nonselective adenosine receptor antagonist, antagonizing A1, A2, and A3 receptors almost equally, which explains many of its cardiac effects
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.
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. Furthermore, theophylline has been shown to directly activate HDAC2. (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 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.)
Theophylline is naturally found in cocoa beans. Amounts as high as 3.7 mg/g have been reported in Criollo cocoa beans.
Trace amounts of theophylline are also found in brewed tea, although brewed tea provides only about 1 mg/L, which is significantly less than a therapeutic dose.
Theophylline is distributed in the extracellular fluid, in the placenta, in the mother's milk and in the central nervous system. The volume of distribution is 0.5 L/kg. The protein binding is 40%. The volume of distribution may increase in neonates and those suffering from cirrhosis or malnutrition, whereas the volume of distribution may decrease in those who are obese.
Theophylline is metabolized extensively in the liver (up to 70%). It undergoes N-demethylation via cytochrome P450 1A2. It is metabolized by parallel first order and Michaelis-Menten pathways. Metabolism may become saturated (non-linear), even within the therapeutic range. Small dose increases may result in disproportionately large increases in serum concentration. Methylation to caffeine is also important in the infant population. Smokers and people with hepatic (liver) impairment metabolize it differently. Both THC and nicotine have been shown to increase the rate of theophylline metabolism.
Theophylline is excreted unchanged in the urine (up to 10%). Clearance of the drug is increased in children (age 1 to 12), teenagers (12 to 16), adult smokers, elderly smokers, as well as in cystic fibrosis, and hyperthyroidism. Clearance of the drug is decreased in these conditions: elderly, acute congestive heart failure, cirrhosis, hypothyroidism and febrile viral illness.
The elimination half-life varies: 30 hours for premature neonates, 24 hours for neonates, 3.5 hours for children ages 1 to 9, 8 hours for adult non-smokers, 5 hours for adult smokers, 24 hours for those with hepatic impairment, 12 hours for those with congestive heart failure NYHA class I-II, 24 hours for those with congestive heart failure NYHA class III-IV, 12 hours for the elderly.
Theophylline was first extracted from tea leaves and chemically identified around 1888 by the German biologist Albrecht Kossel. Seven years later, a chemical synthesis starting with 1,3-dimethyluric acid was described by Emil Fischer and Lorenz Ach. The Traube purine synthesis, an alternative method to synthesize theophylline, was introduced in 1900 by another German scientist, Wilhelm Traube. Theophylline's first clinical use came in 1902 as a diuretic. It took an additional 20 years until it was first reported as an asthma treatment. The drug was prescribed in a syrup up to the 1970s as Theostat 20 and Theostat 80, and by the early 1980s in a tablet form called Quibron.
^Hendeles L, Weinberger M, Milavetz G, Hill M, Vaughan L (1985). "Food-induced "dose-dumping" from a once-a-day theophylline product as a cause of theophylline toxicity". Chest. 87 (6): 758-65. doi:10.1378/chest.87.6.758. PMID3996063.
^Seneff M, Scott J, Friedman B, Smith M (1990). "Acute theophylline toxicity and the use of esmolol to reverse cardiovascular instability". Annals of Emergency Medicine. 19 (6): 671-3. doi:10.1016/s0196-0644(05)82474-6. PMID1971502.
^Daly JW, Jacobson KA, Ukena D (1987). "Adenosine receptors: development of selective agonists and antagonists". Prog Clin Biol Res. 230 (1): 41-63. PMID3588607.
^Yano Y, Yoshida M, Hoshino S, Inoue K, Kida H, Yanagita M, Takimoto T, Hirata H, Kijima T (2006). "Anti-fibrotic effects of theophylline on lung fibroblasts". Biochemical and Biophysical Research Communications. 341 (3): 684-90. doi:10.1016/j.bbrc.2006.01.018. PMID16430859.
^Apgar, Joan L; Tarka, Stanly M. Jr. (1998). "Methylxanthine composition and consumption patterns of cocoa and chocolate products and their uses". In Gene A. Spiller. Caffeine. CRC Press. p. 171. ISBN978-0-8493-2647-9. Retrieved .
^Traube W (1900). "Der synthetische Aufbau der Harnsäure, des Xanthins, Theobromins, Theophyllins und Caffeïns aus der Cyanessigsäure]". Chem. Ber. 33 (3): 3035-3056. doi:10.1002/cber.19000330352.
^Minkowski O (1902). "Über Theocin (Theophyllin) als Diureticum". Ther. Gegenwart. 43: 490-493.
^Schultze-Werninghaus G, Meier-Sydow J (1982). "The clinical and pharmacological history of theophylline: first report on the bronchospasmolytic action in man by S. R. Hirsch in Frankfurt (Main) 1922". Clin. Allergy. 12 (2): 211-215. doi:10.1111/j.1365-2222.1982.tb01641.x. PMID7042115.