PharmacokineticsA diagram featuring

Pharmacokinetics
A diagram featuring 4 skeletal chemical formulas. Top (caffeine) relates to similar compounds paraxanthine, theobromine and theophylline.
Caffeine is metabolized in the liver into three primary metabolites: paraxanthine (84%), theobromine (12%), and theophylline (4%)
Caffeine from coffee or other beverages is absorbed by the small intestine within 45 minutes of ingestion and distributed throughout all bodily tissues.[129] Peak blood concentration is reached within 1–2 hours.[citation needed] It is eliminated by first-order kinetics.[130] Caffeine can also be absorbed rectally, evidenced by suppositories of ergotamine tartrate and caffeine (for the relief of migraine)[131] and chlorobutanol and caffeine (for the treatment of hyperemesis).[132]

Caffeine's biological half-life – the time required for the body to eliminate one-half of a dose – varies widely among individuals according to factors such as pregnancy, other drugs, liver enzyme function level (needed for caffeine metabolism) and age. In healthy adults, caffeine's half-life is between 3–7 hours.[7] Nicotine decreases the half-life by 30–50%,[68] while oral contraceptives can double it[68] and pregnancy can raise it to as much as 15 hours during the last trimester.[68] In newborns the half-life can be 80 hours or more, dropping very rapidly with age, possibly to less than the adult value by age 6 months.[68] The antidepressant fluvoxamine (Luvox) reduces the clearance of caffeine by more than 90%, and increases its elimination half-life more than tenfold; from 4.9 hours to 56 hours.[133]

Caffeine is metabolized in the liver by the cytochrome P450 oxidase enzyme system, in particular, by the CYP1A2 isozyme, into three dimethylxanthines,[134] each of which has its own effects on the body:

Paraxanthine (84%): Increases lipolysis, leading to elevated glycerol and free fatty acid levels in blood plasma.
Theobromine (12%): Dilates blood vessels and increases urine volume. Theobromine is also the principal alkaloid in the cocoa bean (chocolate).
Theophylline (4%): Relaxes smooth muscles of the bronchi, and is used to treat asthma. The therapeutic dose of theophylline, however, is many times greater than the levels attained from caffeine metabolism.[citation needed]
1,3,7-Trimethyluric acid is a minor caffeine metabolite.[7] Each of these metabolites is further metabolized and then excreted in the urine. Caffeine can accumulate in individuals with severe liver disease, increasing its half-life.[135]

A 2011 review found that increased caffeine intake was associated with a variation in two genes that increase the rate of caffeine catabolism. Subjects who had this mutation on both chromosomes consumed 40 mg more caffeine per day than others.[136] This is presumably due to the need for a higher intake to achieve a comparable desired effect, not that the gene led to a disposition for greater incentive of habituation.

Results (Indonesian) 1:

FarmakokinetikDiagram menampilkan 4 rangka rumus kimia. Atas (kafein) berkaitan dengan serupa paraxanthine senyawa, theobromine dan teofilin.Kafein dimetabolisme di hati ke tiga metabolit utama: paraxanthine (84%), theobromine (12%), dan Teofilin (4%)Kafein dari kopi atau minuman lainnya adalah diserap oleh usus kecil dalam waktu 45 menit menelan dan didistribusikan di seluruh jaringan tubuh. [129] konsentrasi darah peak dapat dicapai dalam 1-2 jam. [rujukan?] Hal ini dihilangkan dengan kinetika orde pertama. [130] kafein dapat juga diserap rektal, dibuktikan dengan supositoria dari ergotamine tartrat dan kafein (untuk menghilangkan migrain) [131] dan chlorobutanol dan kafein (untuk pengobatan gravidarum). [132]Caffeine's biological half-life – the time required for the body to eliminate one-half of a dose – varies widely among individuals according to factors such as pregnancy, other drugs, liver enzyme function level (needed for caffeine metabolism) and age. In healthy adults, caffeine's half-life is between 3–7 hours.[7] Nicotine decreases the half-life by 30–50%,[68] while oral contraceptives can double it[68] and pregnancy can raise it to as much as 15 hours during the last trimester.[68] In newborns the half-life can be 80 hours or more, dropping very rapidly with age, possibly to less than the adult value by age 6 months.[68] The antidepressant fluvoxamine (Luvox) reduces the clearance of caffeine by more than 90%, and increases its elimination half-life more than tenfold; from 4.9 hours to 56 hours.[133]Caffeine is metabolized in the liver by the cytochrome P450 oxidase enzyme system, in particular, by the CYP1A2 isozyme, into three dimethylxanthines,[134] each of which has its own effects on the body:Paraxanthine (84%): Increases lipolysis, leading to elevated glycerol and free fatty acid levels in blood plasma.Theobromine (12%): Dilates blood vessels and increases urine volume. Theobromine is also the principal alkaloid in the cocoa bean (chocolate).Theophylline (4%): Relaxes smooth muscles of the bronchi, and is used to treat asthma. The therapeutic dose of theophylline, however, is many times greater than the levels attained from caffeine metabolism.[citation needed]1,3,7-Trimethyluric acid is a minor caffeine metabolite.[7] Each of these metabolites is further metabolized and then excreted in the urine. Caffeine can accumulate in individuals with severe liver disease, increasing its half-life.[135]

A 2011 review found that increased caffeine intake was associated with a variation in two genes that increase the rate of caffeine catabolism. Subjects who had this mutation on both chromosomes consumed 40 mg more caffeine per day than others.[136] This is presumably due to the need for a higher intake to achieve a comparable desired effect, not that the gene led to a disposition for greater incentive of habituation.