Comparison of combined azelaic acid cream plus oral minocycline with oral isotretinoin in severe acne.

BACKGROUND/AIMS: The primary aim of the study was to establish the clinical efficacy and safety of a combined treatment consisting of topical 20% azelaic acid (AA) cream and the oral antibiotic minocycline in the therapy of severe inflammatory acne (nodular papulopustular acne and acne conglobata) in a comparison with oral isotretinoin therapy. The secondary aim was to establish the value of AA cream as maintenance therapy in the prevention of recurrent acne. METHODS: This open-label but randomised study involved 85 patients with nodular papulopustular acne or acne conglobata (Leeds grading scale > 4) who were treated for 6 months. In an immediately subsequent 3-month second phase, eligible patients from the initial combination group used the AA cream as maintenance therapy, while the eligible patients from the isotretinoin group served as untreated control. RESULTS: A 6-month course of treatment with topical 20% AA cream plus oral minocycline in 50 patients proved to be effective in nodular forms of acne (median reduction of facial comedones: 70%; of papules and pustules: 88%; of deep inflammatory acne lesions: 100%). Overall, the combined treatment was not quite as effective as treatment with oral isotretinoin (35 patients; reduction of comedones: 83%; of papules and pustules: 97%; of deep inflammatory acne lesions: 100%). In the 3-month maintenance therapy phase, about half of the patients who received AA monotherapy maintained the very good facial result achieved by the end of phase I. A similar rate was found in the patients of the isotretinoin group, who received no further active acne treatment. In the other 50% of patients, differences existed between the groups as regards the degree of deterioration: Marked deterioration occurred more frequently under AA treatment, while only slight deterioration was more frequent in the isotretinoin group. The combination was tolerated much better than isotretinoin. The incidence of local side effects observed under the combination of AA and minocycline (36.5%, mainly transient burning and itching of mild or moderate intensity) was considerably lower than that seen with isotretinoin (65.7%). The rate of local side effects of marked intensity observed under the combination, i.e. 6%, was well within the range of 5-10% previously reported for AA. The incidence of systemic side effects was lower (8%, mainly gastrointestinal symptoms) under the combined therapy than under isotretinoin (14.3%). CONCLUSION: The combination of topical 20% AA cream and oral minocycline is an highly effective treatment in severe forms of acne. It is better tolerated and associated with fewer risks than oral isotretinoin - in particular, there is no risk of teratogenicity. The combination can be regarded as a valuable alternative in patients for whom isotretinoin is not indicated, who do not wish to use or can not tolerate isotretinoin therapy and particularly in female acne patients of child-bearing potential. Topical 20% AA cream can be used successfully as maintenance therapy to prolong the recurrence-free interval.

Double-blind comparison of azelaic acid 20% cream and its vehicle in treatment of papulo-pustular rosacea.

Previous investigations have indicated that topical azelaic acid has beneficial effects in rosacea. This 3-month randomized, double-blind, multicentre study compared the efficacy and safety of azelaic acid 20% cream with its vehicle, in the treatment of papulo-pustular rosacea. A total of 116 patients were enrolled in the study and medication was applied twice daily. Azelaic acid cream produced significantly greater mean reductions in total inflammatory lesions than did vehicle (azelaic acid: 73.4%; vehicle: 50.6%; (p = 0.011), and erythema severity score (azelaic acid: 47.9%; vehicle: 37.9%; (p = 0.031). Azelaic acid cream treatment also resulted in significantly more favourable overall improvements than vehicle in both physician (p = 0.020) and patient ratings (p = 0.042). Neither azelaic acid cream nor vehicle produced any clinically relevant improvement in telangiectasia. Local adverse events were transient and mainly mild or moderate, and rates were similar for azelaic acid cream (39.5%) and vehicle (38.5%). Burning was the symptom most frequently reported. More than 90% of patients rated the overall local tolerability of their treatment as good or acceptable. In conclusion, azelaic acid 20% cream is effective and well tolerated in the treatment of papulo-pustular rosacea.

Resistance to nondepolarizing neuromuscular blocking agents.

Several case reports of resistance to short-term administration of nondepolarizing neuromuscular blocking agents (NNMBAs) have been reported in research and surgical settings. Recently, several reports documented resistance to NNMBAs during therapy for prolonged paralysis in critically ill patients. Adverse outcomes associated with NNMBA resistance may include inadequate ventilatory management or suppression of patient movement, and an increased risk of dose-dependent cardiovascular adverse effects. Pharmacoeconomic issues must be considered in that the cost of NNMBA therapy in a resistant patient may be significant. Although the specific etiologies of resistance are not clear, several pharmacodynamic and pharmacokinetic alterations may occur as a consequence of disease state or concomitant drug therapy. Pharmacodynamic changes include altered acetylcholine receptor physiology or sensitivity, inhibition of serum cholinesterase activity, and interaction with plasma constituents. Alterations in distribution volume, protein binding, and clearance may also contribute to resistance in several disease states.

Efficacy and safety of topical azelaic acid (20 percent cream): an overview of results from European clinical trials and experimental reports.

Azelaic acid cream (20 percent) is a new topical treatment for acne with an additional therapeutic potential in rosacea and hyperpigmentation disorders. Azelaic acid (AzA; HOOC-(CH2)7-COOH) is a naturally occurring compound that interferes with acne pathogenesis by virtue of its antikeratinizing, antibacterial, and anti-inflammatory properties. Vehicle-controlled studies have verified that AzA exercises a significant and clinically relevant effect on both non-inflammatory and inflammatory acne lesions. Comparisons with clinically proven therapies have shown that 20 percent AzA cream is an effective monotherapy in mild to moderate forms of acne, with an overall efficacy comparable to that of tretinoin (0.05 percent), benzoyl peroxide (5 percent), and topical erythromycin (2 percent). In the treatment of moderate to severe acne, 20 percent AzA cream may be favorably combined with minocycline (90 percent good and excellent results), and may contribute towards reducing recurrences following discontinuation of systemic therapy (maintenance therapy with AzA cream). Particular advantages of AzA therapy include its favorable safety and side effect profile. It is non-teratogenic, is not associated with systemic adverse events or photodynamic reactions, exhibits excellent local tolerability, and does not induce resistance in Propionibacterium acnes.

Follicular concentrations of azelaic acid after a single topical application.

Follicular concentrations of azelaic acid (AzA) were determined in vivo using a rapid, non-invasive method, after a single topical application of 20% (w/w) AzA cream, in order to establish whether the in vitro antimicrobial effects observed in previous studies are relevant in vivo. Preweighed amounts of 20% (w/w) AzA cream were applied over demarcated areas on the forehead and back of nine young adults, and samples were taken over a period of 5 h. AzA was removed from the skin surface by washing with acetone, and follicular casts were collected using cyanacrylate gel. The samples were centrifuged to remove particulate matter, and the supernatants derivatized for analysis by HPLC. Although the results showed wide-ranging variability, the follicular concentration increased as the amount present on the surface declined. The maximum follicular concentrations of AzA attained ranged from 7.5 to 52.5 ng (micrograms of follicular casts)-1 and 0.5 to 23.4 ng (micrograms of follicular casts)-1 in samples taken from the back and forehead, respectively. Assuming an average density of follicular material of 0.9 g ml-1, the mean maximum follicular concentration attained on the back was between 36 and 251 mmol/l, and on the forehead was between 2 and 112 mmol/l, and indicates that the concentration of AzA attained in follicular casts after a single topical application is comparable with the concentration required to inhibit the growth of Propionibacterium acnes and Staphylococcus epidermidis, in vitro.

The treatment of melasma. 20% azelaic acid versus 4% hydroquinone cream.

The efficacy of 20% azelaic acid cream and 4% hydroquinone cream, both used in conjunction with a broad-spectrum sunscreen, against melasma was investigated in a 24-week, double-blind study with 329 women. Over the treatment period the azelaic acid cream yielded 65% good or excellent results; no significant treatment differences were observed with regard to overall rating, reduction in lesion size, and pigmentary intensity. Severe side effects such as allergic sensitization or exogenous ochronosis were not observed with azelaic acid.

Interaction between catalytic and regulatory sites of the pyruvate dehydrogenase from Escherichia coli studied by the ESR technique.

The accessibility of sulfhydryl groups at the pyruvate dehydrogenase component of the pyruvate dehydrogenase multienzyme complex from Escherichia coli was reinvestigated. Hydrophobic interactions appear to control the reactivity of an essential cysteine residue at the active site with thiol reagents. This explains why the essential cysteine residue reacts only with thiol reagents of minor polarity, like p-hydroxymercuribenzoate or phenylmercuric nitrate, but not with Ellman's reagent or jodoacetamide. The pyruvate dehydrogenase component was modified with a nitroxide derivative of p-hydroxymercuribenzoate. The ESR spectrum of the spin-labelled enzyme changed dramatically upon addition of the cofactors thiamine diphosphate and Mg2+. Obviously spin-spin interaction occurs under these conditions caused by a transition of an inactive to an active state of the enzyme. The same conformational change is observed when the allosteric activator AMP instead of the cofactors was bound to the enzyme. The implications of these results for the allosteric regulation of the pyruvate dehydrogenase complex are discussed.

Clinical studies of 20% azelaic acid cream in the treatment of acne vulgaris. Comparison with vehicle and topical tretinoin.

20% azelaic acid cream was compared clinically with it vehicle in a 3-month double-blind study of 92 patients with moderate inflammatory acne. In a single-blind study of 289 patients with comedonal acne, the topical azelaic acid preparation was compared with 0.05% tretinoin cream over a period of 6 months. In both controlled studies, 20% azelaic acid cream significantly reduced the number of acne lesions and yielded clinically relevant improvement rates. Azelaic acid cream was significantly and substantially more effective than its vehicle, indicating that the dicarboxylic acid itself is an active drug in acne treatment. In the study of comedonal acne, 20% azelaic acid cream was equally effective as 0.05% tretinoin cream in reducing the number of comedones and with respect to overall response. However, azelaic acid cream was better tolerated, causing fewer local side effects than the topical retinoid.

Double-blind comparison of azelaic acid and hydroquinone in the treatment of melasma.

Melasma is a macular hypermelanosis of the sun-exposed areas of the face and neck. The clinical efficacy of azelaic acid (20%) and hydroquinone creams (2%) in the treatment of this benign pigmentary disorder was compared in a randomized, double-blind study with 155 patients of Indo-Malay-Hispanic origin. The creams were applied twice daily. A broad spectrum sunscreen was used concomitantly. Over a period of 24 weeks, 73% of the azelaic acid patients, compared with 19% of the hydroquinone patients, had good to excellent overall results, as measured by the reduction of melasma pigmentary intensity and lesion size. Transient mild to moderate irritant reactions were initially seen with both test drugs.

Topographical analysis of proliferation ([3H]thymidine labelling index and mitotic index) as compared with tumour growth and tumour weight in xenotransplanted melanoma. Changes due to local and systemic application of azelaic acid.

Xenotransplanted human melanoma was investigated by measuring the increase in tumour volume and in final tumour weight (macroscopical parameters) and histomorphological parameters of cell proliferation: Mitotic index (MI) and autoradiographic [3H]thymidine labelling index (LI). A total of 87 tumours, derived from a human melanoma metastasis and a primary nodular melanoma respectively, were analysed by these methods in two series. Topical treatment of the tumours with azelaic acid cream resulted in a statistically significant reduction in the increase in tumour volume and, in the first series, in a clear decrease in final tumour weight and in the MI, as compared with controls. The LI was decreased only in the superficial region of the tumours, i.e. at the site of treatment. Subtumoral injection of azelaic acid (disodium salt solution) was the second route of local therapy. It was followed by a significant reduction in the increase in tumour volume, of final tumour weight (first series) and in the MI. The average LI was clearly smaller than in the controls, especially at the tumour base, which was the site of injection (local effect). Systemic (intravenous) injection of azelaic acid (same concentration of the disodium salt solution) had no negative effect on the increase in tumour volume or final tumour weight, but was followed by a clear reduction of the MI. The average LI of this group was significantly smaller than in the controls as well. This effect was most impressive in the perivascular regions of large and small vessels, which fact can be interpreted as a sort of local effect via the blood stream after systemic application of azelaic acid.(ABSTRACT TRUNCATED AT 250 WORDS)