Anti-oxidant action of metronidazole: a possible mechanism of action in rosacea

Topical metronidazole after haemorrhoidectomy to reduce postoperative pain: a systematic review

Excisional haemorrhoidectomy is the gold standard for operating haemorrhoids, but it is accompanied by a significant problem: postoperative pain. Several strategies have been adopted to minimize this condition. Oral metronidazole has been proven to reduce postoperative pain but with some complications. This systematic review was conducted to investigate the effects and general efficacy of topical metronidazole administration and to evaluate its potential superiority over the oral formula. A systematic review of the literature was carried out. Randomized controlled trials published until September 2023 on PubMed, Central, and Web of Science were considered. The primary outcome considered was postoperative pain, which was evaluated using visual analogue scores. The secondary outcomes were analgesic use, return to work, and complications. Six randomized controlled trials were included, with a total of 536 patients. Topical metronidazole was compared with placebo in two studies, with oral formula in three studies, and with placebo and oral administration in one study. Topical metronidazole was found to be effective for treating postoperative pain when compared to a placebo but had no significant advantage over the oral formula. No complications were reported in the studies. Topical and oral metronidazole are effective solutions for postoperative pain after excisional haemorrhoidectomy. No superiority was demonstrated based on the route of administration, and complications were marginal for both formulas. Further studies are required to determine the best metronidazole solution.

Five-year radiological findings from a randomized controlled trial of four periodontitis treatment strategies

Radiographic findings from long-term studies of periodontitis treatment have rarely been reported. Although bone destruction is a prominent feature of periodontitis, the long-term effect on alveolar bone levels of different treatment strategies, with or without adjunctive metronidazole (MTZ), has not been reported. We investigated the 5-year radiographic outcome of therapy in patient groups treated with conventional scaling and root planing (SRP) or same-day full-mouth disinfection (FDIS), with or without adjunctive MTZ. Following a 3-month oral hygiene phase, 184 periodontitis patients were randomly allocated to one of four treatment regimens: (i) FDIS+MTZ; (ii) FDIS+placebo; (iii) SRP+MTZ; or (iv) SRP+placebo. Following active treatment, patients received biannual maintenance. In total, 161 patients (87.5%) completed the 5-year follow-up examination, at which the radiographic bone level (RBL), clinical attachment level, probing pocket depth, presence of plaque, and bleeding were recorded again. At the 5-year follow up examination, minor radiological bone loss was observed in the intervention groups FDIS+placebo, SRP+MTZ, and SRP+placebo; by contrast, the FDIS+MTZ group did not show any change in RBL. Full-mouth disinfection did not generally perform better than conventional SRP performed over a period of 2 to 4 weeks.

Maintenance of Remission after Oral Metronidazole Add-on Therapy in Rosacea Treatment: A Retrospective, Comparative Study

BACKGROUND

Rosacea is a chronic inflammatory disease which requires treatment to maintain remission.

OBJECTIVE

Recently, the effect of Demodex mites in recurrence of rosacea has been described. Although there is limited data, previous reports have suggested that oral metronidazole demonstrated efficacy in treatment of rosacea.

METHODS

Fifty-eight Korean patients with rosacea who received treatment with oral minocycline (50 mg twice daily) only or with two-week of oral metronidazole (250 mg thrice daily) were evaluated retrospectively. Their responses were evaluated by Investigator's Global Assessment (IGA), Clinician's Erythema Assessment (CEA), and patient's Global Assessment. The recurrence rate and odds ratio of risk factors for recurrence were also estimated.

RESULTS

The combination treatment group reported earlier clinical improvement and lower mean IGA and CEA than the monotherapy group. Approximately 48% of patients with combination treatment did not show relapse within 24 weeks, which is significantly higher than that in the monotherapy group (p=0.042).

CONCLUSION

Add-on therapy of oral metronidazole appeared to be a significant protective factor for recurrence of rosacea (p<0.05). This study suggests that oral metronidazole can be added to oral minocycline to reduce relapses in rosacea patients with tolerable safety.

Mediation roles of neutrophils and high-density lipoprotein (HDL) on the relationship between HLA-DQB1 and rosacea

BACKGROUND

Though the previous genome-wide association studies found the association between HLA alleles and rosacea in the European populations, the data is lacking among the Asians. Moreover, neutrophils are important in the immune-related mechanism of rosacea, and dyslipidemia is closely related to rosacea. We aimed to explore the association between HLA genes and rosacea in Chinese rosacea patients, as well as the mediation effect of neutrophils, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) on the relationship between HLA genes and rosacea.

METHODS

A total of 249 rosacea and 150 controls were ranked by the international investigator global rosacea severity scores. HLA genes, neutrophils, HDL, and LDL were detected. And their mediation effects on the relationship between HLA and rosacea risk or severity were analysed.

RESULTS

HLA-DQB1*03:03 allele (OR = 41.89, 95% CI: 9.80 ∼ 179.09, p = 4.7*10-7), HLA-DQB1*04:02 allele (OR = 0.16, 95% CI: 0.03 ∼ 0.81, p = 0.026) and HLA-DQB1*03:03/05:02 genotype (OR = 5.57, 95% CI: 1.13 ∼ 27.52, p = 0.0351) were significantly associated with rosacea. Moreover, HLA-DQB1*03:03 allele (b = 1.434, SE = 0.217, p = 2.0*10-10), HLA-DQB1*05:01 allele (b = 0.894, SE = 0.33520, p = 0.008) and HLA-DQB1*03:03/06:01 genotype (b = 0.998, SE = 0.472, p = 0.040) were positively associated with rosacea severity. Furthermore, we found both neutrophils and HDL, instead of LDL, have mediation effects on the relationship between HLA-DQB1*03:03 and risk or severity of rosacea.

CONCLUSIONS

We discovered novel susceptible HLA alleles for rosacea in the Chinese population, and disclosed the mediation effect of neutrophils and HDL on the relationship between HLA-DQB1 and rosacea, implying a possible correlation between rosacea and inflammatory or metabolic factors, providing hints for future studies in the mechanism of rosacea. Key messagesHLA-DQB1*03:03 allele, HLA-DQB1*04:02 allele and HLA-DQB1*03:03/05:02 genotype were significantly associated with rosacea.HLA-DQB1*03:03 allele, HLA-DQB1*05:01 allele and HLA-DQB1*03:03/06:01 genotype were positively associated with rosacea severity.Neutrophils and HDL have mediation effects on the relationship between HLA-DQB1*03:03 and risk or severity of rosacea.

Immobilization of Metronidazole on Mesoporous Silica Materials

Metronidazole (MTZ) is a widely used drug, but due to its many side effects, there is a growing trend today to use a minimum dose while maintaining high efficacy. One way to meet this demand is to reduce the size of the drug particles. A relatively new method of size reduction is attaching the drug molecules to a mesoporous carrier. In this paper, we studied the fixation of MTZ molecules on mesoporous silica carriers. The drug was immobilized on two mesoporous silica materials (Syloid, SBA-15) with the use of a variety of immersion techniques and solvents. The immobilized drug was subjected to physicochemical examinations (e.g., SEM, XPS, XRD, nitrogen uptake, DSC) and dissolution studies. A significantly higher immobilization was attained on SBA-15 than on a Syloid carrier. Among the processing parameters, the type of MTZ solvent had the highest influence on immobilization. Ultrasonic agitation had a lower but still significant impact, while the concentration of MTZ in the solution made no difference. Under optimal conditions, with the application of an ethyl acetate solution, the surface coverage on SBA-15 reached as much as 91%. The immobilized MTZ exhibited a ca. 10% faster dissolution rate as compared to the pure micron-sized drug particles.

Metronidazole Topically Immobilized Electrospun Nanofibrous Scaffold: Novel Secondary Intention Wound Healing Accelerator

The process of secondary intention wound healing includes long repair and healing time. Electrospun nanofibrous scaffolds have shown potential for wound dressing. Biopolymers have gained much attention due to their remarkable characteristics such as biodegradability, biocompatibility, non-immunogenicity and nontoxicity. This study anticipated to develop a new composite metronidazole (MTZ) immobilized nanofibrous scaffold based on poly (3-hydroxy butyrate) (PHB) and Gelatin (Gel) to be utilized as a novel secondary intention wound healing accelerator. Herein, PHB and Gel were mixed together at different weight ratios to prepare polymer solutions with final concentration of (7%), loaded with two different concentrations 5% (Z₁) and 10% (Z₂) of MTZ. Nanofibrous scaffolds were obtained by manipulating electrospinning technique. The properties of MTZ immobilized PHB/Gel nanofibrous scaffold were evaluated (SEM, FTIR, TGA, water uptake, contact angle, porosity, mechanical properties and antibacterial activity). Additionally, in vitro cytocompatibility of the obtained nanofibrous scaffolds were assessed by using the cell counting kit-8 (CCK-8 assay). Moreover, in vivo wound healing experiments revealed that the prepared nanofibrous scaffold highly augmented the transforming growth factor (TGF-β) signaling pathway, moderately suppressed the pro-inflammatory cytokine (IL-6). These results indicate that MTZ immobilized PHB/Gel nanofibrous scaffold significantly boost accelerating secondary intention wound healing.

Metronidazole gel (0.75%) in Japanese patients with rosacea: A randomized, vehicle-controlled, phase 3 study

Topical metronidazole is not currently approved in Japan as a treatment for the indication of rosacea, although 0.75% metronidazole gel was authorized in 2014 for the management of cancerous skin ulcers. We conducted a randomized, double-blind, vehicle-controlled study to evaluate the efficacy and safety of 0.75% metronidazole gel in Japanese patients with inflammatory lesions (papules/pustules) and erythema associated with moderate to severe rosacea. Overall, 130 patients were randomly assigned to receive 0.75% metronidazole gel (n = 65) or vehicle (n = 65), and 120 patients completed 12 weeks of treatment. The primary efficacy outcome was the proportion of patients who achieved both of the following at week 12: an improvement of >50% in the number of inflammatory lesions (papules/pustules) and a positive change of at least one degree in erythema severity. This composite outcome was achieved by 72.3% of metronidazole-treated patients versus 36.9% of vehicle-treated patients, with the between-group difference demonstrating significant improvement with 0.75% metronidazole gel (p < 0.0001). All secondary efficacy endpoints (patients achieving a score of ≥3 for percent change in the number of inflammatory lesions at week 12; patients achieving a score of ≥3 for change in erythema severity at week 12; patients achieving an Investigator's Global Assessment score of 0 or 1 at week 12; percent change over time in the number of inflammatory lesions; change over time in erythema severity) also showed improvement in the 0.75% metronidazole gel group. The incidence of adverse events was higher with metronidazole (40.0%) than with vehicle (29.2%). Of these, treatment-related, treatment-emergent adverse events occurred in 9.2% and 6.2% in the metronidazole and the vehicle group, respectively, but there were no new safety concerns. Overall, the results of this study have confirmed the efficacy and safety of 0.75% metronidazole gel in Japanese patients with rosacea.

Metronidazole does not show direct antioxidant activity in in vitro global systems

Metronidazole has been widely used topically and systemically for more than 50 years but data on its antioxidant properties are still incomplete, unclear and contradictory. Its antioxidant properties are primarily hypothesized based on in vivo results, therefore, studies have been performed to determine whether metronidazole has antioxidant activity in vitro. We used so-called global spectrophotometric and luminometric methods. Fe³⁺/Fe²⁺-reducing ability, hydrogen donor activity, hydroxyl radical scavenging property and lipid peroxidation inhibitory activity were investigated. Under the condition used, metronidazole has negligible iron-reducing ability and hydrogen donor activity. The hydroxyl radical scavenging capacity cannot be demonstrated. It acts as a pro-oxidant in the H₂O₂/^.OH-microperoxidase-luminol system, but it can inhibit the induced lipid peroxidation. According to our results, metronidazole has not shown antioxidant activity in vitro but can affect redox homeostasis by a ROS-independent mechanism due to its non-direct antioxidant properties.

Metronidazole in the Management of Post-Open Haemorrhoidectomy Pain: Systematic Review

Purpose

Open haemorrhoidectomy is associated with significant postoperative pain. Metronidazole is commonly prescribed in the postoperative period as an adjunct to analgesia in pain management.

Methods

In our systematic review, studies were identified using PubMed/MEDLINE, Embase/Ovid and Cochrane Register of Controlled Trials databases. Studies were included if they were randomised controlled trials (RCTs) involving interventions with oral metronidazole at any dose over any time period. The primary outcome was pain score (visual analogue scale, VAS) after open haemorrhoidectomy. Secondary outcomes included time to return to normal daily activities, additional analgesia usage, and postoperative complications.

Results

Of 14 RCTs reviewed, 4 met inclusion criteria and were selected. The studies comprised 336 study subjects and 169 subjects were randomised to metronidazole while 167 were in the control group. There was a significant reduction in VAS across all time points, with maximal reduction seen on day 5 posthaemorrhoidectomy (mean difference, -2.28; 95% confidence interval, -2.49 to -2.08; P < 0.001). There was no difference in incidence of complications (P = 0.13). The Cochrane Risk of Bias Tool showed 3 of 4 of the studies had a risk of bias.

Conclusion

Metronidazole may be associated with decreased pain but there is insufficient evidence from RCTs to provide a strong grade of recommendation. Further RCTs are required.

Safety of Combination Laser or Intense Pulsed Light Therapies and Doxycycline for the Treatment of Rosacea

BACKGROUND

Current treatment options for rosacea include topical agents, oral therapies, phototherapy using lasers, or intense pulsed light (IPL). Combination therapy for rosacea often yields better results than monotherapy. The safety of laser/light treatments in combination with systemic doxycycline has been questioned because of the theoretical risk of photosensitivity.

OBJECTIVE

The purpose of this study was to assess the incidence of phototoxicity or photosensitivity in rosacea patients receiving concomitant laser or light treatments and systemic doxycycline.

METHODS

Treatment records of 36 patients receiving laser/light treatments while also being treated with standard dose or anti-inflammatory dose of doxycycline were retrospectively reviewed.

RESULTS

No adverse reactions related to doxycycline combined with laser/light therapy were reported. Specifically, no photosensitivity or sensitivity to wavelengths in the pulsed dye laser (PDL), or IPL range was observed in this cohort. All patients achieved some degree of clearance.

CONCLUSION

The results of this retrospective study demonstrate that doxycycline used in conjunction with laser or nonlaser light therapy is a valid combination therapy for improving signs and symptoms of rosacea. No photosensitivity reactions were observed to commonly used IPL or PDL devices.

Treatment of seborrheic dermatitis: a comprehensive review

Seborrheic dermatitis (SD) is a chronic, recurring inflammatory skin disorder that manifests as erythematous macules or plaques with varying levels of scaling associated with pruritus. The condition typically occurs as an inflammatory response to Malassezia species and tends to occur on seborrheic areas, such as the scalp, face, chest, back, axilla, and groin areas. SD treatment focuses on clearing signs of the disease; ameliorating associated symptoms, such as pruritus; and maintaining remission with long-term therapy. Since the primary underlying pathogenic mechanisms comprise Malassezia proliferation and inflammation, the most commonly used treatment is topical antifungal and anti-inflammatory agents. Other broadly used therapies include lithium gluconate/succinate, coal tar, salicylic acid, selenium sulfide, sodium sulfacetamide, glycerin, benzoyl peroxide, aloe vera, mud treatment, phototherapy, among others. Alternative therapies have also been reported, such as tea tree oil, Quassia amara, and Solanum chrysotrichum. Systemic therapy is reserved only for widespread lesions or in cases that are refractory to topical treatment. Thus, in this comprehensive review, we summarize the current knowledge on SD treatment and attempt to provide appropriate directions for future cases that dermatologists may face.

Metronidazole following excisional haemorrhoidectomy: a systematic review and meta-analysis

BACKGROUND

Post-operative pain is a major issue following excisional haemorrhoidectomy. Although metronidazole by both oral and topical administration routes has been shown to reduce pain after haemorrhoidectomy, its use remains a contentious issue. This systematic review and meta-analysis aims to investigate the effect of metronidazole on post-operative pain after excisional haemorrhoidectomy.

METHODS

A systematic review of the literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials (RCTs) published in PubMed/MEDLINE, EMBASE, CENTRAL and CINAHL, from inception to December 2016 were retrieved. The primary outcome investigated was post-operative pain reported as visual analogue score (VAS). Secondary outcomes were analgesia use, complications and time to return to normal activity. Meta-analysis was performed using Review Manager version 5.3 software.

RESULTS

Nine randomized controlled trials including 523 patients were included in the final analysis. Five studies used oral administration and four used topical. Meta-analysis showed that post-operative VAS of patients receiving metronidazole by either route was significantly less than those in comparison groups. VAS means decreased at all the time points for both oral and topical metronidazole. Topical and oral routes of administration were not compared in any study. There was no increase in complication rates and return to normal activity was significantly earlier for patients receiving metronidazole (-4.49 days; 95% confidence interval [-7.70, -1.28]; P = 0.006).

CONCLUSIONS

Both topical and oral metronidazole reduce post-operative pain without an increase in complication rates and result in an earlier return to normal activity. Further work is required to determine which the optimum route of administration is.

Systematic review and meta-analysis of the role of metronidazole in post-haemorrhoidectomy pain relief

AIM

Conventional haemorrhoidectomy is still considered the reference standard for the management of severe or recurrent haemorrhoids. Pain is reported by patients to be the most common postoperative complication. Although the literature lacks a consensus on its effectiveness, metronidazole is often used to reduce postoperative pain. We have performed a meta-analysis of all randomized controlled trials (RCTs) that investigated the use of metronidazole for pain relief after haemorrhoidectomy.

METHOD

A systematic review was undertaken in accordance with the PRISMA protocol using the MESH headings 'haemorrhoidectomy', 'hemorhoidectomy', 'hemorrhoidectomy', 'haemorrhoid', 'metronidazole', 'Flagyl^® ' 'antibiotic' and 'pain'. The search returned 421 articles of which eight were RCTs suitable for inclusion in the review with a total population of 437 patients. The outcomes of interest were postoperative pain intensity on days 1, 2 and 7 and on first defaecation as measured using a visual analogue scale.

RESULTS

The meta-analysis demonstrated a significant reduction in postoperative pain for patients treated with metronidazole with a reduced mean difference for the metronidazole group on day 1 of -1.42 (95% CI: -2.14 to -0.69, P = 0.0001), on day 2 of -1.43 (95% CI: -2.45 to -0.40, P = 0.006) and on day 7 of -2.40 (95% CI: -3.10 to -1.71, P < 0.00001). Pain on first defaecation was likewise reduced with a mean difference of -1.38 (95% CI: -2.15 to -0.60, P = 0.0005). Limitations of this study include variation in the grade of haemorrhoids treated and variability in the quality of included studies.

CONCLUSION

Metronidazole is a cheap, safe and effective intervention for reducing postoperative pain following conventional haemorrhoidectomy.

Anti-inflammatory and Immunomodulatory Effects of Antibiotics and Their Use in Dermatology

Antibiotics (antibacterial, antiviral, and antiparasitic) are class of drugs which result in either killing or inhibiting growth and multiplication of infectious organisms. Antibiotics are commonly prescribed by all specialties for treatment of infections. However, antibiotics have hitherto immunomodulatory and anti-inflammatory properties and can be exploited for various noninfectious dermatoses. Dermatologists routinely prescribe antibiotics in treatment of various noninfectious disorders. This study will review anti-inflammatory and immunomodulatory effects of antibiotics and their use in dermatology.

Erythromycin as a Safe and Effective Treatment Option for Erythema Annulare Centrifugum

Background:

Erythema annulare centrifugum (EAC) is an inflammatory dermatosis with unknown etiology. It is usually self-limited, but chronic disease may be difficult to treat. We observed incidentally the therapeutic effect of erythromycin for EAC among patients taking erythromycin for other diseases.

Aim:

To evaluate the treatment response of erythromycin for EAC.

Materials and Methods:

During the study period, from July 2007 to February 2011, all patients with EAC were assigned to erythromycin stearate tablet 1000 mg per day for two weeks. EAC was diagnosed by a constellation of clinical and pathological findings. The efficacy (before and after the treatment) was assessed clinically by one dermatologist and photographically by two blinded dermatologists. Secondary outcomes included adverse drug effects and recurrence.

Results:

Eight patients were enrolled in this study. Most patients had chronic relapsing disease with poor response to previous treatment. All the patients showed rapid response with profound reduction in the size of lesion and erythema two weeks after initiation of erythromycin treatment. The response was so obvious and complete that a coincidental response was less likely. Three patients had recurrence of disease and they tended to have more extensive lesions. Readministration of erythromycin was effective. All patients tolerated the treatment well.

Conclusion:

Our study documented erythromycin as a safe and cost-effective treatment for EAC.

Microbiologic Observations After Four Treatment Strategies Among Patients With Periodontitis Maintaining a High Standard of Oral Hygiene: Secondary Analysis of a Randomized Controlled Clinical Trial

BACKGROUND

The benefit of full-mouth disinfection (FDIS) over traditional scaling and root planing (SRP), with or without adjunctive metronidazole, when treating chronic destructive periodontitis remains equivocal, as does the long-term association between clinical and microbiologic outcomes after such strategies. The aim of this study is to examine the relationship between clinical and microbiologic outcomes of four different treatment strategies for chronic destructive periodontitis among patients who maintain excellent oral hygiene and low gingival bleeding scores.

METHODS

One hundred eighty-four patients with periodontitis and capable of maintaining a high standard of oral hygiene were randomly allocated to one of four treatment groups: 1) FDIS + metronidazole; 2) FDIS + placebo; 3) SRP + metronidazole; and 4) SRP + placebo. Recordings of plaque, bleeding on probing, probing depth (PD), and clinical attachment level were carried out in four sites per tooth at baseline, 3 and 12 months after treatment. Before treatment, pooled subgingival samples were obtained from the five deepest pockets, which were sampled again 3 and 12 months after treatment. Microbiologic assessments of eight putative periodontal pathogens were performed using the checkerboard DNA-DNA hybridization method.

RESULTS

Levels of bacterial species were already relatively low at baseline. The only microbial factor statistically significantly associated with the clinical outcomes of treatment after 12 months was the association between reductions of Tannerella forsythia and being free from PD ≥5 mm.

CONCLUSION

In this clinical trial, the only microbial factor associated with the clinical outcomes after 12 months was a statistically significant association between the reductions of T. forsythia and being free from PD ≥5 mm.

Serum calprotectin concentrations in dogs with idiopathic inflammatory bowel disease

OBJECTIVE

To measure serum calprotectin concentration in dogs with inflammatory bowel disease (IBD) before and after initiation of treatment and evaluate its correlation with a clinical scoring system (canine IBD activity index), serum canine C-reactive protein concentration, and severity of histopathologic changes.

ANIMALS

34 dogs with idiopathic IBD and 139 healthy control dogs.

PROCEDURES

From dogs with IBD, blood samples were collected immediately before (baseline) and 3 weeks after initiation of 1 of 2 treatments: prednisone (1 mg/kg, PO, q 12 h; n = 21) or a combination of prednisone and metronidazole (10 mg/kg, PO, q 12 h; 13). Blood samples were collected once from each of the control dogs. For all samples, serum calprotectin concentration was determined via radioimmunoassay.

RESULTS

Mean serum calprotectin concentrations for dogs with IBD at baseline (431.1 μg/L) and 3 weeks after initiation of treatment (676.9 μg/L) were significantly higher, compared with that (219.4 μg/L) for control dogs, and were not significantly correlated with the canine IBD activity index, serum C-reactive protein concentration, or severity of histopathologic changes. The use of a serum calprotectin concentration of ≥ 296.0 μg/L as a cutoff had a sensitivity of 82.4% (95% confidence interval, 65.5% to 93.2%) and specificity of 68.4% (95% confidence interval, 59.9% to 76.0%) for distinguishing dogs with idiopathic IBD from healthy dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum calprotectin concentration may be a useful biomarker for the detection of inflammation in dogs, but the use of certain drugs (eg, glucocorticoids) appears to limit its clinical usefulness.

Preparation and evaluation of topical microemulsion system containing metronidazole for remission in rosacea

The aim of this study was to prepare a topical water-in-oil type microemulsion containing metronidazole and to compare its effectiveness with a commercial gel product in the treatment of rosacea. A pseudo-ternary phase diagram (K(m)=2:1) was constructed using lecithin/butanol/isopropyl myristate/water. The microemulsion was chosen from the microemulsion region in the phase diagram. The formulation was a water-in-oil type microemulsion (droplet size: 11.6 nm, viscosity: 457.3 mPa·s, conductivity: 1.5 µs/cm, turbidity: 6.89 NTU) and the addition of the metronidazole did not alter the properties of the system. The release experiment showed that the release rate of metronidazole from the commercial gel product was higher than that of the microemulsion. Stability experiments showed that the metronidazole microemulsion remained stable for at least 6 months; none of the characteristic properties of the microemulsion had changed, the system retained its clarity and there was no sign that crystallization of metronidazole has occurred. Microemulsion was compared to a gel product in a randomized, double-blind, baseline-controlled, split-face clinical trial for the treatment of patients. After the 6-week treatment period there was a statistically significant difference in reduction of the main symptoms of rosacea. Of the patients treated with the microemulsion, 17% experienced complete relief from inflammatory lesions, and 50% from erythema. The microemulsion resulted in complete relief in 38% of the patients with telangiectasia while the commercial product did not provide any relief of telangiectasia symptoms. In conclusion, the microemulsion containing metronidazole was found to be more effective in reducing the symptoms of rosacea compared to the commercial gel product.

Antibiotics used in nonbacterial dermatologic conditions

The majority of nonbacterial dermatological conditions treated with antibiotics benefit from the anti-inflammatory properties of these medications, usually dapsone or tetracycline. Many other antimicrobials are used to treat noninfectious conditions. The following chapter is an overview of select noninfectious dermatological conditions for which antibiotics are used, with a focus on the most common antibiotics used for their nonantimicrobial properties.

Evaluation of mechanical and rheological properties of metronidazole gel as local delivery system

Rosacea is a chronic multifactorial vascular skin disorder that affects about 10 percent of the general population. Metronidazole is an effective antibiotic in the treatment of moderate-to severe rosacea. Metronidazole is a suitable drug in cases of resistance to tetracycline or erythromycin, but it has also been shown that oral metronidazole may increase the side effects (e.g., peripheral neuropathy). Oral metronidazole should not be used for more than three months, and hence topical metronidazole gel is the best therapeutic choice in rosacea (especially during pregnancy). This study examined the mechanical (adhesiveness, cohesiveness, extrudability, spreadability, homogeneity) and rheological (viscosity), skin irritant and drug release properties of different metronidazole gel formulations that contain anionic emulsifying wax, glycerin and lactic acid in different proportions. The release studies were conducted using Franz diffusion cells and Silastic membrane as a barrier. The results indicated that gel compressibility, hardness, and adhesiveness, are the factors that influence the ease of gel removal from the container, ease of gel application onto the mucosal membrane, and gel bioadhesion. The findings showed that there exists a strong negative correlation between the spreadability of a formulation and its cohesiveness, the spreadability of a formulation is inversely proportional to its cohesiveness. However, sorbitol solution (70%) concentration was not significantly correlated with drug release. In addition, drug release was significantly reduced as the concentration of anionic emulsifying wax increased and the concentration of lactic acid decreased. The maximum metronidazole release was achieved at a pH of 4-6. Data obtained from in vitro release studies were fitted to various kinetic models and high correlation was obtained in the Higuchi and first order models. The results showed that all the gel formulations showed good extrudability, viscosity, cohesiveness, homogeneity and spreadability.

Rosacea - global diversity and optimized outcome: proposed international consensus from the Rosacea International Expert Group

BACKGROUND

The absence of specific histological or serological markers, the gaps in understanding the aetiology and pathophysiology of rosacea, and the broad diversity in its clinical manifestations has made it difficult to reach international consensus on therapy guidelines.

OBJECTIVES

The main objective was to highlight the global diversity in current thinking about rosacea pathophysiology, classification and medical features, under particular consideration of the relevance of the findings to optimization of therapy.

METHODS

The article presents findings, proposals and conclusions reached by the ROSacea International Expert group (ROSIE), comprising European and US rosacea experts.

RESULTS

New findings on pathogenesis provide a rationale for the development of novel therapies. Thus, recent findings suggest a central role of the antimicrobial peptide cathelicidin and its activator kallikrein-5 by eliciting an exacerbated response of the innate immune system. Cathelicidin/kallikrein-5 also provide a rationale for the effect of tetracyclines and azelaic acid against rosacea. Clinically, the ROSIE group emphasized the need for a comprehensive therapy strategy - the triad of rosacea care - that integrates patient education including psychological and social aspects, skin care with dermo-cosmetics as well as drug- and physical therapies. Classification of rosacea into stages or subgroups, with or without progression, remained controversial. However, the ROSIE group proposed that therapy decision making should be in accordance with a treatment algorithm based on the signs and symptoms of rosacea rather than on a prior classification.

CONCLUSION

The ROSIE group reviewed rosacea pathophysiology and medical features and the impact on patients and treatment options. The group suggested a rational, evidence-based approach to treatment for the various symptoms of the condition. In daily practice this approach might be more easily handled than prior subtype classification, in particular since patients often may show clinical features of more than one subtype at the same time.

A comparison of metronidazole 1% cream and pimecrolimus 1% cream in the treatment of patients with papulopustular rosacea: a randomized open-label clinical trial

BACKGROUND

There are various treatment options available for rosacea, depending on the subtype, but treatment is still generally unsatisfactory. Some reports have indicated beneficial effects of topical pimecrolimus.

AIM

To compare the efficacy and safety of pimecrolimus 1% cream and metronidazole 1% cream in the treatment of patients with papulopustular rosacea (PR).

METHODS

A group of 49 patients with PR was investigated in this single-centre, randomized, open-label study. Patients were randomly assigned treatment with either pimecrolimus 1% cream or metronidazole 1% cream for 12 weeks. Response was evaluated by the inflammatory lesion count, the severity of facial erythema and telangiectasia, Physician's Global Assessment (PGA), and safety and tolerability at baseline and at weeks 3, 6, 9 and 12.

RESULTS

In total, 48 patients completed the study. Both treatments were very effective in the treatment of PR. There were no significant differences between the treatments in inflammatory lesion counts, overall erythema severity scores and PGA evaluated from baseline to week 12 (P > 0.05). Neither treatment produced any clinically relevant improvement in telangiectasia.

CONCLUSION

Pimecrolimus cream is no more efficacious than metronidazole cream in the treatment of PR.

Treatment of Clostridium difficile-associated disease

Clostridium difficile infection is an increasing burden to the health care system, totaling more than $1 billion/year in the United States. Treatment of patients with C difficile infection with metronidazole or vancomycin reduces morbidity and mortality, although the number of patients that do not respond to metronidazole is increasing. Despite initial response rates of greater than 90%, 15%-30% of patients have a relapse in symptoms after successful initial therapy, usually in the first few weeks after treatment is discontinued. Failure to develop specific antibody response has recently been identified as a critical factor in recurrence. The review discusses the different management strategies for initial and recurrent symptomatic C difficile infections.

Scavenging properties of metronidazole on free oxygen radicals in a skin lipid model system

Reactive oxygen species (ROS) play a vital role in the pathophysiology of the skin disease rosacea, a chronic, genetically-determined and UV-triggered disease, leading to facial redness and blemishes and exhibiting a deep impact on a patient's self-esteem and quality of life. ROS can cause oxidative damage to nucleic acids, sugars, proteins and lipids, thereby contributing to adverse effects on the skin. Metronidazole has been the first-line topical agent therapy for many years; nevertheless the mechanism of action is still not well understood. The therapeutic efficacy of metronidazole has been attributed to its antioxidant effects, which can involve two pathways: decreased generation of ROS within tissues or scavenging and inactivation of existing ROS. Previous investigations have shown that metronidazole reduces ROS by decreasing ROS production in cellular in-vitro systems. The aim of the following study was to demonstrate that metronidazole additionally exhibits antioxidative properties in a cell-free system, by acting as an antioxidant scavenger. A simple skin lipid model (oxidative) system and a complex skin adapted lipid system in conjunction with thiobarbituric acid (TBA) test, a quantitative assay for the detection of malondialdehyde (MDA) and therefore lipid peroxidation, were used to determine the antioxidative properties of metronidazole after UV irradiation. Results clearly show that metronidazole has antioxidative properties in a cell-free environment, acting as a free radical scavenger. Simple skin lipid model: in the presence of 10, 100 and 500 microg mL(-1)metronidazole the MDA concentration was reduced by 25, 36 and 49%, respectively. Complex skin lipid system: in the presence of 100 and 500 microg mL(-1)metronidazole the MDA concentration was reduced by 19 and 34%, respectively. The results obtained in this study and from previous publications strongly suggest that metronidazole exhibits antioxidative effects via two mechanisms: decrease in ROS production through modulation of neutrophil activity and decrease in ROS concentration by exhibiting ROS scavenging properties. The remarkable clinical efficacy of metronidazole in the treatment of rosacea is probably due to its ability to decrease ROS via different mechanisms, thereby protecting skin components from induced damage.

Metronidazole 0.75% gel vs. ketoconazole 2% cream in the treatment of facial seborrheic dermatitis: a randomized, double-blind study

BACKGROUND

Recently, two placebo-controlled studies have shown that topical metronidazole was effective in the treatment of seborrheic dermatitis.

OBJECTIVE

To compare the efficacy and safety of metronidazole 0.75% gel with that of ketoconazole 2% cream in the treatment of facial seborrheic dermatitis.

METHODS

A total of 60 consecutive patients with facial seborrheic dermatitis were included. Patients were randomized into two groups. One group used ketoconazole 2% cream with metronidazole gel as vehicle; the other group used metronidazole 0.75% gel with ketoconazole cream as vehicle for a 4-week treatment period. Main outcome measures were change in clinical severity scores, patients' and investigator's global evaluation of improvement and frequency of side-effects.

RESULTS

All the assessments were made by an investigator who was unaware of which group the patients were allocated to. Mean percentage decrease in clinical severity scores from baseline to last available visit was 63.4% (95% CI 57.7-69) and 54.4% (95% CI 47.9-61) in the ketoconazole- and metronidazole-treated patients, respectively (P = 0.31). Eighty-two per cent of patients in the ketoconazole group vs. 79% of patients in the metronidazole group rated their global improvement as significant or moderate (P > 0.05). No statistically significant difference in the frequency of side-effects was detected between the two groups. The results of this study need to be confirmed in further studies involving large numbers of patients.

CONCLUSION

Our data demonstrated that metronidazole 0.75% gel had a comparable efficacy and safety profile with that of ketoconazole 2% cream in the treatment of facial seborrheic dermatitis.

The effect of azithromycin on reactive oxygen species in rosacea

BACKGROUND

Recent evidence suggests that inflammation in rosacea is associated with generation of reactive oxygen species (ROS) that are released by inflammatory cells. The efficacy of current therapeutic agents for rosacea such as tetracyclines and metronidazole has also been attributed to their antioxidant properties. Recently, a macrolide antibiotic, azithromycin, has been found to be an effective alternative in the treatment of rosacea.

AIM

We planned a study to evaluate the antioxidant effects of azithromycin on ROS in rosacea. We compared basal ROS concentrations measured in the facial skin of patients with rosacea with the post-treatment levels and with those of healthy controls.

METHODS

Facial skin biopsies of 17 papulopustular patients with rosacea and 25 healthy controls were taken. Rosacea patients were assigned to receive oral azithromycin 500 mg on three consecutive days each week for 4 weeks. The total number of inflammatory lesions (the sum of papules and pustules) on the face of each patient with rosacea was counted at each visit. The luminol- and lucigenin-enhanced chemiluminescence (CL) levels of patients with rosacea were measured before and after 4 weeks of treatment and compared with those of healthy controls.

RESULTS

Rosacea patients had higher ROS levels than healthy controls (P < 0.001). A statistically significant decrease of both luminol- and lucigenin-enhanced CL levels were observed in patients with rosacea after treatment with azithromycin (t = 4.602, P < 0.001; vs. t = 4.634, P < 0.001, respectively).

CONCLUSION

Rosacea patients have higher ROS levels than healthy controls. The results of our study support the antioxidant properties of azithromycin in rosacea.

Efficiency of benzoyl peroxide-erythromycin gel in comparison with metronidazole gel in the treatment of acne rosacea

Oral wide-spectrum antibiotics are the linchpin of rosacea treatment. Oral and topical metronidazole, topical tretinoin, and topical benzoyl peroxide may also be used in the treatment of rosacea. We aimed to show that benzoyl peroxide-erythromycin gel is efficient in the treatment of acne rosacea. Fifty-six patients with acne rosacea were enrolled in our study. We administered benzoyl peroxide-erythromycin gel to 27 patients and metronidazole gel to 29 patients. In all the patients, the intensities of erythema, telangiectasia, papules/pustules, and nodules were evaluated before, during and after the treatment. The positivity of Demodex folliculorum from skin scratches was compared between the two groups at each visit. At the end of the therapy on the third examination, in the benzoyl peroxide-erythromycin group, 91.7% of the patients showed marked clinical improvement, and 8.3% of them showed complete remission. In the metronidazole group, 73.3% showed marked clinical improvement, and 26.7% of them showed complete remission. Clinical improvement in the papular component was 65.2% for the benzoyl peroxide-erythromycin group, and 81.5% for metronidazole group. In the first examination, the clinical results of the agents were similar. Although both of the drugs were found to be effective in the second and third examinations, metronidazole gel was more effective than benzoyl peroxide-erythromycin. Both of the drugs were found to be significantly effective especially in treating the papular component of rosacea. Demodex folliculorum was found to be positive in 74.1% of the benzoyl peroxide-erythromycin group and in 62.1% of the metronidazole group at the beginning. In the benzoyl peroxide-erythromycin group, 40.7% of Demodex folliculorum positive patients, became negative by the first examination. This was 17.2% for the metronidazole group. In the benzoyl peroxide-erythromycin group, among the patients who were positive for Demodex folliculorum in the first examination, 37.5% of them became negative. This was 36.7% for the metronidazole group. Benzoyl peroxide-erythromycin gel was superior to metronidazole gel in decreasing Demodex folliculorum by the first examination, but the effect of the two drugs on Demodex folliculorum was similar by the second examination. As a result, topically applied combined benzoyl peroxide-erythromycin gel may be an alternative choice of treatment for acne rosacea.

Temperature regulates bacterial protein production: possible role in rosacea

Facial skin temperature is higher for patients with rosacea. Papules and pustules might arise because bacteria behave differently at these warmer temperatures. We sought to: (1) compare bacteria from facial skin of patients with rosacea with that of control subjects; and (2) grow these bacteria at 30 degrees C and 37 degrees C to compare growth curves and secreted proteins. Bacteria isolated from pustules/skin surfaces of patients with rosacea and skin surfaces of control subjects were identified and cultured at 37 degrees C and 30 degrees C. Secreted proteins were separated by electrophoresis. We found that Staphylococcus epidermidis isolated from patients with rosacea was consistently beta-hemolytic, whereas that from control subjects were nonhemolytic. Bacteria from patients with rosacea grew at the same rate and to the same stationary phase whether cultured at 37 degrees C or 30 degrees C. Isolates from patients with rosacea secreted more proteins, and generally more of each protein at 37 degrees C compared with 30 degrees C. In conclusion, bacteria isolated from patients with rosacea secrete different proteins and different amounts of protein at different temperatures.

Is topical metronidazole effective in seborrheic dermatitis? A double-blind study

BACKGROUND

Seborrheic dermatitis is a common, chronic, papulosquamous dermatosis. Although several types of treatment have been developed, repetitive treatment courses are often necessary.

AIM

To perform a randomized, placebo-controlled, double-blind clinical study with metronidazole 0.75% gel in patients with mild to moderate seborrheic dermatitis of the face.

METHODS

Eighty-four patients (52 males and 32 females) with seborrheic dermatitis were enrolled in the study. Patients were randomly allocated to the application of metronidazole 0.75% gel or placebo to their facial lesions, twice daily for 8 weeks. Patients were scored with regard to the severity of the lesions at the initial evaluation and every 2 weeks for 2 months. All patients were evaluated for a final assessment of improvement at the end of the study.

RESULTS

At baseline, both treatment groups were comparable in terms of demographic data and lesion severity score. Seventy-eight patients (48 males and 30 females), 48 (62%) in the metronidazole group and 30 (38%) in the placebo group, completed the study. Two patients in the metronidazole group and four patients in the placebo group left the study. There was no statistically significant difference in the change in the mean severity score between the two groups at the end of the study (P > 0.05). At the final evaluation of the response at 8 weeks, no statistically significant difference was found between the treatment groups (P > 0.05). Metronidazole gel was generally tolerated well during the study.

CONCLUSIONS

Metronidazole 0.75% gel and placebo show similar efficacy in the treatment of seborrheic dermatitis.

Increased hydrogen peroxide generation by neutrophils from patients with acne inflammation

BACKGROUND

Reactive oxygen species generated by neutrophils are closely correlated with the pathogenesis of a variety of inflammatory skin diseases. The aim of this study was to investigate the possible role of reactive oxygen species generated by neutrophils in the mediation of acne inflammation.

METHODS

Bacterial phagocytotic stimuli, mediated by opsonin activity, were applied to whole blood, and neutrophil hydrogen peroxide production was measured.

RESULTS

Patients with acne inflammation showed a significantly increased level of hydrogen peroxide produced by neutrophils compared to patients with acne comedones and healthy controls. There were no marked differences in the level of hydrogen peroxide produced by neutrophils between patients with acne comedones and healthy controls. In addition, patients with acne inflammation treated by oral administration of minocycline hydrochloride, a drug that inhibits hydrogen peroxide generation by neutrophils, showed a significant decrease in the ability of neutrophils to produce hydrogen peroxide in accordance with a decrease in the inflammatory activity of acne lesions.

CONCLUSIONS

The present study seems to suggest that acne inflammation is mediated in part by hydrogen peroxide generation by neutrophils.

The role of free oxygen radicals in the aetiopathogenesis of rosacea

A possible link between superoxide dismutase activity and malondialdehyde level with the clinical manifestations of rosacea was investigated. We found differences in superoxide dismutase activities between mild rosacea (stages I and II) and severe involvement (stage III) groups, as well as between disease and control groups that were statistically significant (P < 0.05). In the mild involvement group (stages I and II), the superoxide dismutase activity was higher than in the control group (P < 0.05), while the malondialdehyde levels did not differ from the control. In the severe involvement group (stage III), the superoxide dismutase activity was lower than in the control group (P < 0.05), and this was coupled to a raised level of malondialdehyde (P < 0.05). These findings clearly show that in the mild involvement phase of rosacea patients, superoxide dismutase activity was stimulated to protect the skin against reactive oxygen species so that the malondialdehyde levels were maintained. In contrast, in more severe disease, due to a decrease in the capacity of the antioxidant defence system, the malondialdehyde levels were increased. These findings support the 'antioxidant system defect hypothesis' in rosacea patients.

Effects of metronidazole and tinidazole ointments on models for inflammatory dermatitis in mice

We investigated the effects of 1-4% ointments of metronidazole and tinidazole (derivatives of nitroimidazole) on models of inflammatory dermatitis evoked by antigen, hapten and monoclonal anti-dinitrophenol (DNP) IgE antibody in mice. Metronidazole and tinidazole ointments (1) suppressed the late-phase reaction (LPR) of biphasic ear edema in mice sensitized with ovalbumin (OA), (2) suppressed trinitrochlorobenzene-induced inflammatory dermatitis, (3) suppressed the immediate phase reactions and LPR in mice passively sensitized with anti-DNP IgE mAb, and (4) enhanced vascular permeability and the number of scratching reactions, presumably due to itching, in passively sensitized mice. These results strongly indicate that metronidazole and tinidazole 1-4% ointments possess antiinflammatory, immunosuppressive and anti-itching effects, and have the potential for clinical use in the treatment of human inflammatory skin diseases including atopic dermatitis in addition to rosacea and acne vulgaris.

The management of rosacea

Rosacea is a multiphasic disease which is associated with flushing, erythrosis, papulopustular rosacea and phymas; each phase is likely to have its own treatment. Flushing is better prevented rather than treated, and its etiology investigated. Beta-blockers, atenolol in particular, are worthy of prophylactic trials examining their efficacy in treating the flushing associated with rosacea. Currently, clonidine is the only drug available for the treatment of flushing. Treatment for erythrosis includes topical and systemic therapies. Metronidazole 1% cream and azelaic acid 20% cream have been reported to reduce the severity score of erythema. The systemic treatment of erythrosis is based on the association of Helicobacter pylori with rosacea. However, this role is still being debated. Eradication of H. pylori can be achieved using a triple therapy regimen lasting 1 to 2 weeks [omeprazole and a combination of two antibacterials (a choice from clarithromycin, metronidazole or amoxicillin)]. Both the flashlamp-pumped long-pulse dye laser and the potassium-titanyl-phosphate laser may be used in the treatment of facial telangiectases. Both systemic and topical remedies may be used to treat the papulopustules of rosacea. Systemic treatment includes metronidazole, doxycycline, minocycline, clarithromycin and isotretinoin, while topical treatment is based on metronidazole cream and gel. The presence of Demodex folliculorum is important in the inflammatory reaction, whether it is pathogenetic or not. Crotamiton 10% cream or permethrin 5% cream may be useful medications for papulopustular rosacea, although they are rarely successful in eradicating D. folliculorum. Oral or topical ivermectin may also be useful in such cases. Ocular involvement is common in patients with cutaneous rosacea and can be treated with orally administered or topical antibacterials. Once rhinophyma starts to be evident, the only way to correct it is by aggressive dermatosurgical procedures. Decortication and various types of lasers can also be used. Associated conditions, such as seborrheic dermatitis and possible contact sensitizations, deserve attention.

Potential antioxidant mechanism of action for metronidazole: implications for rosacea management

Chronic inflammation is believed to account for some symptoms of rosacea. The efficacy of topical metronidazole in the treatment of rosacea may be due to its antimicrobial as well as anti-inflammatory activity. Neutrophils release potent inflammatory mediators, including reactive oxygen species (ROS), and intrafollicular neutrophils have been observed in stage II disease. ROS and other free radicals may contribute to intrinsic and extrinsic aging, both of which accentuate clinical manifestations of rosacea. If, as in vitro data suggest, metronidazole has antioxidant activity, it may help subdue the oxidative tissue damage of intrinsic and extrinsic aging as well as prevent and treat rosacea symptoms.

Topical metronidazole. A review of its use in rosacea

Topical application of the antibacterial agent metronidazole is effective in the treatment of moderate to severe rosacea, although its mechanism of action has yet to be clearly established. Metronidazole preparations (0.75 and 1% cream, 0.75% gel and 0.75% lotion) were significantly more effective than placebo in patients with moderate to severe rosacea when administered to the affected area once or twice daily for 7 to 12 weeks. The mean number of papules and pustules decreased by between 48 and 65.1% during the treatment period. Reductions were fairly consistent regardless of formulation, strength or application frequency and were significant compared with placebo (p < 0.05). In 1 study, most of the overall effects of metronidazole were observed within the first 3 weeks. Although data are limited, topical metronidazole appears to improve inflammatory lesions and erythema as effectively as oral tetracyclines. Like tetracyclines, however, metronidazole has no effect on telangiectasia. Metronidazole 0.75% gel seems to be effective in maintaining remission of rosacea symptoms in patients successfully treated with both oral tetracycline and topical metronidazole. In the only study, 77% of patients treated with metronidazole gel compared with 58% of placebo recipients (p < 0.05) remained in remission 6 months after the tetracycline was stopped. The effects of topical metronidazole preparations on rosacea symptoms are palliative, not curative, but preliminary data suggest that relapse rates after cessation of therapy are no worse than those after cessation of oral oxytetracycline. Topical metronidazole formulations are generally well tolerated locally, with stinging, dryness, burning and itching reported in < or = 2% of patients. Because minimal concentrations of metronidazole are absorbed after topical administration, systemic adverse events and drug interactions seen with oral or intravenous metronidazole are unlikely.

CONCLUSIONS

Topical metronidazole formulations are significantly more effective than placebo when used in the initial treatment of patients with moderate to severe rosacea. Furthermore, limited evidence suggests that the use of topical metronidazole alone may be as effective as oral tetracyclines against the disorder's inflammatory component. Therefore, for those patients with a preference for topical rather than oral therapy, the use of a topical metronidazole formulation must be a consideration.

Effect of keigai-rengyo-to, a Japanese kampo medicine, on neutrophil functions: a possible mechanism of action of keigai-rengyo-to in acne

On the basis of recent reports that keigai-rengyo-to (TJ-50), an oral Japanese Kampo (herb) medicine, is clinically effective in treating acne, and that tetracyclines are effective against acne by acting directly as an antioxidant on infiltrated neutrophils, we investigated the effect of TJ-50 on the generation of reactive oxygen species (ROS), using human neutrophils and a cell-free, xanthine-xanthine oxidase system. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.). In addition, neutrophil chemotaxis, phagocytosis and calcium concentration, [Ca2+]i in neutrophils were also assessed. TJ-50 significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. Three kinds of ROS generated in the cell-free system were also reduced in the presence of TJ-50. On the other hand, the medicine did not markedly affect neutrophil chemotaxis, phagocytosis or [Ca2+]i in neutrophils. Our results indicate that the clinical effectiveness of TJ-50 in the treatment of acne may be due partly to its antioxidant action on infiltrated neutrophils.

Influence of oral metronidazole on the endocrine milieu and sebum excretion rate

As part of a study of the mechanism of metronidazole's efficacy in the treatment of acne and rosacea, its effects on the endocrine milieu and sebum excretion rate were assessed. Thirteen healthy males received oral metronidazole treatment (500 mg/day) for 4 weeks. Serum sex hormone levels were determined in all 13 subjects and the sebum excretion rate was determined in seven of them, before and after treatment. We measured serum levels of estrone (E1), estradiol (E2), total testosterone (T), free testosterone (FT), dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), and sex hormone-binding globulin (SHBG). There were no significant changes in E1, T, FT, DHT, or SHBG levels, but E2 and DHEA-S levels decreased significantly after treatment. In all seven subjects in whom the sebum excretion rates were determined, the amount of facial skin surface lipids decreased significantly after treatment. These results suggest that metronidazole exerts its clinical effects through suppressing the sebum excretion by a mechanism other than anti-androgenic action.

Inhibitory effect of azelaic acid on neutrophil functions: a possible cause for its efficacy in treating pathogenetically unrelated diseases

It has been shown that acne, hyperpigmentation and lentigo malignant are more or less related pathogenetically to reactive oxygen species (ROS). It has recently been reported that azelaic acid is effective in treating these conditions and that it possesses anti-enzymatic and antimitochondrial activity, including cytochrome-P450 reductase and 5 alpha-reductase in microsomal preparations with nicotinamide adenine dinucleotide phosphate (NADPH). We therefore investigated the effects of azelaic acid on human neutrophil functions, such as chemotaxis, phagocytosis and ROS generation. ROS generation in a cell-free system was also assessed. The results revealed that neutrophil chemotaxis and phagocytosis as well as ROS generated in a xanthine-xanthine-oxidase system were not significantly changed in the presence of azelaic acid. However, azelaic acid markedly decreased O2- and OH. generated by neutrophils. It may be concluded that the reported clinical effectiveness of azelaic acid is partly due to its inhibitory action on neutrophil-generated ROS, leading to a reduction both in oxidative tissue injury at sites of inflammation and in melanin formation.

The inhibition of free radical generation by human neutrophils through the synergistic effects of metronidazole with palmitoleic acid: a possible mechanism of action of metronidazole in rosacea and acne

Metronidazole is clinically effective in treating not only rosacea but also acne inflammation. Yet it is generally considered not to be very effective in inhibiting the growth of anaerobic Propionibacterium acnes. We report here our investigation into the synergistic effects of metronidazole and palmitoleic acid on the anaerobic growth of P. acnes as well as on human neutrophil functions, including the generation of reactive oxygen species (ROS). Both metronidazole and palmitoleic acid, when used alone, only slightly inhibited the growth of P. acnes, and no significant decrease in human neutrophil functions, including the generation of ROS, was observed. But metronidazole used in the presence of palmitoleic acid markedly inhibited the anaerobic growth of P. acnes and decreased ROS generation by neutrophils. However, ROS generated in the xanthine-xanthine oxidase system were not affected. Metronidazole was shown to be clinically effective by decreasing neutrophil-generated ROS at the sites of inflammation with the aid of palmitoleic acid, which is generally present in human skin. By inhibiting oxidative tissue injury under in vivo conditions, treatment with metronidazole results in remarkable improvement of rosacea and acne.

Evaluation of topical metronidazole gel in acne rosacea

Topical metronidazole gel (0.75%) was compared to placebo gel in a randomized, double-blind, placebo-controlled, split-face clinical trial for the treatment of 59 patients with acne rosacea. Statistically significant differences in inflammatory lesions, erythema, and global assessments were seen at three, six, and nine weeks post-baseline in favor of the active treatment side. It did not, however, alter the telangiectatic component of the disease. No known drug-related side effects were detected, and the low topical dose along with low serum levels of metronidazole indicate a high safety profile for this therapeutic agent. This work suggests that metronidazole gel, as specifically formulated, is safe and effective in reducing the symptomatology of acne rosacea.