The preparation of 3,7-dihydro-3,7-dimethyl-1-(5-oxohexyl)-1H-purine-2,6-dione (TRENTAL.sup.R ; generic name: pentoxifylline) and 1-(3',4'-diethoxybenzyl)-6,7-diethoxy-3,4-dihydroisoquinolinium theophylline-7-acetate (Depogen) or its monohydrate, respectively is described inter alia in the following patent specification: GB No. 1,079,267; German No. 2,234,202; Czechoslovak No. 164,343; as well as Hungarian No. 167,246 and Hungarian No. T/42449 made open to public inspection.
It is known that both pentoxifylline and Depogen improve the microcirculation of the blood [Angiology 36, pages 2226-2234 (1984); as well as Hungarian patent specification No. 197,207].
Anastomosis insufficiency is the most severe complication of surgical interventions made in the gastrointestinal system. In spite of the modern suture techniques and up-to-date antibiotic treatments, the occurrence of this complication is very frequent, and significantly prolongs the period of hospital treatment and increases the rate of mortality.
Complications most frequently occur at anastomoses established on various regions of the oesophagus and on the left-side colon. This has partly anatomical, circulation and microbiological reasons; however, in addition, an important role may be attributed in the development of complications to the fact that both the oesophagus and colon possess a very weak antioxidant protective system.
It has been proved by a number of experimental observations that the early phase of the healing process of intestinal anastomosis can be characterized by an early collagenolysis, i.e. by a rapid decrease in the collagen concentration. The tensile strength of anastomosis decreases proportionally to the collagen decomposition in the early postoperative days and a definitive pressure increase is started by the building-up of the new collagen skeleton only after 6 to 7 days. The early wound separation in the line of anastomosis occurs in this period.
In addition to the surgical techniques, the drug-assisted healing of the anastomosis is an important task. In clinical practice no drug process is known, which has been aimed to directly promote the healing of anastomosis. Clinical experiences show that in programmed surgery the occurrence of complications is diminished but not completely eliminated by arrangement of the haematological status of the patient, appropriate protein and electrolyte supply or preparation of the gastrointestinal system by antibiotics.
Another frequent complication of anastomosis surgery appears in the formation of adhesions. The essential problem of inhibiting adhesion is to retain the integrity of anastomosis prepared in the abdominal cavity. Although good adhesion-inhibitory properties of some compounds are known, their use abruptly increases the rate of anastomosis insufficiencies [Obstet. Gynecol. 75 (6), (1990)].
In the experiments of Steinleitner and coworkers, adhesions of abdominal cavities were prevented by the administration of pentoxifylline. A dose of 25 mg/kg/12 hours decreased the adhesions induced by tissue destruction model and inhibited the repeated formation of previously developed and surgically solved adhesions. The good results were explained by the effects of pentoxifylline modulating leukocyte functions.
Based on the negative effects of previously known adhesion inhibitors on the healing of anastomosis, the use of pentoxifylline during the perioperative period is presumably contraindicated because of the occasionally occurring anastomosis insufficiency.
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