Chemistry:Efficacy

From HandWiki
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Short description: Ablility to finish a task satisfactorily

Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as effectiveness, and it has often been used synonymously, although in pharmacology a distinction is now often made between efficacy and effectiveness.[1]

The word efficacy is used in pharmacology and medicine to refer both to the maximum response achievable from a pharmaceutical drug in research settings,[2] and to the capacity for sufficient therapeutic effect or beneficial change in clinical settings.

Pharmacology

Main page: Chemistry:Intrinsic activity

In pharmacology, efficacy (Emax) is the maximum response achievable from an applied or dosed agent, for instance, a small molecule drug.[2] Intrinsic activity is a relative term for a drug's efficacy relative to a drug with the highest observed efficacy.[3] It is a purely descriptive term that has little or no mechanistic interpretation.

In order for a drug to have an effect, it needs to bind to its target, and then to affect the function of this target. The target of a drug is commonly referred to as a receptor, but can in general be any chemically sensitive site on any molecule found in the body. The nature of such binding can be quantified by characterising how tightly these molecules, the drug and its receptor, interact: this is known as the affinity. Efficacy, on the other hand, is a measure of the action of a drug once binding has occurred. The maximum response, Emax, will be reduced if efficacy is sufficiently low.

The definition of efficacy has been object for discussion.[4] The only way in which absolute measures of efficacy have been obtained is by single ion channel analysis of ligand gated ion channels. It is still not possible to do this for G protein-linked receptors.

In the case of the glycine receptor and the nicotinic acetylcholine receptor (muscle type), it has been proposed by Sivilotti et al. that opening of the ion channel involves two steps after agonist is bound. Firstly a conformation change to a higher affinity (but still shut) form, followed by the conformation change from shut to open.[5][6] It was found that partial agonism results from deficiency in the first step, and that the opening and shutting steps are essentially the same for both full and partial agonists. This has been confirmed and extended by Sine and colleagues (2009).[7] The implication of this work[6] is that efficacy has to be defined by at least two equilibrium constants (or, more generally, by four rate constants).

The combined influences of affinity and efficacy determine how effectively a drug will produce a biological effect, a property known as potency.

Medicine

In medicine, efficacy is the capacity for beneficial change (or therapeutic effect) of a given intervention (for example a drug, medical device, surgical procedure, or a public health intervention).[8] Establishment of the efficacy of an intervention is often done relative to other available interventions, with which it will be compared.[9] Specifically, efficacy refers to "whether a drug demonstrates a health benefit over a placebo or other intervention when tested in an ideal situation, such as a tightly controlled clinical trial."[10] These studies focus on a primary parameter to be shown statistically different between placebo and intervention groups. Comparisons of this type are called 'explanatory' randomized controlled trials, whereas 'pragmatic' trials are used to establish the effectiveness of an intervention regarding also non-specific parameters.[citation needed]

Effectiveness refers to "how the drug works in a real-world situation",[11] and is "often lower than efficacy because of interactions with other medications or health conditions of the patient, sufficient dose or duration of use not prescribed by the physician or followed by the patient, or use for an off-label condition that had not been tested."[10][12]

Agriculture

In agriculture and forestry, efficacy is used to describe whether a pesticide is effective in controlling a pest or disease.[13]

Theology

Scripture

In Protestant Theology (esp. in Lutheran but also in Calvinist doctrine) efficacy is an attribute of Scripture. The efficacy of Scripture means that it is united with the power of the Holy Spirit and with it, not only demands, but also creates the acceptance of its teaching[14][15][16] and that this teaching produces faith and obedience. Efficacy further means that Holy Scripture is not a dead letter, but rather, the power of the Holy Spirit is inherent in it[17][18][19] and that Scripture does not compel a mere intellectual assent to its doctrine, resting on logical argumentation, but rather it creates the living agreement of faith.[20][21] The Smalcald Articles affirm, "in those things which concern the spoken, outward Word, we must firmly hold that God grants His Spirit or grace to no one, except through or with the preceding outward Word."[22] The Formula of Concord teaches that when humans reject the calling of the Holy Spirit, it is not a result of the Word being less efficacious. Instead, contempt for the means of grace is the result of "the perverse will of man, which rejects or perverts the means and instrument of the Holy Ghost, which God offers him through the call, and resists the Holy Ghost, who wishes to be efficacious, and works through the Word..."[23]

Prayer

See also

References

  1. ↑ Zimmer, Carl (20 November 2020). "2 Companies Say Their Vaccines Are 95% Effective. What Does That Mean? You might assume that 95 out of every 100 people vaccinated will be protected from Covid-19. But that's not how the math works.". The New York Times. https://www.nytimes.com/2020/11/20/health/covid-vaccine-95-effective.html. 
  2. ↑ 2.0 2.1 "Understanding the dose-effect relationship: clinical application of pharmacokinetic-pharmacodynamic models". Clinical Pharmacokinetics 6 (6): 429–53. 1981. doi:10.2165/00003088-198106060-00002. PMID 7032803. 
  3. ↑ "International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. XXXVIII. Update on terms and symbols in quantitative pharmacology". Pharmacological Reviews 55 (4): 597–606. December 2003. doi:10.1124/pr.55.4.4. PMID 14657418. 
  4. ↑ Colquhoun, D. (November 1998). "Binding, gating, affinity and efficacy: the interpretation of structure-activity relationships for agonists and of the effects of mutating receptors". British Journal of Pharmacology 125 (5): 924–947. doi:10.1038/sj.bjp.0702164. ISSN 0007-1188. PMID 9846630. 
  5. ↑ Burzomato, Valeria; Beato, Marco; Groot-Kormelink, Paul J.; Colquhoun, David; Sivilotti, Lucia G. (2004-12-01). "Single-channel behavior of heteromeric alpha1beta glycine receptors: an attempt to detect a conformational change before the channel opens". The Journal of Neuroscience 24 (48): 10924–10940. doi:10.1523/JNEUROSCI.3424-04.2004. ISSN 1529-2401. PMID 15574743. 
  6. ↑ 6.0 6.1 "On the nature of partial agonism in the nicotinic receptor superfamily". Nature 454 (7205): 722–728. 2008. doi:10.1038/nature07139. PMID 18633353. Bibcode: 2008Natur.454..722L. 
  7. ↑ "On the nature of partial agonism in the nicotinic receptor superfamily". Nature 459 (7245): 451–454. 2009. doi:10.1038/nature07923. PMID 19339970. 
  8. ↑ "3.11 - Mental Health Services Research" (in en). Comprehensive Clinical Psychology. Oxford: Pergamon. January 1998. pp. 225–241. doi:10.1016/b0080-4270(73)00275-3. ISBN 978-0-08-042707-2. 
  9. ↑ Nursing research : generating and assessing evidence for nursing practice (Tenth ed.). Philadelphia. December 2015. ISBN 9781496300232. OCLC 919860667. 
  10. ↑ 10.0 10.1 Thaul, Susan (2012-06-25) (CRS Report for Congress). How FDA Approves Drugs and Regulates Their Safety and Effectiveness (CRS 7-5700, R41983). Washington, DC: Congressional Research Service (CRS). p. 4. https://fas.org/sgp/crs/misc/R41983.pdf. 
  11. ↑ "6 - Issues and Challenges of Public-Health Research in Developing Countries". Manson's Tropical Infectious Diseases (Twenty-third ed.). 2014-01-01. pp. 40–48.e1. doi:10.1016/b978-0-7020-5101-2.00006-6. ISBN 978-0-7020-5101-2. 
  12. ↑ A Dictionary of Epidemiology (5th ed.). Oxford, ENG: Oxford University Press. 2008. 
  13. ↑ "Efficacy Evaluations and Guidelines". https://www.hse.gov.uk/pesticides/pesticides-registration/efficacy-guides/index.htm. 
  14. ↑ Romans 1:16, 1 Thessalonians 2:13
  15. ↑ Gräbner, A. L. (1898). Outlines of doctrinal theology. St. Louis: Concordia Pub. House. p. 11. ISBN 0-524-04891-6. OCLC 889640192. https://web.archive.org/web/20060712193848/showcase.netins.net/web/bilarson/bibliology.txt. 
  16. ↑ Popular Symbolics: The Doctrines of the Churches of Christendom and Of Other Religious Bodies Examined in the Light of Scripture. Saint Louis, MO: Concordia Publishing House. 1934. p. 27. http://www.archive.org/details/MN41551ucmf_1. 
  17. ↑ Romans 1:16, 1 Thessalonians 1:5
  18. ↑ Psalm 119:105, 2 Peter 1:19
  19. ↑ 2 Timothy 1:16-17,Ephesians 3:3-4
  20. ↑ John 6:63, Revelation 1:3, Ephesians 3:3-4
  21. ↑ John 7:17
  22. ↑ Smalcald Articles, part 8, "Of Confession"
  23. ↑ Solid Declaration, article xii, "Election", par. 41



Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Efficacy&oldid=3320480"