Area under the curve ( pharmacokinetics ) - wikipedia Area under the curve ( pharmacokinetics ) In the field of pharmacokinetics, the area under the curve ( AUC ) is the area under the curve ( mathematically known as the definite integral ) in a plot of drug concentration in blood plasma vs. time. In practice, the drug concentration is measured at certain discrete points in time and the trapezoidal rule is used to estimate AUC. Contents 1 Interpretation and usefulness of AUC values 2 AUC and bioavailability 2.1 Absolute bioavailability 2.2 Relative bioavailability 3 See also 4 References Interpretation and usefulness of AUC values The AUC ( from zero to infinity ) represents the total drug exposure over time. Assuming linear pharmacodynamics with elimination rate constant K, one can show that AUC is proportional to the total amount of drug absorbed by the body. The proportionality constant is 1 / K. This is useful when trying to determine whether two formulations of the same dose ( for example a capsule and a tablet ) release the same dose of drug to the body. Another use is in the therapeutic drug monitoring of drugs with a narrow therapeutic index. For example, gentamicin is an antibiotic that can be nephrotoxic ( kidney damaging ) and ototoxic ( hearing damaging ) ; measurement of gentamicin trough concentrations in a patient 's plasma and calculation of the AUC is used to guide the dosage of this drug. AUC becomes useful for knowing the average concentration over a time interval, AUC / t. Also, AUC is referenced when talking about elimination. The amount eliminated by the body ( mass ) = clearance ( volume / time ) * AUC ( mass * time / volume ). AUC and bioavailability In pharmacokinetics, bioavailability generally refers to the fraction of drug absorbed systemically, and is thus available to produce a biological effect. This is often measured by quantifying the `` AUC ''. In order to determine the respective AUCs, the serum concentration vs. time plots are typically gathered using C - 14 labeled drugs and AMS ( accelerated mass spectroscopy ). Bioavailability can be measured in terms of `` absolute bioavailablity '' or `` relative bioavailablity ''. Absolute bioavailability Absolute bioavailablity refers to the bioavailability of drug when administered via a non-intravenous ( non-IV ) dosage form ( i.e. oral tablet, suppository, subcutaneous, etc. ) compared with the bioavailability of the same drug administered intravenously ( IV ). This is done by comparing the AUC of the non-intravenous dosage form with the AUC for the drug administered intravenously. This fraction is normalized by multiplying by each dosage form 's respective dose. F a b s = ( A U C n o n − I V A U C I V ) × ( D o s e I V D o s e n o n − I V ) ( displaystyle F_ ( abs ) = left ( ( \frac ( AUC_ ( non-IV ) ) ( AUC_ ( IV ) ) ) \right ) \times left ( ( \frac ( Dose_ ( IV ) ) ( Dose_ ( non-IV ) ) ) \right ) ) Relative bioavailability Relative bioavailability compares the bioavailability between two different dosage forms. Again, the relative AUCs are used to make this comparison and relative doses are used to normalize the calculation. F r e l = ( A U C d o s a g e A A U C d o s a g e B ) × ( D o s e B D o s e A ) ( displaystyle F_ ( rel ) = left ( ( \frac ( AUC_ ( dosageA ) ) ( AUC_ ( dosageB ) ) ) \right ) \times left ( ( \frac ( Dose_ ( B ) ) ( Dose_ ( A ) ) ) \right ) ) See also Integral References Jump up ^ Lappin, Graham ; Rowland, Malcolm ; Garner, R Colin ( 2006 ). ( 1 ) `` The use of isotopes in the determination of absolute bioavailability of drugs in humans ''. Expert Opinion on Drug Metabolism & Toxicology 2 ( 3 ) : 419 -- 27. Jump up ^ Srinivasan, V. Srini ( 2001 ). ( 2 ) `` Bioavailability of Nutrients : A Practical Approach to In Vitro Demonstration of the Availability of Nutrients in Multivitamin - Mineral Combination Products ''. The Journal of Nutrition 131 ( 4 Suppl ) : 1349S -- 1350S. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Area_under_the_curve_(pharmacokinetics)&oldid=793848827 '' Categories : Pharmacokinetics Talk Contents About Wikipedia Deutsch Français Italiano Română Slovenščina Edit links This page was last edited on 4 August 2017, at 10 : 22. About Wikipedia

Question: what does the area under the curve show
Answer: total drug exposure over time