Glyceryl trinitrate ointment for the treatment of chronic anal fissure: results of a placebo-controlled trial and long-term follow-up

The pharmacology of the internal anal sphincter and new treatments of ano-rectal disorders

Surgical options for faecal incontinence in the presence of intact sphincters are limited. Furthermore, in patients with fissures, lateral sphincterotomy reduces anal sphincter hypertonia but there has been concern about complications. A greater understanding of the basic pharmacology of the internal anal sphincter has led to the development of novel treatments for both these disorders. A Medline review was undertaken for internal anal sphincter pharmacology, anal fissures and faecal incontinence. This review is based on these articles and those found by further cross-referencing. Nitric oxide released from non-adrenergic non-cholinergic nerves is the main inhibitory agent in the internal anal sphincter. Relaxations are also mediated through beta-adrenoceptors and muscarinic receptors. Stimulation of alpha-receptors results in contraction. Calcium and its entry through L-type calcium channels is important for the maintenance of tone. Nitric oxide donors produce reductions in resting anal tone and heal fissures but are associated with side-effects. Muscarinic agents and calcium channel antagonists show promise as low side-effect alternatives. Botulinum toxin appears more efficacious than other agents in healing fissures. To date, alpha-receptor agonists have been disappointing at improving incontinence. Further understanding of the pharmacology of the internal anal sphincter may permit the development of new agents to selectively target the tissue with greater efficacy and fewer side-effects.

Reasons for failure of glyceryl trinitrate treatment of chronic fissure-in-ano: a multivariate analysis

PURPOSE

Although glyceryl trinitrate ointment has become the first-line treatment for chronic anal fissure, healing rates are lower than after lateral internal sphincterotomy. The purpose of this study was to identify which factors are associated with treatment failure of glyceryl trinitrate ointment.

METHODS

All patients who presented with chronic anal fissure from March 1997 to November 1998 were treated with 0.2 percent glyceryl trinitrate ointment. They were prospectively evaluated until healing or lateral internal sphincterotomy occurred, and long-term follow-up was obtained by standardized telephone questionnaire. A Cox model multivariate analysis was used with seven variables to determine significant factors related to healing.

RESULTS

Sixty-four patients (42 men and 22 women; mean age, 37.5 years) with chronic fissure-in-ano were treated with 0.2 percent glyceryl trinitrate ointment. Sentinel piles were observed in 19 patients (29.7 percent). Twenty-six patients (40.6 percent) were healed initially, but 12 (46.2 percent) experienced recurrence. Mean follow-up time was 15.6 (+/-5.5) months. Twenty-nine patients (45.3 percent) had known risk factors for anal fissure, including constipation (n = 21; 32.8 percent), recent childbirth (n = 6; 9.3 percent), colonoscopy (n = 1; 1.6 percent), and anoreceptive intercourse (n = 1; 1.6 percent). Fissures were significantly less likely to heal initially (P < 0.05), more likely to recur (P < 0.05), and more likely to remain unhealed in the long term (P < 0.05) in the presence of a sentinel pile. Fissures with a history of more than six months were less likely to heal initially (P < 0.05).

CONCLUSION

The presence of a sentinel pile adversely affects the outcome of treatment of chronic anal fissures with glyceryl trinitrate ointment, and a long history of the fissure reduces the rate of initial healing. Reasons for these findings are discussed.

A double-blind randomized placebo-controlled trial of oral indoramin to treat chronic anal fissure

BACKGROUND

Indoramin is an alpha1-adrenoceptor antagonist and has been shown to reduce anal resting pressure. Its therapeutic potential has not been explored. The aim of this study was to determine the outcome of treatment with oral indoramin on patients with chronic anal fissure in the setting of a double-blind randomized placebo-controlled trial.

METHODS

Twenty-three patients with chronic anal fissure were computer randomized to receive a 6-week course of oral indoramin (20 mg) or placebo in identical capsules, twice daily and with bulk-forming laxatives. Pain was assessed by a visual analogue scale from 0 to 10. Anal resting pressure, heart rate and blood pressure were recorded. Patients were reviewed 1 h after taking the capsule and at 2, 6 and 12 weeks thereafter.

RESULTS

Fourteen patients were randomized to indoramin and 9 to placebo. Maximum anal resting pressure was reduced from a mean of 96.4 cm H2O (+/- 32) to 67.6 cm H2O (+/- 26), 1 h after indoramin (P=0.02) and there was no significant change after placebo. There were no significant changes in heart rate or blood pressure. Pain was reduced in the placebo group from a score of 4.9 to 2.0 after 6 weeks (P < 0.01) but not in the indoramin group. After 6 weeks, healing had occurred in one (7%) patient in the indoramin group and in 2 (22%) in the placebo group (P > 0.1). After 3 months, the chronic anal fissure in the indoramin group had recurred. The trial was terminated early because of poor healing rates.

CONCLUSION

An oral dose of indoramin (20 mg) administered twice daily reduced anal resting pressure by 30% compared with pretreatment levels but was ineffective in healing chronic anal fissures.

Anal Fissure

Anal fissure is a common condition, and although most are short-lived and heal spontaneously, those that persist and require intervention cause considerable morbidity in an otherwise healthy young population. Traditionally, lateral internal sphincterotomy was the gold standard treatment for chronic fissures, but this procedure is associated with a risk of incontinence to some degree in 30% of patients. The discovery of pharmacologic agents that effectively cause a chemical sphincterotomy and heal most fissures has led to approximately two thirds of patients avoiding surgery. Topical 0.2% GTN ointment probably is the most widely used first-line treatment. Other drugs currently under investigation may offer effective treatment with fewer side effects. Another advantage of these novel treatments is that by acting through different pathways, they may be effective in the 30% of cases in which GTN fails, the risks associated with surgery may be avoided. Studies of botulinum toxin injection into the anal sphincter have reported excellent healing rates, although the procedure is more invasive, and patients may find it uncomfortable and less tolerable. Chemical sphincterotomy is particularly suitable in patients with associated inflammatory bowel disease, in whom sphincterotomy for anal fissure generally is contraindicated. When pharmacologic therapy fails or fissures recur frequently and patients have raised resting anal pressure, lateral internal sphincterotomy is the surgical treatment of choice. The results are satisfactory when patients are selected carefully and the incision is limited to the length of the fissure. When chemical sphincterotomy fails and resting anal pressures are not elevated, as is commonly the case with patients developing fissures postpartum, an advancement flap should be considered.

Treatment of anal fissures with topical nitroglycerin

Anal fissure is a painful condition that is caused by anodermal tearing after the passage of hard stool. Severe cases result in involuntary internal anal sphincter spasm and have traditionally been treated surgically with a lateral sphincterotomy. Investigators have demonstrated that nitric oxide causes relaxation of the smooth muscle of the anal canal, so topical nitroglycerin ointment preparations have recently been studied as an efficacious alternative to surgery. Despite the fact that there are a number of trials examining topical nitroglycerin for the treatment of anal fissures, there remains no consensus about concentrations, compositions and applications necessary to obtain good results. This review summarises current literature regarding topical nitroglycerin pharmacotherapy for anal fissure.

Double-blind manometric assessment of two topical glyceryl trinitrate formulations in patients with chronic anal fissures

BACKGROUND

Chronic anal fissure is a frequent and troubling condition, that may need surgical sphincterotomy for relief of symptoms. However, this approach may yield minor incontinence in up to 30% of cases. Interest has, therefore, recently increased in "chemical sphincterotomy" by using topical glyceryl trinitrate ointment. Unfortunately, there is, to date, no specific pharmaceutical preparation of such compound.

AIMS

To compare, according to a randomized double-blind crossover study, the effects of a pharmaceutical preparation of a specific 0.2% glyceryl trinitrate ointment (PMF 303) and of the common preparation reported in the literature on the anal resting pressure in patients with anal fissure.

PATIENTS AND METHODS

Twelve patients with chronic anal fissure (6 males and 6 females, age range 23-60 years] were recruited for the study. Two paired manometric studies were carried out at one-week intervals. After the basal anal pressure had been assessed, the patients were randomized to receive either one of the two preparations, and manometric measurements were repeated at 20, 40 and 60 minutes.

RESULTS

No differences were found between anal resting pressure in the basal study. Both preparations were able to significantly decrease (p=0.001) anal pressure throughout the study period. No significant differences were found between the two preparations.

CONCLUSIONS

PMF 303 is able to decrease anal pressure in patients with anal fissure, to a similar extent to the widely tested (galenic) literature preparation. Availability of a specific formulation for the treatment of this condition may be clinically useful.

Anorectal Disease

Most symptomatic internal hemorrhoids, grade 1 through 3, can be treated successfully with office-based procedures. Anorectal suppurative diseases must be treated surgically. Control of sepsis with subsequent fistula surgery as necessary is the goal. New nonoperative methods of anal fissure therapy are directed at reducing anal sphincter pressures. These methods have shown significant reduction in the need for sphincterotomy--a proven surgical technique with some risk of impaired continence. Surgery, using an advancement flap and partial internal sphincterotomy, remains the primary treatment for anal stenosis. Solitary rectal ulcer remains a difficult problem to manage medically and surgically. Multiple surgical techniques can effectively treat rectal prolapse. A minimal technique using Silastic wrap (Wright Medical Technologies; Arlington, TX), perineal resection (Altemeier procedure), and sigmoidectomy-rectopexy, or Ripstein suspension, has been the most favored method in selected patients.