Caffeine metabolism occurs mainly in the liver via the cytochrome CYP1A2 enzyme. The products of caffeine metabolism include paraxanthine, theobromine, and theophylline. The first step of caffeine metabolism is demethylation, yielding paraxanthine (a major metabolite), followed by theobromine, and theophylline, which are both minor metabolites. They are then excreted in urine as urates after additional metabolism. The enzymes xanthine oxidase and N-acetyltransferase 2 (NAT2) also participate in the metabolism of caffeine.
Caffeine is metabolized by the cytochrome P-450 (CYP) enzyme system, principally by isoenzyme 1A2. Therefore, caffeine has the potential to interact with drugs that are metabolized by CYP1A2 or with drugs that induce or inhibit this isoenzyme.
来源:Hazardous Substances Data Bank (HSDB)
代谢
在成年人中，该药物在肝脏中被迅速代谢为1-甲基尿酸、1-甲基黄嘌呤和7-甲基黄嘌呤。
In adults, the drug is rapidly metabolized in the liver to 1-methyluric acid, 1-methylxanthine, and 7-methylxanthine.
来源:Hazardous Substances Data Bank (HSDB)
代谢
早产儿中已报告咖啡因和茶碱之间的相互转化...
Interconversion between caffeine and theophylline has been reported in preterm neonates...
In-vivo and in-vitro experiments showed a progressive increase in the activity of the hepatic microsomal enzymes that metabolize caffeine during neonatal development. In beagle puppies, change in caffeine clearance was determined by the rate of maturation of caffeine-7-demethylase. Caffeine is eliminated in animals by biotransformation in the liver to dimethylxanthines, dimethyl- and monomethyluric acids and uracil derivatives; important quantitative differences have been demonstrated in the formation and elimination of metabolites in rats, mice and Chinese hamsters. These differences are even more important in monkeys, where caffeine is almost completely metabolized to theophylline. ... Some species-dependent metabolites have been identified. Trimethylallantoin was first reported in rats. A ... derivative of paraxanthine was found in mice and identified as the 3-beta-D-glucuronide of paraxanthine. Methylated ureas and sulfur-containing derivatives found in urine in trace amounts are produced by the intestinal flora. In contrast, the acetylated uracil derivative, 5-acetylamino-6-formylamino-3-methyluracil, one of the most important caffeine metabolites in humans, has not been identified in rodents or other animal species. Other uracil derivatives produced from caffeine, theobromine and paraxanthine in rats were found in human urine. In rats, the hepatic demethylation of caffeine shows an age-related decline, resulting in a greatly increased elimination half-time in older adult rats.
Caffeine stimulates medullary, vagal, vasomotor, and respiratory centers, promoting bradycardia, vasoconstriction, and increased respiratory rate. This action was previously believed to be due primarily to increased intracellular cyclic 3′,5′-adenosine monophosphate (cyclic AMP) following inhibition of phosphodiesterase, the enzyme that degrades cyclic AMP. It is now thought that xanthines such as caffeine act as antagonists at adenosine-receptors within the plasma membrane of virtually every cell. As adenosine acts as an autocoid, inhibiting the release of neurotransmitters from presynaptic sites but augmenting the actions of norepinephrine or angiotensin, antagonism of adenosine receptors promotes neurotransmitter release. This explains the stimulatory effects of caffeine. Blockade of the adenosine A1 receptor in the heart leads to the accelerated, pronounced "pounding" of the heart upon caffeine intake.
Some degree of caffeine intake is almost universal in modern society and an estimated 90% of adults in the United States consume caffeine daily, the average amount being 200 mg daily. Yet despite its widescale use, there is no evidence that regular consumption of caffeine or coffee has adverse effects on the liver. Indeed, epidemiological studies suggest that regular coffee intake may have modest protective effects against the progression of chronic liver disease and development of liver cancer. In high, toxic doses, caffeine can have severe effects on brain, heart and muscle function but has not been linked to clinically apparent liver injury. In contrast, there have been several reports of liver injury linked to use of caffeine rich energy drinks. These reports have not been very convincing and most were not well documented. In many instances, the hepatic injury resembled acute hepatic necrosis or ischemic hepatitis (Case 1). In other cases, other diagnoses were more likely than liver injury from the energy drinks (Case 2). Furthermore, it remains unclear whether the hepatic effects were caused by caffeine per se or to other components in typical energy drinks, such as vitamins, herbs or other botanical products. In reports of caffeine overdose including cases with autopsies, hepatic injury has been absent or not mentioned. Thus, caffeine is unlikely to cause liver injury, but the various high caffeine energy drinks which are widely used may possibly cause liver injury when used to excess.
Likelihood score for caffeine: E (unlikely cause of clinically apparent liver injury).
Likelihood score for energy drinks: C[H] (probable rare cause of clinically apparent liver injury when used in high amounts).
Caffeine is rapidly absorbed after oral or parenteral administration, reaching peak plasma concentration within 30 minutes to 2 hours after administration. After oral administration, onset of action takes place within 45 to 1 hour. Food may delay caffeine absorption. The peak plasma level for caffeine ranges from 6-10mg/L. The absolute bioavailability is unavailable in neonates, but reaches about 100% in adults.
The major metabolites of caffeine can be found excreted in the urine. About 0.5% to 2% of a caffeine dose is found excreted in urine, as it because it is heavily absorbed in the renal tubules.
Caffeine has the ability to rapidly cross the blood-brain barrier. It is water and fat soluble and distributes throughout the body. Caffeine concentrations in the cerebrospinal fluid of preterm newborns are similar to the concentrations found in the plasma. The mean volume of distribution of caffeine in infants is 0.8-0.9 L/kg and 0.6 L/kg in the adult population.
来源:DrugBank
吸收、分配和排泄
清除
咖啡因的清除率因人而异，但平均大约是0.078升/千克/小时（1.3毫升/分钟/千克）。
The clearance of caffeine varies, but on average, is about 0.078 L/kg/h (1.3 mL/min/kg).
World-wide, many fetuses and infants are exposed to methylxanthines via maternal consumption of coffee and other beverages containing these substances. Methylxanthines (caffeine, theophylline and aminophylline) are also commonly used as a medication for apnea of prematurity. ... Methylxanthines readily passes the placenta barrier and enters all tissues and thus may affect the fetus/newborn at any time during pregnancy or postnatal life, given that the effector systems are mature. ...
[EN] IMIDAZOLE DERIVATIVES USEFUL AS INHIBITORS OF FAAH<br/>[FR] DÉRIVÉS IMIDAZOLE UTILES COMME INHIBITEURS DE LA FAAH
申请人：MERCK & CO INC
公开号：WO2009152025A1
公开（公告）日：2009-12-17
The present invention is directed to certain imidazole derivatives which are useful as inhibitors of Fatty Acid Amide Hydrolase (FAAH). The invention is also concerned with pharmaceutical formulations comprising these compounds as active ingredients and the use of the compounds and their formulations in the treatment of certain disorders, including osteoarthritis, rheumatoid arthritis, diabetic neuropathy, postherpetic neuralgia, skeletomuscular pain, and fibromyalgia, as well as acute pain, migraine, sleep disorder, Alzeimer Disease, and Parkinson's Disease.
[EN] PYRAZOLE DERIVATIVES USEFUL AS INHIBITORS OF FAAH<br/>[FR] DÉRIVÉS DE PYRAZOLE UTILES COMME INHIBITEURS DE FAAH
申请人：MERCK & CO INC
公开号：WO2009151991A1
公开（公告）日：2009-12-17
The present invention is directed to certain imidazole derivatives which are useful as inhibitors of Fatty Acid Amide Hydrolase (FAAH). The invention is also concerned with pharmaceutical formulations comprising these compounds as active ingredients and the use of the compounds and their formulations in the treatment of certain disorders, including osteoarthritis, rheumatoid arthritis, diabetic neuropathy, postherpetic neuralgia, skeletomuscular pain, and fibromyalgia, as well as acute pain, migraine, sleep disorder, Alzheimer disease, and Parkinson's disease
[EN] S-NITROSOMERCAPTO COMPOUNDS AND RELATED DERIVATIVES<br/>[FR] COMPOSÉS DE S-NITROSOMERCAPTO ET DÉRIVÉS APPARENTÉS
申请人：GALLEON PHARMACEUTICALS INC
公开号：WO2009151744A1
公开（公告）日：2009-12-17
The present invention is directed to mercapto-based and S- nitrosomercapto-based SNO compounds and their derivatives, and their use in treating a lack of normal breathing control, including the treatment of apnea and hypoventilation associated with sleep, obesity, certain medicines and other medical conditions.
[EN] SUBSTITUTED N-HETEROCYCLIC CARBOXAMIDES AS ACID CERAMIDASE INHIBITORS AND THEIR USE AS MEDICAMENTS<br/>[FR] CARBOXAMIDES N-HÉTÉROCYCLIQUES SUBSTITUÉS UTILISÉS EN TANT QU'INHIBITEURS DE LA CÉRAMIDASE ACIDE ET LEUR UTILISATION EN TANT QUE MÉDICAMENTS
申请人：BIAL BIOTECH INVEST INC
公开号：WO2021055627A1
公开（公告）日：2021-03-25
The invention provides substituted N-heterocyclic carboxamides and related compounds, compositions containing such compounds, medical kits, and methods for using such compounds and compositions to treat a medical disorder, e.g., cancer, lysosomal storage disorder, neurodegenerative disorder, inflammatory disorder, in a patient.
[EN] AURORA KINASE MODULATORS AND METHOD OF USE<br/>[FR] MODULATEURS D'AURORA KINASE ET PROCÉDÉ D'UTILISATION
申请人：AMGEN INC
公开号：WO2009117157A1
公开（公告）日：2009-09-24
The present invention relates to chemical compounds having a general formula (I) wherein A1-5 and 7-8, D', L1, L2, R1, R3, R6-8, n and o are defined herein, and synthetic intermediates, which are capable of modulating the activity of Aurora kinase proteins and, thereby, influencing various disease states and conditions related to the activities of Aurora kinases. For example, the compounds are capable of influencing the process of cell cycle and cell proliferation to treat cancer and cancer-related diseases. The invention also includes pharmaceutical compositions, including the compounds, and methods of treating disease states related to the activity of Aurora kinase.
