Safety of doxycycline and minocycline: a systematic review

Doxycycline delivery from PLGA microspheres prepared by a modified solvent removal method

We report on the development of a modified solvent removal method for the encapsulation of hydrophilic drugs within poly(lactic-co-glycolic acid) (PLGA). Using a water/oil/oil double emulsion, hydrophilic doxycycline was encapsulated within PLGA spheres with particle diameters ranging from approximately 600 nm to 19 µm. Encapsulation efficiencies of up to 74% were achieved for theoretical loadings from 1% to 10% (w/w), with biphasic release over 85 days with nearly complete release at the end of this time course. About 1% salt was added to the formulations to examine its effects on doxycycline release; salt modulated release only by increasing the magnitude of initial release without altering kinetics. Fourier transform infrared spectroscopy indicated no characteristic differences between doxycycline-loaded and control spheres. Differential scanning calorimetry and X-ray diffraction suggest that there may be a molecular dispersion of the doxycycline within the spheres and the doxycycline may be in an amorphous state, which could explain the slow, prolonged release of the drug.

Minocycline and doxycycline therapy in community patients with rheumatoid arthritis: prescribing patterns, patient-level determinants of use, and patient-reported side effects

INTRODUCTION

Minocycline and doxycycline are safe and moderately effective disease-modifying anti-rheumatic drugs (DMARDs) in the treatment of early, DMARD-naïve rheumatoid arthritis (RA), although little is known about their use outside clinical trials. We characterize the use of minocycline and doxycycline in community-dwelling RA patients by examining associated prescribing patterns, patient-level determinants of use, and side-effect profiles.

METHODS

We studied 15,716 patients with RA observed between 1998 and 2009 while participating in a long-term US observational study.

RESULTS

Minocycline or doxycycline was prescribed by 18% of rheumatologists (interquartile range one to two patients per physician) to 9% of RA patients. Significant differences between minocycline-treated and doxycycline-treated patients and nontreated patients included age (58.4 years vs. 59.8 years), RA duration (14.8 years vs. 13.7 years), Caucasian race (93.7% vs. 89.7%), lifetime DMARDs and biologics (3.3 vs. 2.5), prednisone use (40.1% vs. 35.3%), and Medical Outcomes Study 36-Item Short Form Survey physical component summary score (35.0 vs. 36.4). In multivariable Cox regression, patients initiating minocycline or doxycycline had increased disease activity, more comorbidities, and a greater number of prior nonbiologic DMARDs. Side effects were reported by 17.8% of minocycline users and 11.8% of doxycycline users. Skin complaints accounted for 54% of minocycline patient-reported side effects. The most commonly effected organ systems for doxycycline were gastrointestinal (35.4%) and skin (33.7%). Approximately 75% of side effects were of mild or moderate severity.

CONCLUSIONS

Rheumatologists have not embraced minocycline or doxycycline as primary treatment options for RA and reserve their use primarily in patients with long-standing, refractory disease. These drugs are generally well tolerated, with skin complaints, nausea, and dizziness being the most common patient-reported side effects.

Doxycycline for malaria chemoprophylaxis and treatment: report from the CDC expert meeting on malaria chemoprophylaxis

Doxycycline, a synthetically derived tetracycline, is a partially efficacious causal prophylactic (liver stage of Plasmodium) drug and a slow acting blood schizontocidal agent highly effective for the prevention of malaria. When used in conjunction with a fast acting schizontocidal agent, it is also highly effective for malaria treatment. Doxycycline is especially useful as a prophylaxis in areas with chloroquine and multidrug-resistant Plasmodium falciparum malaria. Although not recommended for pregnant women and children < 8 years of age, severe adverse events are rarely reported for doxycycline. This report examines the evidence behind current recommendations for the use of doxycycline for malaria and summarizes the available literature on its safety and tolerability.

Activities of colistin- and minocycline-based combinations against extensive drug resistant Acinetobacter baumannii isolates from intensive care unit patients

BACKGROUND

Extensive drug resistance of Acinetobacter baumannii is a serious problem in the clinical setting. It is therefore important to find active antibiotic combinations that could be effective in the treatment of infections caused by this problematic 'superbug'. In this study, we analyzed the in vitro activities of three colistin-based combinations and a minocycline-based combination against clinically isolated extensive drug resistant Acinetobacter baumannii (XDR-AB) strains.

METHODS

Fourteen XDR-AB clinical isolates were collected. The clonotypes were determined by polymerase chain reaction-based fingerprinting. Susceptibility testing was carried out according to the standards of the Clinical and Laboratory Standards Institute. Activities of drug combinations were investigated against four selected strains and analyzed by mean survival time over 12 hours (MST12 h) in a time-kill study.

RESULTS

The time-kill studies indicated that the minimum inhibitory concentration (MIC) of colistin (0.5 or 0.25 μg/mL) completely killed all strains at 2 to 4 hours, but 0.5×MIC colistin showed no bactericidal activity. Meropenem (8 μg/mL), minocycline (1 μg/mL) or rifampicin (0.06 μg/mL) did not show bactericidal activity. However, combinations of colistin at 0.5×MIC (0.25 or 0.125 μg/mL) with each of the above were synergistic and shown bactericidal activities against all test isolates. A combination of meropenem (16 μg/mL) with minocycline (0.5×MIC, 4 or 2 μg/mL) was synergitic to all test isolates, but neither showed bactericidal activity alone. The MST12 h values of drug combinations (either colistin- or minocycline-based combinations) were significantly shorter than those of the single drugs (p<0.01).

CONCLUSIONS

This study indicates that combinations of colistin/meropenem, colistin/rifampicin, colistin/minocycline and minocycline/meropenem are synergistic in vitro against XDR-AB strains.

Activities of colistin- and minocycline-based combinations against extensive drug resistant Acinetobacter baumannii isolates from intensive care unit patients

Background

Extensive drug resistance of Acinetobacter baumannii is a serious problem in the clinical setting. It is therefore important to find active antibiotic combinations that could be effective in the treatment of infections caused by this problematic 'superbug'. In this study, we analyzed the in vitro activities of three colistin-based combinations and a minocycline-based combination against clinically isolated extensive drug resistant Acinetobacter baumannii (XDR-AB) strains.

Methods

Fourteen XDR-AB clinical isolates were collected. The clonotypes were determined by polymerase chain reaction-based fingerprinting. Susceptibility testing was carried out according to the standards of the Clinical and Laboratory Standards Institute. Activities of drug combinations were investigated against four selected strains and analyzed by mean survival time over 12 hours (MST_{12 h}) in a time-kill study.

Results

The time-kill studies indicated that the minimum inhibitory concentration (MIC) of colistin (0.5 or 0.25 μg/mL) completely killed all strains at 2 to 4 hours, but 0.5×MIC colistin showed no bactericidal activity. Meropenem (8 μg/mL), minocycline (1 μg/mL) or rifampicin (0.06 μg/mL) did not show bactericidal activity. However, combinations of colistin at 0.5×MIC (0.25 or 0.125 μg/mL) with each of the above were synergistic and shown bactericidal activities against all test isolates. A combination of meropenem (16 μg/mL) with minocycline (0.5×MIC, 4 or 2 μg/mL) was synergitic to all test isolates, but neither showed bactericidal activity alone. The MST_{12 h} values of drug combinations (either colistin- or minocycline-based combinations) were significantly shorter than those of the single drugs (p < 0.01).

Conclusions

This study indicates that combinations of colistin/meropenem, colistin/rifampicin, colistin/minocycline and minocycline/meropenem are synergistic in vitro against XDR-AB strains.

Treatment of postinfectious olfactory disorders with minocycline: a double-blind, placebo-controlled study

OBJECTIVES/HYPOTHESIS

Infection of the upper respiratory tract is one of the most common causes of olfactory loss. One of the possible underlying pathologic pathways is an increase of apoptosis of olfactory receptor neurons. Therefore, treatment with the antibiotic minocycline, which has been shown to act as an antiapoptotic agent, is thought to accelerate improvement of olfactory function. To investigate this idea, 55 patients with postinfectious olfactory dysfunction were tested for their olfactory ability.

STUDY DESIGN

Randomized, prospective, double-blind, placebo-controlled.

METHODS

Olfactory function was examined by means of a standardized psychophysical method (Sniffin' Sticks) before and 7 months after a 3-week treatment with either minocycline (2 × 50 mg/d) or a placebo.

RESULTS

Statistical analyses did not reveal any influence of the treatment on the progress of olfactory function, possibly indicating that pathologic changes other than apoptosis contribute to postinfectious olfactory loss, either on a peripheral level (e.g., scarring/reorganization of the olfactory epithelium) or on a central nervous level.

CONCLUSIONS

In conclusion, the present results indicate that minocycline in the given dosage has little or no effect on the recovery of human olfactory function following postinfectious olfactory loss. However, spontaneous recovery is found in approximately 20% of the patients over an observation period of 7 months.

The position of mefloquine as a 21st century malaria chemoprophylaxis

BACKGROUND

Malaria chemoprophylaxis prevents the occurrence of the symptoms of malaria. Travellers to high-risk Plasmodium falciparum endemic areas need an effective chemoprophylaxis.

METHODS

A literature search to update the status of mefloquine as a malaria chemoprophylaxis.

RESULTS

Except for clearly defined regions with multi-drug resistance, mefloquine is effective against the blood stages of all human malaria species, including the recently recognized fifth species, Plasmodium knowlesi. New data were found in the literature on the tolerability of mefloquine and the use of this medication by groups at high risk of malaria.

DISCUSSION

Use of mefloquine for pregnant women in the second and third trimester is sanctioned by the WHO and some authorities (CDC) allow the use of mefloquine even in the first trimester. Inadvertent pregnancy while using mefloquine is not considered grounds for pregnancy termination. Mefloquine chemoprophylaxis is allowed during breast-feeding. Studies show that mefloquine is a good option for other high-risk groups, such as long-term travellers, VFR travellers and families with small children. Despite a negative media perception, large pharmaco-epidemiological studies have shown that serious adverse events are rare. A recent US evaluation of serious events (hospitalization data) found no association between mefloquine prescriptions and serious adverse events across a wide range of outcomes including mental disorders and diseases of the nervous system. As part of an in-depth analysis of mefloquine tolerability, a potential trend for increased propensity for neuropsychiatric adverse events in women was identified in a number of published clinical studies. This trend is corroborated by several cohort studies that identified female sex and low body weight as risk factors.

CONCLUSION

The choice of anti-malarial drug should be an evidence-based decision that considers the profile of the individual traveller and the risk of malaria. Mefloquine is an important, first-line anti-malarial drug but it is crucial for prescribers to screen medical histories and inform mefloquine users of potential adverse events. Careful prescribing and observance of contraindications are essential. For some indications, there is currently no replacement for mefloquine available or in the pipeline.

Minocycline in acne vulgaris: benefits and risks

Minocycline is a semi-synthetic, second-generation tetracycline. It was introduced in 1972 and has both antibacterial and anti-inflammatory properties. Minocycline is used for a variety of infectious diseases and in acne. Even today, new indications beyond the antibacterial indications are being investigated such as its use in neurologic diseases. Formerly, minocycline was thought to have a superior efficacy in the treatment of inflammatory acne, especially with respect to antibacterial-resistant Propionibacterium acnes. A thorough review of the literature, however, shows that minocycline is not more effective in acne than other tetracyclines. Compared with first-generation tetracyclines, minocycline has a better pharmacokinetic profile, and compared with doxycycline it is not phototoxic. However, minocycline has an increased risk of severe adverse effects compared with other tetracyclines. It may induce hypersensitivity reactions affecting the liver, lung, kidneys, or multiple organs (Drug Reaction with Eosinophilia and Systemic Symptoms [DRESS] syndrome) in the first weeks of treatment and, with long-term treatment, may cause autoimmune reactions (systemic lupus erythematosus, autoimmune hepatitis). In addition, CNS symptoms, such as dizziness, are more frequent compared with other tetracyclines. Long-term treatment may induce hyperpigmentation of the skin or other organs. Resistance of P. acnes to minocycline also occurs, dependent on the prescribing behavior. Considering the aspects of efficacy, its adverse effect profile, resistance, price, and alternatives, minocycline is no longer considered the first-line antibacterial in the treatment of acne.

Reversible cytotoxic oedema in the splenium of the corpus callosum related to tetracycline therapy

We report a symptomatic girl with reversible circumscribed cytotoxic oedema in the splenium of the corpus callosum (CC) that occurred, to our knowledge, for the first time in relation to tetracycline treatment. After stopping tetracycline therapy the girl recovered completely and the CC lesion, clearly visible on diffusion-weighted MR imaging (DWI), disappeared. Reversible circumscribed cytotoxic oedema (CCO) of the splenium of the CC is a well-defined entity that is found to be associated with administration of antiepileptic drugs, alterations in therapy using arginin-vasopressin and metronidazole or infections with influenza and rotavirus. CCO of splenium of the CC is clearly visible on DWI, shows no enhancement after administration of contrast medium and is completely reversible in most cases.

Side effects of minocycline treatment in patients with fragile X syndrome and exploration of outcome measures

Minocycline can rescue the dendritic spine and synaptic structural abnormalities in the fragile X knock-out mouse. This is a review and preliminary survey to document side effects and potential outcome measures for minocycline use in the treatment of individuals with fragile X syndrome. We surveyed 50 patients with fragile X syndrome who received minocycline for at least 2 weeks and found that the most common reported side effect is gastrointestinal difficulty, including loss of appetite. The families reported an improvement in language and behavioral areas. Outcome measures in the design of future randomized clinical trials should include both behavioral and language measures. As with any other treatments, we emphasize that randomized clinical trials are needed to determine the efficacy of minocycline in fragile X syndrome.

Tetracyclines: what a rheumatologist needs to know?

Tetracyclines are broad-spectrum antibiotics that act at the ribosomal level. They were first introduced in 1948 and were widely prescribed by dermatologists in the early 1950s for treatment of acne. More recently, biologic actions of tetracyclines affecting inflammation, angiogenesis, and bone metabolism have been researched. The therapeutic effects of tetracycline and its analogues in rheumatic diseases have also been investigated. This article will review the rheumatological use of tetracycline and its analogues.

Minocycline attenuates HIV infection and reactivation by suppressing cellular activation in human CD4+ T cells

Treatment of human immunodeficiency virus (HIV) infection with highly active antiretroviral therapy (HAART) is effective but can be associated with toxic effects and is expensive. Other options may be useful for long-term therapy. The immunomodulatory antibiotic minocycline could be an effective, low-cost adjunctive treatment to HAART. Minocycline mediated a dose-dependent decrease in single-cycle CXCR4-tropic HIV infection and decreased viral RNA after infection of CD4+ T cells with HIV NL4-3. Reactivation from latency was also decreased in a primary CD4+ T cell-derived model and in resting CD4+ T cells from HIV-infected patients. Minocycline treatment resulted in significant changes in activation marker expression and inhibited proliferation and cytokine secretion of CD4+ T cells in response to activation. This study demonstrates that minocycline reduces HIV replication and reactivation and decreases CD4+ T cell activation. The anti-HIV effects of minocycline are mediated by altering the cellular environment rather than directly targeting virus, placing minocycline in the class of anticellular anti-HIV drugs.

Update on the management of antibiotic allergy

Drug allergy to antibiotics may occur in the form of immediate or non-immediate (delayed) hypersensitivity reactions. Immediate reactions are usually IgE-mediated whereas non-immediate hypersensitivity reactions are usually non-IgE or T-cell mediated. The clinical manifestations of antibiotic allergy may be cutaneous, organ-specific (e.g., blood dyscracias, hepatitis, interstitial nephritis), systemic (e.g., anaphylaxis, drug induced hypersensitivity syndrome) or various combinations of these. Severe cutaneous adverse reactions manifesting as Stevens Johnson syndrome or toxic epidermal necrolysis (TEN) may be potentially life-threatening. The management of antibiotic allergy begins with the identification of the putative antibiotic from a detailed and accurate drug history, complemented by validated in-vivo and in-vitro allergological tests. This will facilitate avoidance of the putative antibiotic through patient education, use of drug alert cards, and electronic medical records with in-built drug allergy/adverse drug reaction prescription and dispensing checks. Knowledge of the evidence for specific antibiotic cross-reactivities is also important in patient education. Apart from withdrawal of the putative antibiotic, immunomodulatory agents like high-dose intravenous immunoglobulins may have a role in TEN. Drug desensitization where the benefits outweigh the risks, and where no alternative antibiotics can be used for various reasons, may be considered in certain situations. Allergological issues pertaining to electronic drug allergy alerts, computerized physician prescriptions and decision support systems, and antibiotic de-escalation in antimicrobial stewardship programmes are also discussed.

Comparison of adverse events between oral and intravenous formulations of antimicrobial agents: a systematic review of the evidence from randomized trials

BACKGROUND

Some clinicians may favor a strategy of early switch to oral antimicrobial therapy for patients responding to initial intravenous therapy. An important relevant consideration refers to the comparative safety and tolerability between oral and intravenous antimicrobial therapy. LITERATURE SEARCH/STUDY SELECTION: We sought to evaluate the above-mentioned issue by performing a systematic review of randomized studies comparing the occurrence of adverse events between oral and intravenous antimicrobial therapy with the same agents.

FINDINGS

Ten relevant studies (five randomized controlled trials, three randomized cross-over studies, and two randomized, placebo-controlled, parallel-design studies) were included. Seven of the studies evaluated antibacterials (fluoroquinolones in four, and telithromycin, amoxicillin-clavulanic acid, and linezolid in one study each, respectively), whereas two studies evaluated ganciclovir, and one evaluated isavuconazole. No difference was observed in the rate of total adverse events between oral and intravenous administration of the same antimicrobial agents in any of the included studies that reported specific relevant data. Injection site reactions were noted more frequently with intravenous treatment in one study. No serious drug-related adverse events were reported, while study withdrawals due to adverse events did not considerably differ between the compared groups in any of the included studies.

CONCLUSION

There are only limited comparative data regarding the adverse events associated with the administration of the same antimicrobial agents by the oral and intravenous route. Our review indicates that the adverse event profile of oral and intravenous antimicrobial therapy does not differ considerably; however, this issue requires validation by further studies.

Differential activation of spinal microglial and astroglial cells in a mouse model of peripheral neuropathic pain

The pharmacological attenuation of glial activation represents a novel approach for controlling neuropathic pain, but the role of microglial and astroglial cells is not well established. To better understand the potential role of two types of glial cells, microglia and astrocytes, in the pathogenesis of neuropathic pain, we examined markers associated with them by quantitative RT-PCR, western blot and immunohistochemical analyses in the dorsal horn of the lumbar spinal cord 7days after chronic constriction injury (CCI) to the sciatic nerve in mice. The mRNA and protein of microglial cells were labeled with C1q and OX42(CD11b/c), respectively. The mRNA and protein of astrocytes were labeled with GFAP. The RT-PCR results indicated an increase in C1q mRNA that was more pronounced than the increased expression of GFAP mRNA ipsilateral to the injury in the dorsal spinal cord. Similarly, western blot and immunohistochemical analyses demonstrated an ipsilateral upregulation of OX42-positive cells (72 and 20%, respectively) and no or little (8% upregulation) change in GFAP-positive cells in the ipsilateral dorsal lumbar spinal cord. We also found that chronic intraperitoneal injection of the minocycline (microglial inhibitor) and pentoxifylline (cytokine inhibitor) attenuated CCI-induced activation of microglia, and both, but not fluorocitrate (astroglial inhibitor), diminished neuropathic pain symptoms and tactile and cold sensitivity. Our findings indicate that spinal microglia are more activated than astrocytes in peripheral injury-induced neuropathic pain. These findings implicate a glial regulation of the pain response and suggest that pharmacologically targeting microglia could effectively prevent clinical pain syndromes in programmed and/or anticipated injury.

Safety and efficacy of doxycycline in the treatment of rosacea

Rosacea is a common, chronic, skin condition characterized by recurrent episodes of facial flushing, transient or persistent erythema, papules, pustules, and telangiectasias, in a symmetrical facial distribution. The etiology of rosacea remains unknown and this condition represents a therapeutic challenge because of its chronic nature, progression, potential for disfigurement and psychological impact. Although there is no curative therapy for rosacea, the most widely used systemic agents are oral tetracycline derivatives, including tetracycline, doxycycline, and minocycline. This article reviews the available evidence for the use of doxycycline, a second-generation tetracycline, in the treatment or rosacea.

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.

Doxycycline is neuroprotective against nigral dopaminergic degeneration by a dual mechanism involving MMP-3

In Parkinson disease (PD), the dopaminergic (DAergic) neurons in the substantia nigra undergo degeneration. While the exact mechanism for the degeneration is still not completely understood, neuronal apoptosis and inflammation are thought to play roles. We have recently obtained evidence that matrix metalloproteinase (MMP)-3 plays a crucial role in the apoptotic signal in DAergic cells as well as activation of microglia. The present study tested whether doxycycline might modulate MMP-3 and provide neuroprotection of DAergic neurons. Doxycycline effectively suppressed the expression of MMP-3 induced in response to cellular stress in the DAergic CATH.a cells. This was accompanied by protection of CATH.a cells as well as primary cultured mesencephalic DAergic neurons via attenuation of apoptosis. The active form of MMP-3, released under the cell stress condition, was also decreased in the presence of doxycycline. In addition, doxycycline led to downregulation of MMP-3 in microglial BV-2 cells exposed to lipopolysaccharide (LPS). This was accompanied by suppression of production of nitric oxide and TNF-alpha, as well as gene expression of iNOS, TNF-alpha, IL-1beta, and COX-2. In vivo, doxycycline provided neuroprotection of the nigral DAergic neurons following MPTP treatment, as assessed by tyrosine hydroxylase immunocytochemistry and silver staining, and suppressed microglial activation and astrogliosis as assessed by Iba-1 and GFAP immunochemistry, respectively. Taken together, doxycycline showed neuroprotective effect on DAergic system both in vitro and in vivo and this appeared to derive from anti-apoptotic and anti-inflammatory mechanisms involving downregulation of MMP-3.

Safety and Efficacy Review of Doxycycline

Doxycycline is a member of the tetracycline class of antibiotics and has been used clinically for more than 40 years. It is a well-tolerated drug that is bacteriostatic and acts via the inhibition of bacterial ribosomes. It is generally given at a dose of 100-mg daily or twice daily. It is well absorbed and has generally good tissue penetration. The serum half-life is 18-22 hours and dosage does not need to be adjusted in the presence of renal or hepatic impairment. Major side effects are gastro-intestinal and dermatological and it is generally contra-indicated in pregnancy or childhood because of concerns about discolouration of developing teeth and potential effects on growing bones. Drug interactions are not common although can occur with the concomitant use of methotrexate and the oral contraceptive pill, and its absorption can be reduced by the co-administration with some antacids and iron preparations. It has activity against many organisms, including Gram-positives, Gram-negatives and atypical bacteria. In addition, it appears to have some potentially clinically useful anti-inflammatory properties.

Clinical trial of doxycycline for matrix metalloproteinase-9 inhibition in patients with an abdominal aneurysm: doxycycline selectively depletes aortic wall neutrophils and cytotoxic T cells

BACKGROUND

Doxycycline has been shown to effectively inhibit aneurysm formation in animal models of abdominal aortic aneurysm. Although this effect is ascribed to matrix metalloproteinase-9 inhibition, such an effect is unclear in human studies. We reevaluated the effect of doxycycline on aortic wall protease content in a clinical trial and found that doxycycline selectively reduces neutrophil-derived proteases. We thus hypothesized that doxycycline acts through an effect on vascular inflammation.

METHODS AND RESULTS

Sixty patients scheduled for elective open aneurysmal repair were randomly assigned to 2 weeks of low-, medium-, or high-dose doxycycline (50, 100, or 300 mg/d, respectively) or no medication (control group). Aortic wall samples were collected at the time of operation, and the effect of doxycycline treatment on vascular inflammation was evaluated. Independently of its dose, doxycycline treatment resulted in a profound but selective suppression of aortic wall inflammation as reflected by a selective 72% reduction of the aortic wall neutrophils and a 95% reduction of the aortic wall cytotoxic T-cell content (median values; P<0.00003). Evaluation of major inflammatory pathways suggested that doxycycline treatment specifically quenched AP-1 and C/EBP proinflammatory transcription pathways (P<0.0158, NS) and reduced vascular interleukin-6 (P<0.00115), interleukin-8 (P<0.00246, NS), interleukin-13 (P<0.0184, NS), and granulocyte colony-stimulating factor (P<0.031, NS) protein levels. Doxycycline was well tolerated; there were no adverse effects.

CONCLUSIONS

A brief period of doxycycline treatment has a profound but selective effect on vascular inflammation and reduces aortic wall neutrophil and cytotoxic T-cell content. Results of this study are relevant for pharmaceutical stabilization of the abdominal aneurysm and possibly for other inflammatory conditions that involve neutrophils and/or cytotoxic T cells.

Information about ADRs explored by pharmacovigilance approaches: a qualitative review of studies on antibiotics, SSRIs and NSAIDs

Background

Despite surveillance efforts, unexpected and serious adverse drug reactions (ADRs) repeatedly occur after marketing. The aim of this article is to analyse ADRs reported by available ADR signal detection approaches and to explore which information about new and unexpected ADRs these approaches have detected.

Methods

We selected three therapeutic cases for the review: antibiotics for systemic use, non-steroidal anti-inflammatory medicines (NSAID) and selective serotonin re-uptake inhibitors (SSRI). These groups are widely used and represent different therapeutic classes of medicines. The ADR studies were identified through literature search in Medline and Embase. The search was conducted in July 2007. For each therapeutic case, we analysed the time of publication, the strengths of the evidence of safety in the different approaches, reported ADRs and whether the studies have produced new information about ADRs compared to the information available at the time of marketing.

Results

79 studies were eligible for inclusion in the analysis: 23 antibiotics studies, 35 NSAID studies, 20 SSRI studies. Studies were mainly published from the end of the 1990s and onwards. Although the drugs were launched in different decades, both analytical and observational approaches to ADR studies were similar for all three therapeutic cases: antibiotics, NSAIDs and SSRIs. The studies primarily dealt with analyses of ADRs of the type A and B and to a lesser extent C and D, cf. Rawlins' classification system. The therapeutic cases provided similar results with regard to detecting information about new ADRs despite different time periods and organs attacked. Approaches ranging higher in the evidence hierarchy provided information about risks of already known or expected ADRs, while information about new and previously unknown ADRs was only detected by case reports, the lowest ranking approach in the evidence hierarchy.

Conclusion

Although the medicines were launched in different decades, approaches to the ADR studies were similar for all three therapeutic cases: antibiotics, NSAIDs and SSRIs. Both descriptive and analytical designs were applied. Despite the fact that analytical studies rank higher in the evidence hierarchy, only the lower ranking descriptive case reports/spontaneous reports provided information about new and previously undetected ADRs. This review underscores the importance of systems for spontaneous reporting of ADRs. Therefore, spontaneous reporting should be encouraged further and the information in ADR databases should continuously be subjected to systematic analysis.

Efficacy of topical azithromycin ophthalmic solution 1% in the treatment of posterior blepharitis

INTRODUCTION

Azithromycin, a broad-spectrum antibiotic with potent anti-inflammatory activities, has the potential to effectively treat blepharitis, an inflammatory disease of the eyelid with abnormal eyelid flora as an etiologic determinant. The present study compared the efficacy of topical azithromycin ophthalmic solution 1% (AzaSite; Inspire Pharmaceuticals, Inc, NC, USA) combined with warm compresses (azithromycin group) to warm compresses alone (compress group) in patients with posterior blepharitis.

METHODS

Twenty-one patients diagnosed with posterior blepharitis were randomized in an open-label study to receive either azithromycin plus warm compresses (10 patients), or compresses alone (11 patients). All patients were instructed to apply compresses to each eye for 5-10 minutes twice daily for 14 days. Each eye in the azithromycin group also received azithromycin solution (1 drop) twice daily for the first 2 days followed by once daily for the next 12 days. Patients were evaluated at study initiation (visit 1) and at end of treatment (visit 2) for the severity of five clinical signs: eyelid debris, eyelid redness, eyelid swelling, meibomian gland (MG) plugging, and the quality of MG secretion. At visit 2, patients also rated their degree of overall symptomatic relief.

RESULTS

Twenty patients completed the study. At visit 2, patients in the azithromycin group demonstrated significant improvements in MG plugging, MG secretions, and eyelid redness as compared with the compress group. In the azithromycin group, MG plugging resolved completely in three patients and MG secretion returned to normal in two patients; no such results were seen in the compress group. Furthermore, a higher percentage of patients in the azithromycin group rated overall symptomatic relief as excellent or good. Visual acuity measurements and biomicroscopic evaluation revealed no ocular safety issues.

CONCLUSION

Azithromycin ophthalmic solution in combination with warm compresses provided a significantly greater clinical benefit than warm compresses alone in treating the signs and symptoms of posterior blepharitis.

Feasibility of minocycline and doxycycline use as potential vasculostatic therapy for brain vascular malformations: pilot study of adverse events and tolerance

BACKGROUND

Tetracyclines may be useful in preventing pathological vascular remodeling, thus decreasing the risk of spontaneous hemorrhage from brain vascular malformations.

METHODS

Arteriovenous malformation (AVM) and intracranial aneurysm patients undergoing noninvasive management were treated with minocycline or doxycycline (200 mg/day) up to 2 years in a prospective open-label safety pilot trial. The primary outcome was to compare dose-limiting intolerance, defined as treatment-related dose reduction or withdrawal between the agents.

RESULTS

Twenty-six patients with AVMs (n = 12) or aneurysms (n = 14) were recruited. Adverse event rates were similar to other reported trials of these agents; 4 of 13 (31%) minocycline and 3 of 13 (23%) doxycycline patients had dose-limiting intolerance (hazard ratio = 3.1, 95% CI = 0.52-18.11, log rank p = 0.70).

CONCLUSIONS

It is feasible to propose a long-term trial to assess the potential benefit of tetracycline therapy to decrease hemorrhagic risk in brain vascular malformations.

Minocycline attenuates hyperlocomotion and prepulse inhibition deficits in mice after administration of the NMDA receptor antagonist dizocilpine

The present study was undertaken to examine whether the second generation antibiotic drug minocycline attenuates behavioral changes (eg, acute hyperlocomotion and prepulse inhibition (PPI) deficits) in mice after the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist (+)-MK-801 (dizocilpine). Dizocilpine (0.1 mg/kg)-induced hyperlocomotion was significantly attenuated by pretreatment with minocycline (40 mg/kg). Furthermore, the PPI deficits after a single administration of dizocilpine (0.1 mg/kg) were attenuated by pretreatment with minocycline (10, 20, or 40 mg/kg), in a dose-dependent manner. Moreover, in vivo microdialysis study in the free-moving mice revealed that pretreatment with minocycline (40 mg/kg, i.p.) significantly attenuated the increase of extracellular dopamine (DA) levels in the frontal cortex and striatum after administration of dizocilpine (0.1 mg/kg), suggesting that the inhibition of dizocilpine-induced DA release by minocycline may, at least in part, be implicated in the mechanism of action of minocycline with respect to dizocilpine-induced behavioral changes in mice. These findings suggest that minocycline could attenuate behavioral changes in mice after the administration of the NMDA receptor antagonist dizocilpine. Therefore, it is possible that minocycline would be a potential therapeutic drug for schizophrenia.

Protective effects of minocycline on the reduction of dopamine transporters in the striatum after administration of methamphetamine: a positron emission tomography study in conscious monkeys

BACKGROUND

Positron emission tomography (PET) studies of methamphetamine (METH) abusers suggest that psychotic symptoms of METH abusers may be attributable to the reduction of dopamine transporters (DAT) in the human brain. However, there are currently no particular pharmacological treatments for the wide range of symptoms associated with METH abuse.

METHODS

Using a PET study in conscious monkeys, we investigated whether the second generation antibiotic minocycline could protect against the reduction of DAT in monkeys treated with METH (2 mg/kg x 3, 3-hour intervals).

RESULTS

Pretreatment and subsequent administration of minocycline significantly attenuated the reduction of DAT in the striatum of monkeys treated with METH. Furthermore, posttreatment and subsequent administration of minocycline also significantly attenuated the reduction of DAT. In contrast, repeated administration of minocycline alone did not alter the density of DAT in the striatum of monkeys treated with METH.

CONCLUSIONS

Our findings suggest that minocycline protects against METH-induced neurotoxicity in the monkey brain. Therefore, minocycline is likely to be a promising therapeutic agent for the treatment of several symptoms associated with METH use in humans.