Efficacy
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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
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
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
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
Prayer
See also
- Average treatment effect
- Efficiency (disambiguation)
- Placebo (origins of technical term)
- Potency (pharmacology)
- Pragmatic clinical trial
- Self-efficacy
- Vaccine efficacy
References
- ^ 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. Retrieved 21 November 2020.
- ^ S2CID 9337877.
- S2CID 1729572.
- PMID 9846630.
- PMID 15574743.
- ^ PMID 18633353.
- PMID 19339970.
- ISBN 978-0-08-042707-2.
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- ^ a b Thaul, Susan (2012-06-25). How FDA Approves Drugs and Regulates Their Safety and Effectiveness (CRS 7-5700, R41983) (CRS Report for Congress). Washington, DC: Congressional Research Service (CRS). p. 4.
- S2CID 168504597.
- ^ Porta M, ed. (2008). A Dictionary of Epidemiology (5th ed.). Oxford, ENG: Oxford University Press.
- ^ "Efficacy Evaluations and Guidelines". www.hse.gov.uk. Retrieved 7 December 2023.
- ^ Romans 1:16, 1 Thessalonians 2:13
- )
- ^ Engelder TE (1934). 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. p. 27.
- ^ Romans 1:16, 1 Thessalonians 1:5
- ^ Psalm 119:105, 2 Peter 1:19
- ^ 2 Timothy 1:16–17,Ephesians 3:3–4
- ^ John 6:63, Revelation 1:3, Ephesians 3:3–4
- ^ John 7:17
- ^ "Smalcald Articles, part 8, "Of Confession"". Archived from the original on 2017-07-31. Retrieved 2009-10-07.
- ^ "Solid Declaration, article xii, "Election", par. 41". Archived from the original on 2017-07-19. Retrieved 2009-10-08.