Furazolidone in the treatment of cholera

Antimicrobial drugs for treating cholera

BACKGROUND

Cholera is an acute watery diarrhoea caused by infection with the bacterium Vibrio cholerae, which if severe can cause rapid dehydration and death. Effective management requires early diagnosis and rehydration using oral rehydration salts or intravenous fluids. In this review, we evaluate the additional benefits of treating cholera with antimicrobial drugs.

OBJECTIVES

To quantify the benefit of antimicrobial treatment for patients with cholera, and determine whether there are differences between classes of antimicrobials or dosing schedules.

SEARCH METHODS

We searched the Cochrane Infectious Disease Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; African Index Medicus; LILACS; Science Citation Index; metaRegister of Controlled Trials; WHO International Clinical Trials Registry Platform; conference proceedings; and reference lists to March 2014.

SELECTION CRITERIA

Randomized and quasi-randomized controlled clinical trials in adults and children with cholera that compared: 1) any antimicrobial treatment with placebo or no treatment; 2) different antimicrobials head-to-head; or 3) different dosing schedules or different durations of treatment with the same antimicrobial.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied inclusion and exclusion criteria, and extracted data from included trials. Diarrhoea duration and stool volume were defined as primary outcomes. We calculated mean difference (MD) or ratio of means (ROM) for continuous outcomes, with 95% confidence intervals (CI), and pooled data using a random-effects meta-analysis. The quality of evidence was assessed using the GRADE approach.

MAIN RESULTS

Thirty-nine trials were included in this review with 4623 participants. Antimicrobials versus placebo or no treatment Overall, antimicrobial therapy shortened the mean duration of diarrhoea by about a day and a half compared to placebo or no treatment (MD -36.77 hours, 95% CI -43.51 to -30.03, 19 trials, 1013 participants, moderate quality evidence). Antimicrobial therapy also reduced the total stool volume by 50% (ROM 0.5, 95% CI 0.45 to 0.56, 18 trials, 1042 participants, moderate quality evidence) and reduced the amount of rehydration fluids required by 40% (ROM 0.60, 95% CI 0.53 to 0.68, 11 trials, 1201 participants, moderate quality evidence). The mean duration of fecal excretion of vibrios was reduced by almost three days (MD 2.74 days, 95% CI -3.07 to -2.40, 12 trials, 740 participants, moderate quality evidence).There was substantial heterogeneity in the size of these benefits, probably due to differences in the antibiotic used, the trial methods (particularly effective randomization), and the timing of outcome assessment. The benefits of antibiotics were seen both in trials recruiting only patients with severe dehydration and in those recruiting patients with mixed levels of dehydration. Comparisons of antimicrobials In head-to-head comparisons, there were no differences detected in diarrhoea duration or stool volume for tetracycline compared to doxycycline (three trials, 230 participants, very low quality evidence); or tetracycline compared to ciprofloxacin or norfloxacin (three trials, 259 participants, moderate quality evidence). In indirect comparisons with substantially more trials, tetracycline appeared to have larger benefits than doxycycline, norfloxacin and trimethoprim-sulfamethoxazole for the primary review outcomes.Single dose azithromycin shortened the duration of diarrhoea by over a day compared to ciprofloxacin (MD -32.43, 95% CI -62.90 to -1.95, two trials, 375 participants, moderate quality evidence) and by half a day compared to erythromycin (MD -12.05, 95% CI -22.02 to -2.08, two trials, 179 participants, moderate quality evidence). It was not compared with tetracycline.

AUTHORS' CONCLUSIONS

In treating cholera, antimicrobials result in substantial improvements in clinical and microbiological outcomes, with similar effects observed in severely and non-severely ill patients. Azithromycin and tetracycline may have some advantages over other antibiotics.

Effect of furazolidone on sister-chromatid exchanges, cell proliferation kinetics, and mitotic index in vivo and in vitro

Furazolidone is an antimicrobial compound used in human and veterinary medicine. The aim of this investigation was to determine its genotoxic capacity in vitro and in vivo. We used the human lymphocyte culture system to detect the effect of 2.0, 4.0, 6.0, 8.0, or 10.0 micrograms/ml, and the mouse bone marrow assay to determine the effect of 8.6, 30.0, or 75.0 mg/kg furazolidone. In both systems we determined the frequency of sister-chromatid exchanges (SCE), the cell proliferation kinetics (CPK), and the mitotic index (MI). The in vitro results showed a significant SCE increase starting from the second dose tested and a CPK and MI decrease starting from the third dose. The in vivo results showed a SCE increase with the two high doses tested, but no significant modification was found in the CPK and MI with the three doses tested in the experiment.

Efficacy of a single dose of furazolidone for treatment of cholera in children

To test the efficacy and safety of furazolidone given as a single dose for childhood cholera, a randomized double-blind placebo-controlled trial was carried out among 118 culture-positive dehydrated children with diarrhea. Patients were randomly assigned to one of four groups to receive medication orally in liquid suspension: furazolidone at 7 mg/kg/day once, furazolidone at 7 mg/kg/day divided into four doses for 3 days, placebo once, or placebo for 3 days. After 12 patients with furazolidone-resistant infections were excluded from the analysis of efficacy, it was determined that both groups treated with furazolidone showed significantly higher rates of bacteriologic success (stool cultures negative for Vibrio cholerae on days 2 to 4 after start of therapy) and clinical success (cessation of diarrhea within 72 h after start of therapy) than corresponding placebo groups (P less than 0.001). There were no significant differences between responses to the 3-day and single-dose regimens of furazolidone, but there was a trend toward better clinical responses in patients who received furazolidone for 3 days. No patient treated with furazolidone dropped out because of side effects. These results indicate that furazolidone, given as either a single dose or divided doses for 3 days, is effective treatment for childhood cholera.

Single-dose treatment of cholera with furazolidone or tetracycline in a double-blind randomized trial

To evaluate single doses of 400 mg of furazolidone and 1 g of tetracycline given orally to patients with diarrhea due to Vibrio cholerae, we studied 87 adults in a randomized, double-blind, placebo-controlled trial. All patients received intravenous fluids for rehydration and no other drugs. The total volumes of stool (mean +/- standard deviation) during a 6-day period after treatment were significantly smaller in the tetracycline group (10.5 +/- 8.6 liters) than in the furazolidone group (20.9 +/- 15.9 liters) and the placebo group (19.1 +/- 10.5 liters) (P less than 0.01). The duration of diarrhea and volumes of intravenous fluids were also significantly reduced in the tetracycline group (P less than 0.05). However, there were no differences between the furazolidone and the placebo groups with regard to stool volume, intravenous fluid, and duration of diarrhea. Within 48 h of treatment, tetracycline significantly reduced the number of patients with positive stool cultures for V. cholerae (37%) compared with furazolidone treatment (96%) and the placebo (97%) (P less than 0.001). Although the tetracycline group had a significantly higher incidence (61%) of bacteriologic relapse (negative stool cultures on days 2 and 3, followed by positive cultures afterward) compared with that in the furazolidone group (40%) and the placebo group (33%), this was not associated with clinical relapse. There were no differences between the furazolidone and placebo groups with regard to any of the bacteriologic responses examined. These data indicate that a single dose of 1 g of tetracycline is effective in the treatment of cholera, but it is asymptomatic bacteriologic relapse. A single dose of 400 mg of furazolidone is not therapeutically effective in cholera.

A comparative study of furazolidone and placebo in addition to oral rehydration in the treatment of acute infantile diarrhea

Between July and October 1987 an outpatient study of 191 children with acute diarrhea was undertaken in two rural communities in Mexico. Through a double-blind randomization we compared the efficacy of a combination therapy of furazolidone, 7.5 mg/kg/day, plus standard oral rehydration therapy (ORT) (96 patients) versus a placebo plus ORT (95 patients), each given for 5 days. Diarrheal stool samples were collected from all patients before therapy. By means of a two-vial transport media system the samples were sent to a university laboratory and examined for viral, bacterial, and parasitic organisms. The most commonly isolated organisms were enterotoxigenic Escherichia coli (13%) and Giardia lamblia (13%). Patients who received furazolidone plus ORT showed a greater reduction in duration of diarrhea when compared with those receiving placebo plus ORT (63.4 h versus 71.44 h). There was also a trend toward shorter duration of diarrhea in patients with Giardia who were treated with furazolidone/ORT compared with Giardia patients in the placebo/ORT group. When fecal leukocytes were present in the stool, the furazolidone/ORT-treated patients had a significantly higher percentage of clinical cures (79% versus 54%, p = 0.03) and an overall shorter duration of diarrhea (62.0 h versus 80.6 h, p = 0.055) at the end of 5 days of therapy than did the placebo/ORT-treated group.

Adverse reactions to furazolidone and other drugs. A comparative review

Furazolidone is a synthetic nitrofuran with a broad spectrum of antimicrobial action and has been widely used in the treatment of gastrointestinal infections. This article reviews the adverse reactions to furazolidone reported in the world literature. Of 10,443 adults and children who were treated with the drug, approximately 8.3% (864) experienced such reactions. Because some of these patients had more than 1 adverse reaction, 1178 reactions were reported in these studies. Nausea with vomiting, the commonest adverse reaction, was reported by 51% of the 864 patients who experienced adverse reactions. The authors compare the adverse reactions to furazolidone with those reported for other antimicrobial and antiprotozoal drugs that are frequently used to treat gastrointestinal infections.

An adaptive response of Vibrio cholerae strain OGAWA 154 to furazolidone

Since furazolidone is an antimicrobial drug, any possibility of its evoking an adaptive response appears to be very important. This response was studied in Vibrio cholerae cells as a model system. In order to determine this response, a dose-response relation of these cells to furazolidone and the kinetics of inactivation of the drug were studied. The study of the adaptive response of these cells to furazolidone reveals that cells treated with a low concentration of furazolidone for a particular period were 100% more resistant to the lethal effects of a subsequent challenging dose than control cultures. Variation of the challenging dose level showed better survival of adapted cells than control cells. A time-dependent response study reveals a maximum response at 15-30 min, and a gradual fall thereafter.

Induction of lambda prophage by furazolidone

A dose-dependent prophage induction by furazolidone exhibited a gradual rise to a maximum, corresponding to an exposure dose of 1.2 microgram/ml X h and a gradual fall thereafter. A 2-3-fold higher level of induction was achieved when the lysogens were treated with furazolidone in the presence of a metabolizing mixture. A maximum of about 70% efficiency of induction was achieved. Kinetics of prophage induction by any concentration of furazolidone exhibited a common pattern, viz., an initial rise for 15-20 min, then a plateau extending up to about 60 min and a faster rise thereafter. Higher concentrations of the drug (10 micrograms/ml) exhibited a toxic effect. Chloramphenicol at a concentration of 20 micrograms/ml inhibited the furazolidone-induced prophage induction, the plaque-forming units gradually decreasing from several minutes after the chloramphenicol treatment. The burst size of the lysogens was not significantly affected by treatment with 2 micrograms/ml of furazolidone up to a period of about 10 min, but thereafter, decreased faster with the duration of furazolidone treatment. The "latent period' of induction decreased linearly with the duration of furazolidone treatment.

Furazolidone versus ampicillin in the treatment of traveler's diarrhea

Ninety-four U.S. students who acquired diarrhea in Mexico were treated with furazolidone (47 subjects) or ampicillin (47 subjects) on a double-blind random basis. Of 47 students, 26 (55%) who received furazolidone (100 mg four times daily for 5 days) recovered from illness within 48 h after initiation of therapy, in contrast to 15 of 47 (32%) who received ampicillin (500 mg four times daily for 5 days) (P less than 0.05). Altogether, 74% of students treated with furazolidone and 49% of those receiving ampicillin were well within 72 h (P less than 0.05). When furazolidone was compared with ampicillin, clinical illness was shortened on the average from 65 to 61 h for enterotoxigenic Escherichia coli diarrhea, from 83 to 58 h for shigellosis, from 82 to 51 h for diarrhea unassociated with a detectable agent, and from 72 to 57 h for all cases irrespective of etiology. Although not dramatically effective in the current trial, the broad spectrum of activity of furazolidone is of interest. Because of in vitro activity against Campylobacter strains and known effectiveness in treating giardiasis, furazolidone should be considered in therapy for diarrhea of unknown etiology in certain settings when laboratory processing of stools for etiological agent is not feasible.

Radiomimetic property of furazolidone and the caffeine enhancement of its lethal action on the vibrios

Sensitivities of the strains belonging to four vibrio biotypes to the action of furazolidone were investigated. Vibrio cholerae (classical) was most and Vibrio parahaemolyticus least sensitive to this drug. Statistical analyses revealed significant differences between any two of the four types of vibrio in respect of their sensitivity to furazolidone. The drug was radiomimetic in action, the doses of UV light (DUV) and furazolidone (Df) required for 10% survival of the vibrios being correlated by the equation, Df = 0.28 exp. (0.008 DUV). Caffeine exhibited lethal synergism with furazolidone and the synergistic effect depended on the mode of caffeine treatment, the effect being maximum when caffeine was present along with and also after furazolidone treatment. UV spectrophotometric study revealed that caffeine did not bind with native DNA but did so with denatured DNA resulting in a bathochromic shift and a quenching of the caffeine absorption maximum at 209.4 nm. The binding isotherm (Scatchard plot) indicated the presence of a heterogeneity in the binding sites and that the parameters for the strongest mode of bonding were n = 0.254 and k = 7.5 X 10(5) M-1.

Controlled comparison of tetracycline and furazolidone in cholera

A controlled comparison of furazolidone and tetracycline in the treatment of cholera indicates that, in either dosage used, furazolidone reduced total stool volume by 50% and duration of diarrhoea by 40%. These results are comparable to those achieved with tetracycline, which was given in presently recommended dosage. Both furazolidone and tetracycline significantly reduced the rate of stool output within 18 to 24 hours of starting antibiotic treatment. Furazolidone was significantly less effective than tetracycline in rapidly and consistently terminating vibrio excretion. One convalescent carrier of cholera vibrios was identified among control patients; none was identified among patients treated with either tetracycline or furazolidone. All Vibrio cholerae strains tested were sensitive to tetracycline and furazolidone, but larger concentrations of the latter were required to achieve inhibition of growth. It is concluded that tetracycline remains the antibiotic of choice in cholera but that furazolidone would be a useful adjunct to cholera therapy when tetracycline is unobtainable or if strains of V. cholerae with clinically significant resistance to tetracycline should be encountered.