Favorable effect of 6-mercaptopurine on fistulae of Crohn's disease

Effect of drugs on colonic eicosanoid accumulation in active ulcerative colitis

The effect of immunosuppressive drugs, 4-aminosalicylic acid (4-ASA), acetyl 5-aminosalicylic acid (5-ASA), and ketotifen on human colonic eicosanoid accumulation was evaluated in view of enhanced accumulation in patients with active ulcerative colitis. Azathioprine (100 micrograms/ml), cyclosporin (100 micrograms/ml), and methotrexate (100 micrograms/ml) significantly inhibited, by 25-35%, prostaglandin E2 (PGE2) accumulation by organ-cultured colonic mucosa of ulcerative colitis patients. Methotrexate was the only immunosuppressive drug that inhibited leukotriene B4 (LTB4) accumulation (50%), whereas azathioprine inhibited the accumulation of leukotriene C4 (LTC4) (25%). 5-ASA and its metabolite, acetyl 5-ASA, inhibited by 20-70% PGE2, LTB4, and LTC4 accumulation in the culture, supporting the contention that acetyl 5-ASA is as active as 5-ASA in these respects. 4-ASA had no effect on any of the eicosanoids. Ketotifen, a mast cell stabilizer, significantly inhibited the accumulation of PGE2, LTB4, and LTC4 by 33-60%. These results suggest a potential, new, unrecognized mode by which the immunomodulators induce part of their therapeutic effects in inflammatory bowel disease and support the contention that acetyl 5-ASA is as active as 5-ASA. The results obtained also indicate that ketotifen, used effectively in the prevention of bronchial asthma, inhibits the accumulation of colonic eicosanoids and, thus, may be of value in the treatment of inflammatory bowel disease.

New therapeutic agents in the treatment of inflammatory bowel disease

Despite intense investigation, the etiology of inflammatory bowel disease (IBD) remains unknown. Recent studies with new therapeutic agents provide insight into the pathogenesis of IBD through analysis of the clinical response to pharmacologic agents whose mechanism of action is understood. Until new agents are established, IBD will be treated with conventional drugs directed toward modifying the inflammatory responses responsible for gastrointestinal mucosal damage. Sulfasalazine, mesalamine (5-aminosalicylic acid), and corticosteroids will continue to be the mainstay of therapy for the foreseeable future. Antibiotics such as metronidazole and immunosuppressants such as 6-mercaptopurine and methotrexate are useful in Crohn's disease and ulcerative colitis in selected cases. Many new exciting agents are being investigated and show encouraging results in the treatment of IBD. This article reviews the agents used in IBD with an emphasis on new therapeutic agents.

Lack of modifying effects of 6-mercaptopurine in a medium term bioassay system for liver carcinogenesis using male F344 rats

Carcinogenic and modification potential of 6-mercaptopurine (6-MP) was studied in a medium-term bioassay system for rat liver carcinogenesis. F344 male rats were initiated with a single dose (200 mg/kg body wt.) of diethylnitrosamine (DEN) i.p. and fed diets containing either 0.005% or 0.02% 6-MP with or without 0.05% phenobarbital (PB) for 6 weeks. Quantitative data revealed that 6-MP did not enhance the appearance of enzyme-altered preneoplastic foci and nodules even when administered at the highest dose (0.02%) despite showing an immunosuppressive effect and slight liver cell damage. Neither of the doses of 6-MP exerted any significant influence on the enhancing effect of PB when administered simultaneously in the medium-term-bioassay.

6-Mercaptopurine and spermatogenesis in the young rat

In recent years, 6-MP treatment has been beneficial in the treatment of inflammatory bowel disease (IBD). Since 6-MP and its metabolites interfere with various steps in nucleic acid biosynthesis, chronic use of 6-MP could theoretically alter normal cell turnover, including spermatogenesis. Therefore, we have investigated the effect of daily 6-MP administration on spermatogenesis in the young rat. 6-Mercaptopurine was administered in clinically relevant doses 24 and 40 mg/m2. Testicular weights of rats treated with 24 mg/m2 for 75 days or 40 mg/m2 for 25 days were not significantly different among 6-MP, pair-fed, or ad libitum chow-fed groups. Quantitation of the stages of seminiferous tubules or the number of homogenization-resistant, mature spermatids per testis were not affected by 6-MP treatment. In addition, 6-MP had no effect on serum testosterone or on HCG-stimulated testosterone release by the testes. These results suggest that chronic low-dose 6-MP therapy, as used in the treatment of IBD, may not carry as great a risk for suppression of spermatogenesis as theorized. Our study in animals indicates that evaluation of 6-MP and spermatogenesis in man is warranted.

Use of azathioprine or 6-mercaptopurine in the treatment of Crohn's disease

The efficacy and safety of therapy with azathioprine/6-mercaptopurine was studied in 78 patients with Crohn's disease. Mean duration of therapy was 1.6 years; 52 patients were treated greater than or equal to 6 months. All patients were also on other antiinflammatory medications. Evaluations included self-assessment and physician's assessment of well-being, functional capacity, general clinical response, clinical activities indices (National Foundation for Ileitis and Colitis/International Organization for the Study of Inflammatory Bowel Disease and Harvey-Bradshaw), and achievement of specific therapeutic goals. General clinical condition improved in 70% of the patients. Median response time was 3 months. The average Harvey-Bradshaw score decreased 37% with therapy, and a decrease of greater than or equal to 30% occurred in 66% of the subjects. An overall 72% achievement rate for specified therapeutic goals included controlling refractory disease, 73%; corticosteroid "sparing," 76%; and lessening fistulization, 63%. Nine patients got worse despite therapy. Adverse effects requiring discontinuation of therapy occurred in 10%, whereas dosages were briefly lowered for mild side effects in another 10%. This study demonstrates the effectiveness and safety of azathioprine/6-mercaptopurine in the majority of selected patients with chronic, unremitting, or steroid-requiring Crohn's disease.

Fistula-in-ano in Crohn's disease. Results of aggressive surgical treatment

The outcome of aggressive surgical treatment of 64 symptomatic anal fistulas in 55 patients with Crohn's disease has been studied. Forty-one fistulas, in 33 patients, were treated by conventional fistulotomy (17 subcutaneous, 19 intersphincteric, 5 low transsphincteric fistulas). Thirty wounds (73 percent) healed within 3 months and eight more wounds (93 percent) healed within 6 months. Three wounds did not heal within 12-18 months. Two of these patients subsequently required proctocolectomy. Wound healing was not influenced by the presence of rectal Crohn's disease or granulomatous inflammation in the tract. No change in continence was experienced by 26 of the 33 patients who underwent fistulotomy. Three patients required proctocolectomy and the remaining four patients experienced minor degrees of incontinence postoperatively. Sixteen high transsphincteric, five suprasphincteric, and one extrasphincteric fistula in 22 patients were treated by laying open external tracts and placing a noncutting seton through the sphincter, which was left in place for prolonged periods to maintain drainage. During follow-up (6 months to 10 years, median 2.5 years), three fistulas healed and seven remained quiescent. Nine patients required further treatment by a new seton and three patients required proctocolectomy. Eight of the 22 patients who had a seton inserted had no change in continence, and six patients in this group developed minor changes in continence, mostly related to diarrhea associated with intestinal disease. Anal fistulas in Crohn's disease, which involve minimal sphincter muscle, can be successfully treated by fistulotomy. High fistulas should be treated with seton drainage to limit recurrent suppuration and preserve sphincter function.

6-mercaptopurine therapy in selected cases of corticosteroid-dependent Crohn's disease

Nineteen patients (12 children and 7 adults) with severe Crohn's disease, all of whom were dependent on corticosteroids, were treated with 6-mercaptopurine. All patients received a daily dose of 6-mercaptopurine of 50 mg; in two pediatric patients with a poor response after 2 months, the dosage was increased to 75 mg/day. A complete or partial response to 6-mercaptopurine therapy was noted in 47% of patients, and therapy failed in 53%. The age of the patients, prior resection, or initial symptoms did not influence the response. The clinical response was better in male than in female patients and in patients with involvement of both the small intestine and the colon than in those with only enteritis. 6-Mercaptopurine is a possible alternative to long-term corticosteroid therapy or surgical treatment in selected patients with severe Crohn's disease.

Risk-benefit assessment of drugs used in the treatment of inflammatory bowel disease

Although the aetiology of inflammatory bowel disease remains elusive, many agents are available for the control of symptoms and inflammation. Knowledge of drug pharmacology, indications and side effects is essential to ensure the best possible clinical care while minimising toxicity and inappropriate use. Sulfasalazine consists of sulfapyridine linked to mesalazine (5-aminosalicylic acid) via an azobond. Its use is indicated in the treatment of mild to moderately active ulcerative colitis and in the prevention of relapse in patients with quiescent disease. Patients with mild to moderate colonic or ileocolonic Crohn's disease also benefit from this drug, as do a proportion of patients with isolated small bowel disease. Sulfasalazine has not been uniformly effective in preventing relapse in Crohn's disease, although many clinicians continue its use in patients who respond initially. A high incidence of side effects which limit therapy include intolerance, hypersensitivity reactions and impairment of male infertility. The newer aminosalicylates offer targeted delivery of mesalazine to the bowel, with fewer side effects. Topical mesalazine has proved extremely effective in patients with distal ulcerative colitis; oral forms are effective in the treatment of mild to moderately active ulcerative colitis and in relapse. Both types appear to be effective in the treatment of Crohn's disease, and possibly in preventing relapse. There is no current clinical advantage of one mesalazine preparation over another, nor is there an indication for their use in sulfasalazine-treated patients who have satisfactory response without adverse effects. Corticosteroids are indicated for more severe disease activity where the aminosalicylates have limited efficacy-specifically to induce remission in patients with severe or refractory ulcerative colitis or Crohn's disease. They should not be used to maintain disease remission or in the prevention of postoperative recurrence. Topical corticosteroids allow their local use in distal colitis with minimal systemic side effects. Long term use is limited by side effects, many of which are dose related, although alternate-day therapy may lessen the incidence. Immunosuppressive agents are beneficial for the treatment of refractory inflammatory bowel disease unresponsive to other medications, and may also facilitate the withdrawal of steroids in refractory patients. Mercaptopurine has an added benefit in the treatment of Crohn's disease fistulae; the role of cyclosporin in bowel disease has not been established and its use cannot currently be recommended. The potential toxicity of immunosuppressive agents warrants careful consideration of their use by both physician and patient. Metronidazole is indicated for the treatment of mild to moderate Crohn's disease, including perineal disease. Common side effects include peripheral neuropathy and nausea.(ABSTRACT TRUNCATED AT 400 WORDS)

Kaposi's sarcoma of the colon in a young HIV-negative woman with Crohn's disease

We report a case of isolated colonic Kaposi's sarcoma in a 36-year-old HIV-negative woman with refractory Crohn's disease of the colon and perineum following 11 months' treatment with azathioprine. The clinical features of this case are quite different from those classically described in Kaposi's sarcoma. Among the known risk factors, iatrogenic immunosuppression would appear to be the most probable.

Closure of refractory perineal Crohn's lesion. Integration of hyperbaric oxygen into case management

A case is reported in which a comprehensive program of hyperbaric oxygen (HBO), surgical debridement and reconstruction, and continuing medical management resulted in complete and sustained closure of an extensive perineal Crohn's lesion refractory to conventional medical and surgical management. It is emphasized that in this case healing occurred in the setting of previous removal of all diseased intestinal tissue and only with the combined use of all three treatment modalities. HBO may be a useful adjunct in the therapy of large nonhealing perineal lesions post-proctocolectomy in patients who are unresponsive to metronidazole or to immunosuppressant therapy or who experience limiting side effects from continued medical therapy.

Newer pharmacologic agents for the therapy of inflammatory bowel disease

Topical 5-ASA Agents. Observations that 5-ASA may be the clinically active component of sulfasalazine have stimulated extensive pharmaceutical efforts to develop a new class of agents for the treatment of the inflammatory bowel diseases. Both oral and rectal forms of 5-ASA have been designed, tested, and released for use in Europe and Canada. Only one rectal 5-ASA formulation is now commercially available in the United States. Studies with topical 5-ASA have demonstrated that this formulation is safe and effective for distal colitis, even in patients with disease refractory to standard therapy. Adverse effects of topical 5-ASA are minimal. However, optimal treatment doses have not been defined, relapse is common after withdrawal of therapy, and issues regarding maintenance regimens are not yet resolved. Other disadvantages include the expense and inconvenience of enema therapy. However, rectally administered 5-ASA is an appropriate initial therapy for the treatment of distal ulcerative colitis, or as a therapeutic option for refractory distal colitis. Data are insufficient to make recommendations regarding the use of topical 5-ASA in Crohn's disease. Whether this class of agents will be of benefit for Crohn's proctitis or for perineal disease must await further clinical trials. Oral 5-ASA Agents. There appears to be a well-substantiated benefit equivalent to that of sulfasalazine achieved by the new oral formulations of 5-ASA when used for the treatment of acute mild to moderate ulcerative colitis, and as maintenance treatment of ulcerative colitis in remission. Adverse reactions to these agents are uncommon, usually mild, and infrequently require withdrawal of therapy. The major problem reported with these agents is watery diarrhea, most commonly associated with olsalazine, but the practical importance of this adverse effect is disputed. Rare occurrences of reversible pericarditis and acute pancreatitis have been encountered during clinical application of these agents. As more experience is obtained, these agents may become the initial therapy of choice for the treatment of mild to moderate ulcerative colitis and for maintenance in inactive disease. Currently available data have defined a role for these agents as an important alternative for the treatment of patients intolerant or allergic to sulfasalazine. As with sulfasalazine, these agents should not be used as the sole treatment for severely active ulcerative colitis. Many unanswered questions remain regarding therapy with these agents for ulcerative colitis. Still undefined are optimal drug dosages, appropriate dosing intervals, and the necessary duration of therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Gastric fistulas in Crohn's disease. Report of cases

Nine cases of gastric fistula occurring in patients with Crohn's disease were treated at The Mount Sinai Hospital over the past three decades. Six cases were found in a review of 1480 patients with Crohn's disease admitted between 1960 and 1983. Three others seen at this institution outside the time frame of the author's study have also been included. Among six new cases, five with cologastric fistula occurred among 907 patients with Crohn's disease involving the colon (0.6 percent), while only one with ileogastric fistula was encountered among 1211 patients with ileal disease (0.08 percent). Fistulas between the stomach and colon always originated in an area of colitis, usually passing from distal transverse colon to greater curvature, but occasionally from midtransverse colon to antrum. The only pathognomonic clinical features were feculent vomiting, eructations, or odor. Diagnosis usually was made by barium enema or, less frequently, by upper gastrointestinal series; rarely, the gastric fistula was found unexpectedly at surgery. The conventional and recommended therapy is colectomy with wedge excision of the stomach. Medical treatment with 6-mercaptopurine has been completely successful in one patient and intermittently successful in a second patient.

Healing of severe perineal and cutaneous Crohn's disease with hyperbaric oxygen

Recurrent perineal Crohn's disease can be an extremely debilitating complication that may be difficult to treat. We report a patient with progressively worsening perineal and biopsy-proven cutaneous Crohn's disease that had been refractory to surgery and medical treatment (sulfasalazine, steroids, 6-mercaptopurine, metronidazole, antibiotics). As the lesions were reminiscent of problem wounds occurring in other situations, hyperbaric oxygen treatment was instituted while the patient was continued on metronidazole. Response was dramatic with almost immediate relief of symptoms and regression within 2.5 mo of wounds that had previously defied therapy for 8 yr. Clinical remission has not been sustained as four subsequent courses of hyperbaric oxygen have been given over a period of 11 mo. However, the patient has been essentially asymptomatic since her initial course and the extent of her cutaneous disease has been minimal compared with that before hyperbaric oxygen. Hyperbaric oxygen treatment is costly and should not be routinely used in every patient with perineal Crohn's disease. However, this case report may herald an advance in the understanding of the pathogenesis of this complication and ultimately, its therapy.

Nature and course of pancreatitis caused by 6-mercaptopurine in the treatment of inflammatory bowel disease

6-Mercaptopurine (6-MP) has an important role in the treatment of inflammatory bowel disease. Its most frequent short-term complication has proven to be pancreatitis, which we have now seen in 13 of 400 (3.25%) patients (12 Crohn's disease, 1 ulcerative colitis) and which we here describe. The timing of the pancreatitis was such that it could not be attributed to sulfasalazine, which was also being taken by 9 patients, or corticosteroids, which were being taken by 7 patients. The dosage of 6-MP ranged from 50 to 100 mg daily, and the pancreatitis, which was uncomplicated in all cases, occurred within 8-32 days with one exception (6.5 mo). Symptoms included epigastric pain, back pain, fever, and nausea. The serum amylase was elevated in 12 patients. The average elevation was 5.9 times normal. In all cases, the 6-MP was discontinued and symptoms and signs returned to normal over a period of 1-11 days. No other complications of 6-MP occurred; there was no leukopenia. Of 7 patients rechallenged with 6-MP, all developed recurrent pancreatitis, including 4 in less than 24 h. In 3 patients, desensitization attempted by a gradual increase in dose from 1/8 tablet (approximately 6 mg) daily also led to recurrence. The timing of the initial pancreatitis and the recurrence at rechallenge are best explained by an allergic reaction. 6-Mercaptopurine should not be reinstituted once it has caused pancreatitis.