Minocycline in acne vulgaris: benefits and risks

Optimization of Minocycline-Containing Bismuth Quadruple Therapy for Helicobacter pylori Rescue Treatment: A Real-World Evidence Study

BACKGROUND

The optimal dosage of minocycline remains unclear for Helicobacter pylori (H. pylori) eradication. We aimed to evaluate the efficacy and safety of four different regimens with minocycline and metronidazole compared to classical bismuth quadruple therapy for H. pylori rescue treatment.

MATERIALS AND METHODS

From March 2021 to March 2024, refractory H. pylori-infected patients with at least two previous treatment failures who received 14-day therapy with b.i.d. proton pump inhibitor 20 mg and bismuth 220 mg, plus tetracycline 400 mg q.i.d and metronidazole 400 mg q.i.d (BQT), or minocycline 50 mg q.i.d and metronidazole 400 mg q.i.d (PBMn4M4), or minocycline 50 mg t.i.d and metronidazole 400 mg t.i.d (PBMn3M3), or minocycline 50 mg b.i.d and metronidazole 400 mg q.i.d (PBMn2M4), or minocycline 50 mg b.i.d and metronidazole 400 mg t.i.d (PBMn2M3) were included in this retrospective study. H. pylori eradication was assessed by 13C-urea breath test at least 6 weeks after treatment. All adverse effects during treatment were recorded.

RESULTS

Totally, 823 patients were enrolled: 251 with BQT, 97 with PBMn4M4, 191 with PBMn3M3, 108 with PBMn2M4, and 176 with PBMn2M3. The eradication rates of BQT, PBMn4M4, PBMn3M3, PBMn2M4, and PBMn2M3 were 89.2%, 87.6%, 91.6%, 88.0%, and 91.5%, respectively, by intention-to-treat analysis; 96.1%, 97.7%, 97.8%, 96.9%, and 97.6%, respectively, by modified intention-to-treat analysis; 97.1%, 97.5%, 97.7%, 96.8%, and 97.6%, respectively, by per-protocol analysis. Metronidazole resistance did not affect the efficacy of all groups. PBMn2M3 group achieved the greatest compliance and the fewest moderate and severe adverse events.

CONCLUSIONS

The novel bismuth-containing quadruple therapy with a low dose of minocycline and metronidazole is an alternative to classical bismuth quadruple therapy for H. pylori rescue treatment with superior safety and compliance.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06332599.

Aptamer-Based fluorescent DNA biosensor in antibiotics detection

The inappropriate employment of antibiotics across diverse industries has engendered profound apprehensions concerning their cumulative presence within human bodies and food commodities. Consequently, many nations have instituted stringent measures limiting the admissible quantities of antibiotics in food items. Nonetheless, conventional techniques employed for antibiotic detection prove protracted and laborious, prompting a dire necessity for facile, expeditious, and uncomplicated detection methodologies. In this regard, aptamer-based fluorescent DNA biosensors (AFBs) have emerged as a sanguine panacea to surmount the limitations of traditional detection modalities. These ingenious biosensors harness the binding prowess of aptamers, singular strands of DNA/RNA, to selectively adhere to specific target antibiotics. Notably, the AFBs demonstrate unparalleled selectivity, affinity, and sensitivity in detecting antibiotics. This comprehensive review meticulously expounds upon the strides achieved in AFBs for antibiotic detection, particularly emphasizing the labeling modality and the innovative free-label approach. It also elucidates the design principles behind a diverse array of AFBs. Additionally, a succinct survey of signal amplification strategies deployed within these biosensors is provided. The central objective of this review is to apprise researchers from diverse disciplines of the contemporary trends in AFBs for antibiotic detection. By doing so, it aspires to instigate a concerted endeavor toward the development of heightened sensitivity and pioneering AFBs, thereby contributing to the perpetual advancement of antibiotic detection methodologies.

Consensus Report on Truncal Acne: The Korean Acne and Rosacea Society Experts Panel

BACKGROUND

More than half of acne patients have truncal acne on their chest, back, and shoulders. However, since most studies on acne have focused on the face, data on clinical characteristics and proper management for truncal acne are insufficient.

OBJECTIVE

To establish a Korean Acne Rosacea Society (KARS) consensus for experts' perception and treatment patterns of truncal acne.

METHODS

We conducted two rounds of the Dephi technique to gather expert opinion and reach a consensus on truncal acne. The first round comprised 48 questionnaires focusing on various aspects such as epidemiology, clinical features, diagnosis, treatment, prognosis and more, while second rounds consisted of 26 questionnaires.

RESULTS

A total of 36 dermatologists (36/38 KARS members, 94.7%) completed this survey. In the first-round survey, consensus was reached on 20 out of the 48 questions (41.7%). In the second-round questionnaire, consensus was achieved on 9 of the 26 questions (34.6%). The most unresponsive lesion to truncal acne treatment was scars (atrophic/hypertrophic). The most commonly used treatments for each non-inflammatory and inflammatory truncal acne lesions were selected to use topical retinoids (78.1% of the responders) and oral antibiotics (93.8% of the responders).

CONCLUSION

Our study has yielded valuable insights into the epidemiology, clinical manifestations, diagnosis, treatment, and quality of life of patients with truncal acne. We anticipate that this study will inspire further comprehensive research for individuals with truncal acne.

Therapeutic effects of minocycline on oleic acid-induced acute respiratory distress syndrome (ARDS) in rats

Acute respiratory distress syndrome (ARDS) is a serious intensive care condition. Despite advances in treatment over the previous few decades, ARDS patients still have high fatality rates. Thus, more research is needed to improve the outcomes for people with ARDS. Minocycline is an antibiotic with antioxidant, anti-inflammatory, and anti-apoptotic effects. In the current investigation, the therapeutic effects of minocycline on oleic acid-induced ARDS were evaluated. Male rats were classified into 6 groups, 1. control (normal saline), 2. oleic acid (100 µL, i.v.), 3-5. oleic acid + minocycline (50, 100, 200 mg/kg, i.p.), and 6. minocycline (200 mg/kg, i.p.) alone. Twenty-four hours after the oleic acid injection, the lung tissue is isolated, weighed, and the middle part of the right lung is immediately placed in the freezer, while the middle part of the left lung is placed in formalin and sent to the laboratory for pathology testing. Then, the amounts of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), cytokines (interleukin-1 beta (IL-1β), tumor necrosis factor-α (TNF-α)), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax), and cleaved caspase-3 were determined in lung tissue. Administration of oleic acid increased emphysema, inflammation, vascular congestion, hemorrhage, MDA amount, Bax/Bcl-2 ratio, cleaved caspase-3, IL-1β, TNF-α levels, and decreased GSH, SOD, and CAT levels in comparison with the control group. The administration of minocycline could significantly reduce pathological and biochemical alterations induced by oleic acid. Minocycline has a therapeutic effect on oleic acid-induced ARDS through antioxidant, anti-inflammatory, and anti-apoptotic properties.

Reduced blood-brain barrier penetration of acne vulgaris antibiotic sarecycline compared to minocycline corresponds with lower lipophilicity

Background

Vestibular side effects such as dizziness and vertigo can be a limitation for some antibiotics commonly used to treat acne, rosacea, and other dermatology indications.

Objective

Unlike minocycline, which is a second-generation tetracycline, sarecycline, a narrow-spectrum third-generation tetracycline-class agent approved to treat acne vulgaris, has demonstrated low rates of vestibular-related adverse events in clinical trials. In this work, we evaluate the brain-penetrative and lipophilic attributes of sarecycline in 2 non-clinical studies and discuss potential associations with vestibular adverse events.

Methods

Rats received either intravenous sarecycline or minocycline (1.0 mg/kg). Blood-brain penetrance was measured at 1, 3, and 6 h postdosing. In another analysis, the lipophilicity of sarecycline, minocycline, and doxycycline was measured via octanol/water and chloroform/water distribution coefficients (logD) at pH 3.5, 5.5, and 7.4.

Results

Unlike minocycline, sarecycline was not detected in brain samples postdosing. In the octanol/water solvent system, sarecycline had a numerically lower lipophilicity profile than minocycline and doxycycline at pH 5.5 and 7.4.

Conclusion

The reduced blood-brain penetrance and lipophilicity of sarecycline compared with other tetracyclines may explain low rates of vestibular-related adverse events seen in clinical trials.

Targeted therapy of cognitive deficits in fragile X syndrome

Breaking an impasse in finding mechanism-based therapies of neuropsychiatric disorders requires a strategic shift towards alleviating individual symptoms. Here we present a symptom and circuit-specific approach to rescue deficits of reward learning in Fmr1 knockout mice, a model of Fragile X syndrome (FXS), the most common monogenetic cause of inherited mental disability and autism. We use high-throughput, ecologically-relevant automated tests of cognition and social behavior to assess effectiveness of the circuit-targeted injections of designer nanoparticles, loaded with TIMP metalloproteinase inhibitor 1 protein (TIMP-1). Further, to investigate the impact of our therapeutic strategy on neuronal plasticity we perform long-term potentiation recordings and high-resolution electron microscopy. We show that central amygdala-targeted delivery of TIMP-1 designer nanoparticles reverses impaired cognition in Fmr1 knockouts, while having no impact on deficits of social behavior, hence corroborating symptom-specificity of the proposed approach. Moreover, we elucidate the neural correlates of the highly specific behavioral rescue by showing that the applied therapeutic intervention restores functional synaptic plasticity and ultrastructure of neurons in the central amygdala. Thus, we present a targeted, symptom-specific and mechanism-based strategy to remedy cognitive deficits in Fragile X syndrome.

A pilot study of combined oral minocycline and narrowband UVB phototherapy in vitiligo: A randomized, double-blind, placebo-controlled trial

Narrowband ultraviolet B (NBUVB) phototherapy is an effective therapeutic option for generalized vitiligo. Previous reports showed the potential benefit of minocycline to stop disease progression in vitiligo. Meanwhile, minocycline has antioxidative, anti-inflammatory, and immunomodulating properties. There is no clinical study combining oral minocycline and NBUVB for treating generalized vitiligo. This study aims to compare the efficacy and safety of the combination treatment of NBUVB plus oral minocycline with NBUVB alone in generalized vitiligo. A randomized, double-blinded, placebo-controlled pilot study was conducted. Patients were randomly treated with either combined oral minocycline 100 mg per day plus NBUVB phototherapy or placebo plus NBUVB. All patients recieved NBUVB two times per week, for 12 weeks. The outcomes were assessed using Vitiligo Area Scoring Index score (VASI) percent change, quartile grading scale (QGS) of repigmentation, and Vitiligo Disease Activity Index (VIDA) score. Fourteen generalized vitiligo patients were included, and seven cases were assigned in each group. At week 12, the mean VASI score was decreased by 28.87% (24.15) in the minocycline group compared to 27.26% (7.98) in placebo group (p = 0.886). No significant difference was observed between both treatment modalities in QGS of repigmentation and mean VIDA score change. Two of the seven patients (29%) receiving minocycline developed hyperpigmentation, dark-brown and muddy brown discoloration, which was only confined to some vitiliginous patches. In conclusion, combination therapy with oral minocycline does not enhance the efficacy of NBUVB in generalized vitiligo. Due to the high incidence of drug-induced skin hyperpigmentation, minocycline plus NBUVB should be avoided.

Micro-Current Stimulation Suppresses Inflammatory Responses in Peptidoglycan-Treated Raw 264.7 Macrophages and Propionibacterium acnes-Induced Skin Inflammation via TLR2/NF-κB Signaling Pathway

Acne is a common inflammatory disorder of the human skin and a multifactorial disease caused by the sebaceous gland and Propionibacterium acnes (P. acnes). This study aimed to evaluate the anti-inflammatory effect of micro-current stimulation (MC) on peptidoglycan (PGN)-treated raw 264.7 macrophages and P. acnes-induced skin inflammation. To specify the intensity with anti-inflammatory effects, nitric oxide (NO) production was compared according to various levels of MC. As the lowest NO production was shown at an intensity of 50 μA, subsequent experiments used this intensity. The changes of expression of the proteins related to TLR2/NF-κB signaling were examined by immunoblotting. Also, immunofluorescence analysis was performed for observing NF-κB p65 localization. All of the expression levels of proteins regarding TLR2/NF-κB signaling were decreased by the application of MC. Moreover, the application of MC to PGN-treated raw 264.7 cells showed a significant decrease in the amount of nuclear p65-protein. In the case of animal models with P. acnes-induced skin inflammation, various pro-inflammatory cytokines and mediators significantly decreased in MC-applied mice. In particular, the concentration of IL-1β in serum decreased, and the area of acne lesions, decreased from the histological analysis. We suggest for the first time that MC can be a novel treatment for acne.

An overview of sarecycline for the treatment of moderate-to-severe acne vulgaris

INTRODUCTION

Sarecycline is a novel, tetracycline-class antibiotic specifically designed to treat inflammatory acne. It offers a narrow spectrum of activity (mainly against Cutinebacterium acnes), and it shows less in vitro activity than other tetracyclines against enteric Gram-negative bacteria, offering advantages over older tetracyclines by decreasing the disruption of the gastrointestinal microbiome and the likelihood of developing bacterial resistance.

AREAS COVERED

The drug's pharmacology, safety profile, and clinical efficacy are discussed. Results of phase I, II and III clinical trials have shown that 1.5 mg/kg/day sarecycline is safe, well tolerated and more effective than placebo in treating inflammatory acne in patients 9 years old and older. Furthermore, sarecycline's narrow spectrum of activity leads to a lower incidence of undesirable off-target antibacterial effects and consequently less adverse events such as diarrhea, fungal overgrowth and vaginal candidiasis.

EXPERT OPINION

Sarecycline could become the first-line antibiotic therapy used in acne in the near future as it is an effective option for treating inflammatory acne lesions. Due to its narrow spectrum of activity, it could have a more adequate safety profile than older tetracyclines; however, head-to-head trials comparing the efficacy and safety profile of sarecycline with other tetracyclines are still needed to prove sarecycline's superiority.

Sarecycline: A Review of Preclinical and Clinical Evidence

Sarecycline is a tetracycline-derived oral antibiotic, specifically designed for acne, and is approved by the Food and Drug Administration (FDA) in 2018 for the treatment of inflammatory lesions of non-nodular moderate to severe acne vulgaris (AV) in patients 9 years of age and older. It has been decades since a novel systemic antibiotic was approved to treat AV, a disease that affects up to 90% of teenagers and young adults worldwide and lasts well into adulthood. Sarecycline holds promise to yield fewer side effects than other commonly used broad-spectrum tetracyclines, including minocycline and doxycycline. The narrower spectrum of antibacterial activity of sarecycline, which specifically targets C. acnes and some Gram-positive bacteria with little or no activity against Gram-negative bacteria, suggests not only the potential for reduced emergence of antibiotic-resistant bacterial strains but also less disruption of the human gut microflora. Here, we review the key preclinical and clinical evidence on sarecycline.

Minocycline Topical Foam: A New Drug for the Treatment of Acne

OBJECTIVE

To review the safety and efficacy of minocycline 4% topical foam for the treatment of moderate to severe acne vulgaris in adults and pediatric patients aged 9 years and older.

DATA SOURCES

A literature search through PubMed and EMBASE was conducted using the following keywords: FMX101, minocycline, foam, and acne.

STUDY SELECTION AND DATA EXTRACTION

Articles selected included those describing preclinical and clinical studies of pharmacokinetics, efficacy, or safety of topical minocycline foam.

DATA SYNTHESIS

Minocycline 4% topical foam was shown in a preclinical study to effectively deliver minocycline to the pilosebaceous unit, with little penetration beyond the stratum corneum. This was consistent with a phase 1 pharmacokinetic study of the foam, which yielded a significantly reduced systemic exposure of minocycline compared with oral minocycline. In phase 2 and phase 3 clinical trials, the foam significantly reduced acne lesion counts and Investigator's Global Assessment scores of acne severity compared with placebo. The foam has a good safety profile, with headache, mild erythema, hyperpigmentation, and mild dryness among the most common adverse effects.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Topical antibiotics have been a mainstay of acne therapy with the benefit of less systemic exposure compared with oral antibiotics. However, the development of bacterial resistance has reduced their use, thereby reducing options for many patients with acne. Minocycline 4% topical foam is a safe and effective alternative, which may help restore this important therapeutic approach for treating acne vulgaris.

Repurposing minocycline for COVID-19 management: mechanisms, opportunities, and challenges

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly grown into a public health emergency that has placed the national health systems as well as scientific research communities under enormous pressures. Drug repurposing or repositioning is a well-known strategy that seeks to deploy existing licensed drugs for newer indications and provides the quickest possible transition from bench to clinics for unmet therapeutic needs. Given the current, urgent, and dire need for effective therapies against novel coronavirus-19, this approach is particularly appealing.

AREAS COVERED

Here, we review the significant anti-inflammatory, immunomodulatory, and antiviral properties of minocycline as potential mechanisms for efficacy against the novel coronavirus and highlight the promises and pitfalls of this approach.

EXPERT OPINION

As compared to other agents being investigated for COVID-19, minocycline offers distinct advantages in terms of potential efficacy in patients with life-threatening acute respiratory distress syndrome (ARDS) and myocardial injury, well-known safety and interaction profile, relatively low costs, and widespread availability. We call upon public and private funders to facilitate urgent and rigorous research efforts before evidence-based recommendations for its widespread use can be made.

A multicentre, randomized, double-masked, parallel group, vehicle-controlled phase IIb study to evaluate the safety and efficacy of 1% and 3% topical minocycline gel in patients with papulopustular rosacea

Background

Papulopustular rosacea is characterized by chronic facial erythema and inflammatory facial lesions. Minocycline has anti‐inflammatory properties which may be effective in the treatment of rosacea inflammatory lesions.

Objectives

To assess the safety and efficacy of once‐daily topical minocycline gel 1% and 3% in patients with papulopustular rosacea.

Methods

This was a prospective, 12‐week, double‐blinded study conducted at 26 sites in the United States; 270 patients with papulopustular rosacea and 12–40 inflammatory lesions were randomized to minocycline 1%, minocycline 3% or vehicle. The primary endpoint was the mean change in inflammatory lesions at week 12. Key secondary endpoints included success on an Investigator's Global Assessment (IGA).

Results

Baseline mean lesion counts were 24·6, 25·1 and 24·3 in the minocycline 1%, minocycline 3% and vehicle groups, respectively; at week 12, the counts had decreased by 12·6, 13·1 and 7·9, respectively. Minocycline significantly decreased lesions, compared with the vehicle [P = 0·01, 95% confidence interval (CI) 7·9 to 0·9, for minocycline 1%; P = 0·007, 95% CI 8·3 to 1·3, for minocycline 3%]. The proportion of patients achieving IGA success was 39% in the minocycline 1% arm [P = 0·34, odds ratio (OR) 1·396 and OR 95% CI 0·71 to 2·75 vs. vehicle], 46% in the minocycline 3% arm (P = 0·04, OR 2·03 and OR 95% CI 1·04 to 3·95 vs. vehicle) and 31% in the vehicle arm.

Conclusions

Minocycline topical gel appears to be safe and tolerable at concentrations of 1% and 3%, and both concentrations significantly decreased inflammatory lesion counts, with a significantly larger proportion of patients achieving IGA success at week 12 in the minocycline 3% arm. These findings support further evaluation of minocycline gel for treating inflammatory lesions associated with papulopustular rosacea.

Linked Comment: Hampton. Br J Dermatol 2020; 183:412–413.

What is already known about this topic?

Papulopustular rosacea is characterized by inflammatory facial lesions and chronic erythema of the face.

Oral minocycline has been reported to have efficacy in the treatment of inflammatory lesions of papulopustular rosacea.

What does this study add?

The study shows that a topical gel preparation of minocycline significantly decreased the number of inflammatory lesions and significantly improved the Investigator's Global Assessment score in patients with papulopustular rosacea.

This may offer a topical therapeutic alternative to oral doxycycline or oral minocycline for the treatment of inflammatory lesions in papulopustular rosacea, with potentially fewer systemic side‐effects, owing to lower systemic drug exposure.

Linked Comment: Hampton. Br J Dermatol 2020; 183:412–413.

Plain language summary available online

Evaluating FMX-101 as a promising therapeutic for the treatment of acne

INTRODUCTION

Oral minocycline is a mainstay of therapy for moderate-to-severe acne; however, systemic side effects which include hepatotoxicity, lupus-like syndrome, drug hypersensitivity syndrome, autoimmune hepatitis, polyarteritis nodosa, gastrointestinal side effects and skin hyperpigmentation are of concern. Topical antibiotics commonly used in acne, such as erythromycin and clindamycin, present high P. acnes resistance rates which has opened the market for new topical antibiotics. FMX-101 is a novel topical minocycline foam that has shown promising results in phase I, II and III trials for the treatment of moderate-to-severe acne with a better safety profile than oral minocycline.

AREAS COVERED

The author provides an overview FMX-101 including its clinical efficacy and safety. The author then provides their expert opinion on this treatment and its potential for the treatment option for acne.

EXPERT OPINION

The topical foam formulation of FMX-101 has been shown to reduce both inflammatory and non-inflammatory lesions and to improve IGA scores in patients with moderate-to-severe acne without significant systemic absorption thus limiting associated side effects. Overall, the proven efficacy and safety profile of FMX-101, together with the low systemic absorption, high skin tolerability and cosmetically acceptable foam formulations render this novel therapy an important addition to the acne treatment armamentarium.

Minocycline attenuates ethanol-induced cell death and microglial activation in the developing spinal cord

Developmental exposure to ethanol may cause fetal alcohol spectrum disorders (FASD), and the immature central nervous system (CNS) is particularly vulnerable to ethanol. In addition to vulnerability in the developing brain, we previously showed that ethanol also caused neuroapoptosis, microglial activation, and neuroinflammation in the spinal cord. Minocycline is an antibiotic that inhibits microglial activation and alleviates neuroinflammation. We sought to determine whether minocycline could protect spinal cord neurons against ethanol-induced damage. In this study, we showed that minocycline significantly inhibited ethanol-induced caspase-3 activation, microglial activation, and the expression of pro-inflammatory cytokines in the developing spinal cord. Moreover, minocycline blocked ethanol-induced activation of glycogen synthase kinase 3 beta (GSK3β), a key regulator of microglial activation. Meanwhile, minocycline significantly restored ethanol-induced inhibition of protein kinase B (AKT), mammalian target of the rapamycin (mTOR), and ERK1/2 signaling pathways, which were important pro-survival signaling pathways for neurons. Together, minocycline may attenuate ethanol-induced damage to the developing spinal cord by inhibiting microglial activation/neuroinflammation and by restoring the pro-survival signaling.

Understanding the Role of Innate Immunity in the Response to Intracortical Microelectrodes

Intracortical microelectrodes exhibit enormous potential for researching the nervous system, steering assistive devices and functional electrode stimulation systems for severely paralyzed individuals, and augmenting the brain with computing power. Unfortunately, intracortical microelectrodes often fail to consistently record signals over clinically useful periods. Biological mechanisms, such as the foreign body response to intracortical microelectrodes and self-perpetuating neuroinflammatory cascades, contribute to the inconsistencies and decline in recording performance. Unfortunately, few studies have directly correlated microelectrode performance with the neuroinflammatory response to the implanted devices. However, of those select studies that have, the role of the innate immune system remains among the most likely links capable of corroborating the results of different studies, across laboratories. Therefore, the overall goal of this review is to highlight the role of innate immunity signaling in the foreign body response to intracortical microelectrodes and hypothesize as to appropriate strategies that may become the most relevant in enabling brain-dwelling electrodes of any geometry, or location, for a range of clinical applications.

Severe Type of Minocycline-Induced Hyperpigmentation Mimicking Peripheral Arterial Occlusive Disease in a Bullous Pemphigoid Patient

Minocycline is a tetracycline group antibiotic that is known to cause significant antibacterial and anti-inflammatory effects. Minocycline has been widely used to treat systemic infection, acne, dermatitis, and rosacea. However, various dose-related side effects of hyperpigmentation in whole body tissues have been reported. Three main types of minocycline-induced hyperpigmentation have been identified. In rare severe hyperpigmentation cases, drug-induced hyperpigmentation can mimic local cellulitis or peripheral arterial occlusive disease (PAOD). These processes require different therapeutic strategies. Therefore, early diagnosis is extremely important for physicians to determine the etiology of the hyperpigmentation, and subsequently discontinue the minocycline if indicated. We describe a rare case presenting a severe form of type III minocycline-induced hyperpigmentation mimicking peripheral arterial occlusive disease in a bullous pemphigoid patient.

The antidepressant impact of minocycline in rodents: A systematic review and meta-analysis

Evidence from recent animal studies suggest that minocycline, a broad-spectrum antibiotic capable of regulating immune processes, may possess antidepressant properties. These studies, however, have yet to be comprehensively reviewed. Accordingly, this systematic review and meta-analysis summarizes the extant literature examining the effect of minocycline on depressive-like behavior in rodent models. PubMed, PsycINFO, and Web of Science databases were systematically searched for articles that met prespecified inclusion and exclusion criteria, and standardized mean differences (SMDs) were calculated for each continuous measure of depressive-like behavior. The overall effect of minocycline on depressive-like behavior was estimated using robust variance estimation meta-analysis. Separate subgroup analyses were conducted on diseased vs healthy animal models, different rodent species, and immobility-based vs anhedonia-based measures of depressive-like behavior. A total of 22 preclinical studies (816 animals) were included. Overall, minocycline reduced depressive-like behavior in rodents (SMD = -1.07, 95% CI -1.41--0.74, p < 0.001). Subgroup analyses revealed that minocycline reduced depressive-like behavior in diseased, but not healthy, animal models. Finally, minocycline was found to reduce both immobility-based and anhedonia-based outcomes. These findings suggest that minocycline may be an effective treatment of core depressive symptoms, and that further investigation of minocycline treatment for clinically relevant depression in humans is warranted.

Microbiological Profile of Sarecycline, a Novel Targeted Spectrum Tetracycline for the Treatment of Acne Vulgaris

Sarecycline is the first narrow-spectrum tetracycline-class antibiotic being developed for acne treatment. In addition to exhibiting activity against important skin/soft tissue pathogens, sarecycline exhibits targeted antibacterial activity against clinical isolates of Cutibacterium acnes.

Sarecycline is the first narrow-spectrum tetracycline-class antibiotic being developed for acne treatment. In addition to exhibiting activity against important skin/soft tissue pathogens, sarecycline exhibits targeted antibacterial activity against clinical isolates of Cutibacterium acnes. In the current study, sarecycline was 16- to 32-fold less active than broad-spectrum tetracyclines—such as minocycline and doxycycline—against aerobic Gram-negative bacilli associated with the normal human intestinal microbiome. Also, reduced activity against Escherichia coli was observed in vivo in a murine septicemia model, with the 50% protective doses, or the doses required to achieve 50% survival, being >40 mg/kg of body weight and 5.72 mg/kg for sarecycline and doxycycline, respectively. Sarecycline was also 4- to 8-fold less active than doxycycline against representative anaerobic bacteria that also comprise the normal human intestinal microbiome. Additionally, C. acnes strains displayed a low propensity for the development of resistance to sarecycline, with spontaneous mutation frequencies being 10⁻¹⁰ at 4 to 8 times the MIC, similar to those for minocycline and vancomycin. When tested against Gram-positive pathogens with defined tetracycline resistance mechanisms, sarecycline was more active than tetracycline against tet(K) and tet(M) strains, with MICs ranging from 0.125 to 1.0 μl/ml and 8 μl/ml, respectively, compared with MICs of 16 to 64 μl/ml and 64 μl/ml for tetracycline, respectively. However, sarecycline activity against the tet(K) and tet(M) strains was decreased compared to that against the wild type, which demonstrated MICs ranging from 0.06 to 0.25 μl/ml, though the decrease in the activity of sarecycline against the tet(K) and tet(M) strains was not as pronounced as that of tetracycline. These findings support sarecycline as a narrow-spectrum tetracycline-class antibiotic that is effective for the treatment of acne, and further investigation into the potential reduced effects on the gut microbiome compared with those of other agents is warranted.

A novel topical minocycline foam for the treatment of moderate-to-severe acne vulgaris: Results of 2 randomized, double-blind, phase 3 studies

BACKGROUND

FMX101 4% is a topical minocycline foam for the treatment of moderate-to-severe acne.

OBJECTIVE

Evaluate the efficacy and safety of FMX101 4% in treating moderate-to-severe acne vulgaris.

METHODS

Two identical phase 3 studies were conducted. Subjects were randomized 2:1 to once-daily FMX101 4% or foam vehicle for 12 weeks. The coprimary end points were the change in inflammatory lesion count from baseline and the rate of treatment success according to the Investigator's Global Assessment (a score of 0 or 1 for clear or almost clear, with a ≥2-grade improvement) at week 12.

RESULTS

A total of 961 subjects were enrolled (study 04, N = 466; study 05, N = 495). Compared with vehicle, FMX101 4% demonstrated a significantly greater reduction in inflammatory lesions in both studies (P < .05) and a greater rate of treatment success in study 05 according to the Investigator's Global Assessment (P < .05). Pooled analyses of the 2 studies demonstrated statistical significance for both coprimary end points (all P < .05). Noninflammatory lesion count was also significantly reduced with FMX101 4% versus with vehicle in both studies. FMX101 4% was generally safe and well tolerated. Skin-related adverse events were reported in less than 1% of subjects treated with FMX101 4%.

LIMITATIONS

Longer-term efficacy and safety outcomes are needed (ongoing).

CONCLUSION

FMX101 4% topical minocycline foam significantly reduced both inflammatory and noninflammatory lesions and improved Investigator's Global Assessment scores in patients with moderate-to-severe acne.

Anti-inflammatory Approaches to Mitigate the Neuroinflammatory Response to Brain-Dwelling Intracortical Microelectrodes

Intracortical microelectrodes are used both in basic research to increase our understanding of the nervous system and for rehabilitation purposes through brain-computer interfaces. Yet, challenges exist preventing the widespread clinical use of this technology. A prime challenge is with the neuroinflammatory response to intracortical microelectrodes. This mini-review details immunomodulatory strategies employed to decrease the inflammatory response to these devices. Over time, broad-spectrum anti-inflammatory approaches, such as dexamethasone and minocycline, evolved into more targeted treatments since the underlying biology of the neuroinflammation was elucidated. This review also presents studies which examine novel prospective targets for future immunomodulatory targeting.

Emerging Therapies for Acne Vulgaris

As we gain a greater understanding of acne pathogenesis, both new agents as well as new uses for established drugs are being considered for the treatment of acne vulgaris. Multiple clinical trials assessing new formulations or combinations of established acne treatments have been conducted, and novel uses of antimicrobials such as modified diallyl disulfide oxide and nitric oxide are being assessed in clinical trials. There are also a multitude of new therapies currently being studied that target the inflammatory cascade of acne pathogenesis, including sebosuppressive and anti-inflammatory phytochemicals, and  small molecule inhibitors targeting sebaceous glands and enzymes, among others. Laser and light therapy is also being modified for the treatment of acne through combination methods with metal nanoshells and vacuum assistance. Probiotics have gained popularity in medicine as greater knowledge of the microbiome and its effects on multiple organ systems is being elucidated. Studies describing the positive effects of certain ammonia-oxidizing bacterial strains in the regulation of the skin's inflammatory response are ongoing. Therapies for acne are constantly evolving and current gold-standard acne therapy may be supplemented with novel treatment modalities in the near future.

Akne

Akne ist eine chronische Erkrankung mit hoher Prävalenz unter Jugendlichen. Pathogenetische Hauptfaktoren (und ihre klinischen Korrelate) sind gesteigerte Talgproduktion (Seborrhoe), follikuläre Hyperkeratose (Komedonen) und perifollikuläre Entzündungsvorgänge (Papulopusteln). Die Krankheit wird von endogenen (Androgene, IGF-1, neuroendokrine Faktoren) und exogenen (Propionibacterium acnes, Diät, mechanische Irritation, Inhaltsstoffe medizinischer oder kosmetischer Externa) Einflüssen moduliert. Akne geht mit zum Teil hoher Morbidität einher und kann bereits bei leichter Ausprägung eine erhebliche Verschlechterung der Lebensqualität bewirken. Zu Therapie stehen wirksame topische und systemische Behandlungsverfahren zur Verfügung. Eine optimale Behandlung erfordert eine stadiengerechtes Management und kontinuierliche ärztliche Begleitung der Patienten über den erforderlichen Behandlungszeitraum.

Mucocutaneous Hyperpigmentation in a Patient With a History of Both Minocycline and Silver Ingestion

Minocycline is a derivative of tetracycline. It has been widely used in dermatology for the treatment of acne and rosacea. One of its adverse effects is pigmentation of various body tissues. Clinically, 3 main distinct types of hyperpigmentation by minocycline have been distinguished: type I, with blue-gray to black pigment on the face in areas of scarring or inflammation; type II, with blue-gray pigment on normal skin of the legs, forearms and on the shins; and type III, with a diffuse muddy-brown discoloration in areas of sun exposure. In the current report, we present the case of a 50-year old man with a history of severe acne treated with minocycline in the past, who currently complained about discoloration of his face. He had also taken colloidal silver supplements for "good health" about 16 years ago. Physical examination revealed gray-blue discoloration on the face, sclera, hard palate and back. Histologic examination showed intracellular pigment deposits in macrophages of the superficial dermis in a perivascular and an interstitial distribution. The pigment stained with Fontana-Masson and von Kossa, whereas it was Perls' iron negative. This case does not fit well into any of the previously described patterns of minocycline-related hyperpigmentation.

Efficacy of photodynamic therapy combined with minocycline for treatment of moderate to severe facial acne vulgaris and influence on quality of life

BACKGROUND

Acne vulgaris is a prevalent skin disorder impairing both physical and psychosocial health. This study was designed to investigate the effectiveness of photodynamic therapy (PDT) combined with minocycline in moderate to severe facial acne and influence on quality of life (QOL).

METHODS

Ninety-five patients with moderate to severe facial acne (Investigator Global Assessment [IGA] score 3-4) were randomly treated with PDT and minocycline (n = 48) or minocycline alone (n = 47). All patients took minocycline hydrochloride 100 mg/d for 4 weeks, whereas patients in the minocycline plus PDT group also received 4 times PDT treatment 1 week apart. IGA score, lesion counts, Dermatology Life Quality Index (DLQI), and safety evaluation were performed before treatment and at 2, 4, 6, and 8 weeks after enrolment.

RESULTS

There were no statistically significant differences in characteristics between 2 treatment groups at baseline. Minocycline plus PDT treatment led to a greater mean percentage reduction from baseline in lesion counts versus minocycline alone at 8 weeks for both inflammatory (-74.4% vs -53.3%; P < .001) and noninflammatory lesions (-61.7% vs -42.4%; P < .001). More patients treated with minocycline plus PDT achieved IGA score <2 at study end (week 8: 30/48 vs 20/47; P < .05). Patients treated with minocycline plus PDT got significant lower DLQI at 8 weeks (4.4 vs 6.3; P < .001). Adverse events were mild and manageable.

CONCLUSIONS

Compared with minocycline alone, the combination of PDT with minocycline significantly improved clinical efficacy and QOL in moderate to severe facial acne patients.

Minocycline Improves the Efficacy of EGFR Inhibitor Therapy: A Hypothesis

Skin rash is a side effect of drugs that inhibit epithelial growth factor receptor (EGFR) as a part of targeted therapy of cancer. Its appearance and severity correlates with survival. Minocycline, an oral tetracycline antibiotic, is recommended as treatment (and increasingly, for prevention) of the rash, though infection is seen in only one-third of the patients. Minocycline has additional anticancer properties such as poly(ADP-ribose) polymerase inhibition. It is proposed that such properties contribute to the efficacy of EGFR inhibitors and can also explain the positive correlation between grade of rash and survival as patients with higher grades of rash are more likely to receive minocycline. Early concurrent administration of minocycline is recommended in patients planned for EGFR therapy while awaiting trials proving this hypothesis.

Critical data-based re-evaluation of minocycline as a putative specific microglia inhibitor

Minocycline, a second generation broad-spectrum antibiotic, has been frequently postulated to be a "microglia inhibitor." A considerable number of publications have used minocycline as a tool and concluded, after achieving a pharmacological effect, that the effect must be due to "inhibition" of microglia. It is, however, unclear how this "inhibition" is achieved at the molecular and cellular levels. Here, we weigh the evidence whether minocycline is indeed a bona fide microglia inhibitor and discuss how data generated with minocycline should be interpreted. GLIA 2016;64:1788-1794.

Toward a noncytotoxic glioblastoma therapy: blocking MCP-1 with the MTZ Regimen

To improve the prognosis of glioblastoma, we developed an adjuvant treatment directed to a neglected aspect of glioblastoma growth, the contribution of nonmalignant monocyte lineage cells (MLCs) (monocyte, macrophage, microglia, dendritic cells) that infiltrated a main tumor mass. These nonmalignant cells contribute to glioblastoma growth and tumor homeostasis. MLCs comprise of approximately 10%-30% of glioblastoma by volume. After integration into the tumor mass, these become polarized toward an M2 immunosuppressive, pro-angiogenic phenotype that promotes continued tumor growth. Glioblastoma cells initiate and promote this process by synthesizing 13 kDa MCP-1 that attracts circulating monocytes to the tumor. Infiltrating monocytes, after polarizing toward an M2 phenotype, synthesize more MCP-1, forming an amplification loop. Three noncytotoxic drugs, an antibiotic - minocycline, an antihypertensive drug - telmisartan, and a bisphosphonate - zoledronic acid, have ancillary attributes of MCP-1 synthesis inhibition and could be re-purposed, singly or in combination, to inhibit or reverse MLC-mediated immunosuppression, angiogenesis, and other growth-enhancing aspects. Minocycline, telmisartan, and zoledronic acid - the MTZ Regimen - have low-toxicity profiles and could be added to standard radiotherapy and temozolomide. Re-purposing older drugs has advantages of established safety and low drug cost. Four core observations support this approach: 1) malignant glioblastoma cells require a reciprocal trophic relationship with nonmalignant macrophages or microglia to thrive; 2) glioblastoma cells secrete MCP-1 to start the cycle, attracting MLCs, which subsequently also secrete MCP-1 perpetuating the recruitment cycle; 3) increasing cytokine levels in the tumor environment generate further immunosuppression and tumor growth; and 4) MTZ regimen may impede MCP-1-driven processes, thereby interfering with glioblastoma growth.

Management of severe acne

Acne is the most common skin disease, affecting up to 95% of adolescents. Severe episodes of acne can cause considerable physical and psychological scarring, and overexpression of transforming growth factor-β can lead to formation of hypertrophic scars and keloids. The severity of acne in adolescence is associated with a positive history of severe acne in first-degree relatives, especially the mother. In most cases acne is a chronic disease, and it is often a component of systemic diseases or syndromes. All forms of severe acne require systemic treatment. The available options include oral antibiotics, hormonal antiandrogens for female patients and oral isotretinoin, as well as other combination treatments. Oral isotretinoin is the only drug available that affects all four pathogenic factors of acne. However, due to possible serious side-effects, a European directive states that oral isotretinoin should be used only as a second-line therapy in cases of severe, nodular and conglobate acne. The pharmaceutical quality of generic isotretinoin products and the obtainability of isotretinoin through e-pharmacies without prescription raise new therapeutic problems. New anti-inflammatory compounds, such as the 5-lipoxygenase inhibitor zileuton, may replace systemic antibiotics in the future, especially under the scope of antibiotic resistance prevention. This review looks into the various options and latest approaches, and factors to consider, when combating severe acne.

The "Heart Sign": An Early Indicator of Dose-Dependent Doxycycline-Induced Phototoxicity

Oral doxycycline is an antibiotic commonly used for the treatment of inflammatory acne in adolescents. Dose-dependent phototoxicity, unrelated to dose duration, is a well-known complication of its use. We present three adolescents who developed bilateral phototoxic rashes on the dorsal thenar spaces of their hands while taking doxycycline for their acne. Identification of the "heart sign" rash as a specific doxycycline-related phototoxic reaction should alert clinicians to the need for prompt intervention, including sun protection counseling and a possible change in antibiotics, in the uniquely vulnerable adolescent population. Early recognition may allow patients to avoid future, more widespread phototoxic drug reactions.

Activation of Adenosine Monophosphate-activated Protein Kinase Suppresses Neuroinflammation and Ameliorates Bone Cancer Pain: Involvement of Inhibition on Mitogen-activated Protein Kinase

BACKGROUND

Activation of adenosine monophosphate-activated kinase (AMPK) has been associated with the inhibition of inflammatory nociception and the attenuation of morphine antinociceptive tolerance. In this study, the authors investigated the impact of AMPK activation through resveratrol treatment on bone cancer pain.

METHODS

The nociception was assessed by measuring the incidence of foot withdrawal in response to mechanical indentation in rats (n = 8). Cytokine expression was measured using quantitative polymerase chain reaction (n = 8). Cell signalings were assayed by western blot (n = 4) and immunohistochemistry (n = 5). The microglial cell line BV-2, primary astrocytes, and neuron-like SH-SY5Y cells were cultured to investigate the in vitro effects.

RESULTS

Resveratrol and 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide, the AMPK activators, significantly attenuated bone cancer pain in rats with tumor cell implantation (TCI; threshold of mechanical withdrawal, resveratrol vs. vehicle: 10.1 ± 0.56 vs. 4.1 ± 0.37; 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide vs. vehicle: 8.2 ± 0.17 vs. 4.1 ± 0.37, mean ± SEM); these effects were reversed by the AMPK inhibitor compound C (compound C vs. resveratrol: 6.2 ± 1.35 vs. 10.1 ± 0.56, mean ± SEM). Resveratrol has an AMPK-dependent inhibitory effect on TCI-evoked astrocyte and microglial activation. The antinociceptive effects of resveratrol were partially mediated by the reduced phosphorylation of mitogen-activated protein kinases and decreased production of proinflammatory cytokines in an AMPK-dependent manner. Furthermore, resveratrol potently inhibited inflammatory factors-mediated protein kinase B/mammalian target of rapamycin signaling in neurons. Acute pain evoked by proinflammatory cytokines in the spinal cord was significantly attenuated by resveratrol.

CONCLUSIONS

AMPK activation in the spinal glia by resveratrol may have utility in the treatment of TCI-induced neuroinflammation, and our results further implicate AMPK as a novel target for the attenuation of bone cancer pain.

Challenges to get axenic cultures of Trichomonas spp. - A new approach in eradication of contaminants and maintenance of laboratory microbiological cultures

Contamination of microbiological and cell cultures is a major problem in many scientific and clinical laboratories as well as bioproduct manufacturers worldwide. In the current study we established a rapid (9day) method to detect and eliminate fungal and bacterial contamination in cultures of the unicellular eukaryote Trichomonas spp. The developed method combines identification of the contaminating microorganisms using PCR and sequencing of the 16/18S regions followed by phylogenetic analysis. The next step was a phylogeny-guided selection of antibiotic treatments. We then used a two-step propidium iodide-resorufin assay to test the effect of selected antibiotics. The result was a quick and worthwhile purification of trichomonad laboratory cultures. Our workflow may also be implemented to obtain new isolates of trichomonads from clinical samples if initial broad-spectrum antibiotic therapy fails.

The Effect of Residual Endotoxin Contamination on the Neuroinflammatory Response to Sterilized Intracortical Microelectrodes

A major limitation to the use of microelectrode technologies in both research and clinical applications is our inability to consistently record high quality neural signals. There is increasing evidence that recording instability is linked, in part, to neuroinflammation. A number of factors including extravasated blood products and macrophage released soluble factors are believed to mediate neuroinflammation and the resulting recording instability. However, the roles of other inflammatory stimuli, such as residual endotoxin contamination, are poorly understood. Therefore, to determine the effect of endotoxin contamination we examined the brain tissue response of C57/BL6 mice to non-functional microelectrodes with a range of endotoxin levels. Endotoxin contamination on the sterilized microelectrodes was measured using a limulus amebocyte lysate test following FDA guidelines. Microelectrodes sterilized by autoclave, dry heat, or ethylene oxide gas, resulted in variable levels of residual endotoxins of 0.55 EU/mL, 0.22 EU/mL, and 0.11 EU/mL, respectively. Histological evaluation at two weeks showed a direct correlation between microglia/macrophage activation and endotoxin levels. Interestingly, astrogliosis, neuronal loss, and blood brain barrier dysfunction demonstrated a threshold-dependent response to bacterial endotoxins. However, at sixteen weeks, no histological differences were detected, regardless of initial endotoxin levels. Therefore, our results demonstrate that endotoxin contamination, within the range examined, contributes to initial but not chronic microelectrode associated neuroinflammation. Our results suggest that minimizing residual endotoxins may impact early recording quality. To this end, endotoxins should be considered as a potent stimulant to the neuroinflammatory response to implanted intracortical microelectrodes.

Tetracyclines cause cell stress-dependent ATF4 activation and mTOR inhibition

Tetracyclines have long been used as valuable broad-spectrum antibiotics. The high antibacterial activity of tetracyclines, combined with their good tolerability, has led to their widespread use in treating various infectious diseases. However, similar to other antibiotics, tetracyclines are also known for their adverse effects on different human tissues, including hepatic steatosis. We observed that tetracyclines, including doxycycline and minocycline, caused enhanced expression of the liver chalone inhibin βE in HepG2 cells, mediated by the cell stress-regulated transcription factor ATF4. ATF4 and its target genes ATF3, CHOP, and inhibin βE are involved in cell cycle control, cell survival, cell metabolism, and modulation of cytokine expression. Furthermore, we observed that long term tetracycline incubation also caused inhibition of the mTOR complex, a central regulator of cell metabolism, further contributing to the observed cell-cycle arrest and autophagy in doxycycline- and minocycline-treated cell lines. ATF4 activation and mTOR inhibition link two crucial regulators of the cellular stress response and cell metabolism to the effects of tetracyclines on eukaryotic cell metabolism, and may help to understand the antibiotic-independent influence of these drugs on human tissues. Since the observed effects of tetracyclines on human cells were also found to be dependent on the magnesium ion concentrations supplied, the data further indicate the importance of magnesium supplementation to reduce or prevent side effects of long term treatment with tetracyclines.

Treatment of preadolescent acne in the United States: an analysis of nationally representative data

The prevalence of acne in younger children is increasing. Of the acne treatments that the U.S. Food and Drug Administration (FDA) has approved for ages 12 years and older, it is unclear which medications are being prescribed off-label for this younger patient population. The purpose of this study is to compare the therapies being prescribed to preadolescent patients with acne (defined in this study as ages 7 to 11 years) with those being prescribed to adolescent patients (ages 12 to 18 years) and to determine whether prescribing patterns differ between dermatologists and pediatricians. Leading therapies for the treatment of children with a diagnosis of acne were collected from the National Ambulatory Medical Care Survey (NAMCS) from 1993 to 2009. Data were stratified according to age group and physician specialty. Physicians prescribed a wide variety of FDA-approved and off-label medications to preadolescent patients with acne. The leading medications were topical treatments, including adapalene (14.4%), benzoyl peroxide (12.8%), and tretinoin (12.5%). Treatment of this age group differed substantially between specialties, with dermatologists frequently prescribing topical retinoids and primary care physicians preferring antibiotics, particularly oral antibiotics. Limitations included a lack of data on acne severity and morphology through NAMCS, as well as the absence of longitudinal data. With the limited number of FDA-approved treatment options, off-label prescribing for acne in preadolescent patients is common. Furthermore, this study identified a potential knowledge gap between pediatricians based on their prescribing patterns in this patient population.

Newer approaches to the treatment of acne vulgaris

The multifactorial etiology of acne vulgaris makes it challenging to treat. Current treatments include topical retinoids, benzoyl peroxide, topical and systemic antibiotics, azelaic acid, and systemic isotretinoin. Adjunctive and/or emerging approaches include topical dapsone, taurine bromamine, resveratrol, chemical peels, optical treatments, as well as complementary and alternative medications. The purpose of this paper is to discuss the therapies available for acne and their latest developments, including new treatment strategies (i.e. re-evaluation of the use of oral antibiotics and avoidance of topical antibiotic monotherapy, use of subantimicrobial antibiotic dosing, use of low-dose isotretinoin, optical treatments), new formulations (microsponges, liposomes, nanoemulsions, aerosol foams), new combinations (fixed-combination products of topical retinoids and topical antibiotics [essentially clindamycin] or benzoyl peroxide), new agents (topical dapsone, taurine bromamine, resveratrol) and their rationale and likely place in treatment. Acne vaccines, topical natural antimicrobial peptides, and lauric acid represent other promising therapies.

Minocycline for acne vulgaris: efficacy and safety

BACKGROUND

Minocycline is an oral antibiotic used for acne vulgaris. Its use has lessened due to safety concerns (including potentially irreversible pigmentation), a relatively high cost, and no evidence of any greater benefit than other acne treatments. A modified-release version of minocycline is being promoted as having fewer side-effects.

OBJECTIVES

To assess new evidence on the effects of minocycline for acne vulgaris.

SEARCH METHODS

Searches were updated in the following databases to November 2011: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library, MEDLINE (from 1946), EMBASE (from 1974), and LILACS (from 1982). We also searched trials registers and checked reference lists for further references to relevant randomised controlled trials (RCTs).The Cochrane Skin Group's Trials Search Co-ordinator undertook searches exploring minocycline's adverse effects in EMBASE and MEDLINE in February 2012.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) comparing minocycline, at any dose, to an active or a placebo control, in participants with inflammatory acne vulgaris. For adverse effects, we selected additional studies that reported the number of adverse effects and the number of participants treated.

DATA COLLECTION AND ANALYSIS

Outcome measures used in the trials included lesion counts, acne grades/severity scores, doctors' and participants' global assessments, adverse effects, and dropout rates. Two authors independently assessed the quality of each study. Effect sizes were calculated, and meta-analyses were undertaken where possible.Sixteen studies met the inclusion criteria for the review of adverse effects.

MAIN RESULTS

We included 12 new RCTs for this update, giving a total of 39 RCTs (6013 participants). These additional 12 RCTs have not changed the original conclusions about the clinical efficacy of minocycline.The identified RCTs were generally small and poor quality. Meta-analysis was rarely possible because of the lack of data and different outcome measures and trial durations. Although minocycline was shown to be an effective treatment for moderate to moderately-severe acne vulgaris, there was no evidence that it is better than any of the other commonly-used acne treatments. One company-sponsored RCT found minocycline to be less effective than combination treatment with topical erythromycin and zinc. No trials have been conducted using minocycline in those participants whose acne is resistant to other therapies. Also, there is no evidence to guide what dose should be used.The adverse effects studies must be interpreted with caution. The evidence suggests that minocycline is associated with more severe adverse effects than doxycycline. Minocycline, but not other tetracyclines, is associated with lupus erythematosus, but the risk is small: 8.8 cases per 100,000 person-years. The risk of autoimmune reactions increases with duration of use. The evidence does not support the conclusion that the more expensive extended-release preparation is safer than standard minocycline preparations.

AUTHORS' CONCLUSIONS

Minocycline is an effective treatment for moderate to moderately-severe inflammatory acne vulgaris, but there is still no evidence that it is superior to other commonly-used therapies. This review found no reliable evidence to justify the reinstatement of its first-line use, even though the price-differential is less than it was 10 years ago. Concerns remain about its safety compared to other tetracyclines.