychoactive drug found in certain kinds of food and herbs, and is synthesized from the essential amino acids L-phenylalanine (PHE) and L-tyrosine (TYR) in the mammalian body and brain. L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine ( (available as Carbidopa/levodopa The combination of carbidopa and levodopa is used to treat Parkinson's disease and Dopa-Responsive Dystonia . It is sold under several brand names, including Sinemet, Parcopa, and Atamet. The generic name under the British Approved Name system is Co-careldopa). Levodopa is used in the management of Parkinson's disease Parkinson's disease is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills, speech, and other functions and must reach the brain in an un-metabolized state to be beneficial. When given by itself, levodopa is metabolized in the peripheral tissues outside the brain, which decreases the effectiveness of the drug and increases the risk of adverse effects. However, since carbidopa inhibits the peripheral metabolism of levodopa, the co-administration of carbidopa with levodopa allows more levodopa to reach the brain un-metabolized and also reduces the risk of side effects.
Drug interactions may be the result of various processes. These processes may include alterations in the pharmacokinetics Pharmacokinetics, sometimes abbreviated as PK, is a branch of pharmacology dedicated to the determination of the fate of substances administered externally to a living organism. In practice, this discipline is applied mainly to drug substances, though in principle it concerns itself with all manner of compounds ingested or otherwise delivered of the drug, such as alterations in the Absorption, Distribution, Metabolism, and Excretion (ADME ADME is an acronym in pharmacokinetics and pharmacology for absorption, distribution, metabolism, and excretion, and describes the disposition of a pharmaceutical compound within an organism. The four criteria all influence the drug levels and kinetics of drug exposure to the tissues and hence influence the performance and pharmacological activity) of a drug. Alternatively, drug interactions may be the result of the pharmacodynamic Pharmacodynamics is the study of the physiological effects of drugs on the body or on microorganisms or parasites within or on the body and the mechanisms of drug action and the relationship between drug concentration and effect. One dominant example is drug-receptor interactions as modeled by properties of the drug, e.g. the co-administration of a receptor antagonist A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses. In pharmacology, antagonists have affinity but no efficacy for their cognate receptors, and binding will disrupt the interaction and inhibit the function of an and an agonist Receptors can be activated or inactivated either by endogenous or exogenous (such as drugs) agonists and antagonists, resulting in stimulating or inhibiting a biological response. A physiological agonist is a substance that creates the same bodily responses, but does not bind to the same receptor for the same receptor.
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Metabolic drug interactions
Many drug interactions are due to alterations in drug metabolism Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. This is a form of xenobiotic metabolism. Drug metabolism often converts lipophilic chemical compounds into more readily excreted polar products. Its rate is an important determinant of the duration and intensity.[2] Further, human drug-metabolizing enzymes are typically activated through engagement of nuclear receptors In the field of molecular biology, nuclear receptors are a class of proteins found within the interior of cells that are responsible for sensing the presence of steroid and thyroid hormones and certain other molecules. In response, these receptors work in concert with other proteins to regulate the expression of specific genes thereby controlling.[2]
One notable system involved in metabolic drug interactions is the enzyme system comprising the cytochrome P450 oxidases Cytochrome P450 is a very large and diverse superfamily of hemoproteins found in all domains of life. Cytochromes P450 use a plethora of both exogenous and endogenous compounds as substrates in enzymatic reactions. Usually they form part of multi-component electron transfer chains, called P450-containing systems. This system may be affected by either enzyme induction or enzyme inhibition, as discussed in the examples below.
- Enzyme induction Enzyme induction is a process in which a molecule induces (i.e. initiates or enhances) the expression of an enzyme - drug A induces the body to produce more of an enzyme which metabolises Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. This is a form of xenobiotic metabolism. Drug metabolism often converts lipophilic chemical compounds into more readily excreted polar products. Its rate is an important determinant of the duration and intensity drug B. This reduces the effective concentration of drug B, which may lead to loss of effectiveness of drug B. Drug A effectiveness is not altered.
- Enzyme inhibition Enzyme induction is a process in which a molecule induces (i.e. initiates or enhances) the expression of an enzyme - drug A inhibits the production of the enzyme metabolising drug B, thus an elevation of drug B occurs possibly leading to an overdose The term drug overdose describes the ingestion or application of a drug or other substance in quantities greater than are recommended or generally practiced. An overdose is widely considered harmful and dangerous as it can result in death.
- Bioavailability In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered intravenously, its bioavailability is 100%. However, when a medication is administered via - drug A influences the absorption In pharmacology , absorption is the movement of a drug into the bloodstream of drug B.
The examples described above may have different outcomes depending on the nature of the drugs. For example, if Drug B is a prodrug A prodrug is a pharmacological substance that is administered in an inactive (or significantly less active) form. Once administered, the prodrug is metabolised in vivo into an active metabolite. The rationale behind the use of a prodrug is generally for absorption, distribution, metabolism, and excretion (ADME) optimization. Prodrugs are usually, then enzyme activation is required for the drug to reach its active form. Hence, enzyme induction by Drug A would increase the effectiveness of the drug B by increasing its metabolism to its active form. Enzyme inhibition by Drug A would decrease the effectiveness of Drug B.
Additionally, Drug A and Drug B may affect each other's metabolism.
Epidemiology
Among US adults older than 55, 4% are taking medication and or supplements that put them at risk of a major drug interaction.[3]
See also
References
- ^ "Forget the colour, shape or brand: It's the active ingredient which counts". National Prescribing Service, 2009. Available at http://nps.org.au/news_and_media/media_releases/repository/Forget_the_colour_shape_or_brand__its
- ^ a b Elizabeth Lipp (2008-06-15). "Tackling Drug-Interaction Issues Early On". Genetic Engineering & Biotechnology News Mary Ann Liebert, Inc. is a publishing company founded by its President, Mary Ann Liebert, in 1980. The company publishes peer-reviewed journals, books, and trade magazines in the areas of biotechnology, biomedical research/life sciences, clinical medicine, alternative/integrative medicine, and surgery, and law. Its headquarters are in New (Mary Ann Liebert, Inc. Mary Ann Liebert, Inc. is a publishing company founded by its President, Mary Ann Liebert, in 1980. The company publishes peer-reviewed journals, books, and trade magazines in the areas of biotechnology, biomedical research/life sciences, clinical medicine, alternative/integrative medicine, and surgery, and law. Its headquarters are in New): pp. 14, 16, 18, 20. http://www.genengnews.com/articles/chitem.aspx?aid=2509. Retrieved 2008-07-06. "(subtitle) Researchers explore a number of strategies to better predict drug responses in the clinic"
- ^ "JAMA -- Abstract: Use of Prescription and Over-the-counter Medications and Dietary Supplements Among Older Adults in the United States, December 24/31, 2008, Qato et al. 300 (24): 2867". http://jama.ama-assn.org/cgi/content/short/300/24/2867.
External links
| This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (February 2008) |
- Drug Interactions: What You Should Know. U.S. Food and Drug Administration, Center for Drug Evaluation and Research
- The Medical Letter's Adverse Drug Interactions Database
- Cytochome P450 table maintained by the Indiana University School of Medicine
- Free Drug Interaction Checker
- OTC drug interaction for iPhone
- OTC drug interaction for Android phones
Categories: Pharmacology Pharmacology (in Greek: pharmacon meaning drug, and logos (λόγος) 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 | Drugs Categories for particular types of drugs are listed in Category:Drugs by target organ system and Category:Drugs by mechanism of action
Examiner.com
This will allow the pharmacist to do a complete drug interaction check each time a prescription is filled. Next, always keep an updated list of medications ...
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Currently on Newsstands at $5 99 pocket pc software iFacts Drug Interaction Facts A drug interaction analyzer covering thousands of brand and generic drugs iFacts enables the practitioner to refer to accurate and reliable
Q. what is their drug interaction?
Asked by fataneh78 - Mon Oct 9 22:21:48 2006 - - 1 Answers - 0 Comments
A. An enzyme inducer is a chemical which can stimulate the production of additional enzyme molecules. This can be a drug or drug metabolite. Enzyme inhibition is the lowering of enzyme activity by a chemical which interferes with the location on the enzyme which interacts with a substrate. It is often called catalytic poisoning.
Answered by Richard - Tue Oct 10 14:09:14 2006
