Terbinafine: an update

Relative impact of traditional vs. newer oral antifungals for dermatophyte toenail onychomycosis: a network meta-analysis study

BACKGROUND

There is a paucity of evidence regarding the relative therapeutic efficacy of treatments for onychomycosis.

OBJECTIVES

We determined the relative efficacy of monotherapies for dermatophyte toenail onychomycosis with Bayesian network meta-analyses (NMAs).

METHODS

We searched PubMed, Scopus, EMBASE (Ovid) and CINAHL to identify studies that investigated the efficacy of monotherapy with oral antifungals for dermatophyte toenail onychomycosis in adults. In this paper, 'regimen' corresponds to a given agent and its dosage. The relative effects and surface under the cumulative ranking curve (SUCRA) values of the various regimens were estimated; evidence quality was assessed at the study level and across networks.

RESULTS

Data from 21 studies were used. Our two efficacy-related endpoints were: (i) mycological and (ii) complete cure at 1 year; safety--related endpoints were: (i) 1-year count of any adverse event (AE), (ii) 1-year odds of discontinuation due to any AE, (iii) 1-year odds of discontinuation due to liver issues. Thirty-five regimens were identified; the newer agents among these included posaconazole and oteseconazole. We compared the efficacy of newer regimens with traditional ones like 'terbinafine 250 mg daily for 12 weeks' and 'itraconazole 200 mg daily for 12 weeks. We found that an agent's dosage was associated with its efficacy; for example, the 1-year odds of mycological cure with terbinafine 250 mg daily for 24 weeks (SUCRA = 92.4%) were significantly greater than those of terbinafine 250 mg daily for 12 weeks (SUCRA = 66.3%) (odds ratio 2.62, 95% credible interval 1.57-4.54). We also found that booster regimens can increase efficacy. Our results showed that some triazoles could be more effective than terbinafine.

CONCLUSIONS

This is the first NMA study of monotherapeutic antifungals - and their various dosages - for dermatophyte toenail onychomycosis. Our findings could provide guidance for the selection of the most appropriate antifungal agent, especially amid the growing concerns about terbinafine resistance.

Clinical Manifestations and Management of Terbinafine-Induced Acute Generalized Exanthematous Pustulosis

Background. Acute generalized exanthematous pustulosis (AGEP) is a rare and serious adverse reaction of terbinafine. Understanding AGEP and terbinafine is primarily based on case reports. The purpose is to explore the clinical characteristics of terbinafine-induced AGEP, and to provide reference for clinical diagnosis and treatment. Methods. Case reports and original studies of terbinafine-induced AGEP were retrieved by searching Chinese and English databases from January, 1991, to May 31, 2022. Results. The median age of the 32 patients (17 males and 15 females) was 55 years (range: 6–84). The median time to onset of AGEP is 8 days (range: 1–77) and is usually accompanied by fever (>38°C) and elevated neutrophil levels (>8000/mm3). Four patients (12.5%) had oral mucosal involvement, and 10 patients (31.3%) developed postpustular desquamation. The lesions were mainly distributed in the trunk (43.8%), the whole body (34.4%), and the extremities (53.1%). Skin biopsy revealed subcorneal pustules (65.6%), intraepidermal cavernous pustules (43.8%), necrotic keratinocytes (15.6%), spongy hyperplasia (25.0%), neutrophil exocytosis (34.4%), and papillary dermal edema (40.6%). AGEP resolved completely in all patients at a median time of 12 days (range: 2–90) after discontinuation of terbinafine and symptomatic therapy. Conclusion. Clinicians should be aware that terbinafine-induced AGEP is a rare cutaneous adverse reaction. AGEP usually occurs within 2 weeks after administration and has a good prognosis after discontinuation.

Dehydrative Cross-Coupling for C-N Bond Construction under Transition-Metal-Free Conditions

A transition-metal-free catalytic system was designed to address the dehydrative cross-coupling of unactivated primary/secondary alcohols with amines/amides under environmentally benign conditions. Mg²⁺ and counteranion (PF₆^-) worked synergistically to realize C-OH bond cleavage and concomitant C-N bond formation. A wide range of allylic alcohols and amines/amides were tolerated well in this transformation, which allowed C-N bond construction with high efficiency.

A multicentre, randomised, parallel-group, double-blind, vehicle-controlled and open label versus amorolfine 5% study, to evaluate the efficacy and safety of terbinafine 10% nail lacquer in the treatment of onychomycosis

BACKGROUND

Onychomycosis is a difficult-to-treat fungal nail infection whose treatment can involve systemic or topical antifungal approaches.

OBJECTIVES

To assess the efficacy and safety of terbinafine 10% nail lacquer in distal lateral subungual onychomycosis (DLSO).

PATIENTS/METHODS

Patients with mild-to-moderate DLSO were randomised (3:3:1) to receive double-blind topical terbinafine 10% (n = 406) or its vehicle (n = 410) administered once daily for 4 weeks and then once weekly for 44 weeks, or open-label topical amorolfine 5% (n = 137) for 48 weeks, with a 12-week follow-up period. The primary efficacy endpoint, complete cure rate at Week 60, was a composite of negative potassium hydroxide (KOH) microscopy, negative culture for dermatophytes and no residual clinical involvement of the target big toenail.

RESULTS

Complete cure rates at Week 60 in the terbinafine, vehicle and amorolfine groups were 5.67%, 2.20% and 2.92%, respectively (odds ratio (OR) vs vehicle = 2.68; 95% confidence intervals (CI): 1.22-5.86; p = .0138). Statistically significant differences in responder (negative KOH and negative culture and ≤10% residual clinical involvement) and mycological cure rates (negative KOH and negative culture) at Week 60 were obtained between terbinafine and vehicle. Terbinafine was well-tolerated with no systemic adverse reactions identified; the most common topical adverse reactions were erythema and skin irritation.

CONCLUSIONS

Terbinafine 10% nail lacquer was an effective treatment for mild-to-moderate onychomycosis improving both clinical and mycological criteria compared with vehicle. Furthermore, there may be some benefits compared to the currently available topical agent, amorolfine 5%. Treatment was well-tolerated and safe.

Multistep batch-flow hybrid synthesis of a terbinafine precursor

A three-step batch-flow hybrid process has been developed for an expeditious synthesis of the enynol key intermediate of antifungal terbinafine. This procedure involves consecutive organometallic steps without the necessity of any in-line purification: after a metalation by n-butyllithium, a selective addition of the lithium salt was elaborated followed by a Grignard reaction resulting in a high yield of 6,6-dimethylhept-1-en-4-yn-3-ol. Moreover, as an alternative to tetrahydrofuran, cyclopentyl methyl ether was used as solvent implementing a safe, sustainable, yet selective synthetic process. Even on a laboratory-scale, the optimized batch-flow hybrid process had a theoretical throughput of 41 g/h. Furthermore, the newly developed process provides an efficient synthesis route to the key-intermediate, while making acrolein obsolete, minimizing side-products, and enabling safe and convenient scale-up.

Computationally Assessing the Bioactivation of Drugs by N-Dealkylation

Cytochromes P450 (CYPs) oxidize alkylated amines commonly found in drugs and other biologically active molecules, cleaving them into an amine and an aldehyde. Metabolic studies usually neglect to report or investigate aldehydes, even though they can be toxic. It is assumed that they are efficiently detoxified into carboxylic acids and alcohols. Nevertheless, some aldehydes are reactive and escape detoxification pathways to cause adverse events by forming DNA and protein adducts. Herein, we modeled N-dealkylations that produce both amine and aldehyde metabolites and then predicted the reactivity of the aldehyde. This model used a deep learning approach previously developed by our group to predict other types of drug metabolism. In this study, we trained the model to predict N-dealkylation by human liver microsomes (HLM), finding that including isozyme-specific metabolism data alongside HLM data significantly improved results. The final HLM model accurately predicted the site of N-dealkylation within metabolized substrates (97% top-two and 94% area under the ROC curve). Next, we combined the metabolism, metabolite structure prediction, and previously published reactivity models into a bioactivation model. This combined model predicted the structure of the most likely reactive metabolite of a small validation set of drug-like molecules known to be bioactivated by N-dealkylation. Applying this model to approved and withdrawn medicines, we found that aldehyde metabolites produced from N-dealkylation may explain the hepatotoxicity of several drugs: indinavir, piperacillin, verapamil, and ziprasidone. Our results suggest that N-dealkylation may be an under-appreciated bioactivation pathway, especially in clinical contexts where aldehyde detoxification pathways are inhibited. Moreover, this is the first report of a bioactivation model constructed by combining a metabolism and reactivity model. These results raise hope that more comprehensive models of bioactivation are possible. The model developed in this study is available at http://swami.wustl.edu/xenosite/ .

Novel investigational therapies for onychomycosis: an update

INTRODUCTION

Onychomycosis is an infection of the nail plate that is prevalent among the ageing population. Onychomycosis is difficult to treat with low initial cure rates, high rates of relapse, and reinfection. Present treatment options include oral and topical therapies, with oral therapies yielding better results. However, there has been a greater emphasis on the development of topical antifungal therapies as they have fewer side effects and drug interactions.

AREAS COVERED

This review summarizes new and reformulated drugs. Results from in vitro studies to Phase III clinical trials are discussed. Novel drugs include: the oral azole VT-1161, the topical azole efinaconazole, the benzoxaborole tavaborole, reformulations of terbinafine P-3058 and LI-P, novel inhibitor of succinate dehydrogenase ME1111, and off-label use of tazarotene. Enhanced permeation of the morpholine amorolfine through the nail plate is also discussed using ultraviolet (UV) curable gels, and a fractional CO2 laser.

EXPERT OPINION

Novel topical antifungals and the reformulation of current antifungals have demonstrated marked improvement in nail penetration. Current research has an emphasis on topical therapies due to their minimized risk for adverse effects and higher patient demand. Nevertheless, few topical agents have surfaced in the past few years and the investigation of efficacious combination therapies may become more important.

Oral Terbinafine-Induced Bullous Pemphigoid

OBJECTIVE:

To report a case of drug-induced bullous pemphigoid (BP) in an otherwise healthy elderly patient after taking terbinafine for 20 days.

CASE SUMMARY:

A 78-year-old man presented with distal subungual onychomycosis of the toenails. Oral terbinafine 250 mg/d was started for treatment. Twenty days after the beginning of the treatment, the patient presented with widespread pruritic blistering eruption, more severe on the extremities. He had not received terbinafine before and was not receiving any other drug. The diagnosis of BP was confirmed with histopathologic examination. The patient was treated successfully with oral steroids.

DISCUSSION:

Drug-induced BP is a well-known complication of many drugs and represents a spectrum from an acute and self-limited condition to a chronic disease. Terbinafine is frequently used in the elderly. It is known to have less drug interactions and adverse effects compared with the other antifungal agents. Use of the Naranjo probability scale indicated a probable relationship between BP and terbinafine treatment in this patient.

CONCLUSIONS:

To the best of our knowledge, this is the first report in the English-language literature of BP in a patient taking terbinafine. As with any other medication, oral terbinafine has the potential for severe adverse reactions. Healthcare professionals should be aware of this possibility.

Novel topical formulations of Terbinafine-HCl for treatment of onychomycosis

Terbinafine hydrochloride (TBF-HCl) is an active substance that is using for treatment of onychomycosis. Onychomycosis is a fungal infection which is the most common disease of nail plate. The nail plate is a barrier which prevents effective topical treatment of ungual disorders. In this study, TBF-HCl loaded liposome and ethosome formulations and also gel form of these formulations were prepared. The formulations were characterized and in vitro and ex vivo release studies were performed. Nail characterization studies were also performed to examine the effect of formulations and experimental conditions on nail surface. As a result, all formulations can serve as efficient formulations for ungual application of TBF-HCl. By the way, the results of the accumulation studies suggested that liposome poloxamer gel formulation could be promising system for ungual drug delivery due to the better accumulation and easier application of the formulation.

Stereoselective synthesis of conjugated fluoro enynes

Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propargyl sulfones gave corresponding BT fluoropropargyl sulfones, Julia-Kocienski reagents for the synthesis of fluoro enynes. Both reagents reacted with aldehydes under mild DBU- or LHMDS-mediated conditions, giving high yields of conjugated fluoro enynes with E-stereoselectivity. In comparison to DBU-mediated reactions, stereoselectivity was higher in low-temperature LHMDS-mediated reactions. Two ketones were shown to react as well, using LHMDS as base. In situ removal of the TMS group gave terminal conjugated 2-fluoro 1,3-enynes. Synthetic utility of the fluoro enynes was demonstrated by conversion to internal alkynes and to stereoisomeric fluoro dienes via Sonogashira and Heck couplings.

Comparison of once-daily versus twice-weekly terbinafine administration for the treatment of canine Malassezia dermatitis - a pilot study

BACKGROUND

Terbinafine, an allylamine antifungal, is used in pulsatile dose regimens for superficial mycoses in human medicine.

OBJECTIVES

To compare the clinical efficacy of twice-weekly versus once-daily terbinafine administration to determine whether preliminary proof-of-concept evidence exists for pulsatile administration of terbinafine in the treatment of canine Malassezia dermatitis and to determine whether twice-weekly treatment results in fewer clinical and owner-perceived adverse events.

ANIMALS

Twenty client-owned dogs with Malassezia dermatitis.

METHODS

In this randomized, single-blinded clinical trial, dogs were randomly assigned to receive terbinafine (30 mg/kg) either once daily for 21 days (n = 10) or once daily on two consecutive days per week for six doses (n = 10). On day 0 and day 21, a mean yeast count was calculated from eight anatomical locations via adhesive tape-strip cytology, clinical lesion scores were assigned to the same locations, and owners assessed pruritus using a visual analog scale.

RESULTS

There was no significant difference between treatment groups with respect to the reduction in mean yeast count (P = 0.343) and clinical lesion scores (P = 0.887). Pruritus measured by visual analog scale was significantly decreased in the twice-weekly treatment group compared with the daily treatment group (P = 0.047). Seven of 20 dogs had a clinically measurable or owner-reported adverse event during treatment that included gastrointestinal disturbances, excessive panting and elevated hepatic enzymes, with no significant difference noted between treatment groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

This pilot study indicates that twice-weekly terbinafine administration may be an effective alternative treatment for canine Malassezia dermatitis and merits further investigation.

Terbinafine inhibits oral squamous cell carcinoma growth through anti-cancer cell proliferation and anti-angiogenesis

Terbinafine (TB), an oral antifungal agent used in the treatment of superficial mycosis, has been reported to exert an anti-tumor effect in various cancer cells. However, the effect of TB on oral cancer has not been evaluated. Herein we demonstrate that TB (0-60 µM) concentration-dependently decreased cell number in cultured human oral squamous cell carcinoma (OSCC), KB cells. The anti-proliferation effect of TB was also observed in two other OSCC cell lines, SAS and SCC 15. TB (60 µM) was not cytotoxic and its inhibition on KB cell growth was reversible. [(3) H]thymidine incorporation and flow cytometric analyses revealed that TB-inhibited DNA synthesis and induced the G0/G1 cell-cycle arrest. The TB-induced cell-cycle arrest occurred when the cyclin-dependent kinase 2 activity was inhibited just as the protein levels of p21(cip1) and p27(kip1) were increased. The TB-induced G0/G1 cell-cycle arrest was completely blocked when the expressions of p21(cip1) and p27(kip1) were knocked-down together. Taken together, these results suggest that the p21(cip1) - and p27(kip1) -associated signaling pathways might be involved in the TB-induced anti-proliferation in KB cells. In vivo, TB (50 mg/kg, i.p.) significantly inhibited the KB tumor size. In these TB-treated tumors, increases in the levels of p21(cip1) and p27(kip1) protein and decreases in the number of proliferating cell nuclear antigen-positive cells and the microvessel density were observed. These findings demonstrate for the first time that TB might have potential to serve as a therapeutic tool in the treatment of oral cancer.

Terbinafine stimulates the pro-inflammatory responses in human monocytic THP-1 cells through an ERK signaling pathway

AIMS

Oral antifungal terbinafine has been reported to cause liver injury with inflammatory responses in a small percentage of patients. However the underlying mechanism remains unknown. To examine the inflammatory reactions, we investigated whether terbinafine and other antifungal drugs increase the release of pro-inflammatory cytokines using human monocytic cells.

MAIN METHODS

Dose- and time-dependent changes in the mRNA expression levels and the release of interleukin (IL)-8 and tumor necrosis factor (TNF)α from human monocytic THP-1 and HL-60 cells with antifungal drugs were measured. Effects of terbinafine on the phosphorylation of extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK)1/2 were investigated.

KEY FINDINGS

The release of IL-8 and TNFα from THP-1 and HL-60 cells was significantly increased by treatment with terbinafine but not by fluconazole, suggesting that terbinafine can stimulate monocytes and increase the pro-inflammatory cytokine release. Terbinafine also significantly increased the phosphorylation of ERK1/2 and p38 MAP kinase in THP-1 cells. Pretreatment with a MAP kinase/ERK kinase (MEK)1/2 inhibitor U0126 significantly suppressed the increase of IL-8 and TNFα levels by terbinafine treatment in THP-1 cells, but p38 MAPK inhibitor SB203580 did not. These results suggested that an ERK1/2 pathway plays an important role in the release of IL-8 and TNFα in THP-1 cells treated with terbinafine.

SIGNIFICANCE

The release of inflammatory mediators by terbinafine might be one of the mechanisms underlying immune-mediated liver injury. This in vitro method may be useful to predict adverse inflammatory reactions that lead to drug-induced liver injury.

Iontophoresis mediated in vivo intradermal delivery of terbinafine hydrochloride

The objective of this study was to investigate the use of iontophoresis for the delivery of terbinafine hydrochloride (TH) into hairless rat skin in vivo. Drug formulation was applied to the abdominal skin and studies were performed using anodal iontophoresis. A current density of 250 microA/cm(2) was applied for 10, 15 and 20 min. Tape stripping and skin extraction were performed thereafter. For depot clearance studies, 20 min treatment was followed by tape stripping and skin extraction at 12, 24 and 48 h. Results indicated that iontophoresis delivered significantly more drug into the deeper skin as compared to controls (p<0.05). Drug levels in the stratum corneum (SC) and underlying skin increased with increasing duration of current application. Depot clearance studies suggested drug depletion within 24 h from SC. A redistribution of terbinafine from the SC to the underlying skin over time was observed. Drug was detectable in the underlying skin for at least 48 h suggesting that formation of a drug depot persisted for at least 2 days following iontophoretic treatment. Thus, iontophoresis of TH may be useful in delivering higher drug levels more rapidly into the superficial and deep seated skin infection sites to form a depot providing sustained release.

Transdermal iontophoretic delivery of terbinafine hydrochloride: quantitation of drug levels in stratum corneum and underlying skin

The objective of this study was to determine the effect of iontophoresis on the delivery of terbinafine hydrochloride (4%, w/w) into and across hairless rat skin. In vitro skin uptake and permeation studies were performed using Franz diffusion cells. Anodal iontophoresis was applied for 1h at current densities of 0.2, 0.3 and 0.4mA/cm(2). In addition, iontophoresis was applied for 15, 30, 45 and 60min. Studies were conducted in which the formulation was either removed or left in contact with the skin following iontophoresis and then passive delivery was assessed 23h later. Tape stripping and skin extraction were performed to quantify drug levels in the stratum corneum and the underlying skin, respectively. The samples were analyzed using HPLC. The amount of drug delivered into the stratum corneum following iontophoresis was not significantly different from the amount delivered passively (p>0.05). However, drug levels in the underlying skin were significantly higher for the iontophoretic group. The amount of terbinafine delivered into the skin layers was influenced by current density and duration of current application. Leaving the drug formulation in contact with the skin during the post-iontophoretic period had a significant effect on drug levels delivered into skin layers. Iontophoresis enhanced the delivery of terbinafine hydrochloride into the skin layers and, therefore, may be used to improve the treatment of skin fungal infections.

Modes of action of the new arylguanidine abafungin beyond interference with ergosterol biosynthesis and in vitro activity against medically important fungi

BACKGROUND

In contrast to the increasing numbers of agents for the treatment of invasive fungal infections, discoveries of new antifungal agents with therapeutic value in dermatomycoses are reported only rarely.

METHODS

Abafungin (chemical abstracts service registry No. 129639-79/8) is the first member of a novel class of synthetic antifungal compounds, the arylguanidines. It was first synthesized at Bayer AG, Leverkusen, Germany, and its antifungal action was discovered during the screening of H(2)-receptor antagonists based on the structure of famotidine. To obtain insight into its mode of action and antifungal activity, various tests were carried out with different fungal pathogens in vitro.

RESULTS

Abafungin was found to have potent antifungal activity. Furthermore, mode-of-action studies suggested that abafungin exerts its antifungal activity regardless of whether the pathogens are growing or in a resting state. One target of abafungin was found to be the inhibition of transmethylation at the C-24 position of the sterol side chain, catalyzed by the enzyme sterol-C-24-methyltransferase. A second action of abafungin seems to be a direct effect on the fungal cell membrane.

CONCLUSION

The observed characteristics of abafungin indicate that abafungin might be a promising antifungal agent defining a new class of antimycotics.

Involvement of proapoptotic Bcl-2 family members in terbinafine-induced mitochondrial dysfunction and apoptosis in HL60 cells

Terbinafine (TB, lamisil), a promising world widely used oral-anti-fungal agent, has been used in the treatment of superficial mycosis. In this study, we found that apoptosis but not cell growth arrest was induced by TB (1 microM, for 24 h) in human promyelocytic leukemia (HL60) cells. The apoptotic effect induced by TB in the HL60 cell was not through the general differentiation mechanisms evidenced by evaluation of three recognized markers, including CD11b, CD33, and morphological features. In addition, our results also revealed that TB-induced apoptosis was not through the cellular surface CD 95 receptor-mediated signaling pathway. We found that the mitochondria membrane in the TB-treated HL60 cells was dissipated by decreasing of the electrochemical gradient (DeltaPsi(m)) led to leakage of cytochrome c from mitochondria into cytosol. Such effects were completely blocked by in vitro transfection of the HL60 cells with Bcl-2 overexpression plasmid (HL60/Bcl-2). However, our data found that TB-mediated apoptosis could not be completely prevented in the Bcl-2 over expressed (HL60/Bcl-2) cells. Such results implied that additional mediators (such as caspase-9) other than mitochondria membrane permeability might contribute to the TB-induced cellular apoptosis signaling. This hypothesis was supported by the evidence that administration of caspases-9 specific inhibitor (z-LEHD-fmk) blocked the TB-induced apoptosis. Our studies highlight the molecular mechanisms of TB-induced apoptosis in human promyelocytic leukemia (HL60) cells.

Terbinafine-Induced Subacute Cutaneous Lupus Erythematosus

BACKGROUND

Nearly 10% of lupus erythematosus (LE) are drug induced. More than 60 different drugs are involved in iatrogenic LE. We report herein 3 cases of terbinafine-induced LE.

OBSERVATIONS

Three patients receiving terbinafine for a suspected dermatophytic infection developed a subacute cutaneous LE, within 7 weeks following terbinafine introduction. The patients' medical history included sicca syndrome, lung carcinoma and Kikuchi disease, respectively. Clinical remission occurred within 15 weeks following terbinafine withdrawal.

DISCUSSION

Sixteen cases of terbinafine-induced LE have been previously reported, including 13 women. The median age was 54 years. Prior autoimmunity was reported in 10 cases, including 5 pre-existing LE. The median delay between terbinafine introduction and LE onset was 5 weeks. The median time until clinical recovery following terbinafine withdrawal was 8 weeks.

CONCLUSION

Terbinafine should be prescribed only in patients with proven dermatophytosis. We recommend cautious monitoring in patients with pre-existing autoimmunity. The diagnosis of terbinafine-induced LE should lead to the immediate and definitive withdrawal of the drug.

Catalytic Four-Component Assembly Based on Allenylboronate Platform: New Access to Privileged Allylic Amine Structures

We developed a novel palladium-catalyzed four-component assembly based on allenylboronate platform, by which privileged allylic amine structures can be constructed in a regioselective, stereoselective, and diversity-oriented manner. The boryl group acts not only as a useful group that can be transformed to various functional groups afterward but also as a stereochemical controller in the generation of key (pi-allyl)palladium intermediates. A short synthesis of rolipram (selective phosphodiesterase-4 inhibitor) is also demonstrated.

Current use of anti-infectives in dermatology

Dermatologic diseases encompass a broad category of pathologic situations. Infection remains a significant aspect of the pathology faced in patient encounters, and it is natural to expect that anti-infectives play a major element in the armamentarium utilized by dermatologists. Aside from the treatment of the classic bacterial and fungal infections, there are now new uses for antiviral agents to help suppress recurrent disease, such as herpes simplex. There is also the novel approach of using anti-infectives, or agents that have been thought to have antimicrobial activity, to treat inflammatory diseases. This review describes anti-infectives, beginning with common antibiotics used to treat bacterial infections. The discussion will then cover the current use of antivirals. Finally, the description of antifungals will be separated, starting with the oral agents and ending with the topical antimycotics. The use of anti-infectives in tropical dermatology has been purposefully left out, and perhaps should be the subject of a separate review. Cutaneous bacterial infections consist chiefly of those microorganisms that colonize the skin, such as species of staphylococcus and streptococcus. Propionibacterium acnes and certain other anaerobes can be involved in folliculitis, pyodermas and in chronic conditions such as hidradenitis suppurativa.

New agents for the treatment of systemic fungal infections – current status

Systemic antifungal chemotherapy is enjoying its most dynamic era. More antifungal agents are under development than ever before, including agents in entirely new classes. Major goals of current investigations are to identify compounds with a wide spectrum of activity, minimal toxicity and a high degree of target specificity. The antifungal drugs in development include new azoles {voriconazole, posaconazole (formerly SCH-56592), ravuconazole (formerly BMS-207147)}, lipid formulations of amphotericin B, a lipid formulation of nystatin, echinocandins {anidulafungin (formerly, LY-303366, VER-002), caspofungin (formerly MK-991), micafungin (formerly FK-463)}, antifungal peptides other than echinocandins, and sordarin derivatives. This discussion reviews the currently available antifungal agents and summarises the developmental issues that surround these new systemic antifungal drugs.

Terbinafine resistance mediated by salicylate 1-monooxygenase in Aspergillus nidulans

Resistance to antifungal agents is a recurring and growing problem among patients with systemic fungal infections. UV-induced Aspergillus nidulans mutants resistant to terbinafine have been identified, and we report here the characterization of one such gene. A sib-selected, 6.6-kb genomic DNA fragment encodes a salicylate 1-monooxygenase (salA), and a fatty acid synthase subunit (fasC) confers terbinafine resistance upon transformation of a sensitive strain. Subfragments carrying salA but not fasC confer terbinafine resistance. salA is present as a single-copy gene on chromosome VI and encodes a protein of 473 amino acids that is homologous to salicylate 1-monooxygenase, a well-characterized naphthalene-degrading enzyme in bacteria. salA transcript accumulation analysis showed terbinafine-dependent induction in the wild type and the UV-induced mutant Terb7, as well as overexpression in a strain containing the salA subgenomic DNA fragment, probably due to the multicopy effect caused by the transformation event. Additional naphthalene degradation enzyme-coding genes are present in fungal genomes, suggesting that resistance could follow degradation of the naphthalene ring contained in terbinafine.

Inhibition of human vascular endothelial cells proliferation by terbinafine

We have demonstrated previously that terbinafine (TB), an oral antifungal agent used in the treatment of superficial mycosis, suppresses proliferation of various cultured human cancer cells in vitro and in vivo by inhibiting DNA synthesis and activating apoptosis. In our study, we further demonstrated that TB at a range of concentrations (0-120 microM) dose-dependently decreased cell number in cultured human umbilical vascular endothelial cells (HUVEC). Terbinafine was not cytotoxic at a concentration of 120 microM, indicating that it may have an inhibitory effect on the cell proliferation in HUVEC. The TB-induced inhibition of cell growth rate is reversible. [(3)H]thymidine incorporation revealed that TB reduced the [(3)H]thymidine incorporation into HUVEC during the S-phase of the cell-cycle. Western blot analysis demonstrated that the protein levels of cyclin A, but not cyclins B, D1, D3, E, CDK2 and CDK4, decreased after TB treatment. The TB-induced cell-cycle arrest in HUVEC occurred when the cyclin-dependent kinase 2 (CDK2) activity was inhibited just as the protein level of p21 was increased and cyclin A was decreased. Pretreatment of HUVEC with a p21 specific antisense oligonucleotide reversed the TB-induced inhibition of [(3)H]thymidine incorporation. Taken together, these results suggest an involvement of the p21-associated signaling pathway in the TB-induced antiproliferation in HUVEC. Capillary-like tube formation and chick embryo chorioallantoic membrane (CAM) assays further demonstrated the anti-angiogenic effect of TB. These findings demonstrate for the first time that TB can inhibit the angiogenesis.

Disseminated dermatophytosis caused by Microsporum gypseum in an AIDS patient: response to terbinafine and amorolfine. Fallbericht. Disseminierte Dermatophytose durch Microsporum gypseum bei einem AIDS- Patienten mit Ansprechen auf Terbinafin und Amorolfin

A 51-year-old white male, native of Rio de Janeiro, Brazil, with advanced AIDS and in chronic use of imidazoles for oral candidosis, presented erythematous, desquamative, pruriginous plaques of 1 month evolution on the trunk, inguinal/crural region, and lower limbs. The diagnosis of dermatophytosis was based on the isolation of Microsporum gypseum from scales scraped from the skin lesions. The lesions regressed after 30 days treatment with itraconazole, 100 mg day(-1). After interruption of this antifungal, the mycosis recurred 2 months later, along with a toe onychomycosis also caused by M. gypseum. Attempted reintroduction of itraconazole at higher dose was unsuccessful. Patient responded well to treatment with terbinafine 250 mg day(-1) for 45 days. However, the medication had to be interrupted as a result of the emergence of a disseminated erythematous/papulous rash. Topical treatment with amorolfine cream was then performed, with a good clinical and mycological response.

In vitro and in vivo studies of the anticancer action of terbinafine in human cancer cell lines: G0/G1 p53-associated cell cycle arrest

Terbinafine (TB) (Lamisil), a promising oral antifungal agent used worldwide, has been used in the treatment of superficial mycosis. In our study, we demonstrated that TB dose-dependently decreased cell number in various cultured human malignant cells. Flow cytometry analysis revealed that TB interrupts the cell cycle at the G0/G1 transition. The TB-induced cell cycle arrest in colon cancer cell line (COLO 205) occurred when the cyclin-dependent kinase (cdk) system was inhibited just as the levels of p53, p21/Cip1 and p27/Kip1 proteins were augmented. In the TB-treated COLO 205, the binding between p53 protein and p53 consensus binding site in p21/Cip1 promoter DNA probe was increased. Pretreatment of COLO 205 with p53-specific antisense oligodeoxynucleotide decreased the TB-induced elevations of p53 and p21/Cip1 proteins, which in turn led to arrest in the cell cycle at the G0/G1 phase. Moreover, in the p53 null cells, HL60, TB treatment did not induce cell cycle arrest. Taken together, these results suggest an involvement of the p53-associated signaling pathway in the TB-induced antiproliferation in COLO 205. We further examined whether administration of TB could affect the growth of tumors derived from human colon cancer cells in an in vivo setting. COLO 205 cells implanted subcutaneously in nude mice formed solid tumor; subsequent intraperitoneal injections of TB (50 mg/kg) led to obvious decline in tumor size, up to 50-60%. In these tumors, increases in the p21/Cip1, p27/Kip1 and p53 proteins and the occurrence of apoptosis were observed. Combined treatment with TB and nocodazole (ND), a clinically used anticancer agent, potentiated the apoptotic effect in COLO 205. These findings demonstrate for the first time that TB can inhibit the proliferation of tumor cells in vitro and in vivo.

Update on antifungal therapy

Fungal pathogens are becoming increasingly important for human and small animal medicine. This article highlights many standards-of-care and new agents for treatment of these pathogens for small animals and people.

Identification of genes involved in terbinafine resistance in Aspergillus nidulans

AIMS

To determine the pattern and the genetic basis of resistance to terbinafine, a drug extensively used for the treatment of fungal infections in humans.

METHODS AND RESULTS

Four resistant mutants from Aspergillus nidulans isolated after irradiation with ultraviolet light were crossed with the master strain F (MSF). Genetic analysis revealed that a single gene, located on chromosome IV, is responsible for resistance to terbinafine and that the alleles responsible for this resistance in these mutants are of a codominant or dominant nature at high terbinafine concentrations. Furthermore, the interaction of this mutation with another one identified on chromosome II causes the double mutant to be highly resistant.

CONCLUSIONS

Periodic surveillance of antimycotic susceptibility would be an important measure in detecting the emergence and spread of resistance. Mutation in a single gene could be responsible for resistance to terbinafine and a genic interaction may be responsible for a higher level of antimycotic resistance.

SIGNIFICANCE AND IMPACT OF THE STUDY

The understanding of the mechanisms that lead to changes in the sensitivity of a fungus to a given antifungal agent is important both in order to define strategies for the use of such agent and to guide the development of new antifungal agents.

Alternate week and combination itraconazole and terbinafine therapy for chromoblastomycosis caused by Fonsecaea pedrosoi in Brazil

Patients with long-standing chromoblastomycosis may respond poorly to standard treatments such as amphotericin B, oral antifungals, surgical measures or thermotherapy. The objective of this study was to determine the potential of alternate week and combination therapy with itraconazole and terbinafine in the treatment of poorly responsive, or non-responsive, chromoblastomycosis. Four patients with longstanding chromoblastomycosis (8-23 years) caused by Fonsecaea pedrosoi had responded poorly to standard therapies including monotherapy with the oral antifungal agents. In order to try and improve the response to oral itraconazole and terbinafine, alternate week or combination therapy with itraconazole and terbinafine was initiated. Bloodwork including complete blood count and liver function tests were performed every 3-8 weeks to ensure patient safety. Reduction or resolution of lesions of chromoblastomycosis was noted with alternate week or combination treatment using oral itraconazole and terbinafine. Three of four patients experienced no clinical side-effects; the third reported mild, transient gastric discomfort which responded to antacids. Bloodwork generally remained within normal limits throughout the entire course of treatment with no clinically significant changes. The combination therapy was considered effective in treating the poorly responsive chromoblastomycosis of all four patients. Some success with alternative week therapy was also noted in one patient. The favorable response and lack of significant adverse effects suggests that these regimens may be an option for some patients with chromoblastomycosis.

Physiologically based pharmacokinetic model for terbinafine in rats and humans

The aim of this study was to develop a physiologically based pharmacokinetic (PB-PK) model capable of describing and predicting terbinafine concentrations in plasma and tissues in rats and humans. A PB-PK model consisting of 12 tissue and 2 blood compartments was developed using concentration-time data for tissues from rats (n = 33) after intravenous bolus administration of terbinafine (6 mg/kg of body weight). It was assumed that all tissues except skin and testis tissues were well-stirred compartments with perfusion rate limitations. The uptake of terbinafine into skin and testis tissues was described by a PB-PK model which incorporates a membrane permeability rate limitation. The concentration-time data for terbinafine in human plasma and tissues were predicted by use of a scaled-up PB-PK model, which took oral absorption into consideration. The predictions obtained from the global PB-PK model for the concentration-time profile of terbinafine in human plasma and tissues were in close agreement with the observed concentration data for rats. The scaled-up PB-PK model provided an excellent prediction of published terbinafine concentration-time data obtained after the administration of single and multiple oral doses in humans. The estimated volume of distribution at steady state (V(ss)) obtained from the PB-PK model agreed with the reported value of 11 liters/kg. The apparent volume of distribution of terbinafine in skin and adipose tissues accounted for 41 and 52%, respectively, of the V(ss) for humans, indicating that uptake into and redistribution from these tissues dominate the pharmacokinetic profile of terbinafine. The PB-PK model developed in this study was capable of accurately predicting the plasma and tissue terbinafine concentrations in both rats and humans and provides insight into the physiological factors that determine terbinafine disposition.

Drugs in pregnancy. Drugs to avoid

Drugs given in pregnancy can adversely affect the fetus in many ways. Anxiety about birth defects is a major parental concern during pregnancy. Doctors, midwives and their patients often seek information about the potential teratogenicity of drugs that are taken by, or prescribed for, the pregnant woman. Because no drug is entirely without side-effects, great caution should be taken when prescribing in pregnancy. The development of knowledge in understanding the use of drugs during pregnancy has been in stalemate in comparison to other areas of therapeutics, due mainly to difficulties in testing new products in pregnant women and lack of good quality research. In this chapter, we review current knowledge of the epidemiology of drug use among pregnant women, drug metabolism in pregnancy, adverse fetal and neonatal effects of drugs and specific effects of drugs that are relatively or absolutely contraindicated in pregnancy.