茶碱

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? ✍　 茶碱
IUPAC中文名称
3,7-二氢-1,3-二甲基-1氢-嘌呤-2,6-二酮（或者1,3-二甲基黄嘌呤）
INN通用名	Theophilline
CADN通用名	茶碱
分子式	C7H8N4O
分子量	180.16 g/mol
CAS号	[58-55-9]
ATC代码	R03DA04
半衰期	{{{半衰期}}} 小时
适应症	{{{適應症}}}
适应症	{{{适应症}}}
代谢途径	{{{代谢}}}
排泄途径	{{{排泄}}}
商品名／生产商	{{{商品名／生産商}}}
商品名／生产商	{{{商品名／生产商}}}
妊娠期用药类别	澳大利亚: A 美国: C
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茶碱是一种药物，一种磷酸二酯酶 (PDE) 抑制剂，因此广泛用于呼吸系统疾病的质量。它具有与咖啡因类似的结构和药理学特性。茶碱可以在自然界中的红茶和绿茶中发现。

茶碱的主要作用有：

• 放松支气管平滑肌
• 加强心肌收缩
• 加快心律
• 降低血压
• 增加肾血流
• 一些消炎作用

茶碱与许多种药物（如苯妥英类的抗癫痫药物和西咪替丁之类的抗溃疡药物）都有相互作用，使用时要注意配伍禁忌。茶碱在治疗方面主要应用在：

• 慢性气道阻塞（chronic obstructive diseases of the airways）
  • 气道胆碱能神经功能亢进在慢性阻塞性肺疾病（chronic obstructive palmonary diseases，COPD
  • 支气管哮喘

目录 1 History 2 Metabolism 3 Side effects 4 References 5 External links

[编辑] History

Theophylline was first extracted from tea leaves around 1888 by the German biologist Albrecht Kossel. The drug was chemically identified in 1896 and eventually it was synthesized by another German scientist, Wilhelm Traube. Theophylline's first clinical use in asthma treatment came in the 1950s.

[编辑] Metabolism

Initial metabolism of theophylline is primarily by the hepatic cytochromes P450 enzymes CYP1A2 and CYP2E1 ^[1] The major metabolites formed are 1-methylxanthine, 3-methylxanthine and 1,3-dimethyluric acid.

[编辑] Side effects

The use of theophylline is complicated by the fact that it interacts with various drugs, chiefly cimetidine and phenytoin, and that it has a narrow therapeutic index, so its use must be monitored to avoid toxicity. It can also cause nausea, diarrhea, increase in heart rate, arrhythmias and CNS excitation. Its toxicity is increased by erythromycin, cimetidine and fluoroquinolones.

The main therapeutic uses of theophylline are:

• chronic obstructive diseases of the airways
• chronic obstructive pulmonary disease (COPD)
• bronchial asthma.

A proposed mechanism of action includes a non-specific inhibition of phosphodiesterase enzymes, producing an increase in intracellular cyclic AMP; however, this is not known with certainty.[1][2][3]

Theophylline has been shown to inhibit TGF-beta mediated conversion of pulmonary fibroblasts into myofibroblasts in COPD and asthma via cAMP-PKA pathway and suppresses COL1 mRNA which codes for the protein collagen. (Yano, Biochem and Biophys Res Comm V341-3, 2006)

It has been shown that theophylline may reverse the clinical observations of steroid insensitivity in patients with COPD and asthmatics who are active smokers (a condition resulting in oxidative stress) via a distinctly separate mechanism. Theophylline in vitro can restore the reduced HDAC (histone deacetylase) activity that is induced by oxidative stress (i.e. in smokers), returning steroid responsiveness toward normal (Ito et al., 2002a). Furthermore, theophylline has been shown to directly activate HDAC2 (Ito et al., 2002b). (Corticosteroids switch off the inflammatory response by blocking the expression of inflammatory mediators through deacetylation of histones, an effect mediated via histone deacetylase-2 (HDAC2). Once deacetylated, DNA is rewound around histones and repackaged so that the promoter regions of inflammatory genes are unavailable for binding of transcription factors such as NFB that act to turn on inflammatory activity. It has recently been shown that the oxidative stress associated with cigarette smoke can inhibit the activity of HDAC2, thereby blocking the anti-inflammatory effects of corticosteroids.) Thus theophylline could prove to be a novel form of adjunct therapy in improving the clinical response to steroids in smoking asthmatics.

[编辑] References

[编辑] External links

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