Liver damage associated with minocycline use in acne: a systematic review of the published literature and pharmacovigilance data

[Minocycline-induced neutrophilic alveolitis?]

A 53-year-old man was treated for hypoxic pneumonia. Alveolar lavage revealed neutrophilic alveolitis and search for an infectious agent was negative. Lung biopsy revealed discrete endo-alveolar edema and polymorphous infiltration in moderately thickened alveolar walls. After 17 days, an ineffective antibiotic regimen was replaced by corticosteroids. Clinical and radiological signs improved in a few days and pneumonia did not recur after corticosteroid withdrawal. The most likely causal agent was minocycline which the patient had received for two Years for the treatment of rhinophyma. Minocycline had been interrupted several weeks when the pulmonary disorder developed after re-introduction of minocycline. Different clinical manifestations of minocycline-induced lung disease have been described including eosinophilic pneumopathy, bronchiolitis obliterans with organized pneumonitis, and hypersensitivity pneumonitis. There has only been one report of polymorphonuclear neutrophils observed in the lavage fluid.

Antibiotics in cutaneous medicine: an update

Antibiotics play a vital role in contemporary cutaneous medicine and surgery. They are prescribed more commonly than perhaps any other group of medications with the exception of the corticosteroids. This review discusses the major oral antibacterial agents used in dermatology today, including the beta-lactams, macrolides, tetracyclines, quinolones, sulfonamides, clindamycin, and rifampin.

Minocycline for acne vulgaris: efficacy and safety

BACKGROUND

Minocycline is a tetracycline antibiotic that is commonly used in the treatment of moderate to severe acne vulgaris. Although it is more convenient for patients to take than first-generation tetracyclines, as it only needs to be taken once or twice a day and can be taken with food, it is more expensive. Concerns have also been expressed over its safety following the deaths of two patients taking the drug. There is a lack of consensus among dermatologists over the relative risks and benefits of minocycline. As most acne prescribing is undertaken by general practitioners, it is important that guidelines issued to them are based on the best available evidence rather than personal judgements.

OBJECTIVES

To collate and evaluate the evidence on the clinical efficacy of minocycline in the treatment of inflammatory acne vulgaris. Specific objectives were to compare the efficacy of minocycline with other drug treatments for acne and to collate information on the incidence of adverse drug reactions.

SEARCH STRATEGY

Randomised controlled trials (RCTs) of minocycline for acne vulgaris were identified by searching the following electronic databases; MEDLINE, EMBASE, Biosis, Biological Abstracts, International Pharmaceutical Abstracts, Cochrane Skin Group's Trial Register, Theses Online, BIDS ISI Science Citation Index, National Research Register, Current Controlled Trials and Bids Index to Scientific and Technical Proceedings. Other strategies used were scanning the references of articles retrieved, hand-searching of major dermatology journals and personal communication with trialists and drug companies.

SELECTION CRITERIA

To be eligible for the review, studies had to be RCTs comparing the efficacy of minocycline at any dose to active or placebo control, in subjects with inflammatory acne vulgaris. Diagnoses of papulo-pustular, polymorphic and nodular acne were also accepted. Trials were not excluded on the basis of language.

DATA COLLECTION AND ANALYSIS

27 randomised controlled trials met the inclusion criteria and were included in this review. The comparators used were placebo (2 studies), oxytetracycline (1), tetracycline (6), doxycycline (7), lymecycline (2), topical clindamycin (3), topical erythromycin/zinc (1), cyproterone acetate/ ethinyloestradiol (1), oral isotretinoin (2), topical fusidic acid (1) and there was one dose response study. Two studies are ongoing and it remains to be clarified whether one further study is a RCT. Major outcome measures used in the trials included lesion counts, acne grades/severity scores, doctors' and patients' global assessments, adverse drug reactions and drop out rates. The quality of each study was assessed independently by two assessors and an effect size calculated where possible. An additional three RCTs and three safety studies were identified by searches conducted in November 2002; these will be reviewed for a major update in early 2003 when it is anticipated that the results of the two ongoing studies will be available.

MAIN RESULTS

The trials were generally small and of poor quality and in many cases the published reports were inadequate for our purpose. Pooling of the studies was not attempted due to the lack of common outcome measures and endpoints and the unavailability of some primary data. Although minocycline was shown to be an effective treatment for acne vulgaris, in only two studies was it found to be superior to other tetracyclines. Both of these were conducted under open conditions and had serious methodological problems. A third study showed it to be more effective than 2% fusidic acid, applied topically, against inflammatory lesions in mild to moderate acne. Differences in the way adverse drug reactions were identified could have accounted for the wide variation between studies in numbers of events reported. This meant that no overall evaluation could be made of incidence rates of adverse events associated with minocycline therapy. No RCT evidence was found to support the benefits of minocycline in acne resistant to other therapies and the dose response has only been evaluated up to eight weeks of therapy.

REVIEWER'S CONCLUSIONS

Minocycline is likely to be an effective treatment for moderate acne vulgaris, but this review found no reliable RCT evidence to justify its continued use first-line, especially given the price differential and the concerns that still remain about its safety. Its efficacy relative to other acne therapies could not be reliably determined due to the poor methodological quality of the trials and lack of consistent choice of outcome measures. Similarly the relative risk of adverse drug reactions could not be ascertained reliably and no recommendations can be made concerning the appropriate dose that should be used. It is hoped that this review will highlight the inadequacy of acne trials in general and encourage improvements in methodological quality and standards of reporting.

Is antibiotic resistance in cutaneous propionibacteria clinically relevant? : implications of resistance for acne patients and prescribers

It is well recognized that some patients with acne do not respond adequately to antibiotic therapy. It is important to distinguish antibiotic recalcitrant acne which we would suggest represents acne that shows a diminished response to treatment irrespective of the cause as opposed to 'antibiotic-resistant acne' which is acne that is less responsive to treatment as a direct consequence of skin colonization with resistant propionibacteria. Here we show that antibiotic-resistant acne is not just a theoretical possibility but a real phenomenon that could have important consequences for patients and prescribers. The relationship between skin colonization by antibiotic-resistant propionibacteria and treatment outcomes is a complex one that is explained at the follicular level by physiological differences affecting local drug concentrations. A systematic review of the literature on antibiotic-resistant propionibacteria revealed methodological shortcomings in studies of their prevalence and a paucity of evidence on their clinical significance. Despite the elucidation of resistance mechanisms in cutaneous propionibacteria, our continuing inability to distinguish between strains of Propionibacterium acnes means that we still do not fully understand how resistance spreads, although person-to-person transfer is most likely. Finally, we present a decision tree for acne management in an era of prudent antimicrobial prescribing that provides an alternative to existing treatment algorithms by placing topical retinoids and not antibiotics at the cornerstone of acne management.

Immune-mediated drug-induced liver disease

Drug-induced immune-mediated hepatic injury is an adverse immune response against the liver that results in a disease with hepatitic, cholestatic, or mixed clinical features. Drugs such as halothane, tienilic acid, dihydralazine, and anticonvulsants trigger a hepatitic reaction, and drugs such as chlorpromazine, erythromycins, amoxicillin-calvulanic acid, sulfonamides and sulindac trigger a cholestatic or mixed reaction. Unstable metabolites derived from the metabolism of the drug may bind to cellular proteins or macromolecules, leading to a direct toxic effect on hepatocytes. Protein adducts formed in the metabolism of the drug may be recognized by the immune system as neoantigens. Immunocyte activation may then generate autoantibodies and cell-mediated immune responses, which in turn damage the hepatocytes. Cytochromes 450 are the major oxidative catalysts in drug metabolism, and they can form a neoantigen by covalently binding with the drug metabolite that they produce. Autoantibodies that develop are selectively directed against the particular cytochrome isoenzyme that metabolized the parent drug. The hapten hypothesis proposes that the drug metabolite can act as a hapten and can modify the self of the individual by covalently binding to proteins. The danger hypothesis proposes that the immune system only responds to a foreign antigen if the antigen is associated with a danger signal, such as cell stress or cell death. Most clinically overt adverse hepatic events associated with drugs are unpredictable, and they have intermediate (1 to 8 weeks) or long latency (up to 12 months) periods characteristic of hypersensitivity reactions. Immune-mediated drug-induced liver disease nearly always disappears or becomes quiescent when the drug is removed. Methyldopa, minocycline, and nitrofurantoin can produce a chronic hepatitis resembling AIH if the drug is continued.

The risk of liver damage associated with minocycline: a comparative study

Using the General Practice Research Database, the authors performed (1) a cohort analysis comparing the incidence of liver dysfunction in new users of minocycline with new users of oxytetracycline/tetracycline and (2) a case control study assessing antibiotic exposure in new cases of liver dysfunction and controls without liver dysfunction. In new users, the incidence of liver dysfunction in those exposed to minocycline was 1.04 cases/10,000 exposed person months (EPM) and 0.69 cases/10,000 EPM in those exposed to oxytetracycline/tetracycline (relative risk 1.51 [CI95: 0.63, 3.65]). The risk in both groups was greatest in the first month of use. The adjusted odds ratio (ORadj) of liver dysfunction associated with exposure to minocycline compared with nonuse was 2.10 (CI95: 1.30, 3.40); for oxytetracycline/tetracycline, the ORadj was 1.46 (CI95: 0.81, 2.64); and for exposure to erythromycin, the ORadj was 1.64 (CI95: 0.71, 3.80). The authors thus support a weak association between the use of oral antibiotics and liver dysfunction in patients with acne. The risk associated with exposure to minocycline appears to be very small. The cohort analysis demonstrated that any risk associated with minocycline was not significantly greater than that associated with oxytetracycline/tetracycline exposure.