Absorption of minocycline

Antimicrobial Treatment Options for Difficult-to-Treat Resistant Gram-Negative Bacteria Causing Cystitis, Pyelonephritis, and Prostatitis: A Narrative Review

Urinary tract infections, including cystitis, acute pyelonephritis, and prostatitis, are among the most common diagnoses prompting antibiotic prescribing. The rise in antimicrobial resistance over the past decades has led to the increasing challenge of urinary tract infections because of multidrug-resistant and "difficult-to-treat resistance" among Gram-negative bacteria. Recent advances in pharmacotherapy and medical microbiology are modernizing how these urinary tract infections are treated. Advances in pharmacotherapy have included not only the development and approval of novel antibiotics, such as ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, ceftolozane/tazobactam, cefiderocol, plazomicin, and glycylcyclines, but also the re-examination of the potential role of legacy antibiotics, including older aminoglycosides and tetracyclines. Recent advances in medical microbiology allow phenotypic and molecular mechanism of resistance testing, and thus antibiotic prescribing can be tailored to the mechanism of resistance in the infecting pathogen. Here, we provide a narrative review on the clinical and pre-clinical studies of drugs that can be used for difficult-to-treat resistant Gram-negative bacteria, with a particular focus on data relevant to the urinary tract. We also offer a pragmatic framework for antibiotic selection when encountering urinary tract infections due to difficult-to-treat resistant Gram-negative bacteria based on the organism and its mechanism of resistance.

Use of Oral Tetracyclines in the Treatment of Adult Patients with Community-Acquired Bacterial Pneumonia: A Literature Review on the Often-Overlooked Antibiotic Class

Oral tetracyclines have been used in clinical practice for over 60 years. Overall, one of the most common indications for use of oral tetracyclines is for treatment of adult outpatients with lower respiratory tract infections, including community-acquired pneumonia (CAP). Despite the longstanding use of oral tetracyclines, practice patterns indicate that they are often considered after other guideline-concordant oral CAP treatment options (namely macrolides, fluoroquinolones, and β-lactams). However, there are growing resistance or safety concerns with the available oral agents listed for outpatients with CAP in the updated American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) CAP guidelines, especially among patients with comorbidities or notable risk factors for resistant pathogens. Given the need for alternative oral agents to macrolides, fluoroquinolones, and beta-lactams for adult outpatients with CAP, this review summarizes the literature on the use of oral tetracyclines (i.e., doxycycline, minocycline, and omadacycline) for this indication. As part of this review, we described their mechanism of action, common mechanisms of resistance, susceptibility profiles against common CAP pathogens, pharmacokinetics, pharmacodynamics, clinical data, and safety. The intent of the review is to highlight the important considerations when deciding between doxycycline, minocycline, and omadacycline for an adult outpatient with CAP in situations in which use of an oral tetracycline is warranted.

Minocycline accelerates hypoxia-inducible factor-1 alpha degradation and inhibits hypoxia-induced neovasculogenesis through prolyl hydroxylase, von Hippel-Lindau-dependent pathway

Hypoxia-mediated stress responses are important in tumor progression, especially when tumor growth causes the tumor to become deprived of its blood supply. The oxygen-labile transcription factor hypoxia-inducible factor-1 alpha (HIF-1α) plays a critical role in regulating hypoxia stress-related gene expression and is considered a novel therapeutic target. Lung adenocarcinoma cell lines were exposed to minocycline, followed by incubation at hypoxic condition for 3-6 h. Here, we show that minocycline, a second-generation tetracycline, can induce HIF-1α proteasomal degradation under hypoxia by increasing the expression prolyl hydroxylase-2 and HIF-1α/von Hippel-Lindau protein interaction, thereby overcoming hypoxia-induced HIF-1α stabilization. Neither repression of hypoxia-induced phosphatidylinositol-3 kinase/Akt/mammalian target of rapamycin pathway nor inhibition of Hsp90 was required for minocycline-induced HIF-1α degradation. The HIF-1α degradation-enhancing effect of minocycline was evident in both cancerous and primary cells. Minocycline-pretreated, hypoxia-conditioned cells showed a clear reduction in hypoxia response element reporter expression and amelioration of vascular endothelial growth factor C/D (VEGF-C/D), matrix metalloproteinase 2, and glucose transporter 1 expression. By decreasing VEGF secretion of cancerous cells, minocycline could suppress endothelial cell neovasculogenesis. These findings suggest a novel application of minocycline in the treatment of tumor angiogenesis as well as hypoxia-related diseases.

Minocycline suppresses interleukine-6, its receptor system and signaling pathways and impairs migration, invasion and adhesion capacity of ovarian cancer cells: in vitro and in vivo studies

Interleukin (IL)-6 has been shown to be a major contributing factor in growth and progression of ovarian cancer. The cytokine exerts pro-tumorigenic activity through activation of several signaling pathways in particular signal transducer and activator of transcription (STAT3) and extracellular signal-regulated kinase (ERK)1/2. Hence, targeting IL-6 is becoming increasingly attractive as a treatment option in ovarian cancer. Here, we investigated the effects of minocycline on IL-6 and its signaling pathways in ovarian cancer. In vitro, minocycline was found to significantly suppress both constitutive and IL-1β or 4-hydroxyestradiol (4-OH-E2)-stimulated IL-6 expression in human ovarian cancer cells; OVCAR-3, SKOV-3 and CAOV-3. Moreover, minocycline down-regulated two major components of IL-6 receptor system (IL-6Rα and gp130) and blocked the activation of STAT3 and ERK1/2 pathways leading to suppression of the downstream product MCL-1. In female nude mice bearing intraperitoneal OVCAR-3 tumors, acute administration (4 and 24 h) of minocycline (30 mg/kg) led to suppression of IL-6. Even single dose of minocycline was effective at significantly lowering plasma and tumor IL-6 levels. In line with this, tumoral expression of p-STAT3, p-ERK1/2 and MCL-1 were decreased in minocycline-treated mice. Evaluation of the functional implication of minocycline on metastatic activity revealed the capacity of minocycline to inhibit cellular migration, invasion and adhesion associated with down-regulation of matrix metalloproteinases (MMP)-2 and 9. Thus, the data suggest a potential role for minocycline in suppressing IL-6 expression and activity. These effects may prove to be an important attribute to the upcoming clinical trials of minocycline in ovarian cancer.

Minocycline inhibits growth of epithelial ovarian cancer

OBJECTIVE

These studies were designed to determine whether minocycline inhibits ovarian cancer growth in vitro and in vivo and the molecular mechanisms involved.

MATERIALS AND METHODS

The effect of minocycline on ovarian cancer cell proliferation, cell cycle progression and apoptosis was assessed using human ovarian cancer cell lines OVCAR-3, SKOV-3 and A2780. Then, the capacity of minocycline to inhibit growth of OVCAR-3 xenografts in female nude mice was examined.

RESULTS

Minocycline inhibited cell proliferation and colony formation, down-regulated cyclins A, B and E leading to arrest of cells in the G(0) phase of the cycle and suppression of DNA synthesis. Furthermore, exposure of these cells to minocycline led to DNA laddering, activation of caspase-3 and cleavage of PARP-1. In nude mice bearing sub-cutaneous tumors, minocycline suppressed tumor proliferation index, angiogenesis and tumor growth.

CONCLUSION

These findings provide the initial basis for further evaluation of minocycline in the treatment of ovarian cancer.

Minocycline--an old drug for a new century: emphasis on methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii

The epidemiology of nosocomial and community-acquired infections has changed in recent years. Methicillin-resistant Staphylococcus aureus (MRSA), especially community-associated MRSA (CA-MRSA), has emerged as a gram-positive organism with an increasing impact in clinical practice. Infections with Acinetobacter baumannii have become a major cause of morbidity and mortality. Minocycline has significant in vitro activity against MRSA and A. baumannii that is comparable with agents currently used against these organisms. The absence of an intravenous (i.v.) minocycline formulation in recent years has limited its use in seriously ill patients infected with these organisms. However, minocycline i.v. has recently been reintroduced to the US market. The objective of this study was to review available information on the chemistry, mechanism of action, in vitro activity, resistance mechanisms, pharmacokinetics, tolerability and efficacy of minocycline against MRSA and A. baumannii. This article provides suggestions for future studies and potential uses of minocycline and is designed to trigger interest in systematic clinical evaluation of minocycline for patients infected with these organisms. In conclusion, minocycline is an old drug that has the potential to become an important part of the armamentarium against emerging infections such as CA-MRSA and A. baumannii. Owing to its promising profile against these clinically important pathogens as well as excellent pharmacokinetic properties, minocycline merits evaluation in serious infections.

Clinical pharmacokinetics of doxycycline and minocycline

Doxycycline and minocycline are second-generation tetracyclines. They are readily absorbed, distributed throughout the organism as a function of their lipophilicity and eliminated in both the urine and the faeces. The influence of age, renal disease, malnutrition and hyperlipidaemia is reviewed, together with the main pharmacokinetic interactions.

A general practice study investigating the effect of Minocin 50 mg b.d. for 12 weeks in the treatment of acne vulgaris

In a multicentre general practice open study, 338 acne sufferers were treated with Minocin 50 mg b.d. (254 for 12 weeks). A highly significant improvement trend (p less than 0.0001) was found following analysis of visual analogue scales measuring (i) severity of acne, (ii) area covered by acne, (iii) number of inflamed lesions, (iv) density of acne lesions. Over all, 79% of patients thought the therapy to be effective or very effective; 70% of patients continued on the same therapy after the study period. Mean first improvement was noted by the patients after 4 1/2 weeks of treatment. One hundred and twenty-two patients had taken prior oxytetracycline therapy, of these, ninety-four (77%) stopped oxytetracycline therapy because of lack of efficacy. After treatment of these oxytetracycline failures with Minocin, a highly significant improvement trend (p less than 0.0001) of acne was again seen. In this group, 75% of patients thought the Minocin therapy to be effective or very effective; 69% continued Minocin therapy after the study period. In all, 74% of patients having received prior oxytetracycline thought that Minocin therapy was better than their previous therapy. Ninety-three patients had received either no previous therapy or topical therapy alone. Once again Minocin treatment resulted in a highly significant improvement trend (p less than 0.0001) in the severity of acne. Seventy six (82%) of these patients thought that Minocin therapy was effective or very effective. A total of 73% of patients continued with Minocin therapy following the study period. Adverse events were noted in 6% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)