Cmax (pharmacology)

{{DISPLAYTITLE:Cmax (pharmacology)}}

{{Short description|Peak concentration of a drug in a body compartment}}

{{ou|Cmax (disambiguation)}}

{{math|Cmax}} is the maximum (or peak) serum concentration that a drug achieves in a specified compartment or test area of the body after the drug has been administered and before the administration of a second dose.{{cite book | veditors = Stitzel RE, Craig CF | author = Tracy TS | chapter = Pharmacokinetics | title = Modern pharmacology with clinical applications | publisher = Lippincott Williams & Wilkins | location = Hagerstwon, MD | year = 2004 | page = 49 | isbn = 0-7817-3762-1 }} It is a standard measurement in pharmacokinetics.

Description

{{math|Cmax}} is the opposite of {{math|Cmin}}, which is the minimum (or trough) concentration that a drug achieves after dosing. The related pharmacokinetic parameter {{math|tmax}} is the time at which the {{math|Cmax}} is observed.{{cite web | url = http://www.lexjansen.com/phuse/2006/st/st03.pdf | title = Statistics and Pharmacokinetics in Clinical Pharmacology Studies | author = Amy Newlands | url-status = dead | archive-url = https://web.archive.org/web/20131113232412/http://www.lexjansen.com/phuse/2006/st/st03.pdf | archive-date = 2013-11-13 }}

After an intravenous administration, {{math|Cmax}} and {{math|tmax}} are closely dependent on the experimental protocol, since the concentrations are always decreasing after the dose. But after oral administration, {{math|Cmax}} and {{math|tmax}} are dependent on the extent, and the rate of drug absorption and the disposition profile of the drug. They could be used to characterize the properties of different formulations in the same subject.{{cite journal | vauthors = Urso R, Blardi P, Giorgi G | title = A short introduction to pharmacokinetics | journal = Eur Rev Med Pharmacol Sci | volume = 6 | issue = 2-3 | pages = 33–44 |date=March 2002 | pmid = 12708608 }}

Short term drug side effects are most likely to occur at or near the {{math|Cmax}}, whereas the therapeutic effect of drug with sustained duration of action usually occurs at concentrations slightly above the {{math|Cmin}}.{{Citation needed|date=September 2019}}

The {{math|Cmax}} is often measured in an effort to show bioequivalence (BE) between a generic and innovator drug product.{{cite journal | vauthors = Midha KK, Rawson MJ, Hubbard JW | title = The bioequivalence of highly variable drugs and drug products | journal = Int J Clin Pharmacol Ther | volume = 43 | issue = 10 | pages = 485–98 |date=October 2005 | pmid = 16240706 | doi = 10.5414/cpp43485}} According to the FDA, drug quality bioavailability (BA) and BE rely on pharmacokinetic measurements such as AUC and {{math|Cmax}} that are reflective of systemic exposure.{{cite web|title=Bioavailability and Bioequivalence Studies for Orally Administered Drug Products — General Considerations|url=https://www.fda.gov/media/88254/download|publisher=FDA|access-date=18 February 2021}}

See also

References