Topical administration of 5-aminosalicylic acid enemas in patients with ulcerative colitis. Studies on rectal absorption and excretion

Anti-Inflammatory Activity of Chitosan and 5-Amino Salicylic Acid Combinations in Experimental Colitis

Chitosan is used in various drug delivery approaches as a pharmaceutical excipient. Although its potential as an immunomodulatory agent has been reported, its use in this capacity has not been fully explored. The efficacy of chitosan as an active pharmacological agent, particularly in anti-inflammatory therapy in inflammatory bowel diseases (IBD), was investigated in this study. The potential impact of the molecular weight (MW) and degree of deacetylation (DD) of chitosan was investigated together with 5-amino salicylic acid (5-ASA) for its efficacy in a combination anti-inflammatory therapy in murine experimental colitis. Such a combination would potentially be developed into novel dual strategies whereby chitosan acts as a mucoadhesive excipient as well as provide an additional anti-inflammatory benefit. Chitosan grades with different MW and DD were administered intrarectally alone or in combination with 5-ASA to colitis mice for 3 days. Myeloperoxidase (MPO) and alkaline phosphatase (ALP) activity and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nuclear factor kappa-B (NF-κB) levels were assessed from the colon. Intrarectal treatment of colitis with 30 mg/kg chitosan alone and with 30 mg/kg 5-ASA for 3 days led to a significant decrease in MPO, ALP, TNF-α, IL-6, IL-1β and NF-κB in colitis mice compared to untreated mice. Surprisingly, the efficacy of chitosan as an anti-inflammatory polymer was relatively independent from its structural properties, namely DD and MW. However, combinations of chitosan with 5-ASA showed a significant pharmacological improvement, whereby the additive anti-inflammatory efficacy observed shows the possibility of finetuning chitosan by combining it with anti-inflammatory agents to optimize its anti-inflammatory potential.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.

Ulcerative colitis flair induced by mesalamine suppositories hypersensitivity

Mesalamine suppositories have been used widely for the treatment of distal ulcerative colitis and considered to be safer than systemic administration for its limited systemic absorption. However, previous studies have shown that mesalamine suppository occasionally causes severe hypersensitivity reactions including fever, rashes, colitis exacerbation and acute eosinophilic pneumonia. Here we present a 25-year-old woman with ulcerative colitis with bloody diarrhea accompanied by abdominal pain and fever which were aggravated after introduction of mesalamine suppositories. In light of symptom exacerbation of ulcerative colitis, increased inflammatory injury of colon mucosa shown by colonoscopy and elevated peripheral eosinophil count after mesalamine suppositories administration, and the Naranjo algorithm score of 10, the possibility of hypersensitivity reaction to mesalamine suppositories should be considered, warning us to be aware of this potential reaction after administration of mesalamine formulations even if it is the suppositories.

Mesalazine vanishing time from rectal mucosa following its topical administration

To investigate how long and how much Mesalazine (M) is available inside the rectal mucosa following its topical instillation, in patients (pts) with Ulcerative Colitis (UC). Two rectal biopsies for M concentration were obtained from 45 UC pts in clinical remission and on oral M treatment (OT), before a 4g enema randomly given to consentient pts every day (Group A, 15 pts), every 2 days (Group B, 15 pts) and every 3 days (Group C, 15 pts). Two additional biopsies were taken 1, 2 and 3 days after the last enema in group A, B and C respectively, at least 10 days later. All biopsies were immediately frozen at -80°C for later assay by means of high-performance light chromatography (HPLC). Data were analyzed using Student's t-test. Mean values±standard deviation of M mucosal concentration (ng/mg of tissue) were 1.32±1.41, 56.1±39.2, 9.65±6.60, and 6.39±5.03 in pts receiving OT alone, groups A, B and C, respectively. Values in Group A were statistically higher (p<0.001) than those in Groups B and C while no differences were found between Groups B and C. Values of OT were lower than groups A, B and C. M mucosal concentration rapidly decreases 2 days after a 4g enema, but after three days is still higher than OT alone. These results may provide data which would be useful to plan topical therapy and improve adherence to treatment.

A clinical trial on absorption and N-acetylation of oral and rectal mesalazine

BACKGROUND

Mesalazine (5-ASA) is a standard treatment for ulcerative colitis. Extent of absorption and N-acetylation determine systemic exposure to 5-ASA, and are thereby relevant for the safety of the treatment. The aim of the study was to compare absorption and N-acetylation of 5-ASA following rectal or oral drug administration. Healthy subjects were compared to patients with ulcerative colitis to evaluate the impact of chronic inflammation of colorectal mucosa on disposition of 5-ASA.

MATERIALS AND METHODS

First, 12 healthy adults were randomized to receive 2 g of 5-ASA by each of four different formulations: oral delayed release granules, 30 mL enema, 60 mL rectal foam, and 120 mL rectal foam. Second, 12 patients with active ulcerative colitis received 60 mL rectal foam. Pharmacokinetic analysis was performed by determination of 5-ASA and its acetylated, pharmacologically inactive metabolite (Ac-5-ASA) in plasma and urine.

RESULTS

First, systemic exposure to 5-ASA was markedly lower after rectal drug administration as compared to oral dosing (P < 0.001; e.g. median relative bioavailability of 60 mL rectal foam: 36%). Second, N-acetylation of rectal 5-ASA was lower in patients than in healthy subjects [area under the curve (AUC) ratio Ac-5-ASA/5-ASA: 1.6 +/- 0.5 vs. 2.3 +/- 0.4, mean +/- SD, P < 0.01]. High peak plasma concentrations of 5-ASA were correlated with high microscopic disease activity (r = 0.67, P < 0.05).

CONCLUSIONS

Rectal delivery of 5-ASA results in low systemic drug exposure with potentially reduced toxicity in comparison with oral drug administration. Chronic inflammation of colorectal mucosa might be a relevant source of variability in pharmacokinetics of 5-ASA.

How important is onset of action in ulcerative colitis therapy?

Pharmacotherapy is the cornerstone of management in ulcerative colitis. However, controversy remains over optimal medical strategies. Specifically, differences in the onset of action of various drug therapies are thought to influence the achievement and maintenance of remission of disease, yet this is poorly characterised. There is a wide range of recent data concerning aminosalicylates, with much debate as to the relative merits of the various formulations and delivery systems. Meta-analyses confirm the efficacy of aminosalicylates for the induction and maintenance of remission and suggest that the newer agents are comparable in efficacy to sulfasalazine. Among aminosalicylates, data from clinical trials reveal that the onset of action is earlier with balsalazide than mesalazine. Although the efficacy of the newer 5-aminosalicylate agents is no greater than that of sulfasalazine, they have better adverse effect profiles. Factors such as tolerability and adherence appear more important than onset of action in long-term maintenance. Corticosteroids have long been used in the treatment of ulcerative colitis, yet there is a paucity of data regarding this. They have a rapid onset of action but considerable systemic adverse effects. Therefore, corticosteroids are reserved for disease that fails to respond to other agents or for primary therapy in patients with severe disease, although there is no universal acceptance of a threshold at which to initiate corticosteroid treatment.Rectal preparations of both aminosalicylates and corticosteroids have been developed in an attempt to exert a more rapid and direct onset of action while minimising adverse systemic effects. In clinical trials, topical preparations of both aminosalicylates and corticosteroids are effective in inducing remission. However, patient acceptability and proximal extent of disease dictate selection of a topical agent more than concern with rate of onset.A wide range of immunomodulators have been investigated in patients with steroid-refractory ulcerative colitis. The thioguanine derivatives are the most widely used but have a limited evidence base to support this use with controlled trials providing equivocal results regarding efficacy in severe ulcerative colitis. In addition, the thioguanine derivatives have a protracted onset of action and a considerable serious adverse effect profile. Calcineurin inhibitors and methotrexate have a more rapid onset of action than the thiopurines but have even less data to support their widespread use. They are widely regarded as salvage therapy and further data are required. Regarding biological agents, infliximab revolutionised the treatment of Crohn's disease, yet results in ulcerative colitis have been disappointing. Further trials are ongoing with great anticipation for more favourable data. The practical clinical implications of any differences between the agents depend on patient satisfaction with various therapies. Noncompliance is a major concern in maintenance therapy and is probably associated with relapse. Dose administration schedules and acceptability of therapy appear to be important factors in adherence. Overall, it is not clear that onset of action has a major influence on patient adherence and addressing issues of compliance may have more direct clinical impact.

Mesalamine delivery systems: do they really make much difference?

Sulfasalazine's role as the first-line of therapy in patients with inflammatory bowel disease has led to the development of other "designer" aminosalicylates, which eliminate the sulfa-moiety, and attempt to target the topically active mesalamine to the inflamed bowel. Olsalazine sodium and balsalazide disodium utilize the same azo-bond structure as sulfasalazine, requiring release of active mesalamine by colonic bacteria, and thus targeting these agents to the colon. Other mesalamine delivery systems use pH-dependant- or moisture-release to liberate the active mesalamine in both the large and small bowel. Direct application of mesalamine via enema or suppository is also effective in patients with distal colitis. The pharmacology and thus the undesirable drug absorption rates differ between drugs, although the clinical importance of these characteristics is debatable. Differences in release-systems, the impact of the fed and fasting state, and unique patient intolerances to individual agents demand an understanding of each of these products, and their application to patient therapy.

Rectal ropivacaine is absorbed proportionally to the dose, with low intraindividual variability

AIMS

This study investigated the absorption characteristics and the tolerability of rectally administered ropivacaine, a local anaesthetic, intended as a new local therapy for ulcerative colitis.

METHODS

Thirty-two healthy volunteers participated in a randomized, placebo-controlled study. In study phase 1 (n = 16, double-blind, crossover) single rectal doses of ropivacaine corresponding to 50, 100 and 200 mg base were given as 20-ml gel enemas. Eight of these subjects also received an i.v. infusion corresponding to 20 mg (2H3)ropivacaine base given with the last rectal dose. In study phase 2 (n = 16, single-blind, crossover) the same rectal doses were given but formulated in 20, 40 and 80 ml gel, respectively. Peripheral venous plasma samples and urine were collected over 12 h after dosing and analysed for ropivacaine base by gas chromatography and (2H3)ropivacaine by gas chromatography-mass spectrometry. Ropivacaine and metabolites were analysed in urine by reversed phase liquid chromatography.

RESULTS

AUC was proportional to the dose with a point estimate [95% confidence interval (CI)] for the increase, after doubling the dose, of 1.91 (1.66-2.20) and 1.95 (1.78-2.13) in study phases 1 and 2, respectively. The increase in Cmax was also proportional to the dose with corresponding results of 1.76 (1.52-2.04) and 1.84 (1.70-1.99). The volume of the rectal formulation had no influence on either the extent or the time course of absorption. The mean (s.d.) absolute bioavailability (%F) was 56 (18)%. AUC and Cmax showed a two- to three-fold lower intra- than interindividual variability. Zero-order kinetics dominated the first 4 h of the absorption phase. Thereafter first-order kinetics were observed. The terminal half-lives were similar between the rectal doses and were longer than that after the i.v. administration, indicating an absorption-dependent half-life. The main urinary metabolite was 3-hydroxyropivacaine corresponding to about 23% of the dose. The subjects had no difficulties in retaining the doses and rectal administration of ropivacaine was well tolerated, both locally and systemically.

CONCLUSIONS

Plasma drug concentrations were proportional to the dose after rectally administered doses corresponding to 50-200 mg ropivacaine base in a gel formulation. The drug was well-tolerated. Mean bioavailability was about 60% and not influenced by variations in the enema volume. Initial absorption seemed to follow zero-order kinetics and then first-order kinetics after about 4 h. Cmax and AUC showed considerably less intra- compared with inter-individual variability, resulting in more consistent plasma concentrations within subjects.

Clinical pharmacokinetics of slow release mesalazine

Slow release oral mesalazine (Pentasa) contains microgranules covered by a semipermeable ethylcellulose membrane. The microgranules continuously release their content from duodenum to ileum in a pH- and time-dependent way. About 75% of the microgranules pass into the colon, where further release is slower. This release pattern does not appear to be affected by food, diarrhoea or the simultaneous use of H2 antagonists. Rectal forms of mesalazine deliver active drug directly to the rectum and left colon. Plasma concentrations of mesalazine and its metabolite acetyl-5-aminosalicylic acid after oral or local administration are the result of systemic absorption and hepatic metabolism by N-acetyltransferase. Most studies report maximal plasma concentrations of less than 1 mg/L after oral administration of slow release mesalazine, much lower than those observed after uncoated mesalazine but generally higher than after azo-bound drugs such as sulfasalazine. Urinary recovery is an indicator of absorption and metabolism, and is lower after rectal administration (10 to 30%) than after oral administration (30 to 40%). Faecal recovery after oral administration of slow or delayed release mesalazine is lower than with azo-bound drugs. Mesalazine acts locally after absorption by colonic and ileal mucosa. Mean steady-state concentrations of 25.7+/-2.2 microg/kg wet weight are found in ileocolonic biopsy specimens from patients with irritable bowel syndrome treated for 1 week with slow release mesalazine 1.5 g/day. Intramucosal concentrations after slow release mesalazine differ little between healthy individuals and patients with inflammatory bowel disease. Although significant differences are found between the various aminosalicylates in release patterns and the resulting pharmacokinetic parameters, no differences in therapeutic effects have been found in comparative studies. High doses of oral mesalazine (2 to 4 g/day) are more effective than lower doses in the treatment of patients with mild to moderate active ulcerative colitis. High doses (4 g/day) are also effective in the treatment of Crohn's disease, predominantly in patients with ileitis. In contrast, no dose ranging effects were demonstrated with local treatment forms: mesalazine 1g enema seems sufficient for patients with distal colitis. Higher serum concentrations and urinary recoveries after the administration of slow or delayed release mesalazine compared with azo-bound drugs suggest a higher risk for renal adverse effects, although the reported occurrence is extremely low. Although preliminary data support an association between mucosal concentrations of mesalazine and its clinical activity, further studies are needed to correlate the effects of this drug with its pharmacokinetic parameters.

Putting rectal 5-aminosalicylic acid in its place: the role in distal ulcerative colitis

Oral aminosalicylates such as sulfasalazine and mesalamine are widely prescribed for the treatment of mild or moderately active distal ulcerative colitis. However, a critical review of the literature demonstrates that rectal 5-aminosalicylic acid (5-ASA) is the optimal therapy for this disease. Meta-analyses of published trials show that rectally delivered 5-ASA is superior to placebo and to conventional rectal corticosteroids in inducing remission of distal ulcerative colitis, whereas the combination of rectal 5-ASA with a rectal corticosteroid or oral aminosalicylate is superior to rectal 5-ASA alone. For maintaining remission of distal ulcerative colitis, rectal 5-ASA is significantly better than placebo and at least as effective as oral 5-ASA. The dosage forms available for rectal delivery include suppositories, foams, and liquid enemas, and selection among these preparations should be guided by the proximal extent of disease and patient preference. The efficacy of rectal 5-ASA is complemented by its low rate of reported adverse effects, which may reflect its reduced potential for systemic absorption. This review summarizes the evidence supporting the role of rectal 5-ASA as a first-line therapy for mild or moderately active distal ulcerative colitis, and offers guidelines for its use.

Dose loading with delayed-release mesalazine: a study of tissue drug concentrations and standard pharmacokinetic parameters

AIMS

Tissue concentrations of 5-aminosalicylic acid (5ASA) and its metabolites may influence the clinical course of inflammatory bowel disease. Since the factors that determine tissue drug concentrations are unknown we have studied the relationships between the oral dose of delayed-release mesalazine, rectal tissue drug concentrations and standard pharmacokinetic parameters.

METHODS

Twelve healthy volunteers were studied following 7 days treatment with 1.2, 2.4 and 4.8 g of delayed-release mesalazine daily. 5-aminosalicylic acid and N-acetyl 5-aminosalicylic acid concentrations were measured in serum, urine, stool and rectal tissue biopsies.

RESULTS

Serum concentrations and 24 h urinary excretion of 5ASA and N-acetyl 5ASA increased as the oral dose of mesalazine was increased from 1.2 g through 2.4 g to 4.8 g daily (serum area under curve (AUC):5ASA = 3. 9, 15.4 and 46.8 microg ml-1 h, P < 0.0001; N-acetyl 5ASA = 17.2, 30. 9 and 57.8 microg ml-1 h, P < 0.0001: urinary excretion: 5ASA = 1.8, 85.5 and 445 mg, P < 0.0001; N-acetyl 5ASA = 250, 524 and 1468 mg, P < 0.0001, respectively). Faecal 5ASA excretion increased as the oral dose increased from 1.2 g to 2.4 g but did not increase further with 4.8 g daily dosing whereas faecal N-acetyl 5ASA excretion was similar at all three doses. Rectal tissue concentrations of 5ASA increased markedly, and N-acetyl 5ASA increased modestly, as the dose of oral mesalazine increased from 1.2 g to 2.4 g daily but neither increased further with 4.8 g daily dosing.

CONCLUSIONS

The relationship between the ingested dose of delayed-release mesalazine and rectal tissue drug concentrations is complex. Factors other than dose are likely to be important determinants of rectal tissue drug concentrations.

Prevention of post-operative recurrence of Crohn's disease requires adequate mucosal concentration of mesalazine. Gruppo Italiano per lo Studio del Colon e del Retto

BACKGROUND

Surgical resection of Crohn's disease is followed by early recurrence in a high percentage of patients. Mesalazine has been shown to be effective in the prevention of post-operative recurrence, but some 50% of patients under treatment recur at 3 years of follow-up.

AIM

To establish whether the mucosal concentration of mesalazine might affect the development of post-operative recurrence.

METHODS

Colon-ileoscopy was performed in 25 consecutive patients resected for Crohn's disease. The mean time from surgery was 14 months. After the operation, all patients were taking oral mesalazine (Asacol, 2.4 g/day). Ten patients showed signs of endoscopic recurrence (apthae, ulcers, narrowing of the lumen) in the neoterminal ileum, five of whom also showed juxta-anastomotic colonic involvement. Fifteen patients were free of recurrence. At endoscopy, four biopsies were taken from the perianastomotic area (two specimens at the ileal site and two specimens at the colonic site of the anastomosis). The specimens were weighed and immediately frozen at -80 degrees C. Mesalazine concentration (ng/mg) was measured in tissue homogenates by high- performance liquid chromatography with electrochemical detection. Fisher's exact test was used for the statistical analysis.

RESULTS

The mean value of mucosal mesalazine concentration, expressed as ng/mg of tissue, was significantly lower in patients with recurrence than in those without recurrence both in the ileum (mean +/- s.d.: 21.6+/-28.3 vs. 70.9+/-47.4; P = 0.007) and in the colon (25.8+/-26.4 vs. 60.3+/-32.5; P = 0.010).

CONCLUSIONS

The mucosal concentration of mesalazine in the juxta-anastomatic area is significantly lower in patients with recurrence than in those free of recurrence. These data could suggest an association between mucosal mesalazine concentrations and the clinical effectiveness of the drug.

A new mesalazine gel enema in the treatment of left-sided ulcerative colitis: a randomized controlled multicentre trial

BACKGROUND

A new mesalazine rectal gel preparation (without propellant gas) has been recently developed to improve topical treatment in distal ulcerative colitis.

AIM

To evaluate the efficacy, safety and patient tolerability of mesalazine gel enema compared with mesalazine foam enema in the treatment of patients with acute left-sided ulcerative colitis.

METHODS

In a randomized multicentre investigator-blind parallel group trial, 103 patients with mild to moderate left-sided colitis or proctosigmoiditis were randomly allocated to mesalazine 2 g gel enema (n = 50 evaluable patients) and mesalazine 2 g foam enema (n = 53 evaluable patients) for 4 weeks. Clinical symptoms, endoscopic and histological findings were assessed at entry, 2 and 4 weeks. Patients' evaluation of treatment tolerability and acceptability was assessed at 2 and 4 weeks.

RESULTS

After 4 weeks of treatment, clinical remission was achieved by 76% of mesalazine gel enema-treated patients and 69% of patients treated with mesalazine foam enema (P = 0.608). Endoscopic remission rates at week 4 were 51 and 52% for the mesalazine gel and foam enemas, respectively (P = 0.925). Histological remission was achieved by 30% of patients in both groups. Patients reported that the new mesalazine gel preparation was significantly better tolerated than the foam enema. Patients in the foam group had significantly more difficulty in retention (25% vs. 6%, P < 0.05), abdominal bloating (50% vs. 26%, P < 0.005) and discomfort during administration (48% vs. 26%, P < 0.05).

CONCLUSION

The new mesalazine gel enema is efficacious and significantly better tolerated than the mesalazine foam enema.

Retrograde colonic spread of a new mesalazine rectal enema in patients with distal ulcerative colitis

BACKGROUND

Rectal treatment with mesalazine enemas is the first-line therapy for distal ulcerative colitis. In order to improve the benefits of rectal therapy, a new 60 mL 5-ASA rectal gel enema preparation has been developed using a device which excludes direct contact of the inert propellant gas with the active drug. The purpose of the present study was to assess by scintigraphy the colonic distribution of this new mesalazine rectal gel enema.

METHODS

Twelve patients with active ulcerative colitis were administered 4 g of the mesalazine rectal enema labelled with 100 MBq technetium sulphur colloid (99mTc-SC). Anterior scans of the abdomen were acquired at intervals for 4 h. Scans were analysed to evaluate the extent of retrograde flow and homogeneity of distribution of the radiolabelled enema in the rectum, sigmoid, descending and transverse colon. In addition, plasma levels of 5-ASA and Ac-5-ASA were measured for 6 h.

RESULTS

All patients retained the entire rectal gel throughout the course of the study without reporting adverse events. In 11 out of 12 patients (92%) the gel had spread homogeneously beyond the sigmoid colon and had reached the upper limit of disease in all cases. The maximum spread (splenic flexure) was observed in 6 out of 12 patients (50%) within the first 2 h. The systemic absorption of mesalazine and its metabolite Ac-5-ASA was low.

CONCLUSIONS

The new mesalazine enema represents an adequate alternative and a further technological improvement in the topical treatment of distal ulcerative colitis.

A randomised trial comparing mesalazine and prednisolone foam enemas in patients with acute distal ulcerative colitis

Distal ulcerative colitis can be treated with oral or rectal mesalazine, or both. A foam enema preparation has been developed and its efficacy investigated. The aim of this study was to evaluate the efficacy and safety of mesalazine foam enemas compared with prednisolone foam enemas in the treatment of patients with acute distal ulcerative colitis. Patients aged over 18 years presenting with a relapse of distal ulcerative colitis were randomly allocated treatment with mesalazine foam enema (n = 149 evaluable patients) and prednisolone foam enema (n = 146 evaluable patients) for four weeks. A randomised multicentre investigator blind parallel group trial was conducted. It was found that after four weeks of treatment, clinical remission was achieved by 52% of mesalazine treated patients and 31% of patients treated with prednisolone (p < 0.001). There was a trend in favour of more patients in the mesalazine group achieving sigmoidoscopic remission (40% v 31%, p = 0.10). Histological remission was achieved by 27% and 21% of patients receiving mesalazine and prednisolone respectively. Symptoms improved in both treatment groups. Significantly more mesalazine patients had no blood in their stools after four weeks of treatment (67% v 40%, p < 0.001). Prednisolone treated patients had significantly fewer days with liquid stools than mesalazine patients, with a median of 0 and 1 days respectively by week 4 (p = 0.001). In this study mesalazine foam enema was superior to prednisolone foam enema with regards to clinical remission, this was supported by favourable trends in sigmoidoscopic and histological remission rates. Both treatments were well tolerated.

Rectal aminosalicylate therapy for distal ulcerative colitis: a meta-analysis

BACKGROUND

To summarize and quantify the evidence supporting rectal 5- or 4-aminosalicylate (ASA) therapies for disease exacerbation or remission maintenance in distal ulcerative colitis, we performed a meta-analysis.

METHODS

All randomized, double-blind controlled trials involving aminosalicylate therapy were retrieved from a MEDLINE search, review articles on ulcerative colitis therapy or their bibliographies. Of 55 studies retrieved, 19 met the inclusion criteria. Appraisal and data extraction were performed by two observers and scoring disagreements were resolved by consensus.

RESULTS

Eleven trials tested 5-ASA and three tested 4-ASA in active ulcerative colitis. 5-ASA was superior to placebo for inducing remission or symptomatic improvement in active ulcerative colitis with a pooled odds ratio of 7.36 (95% Confidence interval (CI): 4.72-11.47). In four trials the pooled odds ratio for endoscopic improvement was 10.04 (95% CI: 5.72-17.61) and for histological improvement 10.31 (95% CI: 5.85-18.18). Studies evaluating 4-ASA suggest a benefit similar to prednisolone in treating active disease. Five trials assessed remission maintenance with 5-ASA, and when compared to placebo gave a pooled odds ratio of 16.22 (95% CI: 4.71-55.92). No dose-response relationship was observed. ASA compounds were not therapeutically superior to other treatments.

CONCLUSIONS

We conclude that rectal 5-ASA is effective therapy for active distal ulcerative colitis. More trials are needed to assess 4-ASA, dose-response effects and the ideal regimen for remission maintenance.

Mesalazine induced interstitial nephritis

5-Aminosalicylic acid (5-ASA) has structural similarities to both phenacetin and aspirin, which are known to cause 'analgesic nephropathy'. Because of the increasing use of 5-ASA, this paper draws attention to two cases of severe interstitial nephritis resulting from 5-ASA and emphasises the importance of monitoring renal functions of patients with inflammatory bowel diseases who are receiving 5-ASA preparations.

Better quality of therapy with 5-ASA colonic foam in active ulcerative colitis. A multicenter comparative trial with 5-ASA enema

We evaluated the efficacy, tolerance, and acceptance of a new 5-ASA colonic foam versus 5-ASA liquid enema in the short-term treatment of active ulcerative colitis in a three-week prospective, randomized, investigator-blind study, enrolling 233 patients from 12 outpatient clinics in Italy. In arm 1 of the study, 117 patients with mild attacks received 2 g of 5-ASA as foam or enema at bedtime. In arm 2, 116 patients with moderate attacks were given 4 g of 5-ASA as foam or enema at bedtime. End points were defined as complete relief of symptoms, and endoscopic and histological evidence of remission or improvement. In patients with mild relapse, 34 of 63 (54%) treated with foam were in clinical remission after only 10 days compared with 17 of 51 (31%) treated with enemas (P < 0.05). However, there was no statistically significant difference between foam (83%) and enema (74%) after three weeks. In patients with moderate relapse, a higher proportion of patients achieved complete clinical remission in the foam group (63%) compared with enema group (52%) after three weeks (difference 11%, 95% CI -7 to 29). No significant differences were observed in endoscopic and histological evaluation of colonic mucosa between treatment groups in either arm. 5-ASA foam was well tolerated. No unexpected adverse events were reported. Patient evaluation of therapy showed that foam was much better accepted than enema because foam was more comfortable, more practical, easier to retain, and interfered less with daily living.(ABSTRACT TRUNCATED AT 250 WORDS)

Spread and distribution of 5-ASA colonic foam and 5-ASA enema in patients with ulcerative colitis

Rectal treatment with enemas, foams, and suppositories is the most efficient method of delivering an adequate quantity of locally active drugs to the distal colon. In a pilot study carried out by colonoscopy in four patients, it was observed that 4 g 5-ASA in 20 ml foam spread up or beyond the splenic flexure and more extensively than 2 g 5-ASA in 10 ml foam. Therefore we have undertaken a study in order to compare by scintigraphy the colonic distribution of 4 g 5-ASA foam versus 4 g 5-ASA in 100 ml liquid enemas in 10 patients with ulcerative colitis using a crossover randomized design. Both preparations were labeled with 100 MBq [99mTc]sulfur colloid before administration. Anterior scans were taken at intervals for 4 hr. Activity, expressed as a percentage of total radioactivity, was measured in the rectum, sigmoid, descending, transverse, and ascending colon. Six patients had the same extent of spread with the two formulations; in three patients with foam and in one patient with enema a greater spread was observed. The foam reached the upper limit of disease in all cases, while enema failed in two cases. The maximum spread with foam was observed within 30 min in nine of 10 patients compared with seven of 10 after enema. Compared to enema, foam distributes more uniformly and seems to persist longer in the descending and sigmoid colon. The 5-ASA colonic foam shows some more favorable characteristics than enema for the local treatment of left-sided ulcerative colitis.

Pharmacokinetics of 5-aminosalicylic acid in man following administration of intravenous bolus and per os slow-release formulation

The fate of 5-aminosalicylic acid (5-ASA), which is used in the treatment of chronic inflammatory bowel diseases, was studied in six healthy volunteers receiving doses of 100 mg and 250 mg intravenous bolus as well as 250 mg per os (slow release). Following intravenous administration, the drug was rapidly eliminated with a plasma half-life of about 40 min, mainly due to rapid metabolism. No parent drug was recovered in feces, and the total recovery following oral administration (30%) was significantly lower than following the intravenous doses (77% and 72%). Nonlinear pharmacokinetics were suggested as the 2.5-fold increase in intravenous dose was followed by a significant relative increase (greater than 2.5) in the renal elimination of 5-ASA, as well as a significant decrease (less than 2.5) in the elimination of the metabolite N-acetyl-5-ASA. There was also a trend towards a decreasing total body clearance and metabolic ratio. The present study confirms earlier findings on the pharmacokinetics of 5-ASA and suggests a possible saturation of the N-acetylating system in the dose range studied. This may be of interest in the design of controlled-release formulations and dosage regimes for the treatment of diseases of the small-bowel, where 5-ASA is easily absorbed. Further, for the first time, a marked difference in the intestinal fate compared to the systemic fate of the drug is demonstrated, suggesting alternative presystemic metabolism of 5-ASA, which may bear relevance to its mode of action. Further studies on the pharmacokinetics of 5-ASA, preferably in patients, are warranted.

Pharmacokinetics of rectal drug administration, Part II. Clinical applications of peripherally acting drugs, and conclusions

Part I of this article, which appeared in the previous issue of the Journal, covered general considerations, the physiology of the rectum, spreading of drugs into the colon, rectal absorption, partial avoidance of first-pass elimination, rate-controlled rectal delivery of drugs, irritation of the rectal mucosa and clinical applications of rectal administration, and discussed centrally acting drugs. In Part II, this discussion is extended to drugs which act peripherally and to methods of enhancing rectal drug absorption. The overall summary appeared in Part I.

Availability of mesalazine (5-aminosalicylic acid) from enemas and suppositories during steady-state conditions

The local and systemic bioavailability of a mesalazine enema (Pentasa, Ferring A/S, Denmark) and a mesalazine suppository (Pentasa, Ferring) was assessed during steady-state conditions. Eleven healthy subjects took 1 g of the enema or the suppository twice daily for 1 week, with a drug-free period of at least 1 week in between. At the end of each treatment period the urine and faeces were collected for 48 h, and the concentrations of mesalazine and the metabolite acetyl-mesalazine were measured. Plasma concentrations of drug and metabolite were measured hourly during a 12-h dose interval. The faecal water concentration of mesalazine was significantly higher after suppository treatment (55.7 mmol/l) compared with enema treatment (31.7 mmol/l) (p less than 0.01). The systemic absorption was low; 15% of daily mesalazine dose was recovered in urine after enema treatment and 10% after suppositores (p less than 0.01). Plasma concentrations were low, and no accumulation of either mesalazine or acetyl-mesalazine occurred. In conclusion, the enema and the suppository can be continuously administered as 1 g of mesalazine twice daily, respectively, giving high faecal water concentrations of mesalazine and a low systemic absorption.

Steady-state pharmacokinetics of a new 4-gram 5-aminosalicylic acid retention enema in patients with ulcerative colitis in remission

The pharmacokinetic profile of a new 4-g 5-aminosalicyclic acid (5-ASA) retention enema, Mesasal, was investigated. Nine patients with ulcerative colitis in remission and one patient with mild disease activity received one enema for seven consecutive nights. They were admitted to hospital for administration of the eighth enema. Plasma concentration and urinary excretion of 5-ASA and acetyl-5-aminosalicyclic acid (Ac-5-ASA) were studied for 45 h and faecal excretion for 24 h after administration of the last enema. The median peak plasma concentration of 5-ASA was 0.92 (range, 0.59-1.87) micrograms/ml at a median of 11 h after administration, and of Ac-5-ASA 1.62 (range, 1.03-4.36) micrograms/ml at a median of 12 h after administration. On average, the plasma concentration of Ac-5-ASA was almost twice that of 5-ASA at each sampling period. At 24 h after administration the median plasma concentration for 5-ASA was 0.12 (range, 0-0.77) micrograms/ml and for Ac-5-ASA 0.36 (range, 0.01-1.6) micrograms/ml. At 45 h after administration low levels of both 5-ASA (less than 0.2 micrograms/ml) and Ac-5-ASA (less than 0.3 microgram/ml) were noted in two patients, low levels of only Ac-5-ASA (less than 0.1 microgram/ml) in two patients, and neither 5-ASA nor Ac-5-ASA in the other six patients. All patients had detectable urinary levels of both 5-ASA and Ac-5-ASA during the first 4 h after administration. Median urinary recovery during 45 h was 12.6% (range, 5.6-22.2%), indicating a low absorption at steady-state conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Mesalamine in ulcerative colitis

Sulfasalazine has been used for many years in the management of ulcerative colitis. As many as 20 percent of patients treated with it experience intolerable adverse effects usually attributed to its sulfapyridine component. The other active component is 5-aminosalicylic acid (5-ASA); the only 5-ASA enema preparation currently available in the U.S. is mesalamine (Rowasa, Reid-Rowell) containing 5-ASA 4 g in 60 mL. In clinical trials, mesalamine has proved efficacious in treating refractory cases of distal ulcerative colitis, proctitis, and proctosigmoiditis. Because of its high cost compared with more conventional treatment modalities, it should be reserved for cases that are either refractory or intolerant to conventional treatment.

Mesalazine (5-aminosalicylic acid) suppositories in the treatment of ulcerative proctitis or distal proctosigmoiditis. A randomized controlled trial

A multicentre double-blind study was conducted to evaluate the efficacy and tolerability of 1 g or 1.5 g mesalazine daily compared with placebo in 94 patients with mild to moderate distal proctosigmoiditis (less than 20 cm). The study end point was the determination of clinical, endoscopic, and histologic remission rates at 4 weeks. Eleven patients, nine receiving placebo and two receiving 1.5 g mesalazine, withdrew during trial, mostly because of worsening of symptoms. At 4 weeks clinical remission was achieved in 7 of 31 (39%) patients with placebo, in 22 of 32 (69%) patients in the 1 g mesalazine group, and 23 of 31 (74%) patients in the 1.5 g mesalazine group. No serious clinical or biochemical side effect of treatment was reported. Mesalazine suppositories are safe, well tolerated, and very effective in patients with active distal proctosigmoiditis: 500 mg twice daily appears a suitable dose regimen.

Evolution of the concept of proctosigmoiditis: clinical observation

Proctosigmoiditis, or distal colon ulcerative colitis, has been recognized as a clinical entity for over 50 years and considerable information has emerged from the study of the clinical course of patients with distal colon ulcerative colitis who are followed for a period of years. For most patients the condition is benign, although periods of exacerbation can occur between remissions, characterized by rectal bleeding. However, extension of the disease, development of cancer, and the requirement of surgery are all relatively unusual. It has recently been recognized that there are many other causes of proctitis than the idiopathic form, and this has raised important questions in differential diagnosis, particularly in the proctitis occurring in homosexual males. Proctitis, proctosigmoiditis, and distal colon ulceratice colitis and not Crohn's disease; conversely perianal fistulae and abscesses are rare in distal colon ulcerative colitis. Treatment with various forms of topical agents has often been satisfactory.

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)

Role of rectal formulations: enemas

Clinical experience with mesalazine enemas in the treatment of ulcerative colitis is reviewed. After rectal administration, plasma mesalazine levels remain low, and 15% of the administered dose is recovered in the urine. Enemas containing 2 and 4 g of mesalazine have been shown to be effective, safe, and well tolerated by patients with mild and moderate ulcerative colitis. Patients who cannot tolerate sulfasalazine and patients who do not respond to other treatments have been successfully treated with mesalazine enemas. Suppositories of mesalazine are more suitable for patients with disease confined to the distal region of the colon, whereas mesalazine enemas should be used in patients with more extensive disease. Mesalazine enemas have also been used for maintenance therapy in ulcerative colitis.

Topical treatment of ulcerative colitis

It is clear that the therapeutic options available for the treatment of ulcerative proctosigmoiditis have increased over the last few years and in the future additional therapies will be available. Therapy will have to be individualized. Studies to date have generally failed to confirm the superiority of one form of treatment over another, although there is some evidence that high-dose 5-ASA enemas are superior to hydrocortisone enemas. Patients who fail to respond to one form of therapy may respond to another therapeutic modality. Continued evaluation of topical therapies provides not only an opportunity to improve the treatment prospects for patients but also allows for examination of potential mechanisms of action of therapeutically active compounds. Future research directions should also include assessment of combination therapy, the more widespread use of suppositories, and strategies to encourage patient compliance. Larger multicenter trials are needed to assess the effectiveness of some of the newer compounds. The role of topical therapy for patients with Crohn's disease confined to the left colon requires evaluation.

Mesalazine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in chronic inflammatory bowel disease

Mesalazine (5-aminosalicylic acid; mesalamine), the active moiety of sulphasalazine (salazosulfapyridine), is available in specially formulated oral and rectal forms for the treatment of active ulcerative colitis of mild to moderate severity and for maintenance therapy during disease remission. Tablets or capsules coated with acrylic-based resin and tablets containing microgranules coated with ethylcellulose deliver mesalazine to the distal small intestine and colon, thus avoiding the need for the carrier, sulphapyridine, which is responsible for many of the adverse effects associated with sulphasalazine. Since mesalazine is released in the small intestine from some coated preparations in contrast to sulphasalazine, these oral formulations have therapeutic potential in Crohn's disease. A limited number of therapeutic trials suggest that orally administered mesalazine 1.5 to 2.4g daily is of similar efficacy to sulphasalazine 2 to 3g daily in patients with mild to moderate ulcerative colitis. The efficacy of mesalazine enemas has been more widely investigated, a dose of 1 to 4g once daily being consistently more effective than placebo and apparently similar to enemas of prednisone 25mg or oral sulphasalazine 3g. Initial results suggest that mesalazine 4g enemas may be more effective than those containing hydrocortisone 100mg. Mesalazine and sulphasalazine in approximately equivalent oral dosages are similarly effective in maintaining remission in ulcerative colitis. Orally administered coated mesalazine is generally well tolerated by about 85% of patients allergic to or intolerant of sulphasalazine, the remainder experiencing similar reactions to both drugs. Adverse effects of mesalazine enemas are confined to local irritation and effects resulting from enema-tip insertion. Thus, orally administered coated mesalazine is a suitable alternative to sulphasalazine in the treatment of patients with mild to moderate active distal ulcerative colitis and for maintaining remission particularly in patients allergic to or intolerant of sulphasalazine. In patients who find enema therapy acceptable, mesalazine enemas are effective and well tolerated.

5-Aminosalicylic acid concentration in mucosal interstitium of cat small and large intestine

Uncertainty regarding the concentration of 5-ASA within the mucosal interstitium has been a major limitation of defining the protective mechanisms of 5-ASA in intestinal inflammation. Therefore, we measured the concentration of 5-ASA in intestinal lymph and venous plasma during luminal perfusion of the cat small and large intestine with 10 mM 5-ASA. Blood and lymph flows were measured in each segment. 5-ASA and N-acetyl-5-ASA were extracted from plasma and lymph and quantified using fluorescence spectroscopy. Luminal perfusion of the terminal ileum with 5-ASA resulted in the following concentration profile: intestinal venous plasma (143 +/- 30 micrograms/ml) much greater than lymph (43 +/- 17 micrograms/ml) = systemic arterial plasma (40 +/- 11 micrograms/ml). In the colon the local venous plasma concentration of 5-ASA was 20 +/- 6 micrograms/ml compared to 2.0 +/- 1.0 micrograms/ml in systemic arterial plasma. N-Acetyl-5-ASA was found to comprise less than 5% of the total metabolite concentration in both ileum and colon. We also found that 58% of luminal 5-ASA was absorbed per minute in the terminal ileum, whereas only 3%/min was absorbed from the colon. The results of this study suggest that: (1) the mucosal interstitial concentration of 5-ASA in the terminal ileum and colon are approximately 100 micrograms/ml (654 microM) and 20 micrograms/ml (164 microM), respectively; and (2) the rate of 5-ASA absorption in the terminal ileum is approximately seven times greater than that in the colon.

Newer 5-aminosalicylic acid based drugs in chronic inflammatory bowel disease

Since the discovery that 5-aminosalicylic acid (5-ASA) is the active moiety of sulphasalazine in the treatment of chronic inflammatory bowel disease, several new 5-ASA based drugs have been developed. These consist either of slow- or delayed-release formulations of plain 5-ASA or sulpha-free azo compounds of 5-ASA. The different formulations and compounds have varying bioavailabilities, which makes it possible to use them alternatively in different clinical situations. A review of the literature is given, together with suggestions as to how the new drugs might be used in different clinical situations.

Delayed-release mesalazine (5-aminosalicylic acid): coat dissolution and excretion in ileostomy subjects

1. Delayed-release mesalazine has been formulated to deliver 5-aminosalicylic acid to the colon. We have therefore studied the ileostomy excretion and coat dissolution of this preparation. 2. Following ingestion of a single tablet 88% (range 69-114%) of the 400 mg dose appeared unchanged in the ileosomy effluent over the subsequent 12 h. 3. Ileostomy effluent pH appeared to be a major determinant of 5-aminosalicylic acid release. 4. In vitro studies revealed rapid coat dissolution above pH 7.0, slow dissolution between pH 6.0 and 7.0 and non-dissolution at pH 2.0 and 4.0.

Comparison of delayed release 5 aminosalicylic acid (mesalazine) and sulphasalazine in the treatment of mild to moderate ulcerative colitis relapse

Oral formulations of 5-aminosalicylic acid (mesalazine) appear less toxic than sulphasalazine. We have therefore compared sulphasalazine, low dose mesalazine and high dose mesalazine in the treatment of mild to moderate relapse of ulcerative colitis. Sixty one patients (32 men, aged 20-78 years) were randomly allocated to sulphasalazine 2 g daily, mesalazine 800 mg daily, or mesalazine 2.4 g daily in a double blind, double dummy, four week trial. Groups were comparable for age, sex, extent of disease, and pretrial sulphasalazine intake. Four patients were unable to complete the study because of treatment failure (two taking sulphasalazine and two high dose mesalazine). A further two patients taking sulphasalazine developed side effects necessitating withdrawal. Within treatment comparisons revealed significant improvement of: sigmoidoscopic grade in the sulphasalazine group; rectal bleeding, sigmoidoscopic and histological grade in the low dose mesalazine group; stool frequency, rectal bleeding and sigmoidoscopic grade in the high dose mesalazine group. Greater improvement in rectal bleeding (p less than 0.05) and sigmoidoscopic appearances (p less than 0.05) occurred in patients taking high dose mesalazine than in those taking sulphasalazine. In two patients taking high dose mesalazine minor rises of plasma creatinine concentrations occurred, suggesting the need to monitor renal function.

Disposition of 5-aminosalicylic acid by 5-aminosalicylic acid-delivering compounds

Time-related urinary excretion and faecal excretion of 5-ASA and acetyl-5-ASA were measured in eight healthy volunteers after a single oral dose of the azo compounds sulphasalazine and olsalazine, the slow release compounds Pentasa, Asacol and Salofalk, and plain 5-ASA. After ingestion of both azo compounds and slow-release compounds, urinary excretion of 5-ASA was markedly delayed and reduced, and faecal excretion was enhanced. At all points of time, there was a significant, but not very marked difference in urinary excretion of 5-ASA after ingestion of the azo compounds and the slow-release compounds, in favour of the azo compounds. A significantly larger proportion of the ingested 5-ASA, moreover, was excreted in faeces after the intake of azo compounds as compared with slow-release compounds.

Disposition of 5-aminosalicylic acid by 5-aminosalicylic acid-delivering compounds

The disposition of 5-aminosalicylic acid (5-ASA) from 5-ASA-delivering drugs was studied in eight healthy volunteers. Time-related urinary excretion and faecal excretion of 5-ASA and acetyl-5-ASA were measured after a single oral dose of the azo compounds sulphasalazine and olsalazine, of the slow-release compounds Pentasa, Asacol, and Salofalk, and of plain 5-ASA. Plain 5-ASA was rapidly excreted into urine and had a low faecal recovery, indicating fast absorption proximally in the intestine and little availability to the colon. After ingestion of both azo compounds and slow-release compounds, urinary excretion of 5-ASA was markedly delayed and reduced, and faecal excretion was enhanced. At all points of time there was a significant but not very marked difference in urinary excretion of 5-ASA after ingestion of the azo compounds and the slow-release compounds, in favour of the azo compounds. A significantly larger proportion of the ingested 5-ASA, moreover, was excreted in faeces after intake of azo compounds as compared with slow-release compounds.

Efficacy of 5-aminosalicylic acid enemas versus hydrocortisone enemas in ulcerative colitis

A controlled trial has been carried out in order to compare the efficacy of enemas containing a high dosage of 5-ASA (4 g) versus enemas containing hydrocortisone 100 mg. The trial was conducted on 86 patients, 44 of whom received 5-ASA and 42 received hydrocortisone. The results were favorable in terms of clinical, sigmoidoscopic, and histologic criteria for 5-ASA treatment. Other aspects have been investigated, such as retrograde spread of enemas which have been shown to reach the left colon. No nephrotoxicity was detected. The long term experience confirmed the preliminary positive results.

Effect of polymer coating on faecal recovery of ingested 5-amino salicylic acid in patients with ulcerative colitis

It has been suggested that polymer coating might retard jejunal absorption of 5-amino salicylic acid (5-ASA) and thus promote delivery to its colonic site of action. Twenty three patients with active (nine), or quiescent (14) ulcerative colitis were given either uncoated or coated 5-ASA (Asacol) 400 mg qds for one to three weeks, after which they ingested five 1.5 ml dialysis membrane sachets which were recovered from the stool in the next 72 hours. After one week of treatment the concentration of 5-ASA in the faecal dialysate, urine, and fasting plasma in those receiving the coated and uncoated preparations were respectively: 25.4 +/- 5.1 compared with 1.2 +/- 0.4 mmol/l (p less than 0.001); 0.34 +/- 0.21 compared with 0.70 +/- 0.29 mmol/24h (NS) and 11.1 +/- 4.2 compared with 0.07 +/- 0.03 mumol/l (p less than 0.02). Faecal excretion of the drug appeared to be greater in patients with active colitis than in those with quiescent disease. Thus coating with pH dependent methacrylic acid copolymer B is a very effective method of promoting delivery of 5-ASA to the colon, stool dialysate concentrations being 20 fold more than those in controls. Increased trough plasma concentrations in the polymer coating group probably reflect delayed intestinal absorption but no evidence of plasma accumulation after 21 days of therapy was found.

Evaluation of an enteric-coated delayed-release 5-aminosalicylic acid tablet in patients with inflammatory bowel disease

Gastrointestinal transit of an enteric coated delayed release 5-aminosalicylic acid tablet radiolabelled with 111indium has been monitored in a total of 13 patients with Crohn's disease and ulcerative colitis. More than 70% of the tablets disintegrated in the small intestine, on average 3.2 hours after emptying from the stomach. Dispersed preparation was detected in the proximal colon of all the patients, except one with an ileostomy. Mean peak plasma concentrations of 5-aminosalicylic acid and its metabolite acetyl-5-aminosalicylic acid occurred 3-4 hours after gastric emptying. The tablets provide a reliable means of drug delivery to the ileum and proximal colon.

Gastrointestinal transit of an enteric-coated delayed-release 5-aminosalicylic acid tablet

Gastrointestinal transit of an enteric-coated, delayed-release 5-aminosalicylic acid tablet radiolabelled with indium-111 has been monitored in a preliminary study with eight healthy subjects using gamma scintigraphy. Gastric emptying of the tablet was delayed by the presence of food in the stomach. Disintegration occurred about 5 hours after the tablet left the stomach. There was close agreement between the tablet disintegration times and the initial detection of drug in the blood. The site of disintegration could be established in most instances; approximately 80% of the doses resulted in drug dispersion within the ascending colon. The coated tablets provide an effective means of drug delivery to the proximal colon.

Adverse reactions to sulphasalazine and 5-amino salicylic acid in the same patient

We report a patient who developed sulphasalazine-related hepatitis with a subsequent adverse reaction to rectal 5-amino salicylic acid, in the form of pain and fever without associated liver dysfunction, suggesting reactions to both components of sulphasalazine. Included is a review of the literature. Caution should be observed when prescribing 5-amino salicylic acid to sulphasalazine-intolerant patients.

Retrograde spread of 5-aminosalicylic acid enemas in patients with active ulcerative colitis

In an attempt to know the exact retrograde spread of high-dosage 5-aminosalicylic acid enemas, we have studied eight patients with active left-sided colitis, by adding a small amount of barium sulfate to the enemas and by checking the spread radiologically after 15 minutes, 1 hour, and 6 hours. Four grams of 5-aminosalicylic acid in 100-ml enemas and 4 gm in 200-ml enemas were used. The same experiment was repeated in a subsequent attack, with enemas labeled with technetium-99m and checked by scintiscans in five of these patients. We always have observed a volume-dependent spread of enemas but, interestingly, in the patients studied with technetium-99m there was always a wider spread than that which was detected with barium enemas. In all five patients, 100-ml enemas reached the splenic flexure. In two patients with total colitis, a progression of 100-ml technetium-99m enemas was performed in the transverse colon, but the maximum opacity remained in the left side. We can conclude that 4 gm of 5-aminosalicylic acid in 100-ml enemas can be suitable for treating patients with left-sided colitis, and will represent a valid addition for patients with more extensive colitis.