Bullous photodermatosis after lomefloxacin

Effects of PACAP in UV-A radiation-induced retinal degeneration models in rats

The retina is constantly exposed to ultraviolet (UV) light with different wavelengths, which may lead to chronic UV-induced retinal injury. In our previous studies, we have shown the protective effects of pituitary adenylate cyclase activating polypeptide (PACAP) in toxic and ischemic retinal injuries. The aim of the present study was to investigate the effects of PACAP in UV-A-induced retinal lesion. We used diffuse UV-A radiation (315-400 nm) to induce acute retinal damage over a short period of exposure. Using standard histological (morphological and morphometrical) analysis, we assessed the actions of intravitreal PACAP (100 pmol/5 µl) treatment on acute UV-A-induced retinal damage. We measured the thickness of nuclear and plexiform layers as well as the number of cells in the outer nuclear and inner nuclear layers and in the ganglion cell layer. Outer limiting membrane-inner limiting membrane distances in the cross-section of the retina were also examined. Our results show that UV-A light-induced retinal damage led to severe degeneration in the photoreceptor layer, and in the outer and inner nuclear layers. Alteration in the plexiform layers was also observed. We found that post-irradiation PACAP treatment significantly attenuated the UV-A-induced retinal damage. Our results provide the basis for future clinical application of PACAP treatment in retinal degeneration and may have clinical implications in several ophthalmic diseases.

Induction of eosinophil-infiltrating drug photoallergy in mice

BACKGROUND

Drug photoallergy is one of the highly incident adverse effects. Several different histological patterns have been recognized.

OBJECTIVE

To establish a murine model of the eosinophil-infiltrating type of drug photoallergy by using afloqualone (AQ), a representative photosensitive drug.

METHODS

AKR/J mice were sensitized by intraperitoneal injection of afloqualone solution (2mg/kg/mouse) and irradiation of shaved abdomen with ultraviolet A light (UVA) (12J/cm(2)). This sensitization procedure was repeated 2-12 times, and 3 days after the last immunization, mice were challenged by a subcutaneous injection of AQ solution and irradiation of the same site with UVA. The draining lymph node cells (LNCs) were used for transfer and cytokine production studies, and the challenged skin was analyzed for chemokine expression.

RESULTS

More than 10 times of sensitization induced a massive infiltrate of eosinophils and lymphocytes at the challenged site. AKR/J mice were a high responder strain. The sensitivity was transferred with 5-8 x 10(7) immune lymph node and spleen cells into naïve mice. CD4(+) T cells were mainly responsible for this sensitivity, since 1 x 10(7) CD4(+) cells alone induced a high level of sensitivity, but CD8(+) T cells evoked the sensitivity to a lesser degree. Culture supernatants from AQ-photoimmuned lymph node cells contained a higher level of IL-4 and lower interferon-gamma than those from mice immunized with dinitrofluorobenzene. Finally, the skin of AQ-photochallenged site exhibited high expression of CCL24/eotaxin-2, a chemokine for eosinophils.

CONCLUSION

It is suggested that eosinophilic drug photoallergy is mediated by sensitized Th2 cells and locally produced eosinophil-attracting chemokines.

A randomized controlled trial (volunteer study) of sitafloxacin, enoxacin, levofloxacin and sparfloxacin phototoxicity

BACKGROUND

Fluoroquinolone antibiotics (FQs) are associated with phototoxic skin reactions following exposure to sunlight.

OBJECTIVES

We aimed to compare the phototoxic potential of sitafloxacin, a novel FQ with three others: sparfloxacin, enoxacin, levofloxacin and placebo in Caucasian volunteers. In a second study, two dosage regimens of sitafloxacin were compared with placebo in Oriental subjects.

METHODS

Randomized, placebo-controlled, assessor-blinded clinical trial. In 40 healthy Caucasians, sitafloxacin 100 mg twice a day (n = 8), sparfloxacin 200 mg day-1 (n = 8), enoxacin 200 mg three times a day (n = 8), levofloxacin 100 mg three times a day (n = 8) and placebo (n = 8) were given in oral doses for 6 days. In the second study, sitafloxacin 50 mg and 100 mg, both twice daily, were compared with placebo in 17 healthy Oriental subjects. Using an established monochromator technique, baseline threshold erythema levels were established pre-drug and on-drug. The phototoxic index (PI) baseline, minimal erythema dose (MED) divided by on-drug MED for each medication at each wavelength was determined and related to sitafloxacin peak plasma levels. The duration of susceptibility to phototoxicity was assessed by repeat phototesting daily after stopping medication.

RESULTS

In the Caucasian study, sitafloxacin 100 mg twice a day produced mild ultraviolet (UV) A-dependent phototoxicity (median PI = 1.45) at 365 +/- 30 nm (half-maximum bandwidth), maximal at 24 h with normalization by 24 h postdrug cessation. The sparfloxacin group experienced severe phototoxicity maximal at 24 h and, unusually for an FQ, extended in the visible region (430 +/- 30 nm), maximal at 400 +/- 30 nm (median PI = 12.35) with abnormal pigmentation at on-drug phototest sites lasting, although fading, for up to 1 year. Enoxacin showed UVA-dependent phototoxicity (335-365 +/- 30 nm) median PI 3.94 (at 365 +/- 30 nm) returning to normal 48 h after stopping the drug. Fading pigmentation at phototoxic sites also lasted up to 1 year. Phototoxicity was not detected in the levofloxacin or placebo groups. In the Oriental study, no clinically relevant phototoxicity was seen with either sitafloxacin or placebo groups.

CONCLUSIONS

We conclude that 100 mg twice a day sitafloxacin in Caucasians is associated with a mild degree of cutaneous phototoxicity. Enoxacin 200 mg three times a day and sparfloxacin 200 mg day-1 are much more photoactive. Sparfloxacin phototoxicity is induced by UVA and visible wavelengths. Levofloxacin and placebo failed to show a phototoxic effect. In the Oriental study, sitafloxacin 50 mg twice a day and 100 mg twice a day failed to demonstrate a clinically significant phototoxic effect.

Quinolone hypersensitivity

PURPOSE OF REVIEW

Quinolones are potent antibacterial agents that can cause drug hypersensitivity reactions affecting different organs. A better understanding of the underlying mechanism and the level of crossreactivity within different quinolones is needed to handle and prevent these diseases.

RECENT FINDINGS

The adverse side-effects caused by quinolones are the result of different immunological mechanisms and cause quite different diseases. The development of an assay detecting quinolone-specific IgE revealed specific antibodies in more than 50% of patients with immediate-type reactions, and the majority of sera also reacted with related compounds. In maculopapular drug exanthemas caused by ciprofloxacin, specific T cells could be detected and cloned. They reacted with ciprofloxacin directly, and crossreactivity to related compounds was detected in approximately 50% of the clones.

SUMMARY

Quinolones can cause drug hypersensitivity reactions by different immunological mechanisms. In-vitro analysis suggests that crossreactivity is common.

Photoallergenicity of a fluoroquinolone antibacterial agent with a fluorine substituent at the 8-position in guinea pigs exposed to long-wavelength UV light

The 8-position of the quinolone ring of balofloxacin (BLFX), one of fluoroquinolones, was replaced with fluorine to obtain the 8-F. When an aqueous solution of bovine serum albumin (BSA) containing the 8-F was exposed to long-wavelength UV light (UVA) at a rate of 2.5 J/cm2, the absorbance of BSA at 300 nm or longer wavelengths increased markedly in comparison to that of native BSA. In addition, when a homogenate of skin tissue from Hartley guinea pigs was exposed to UVA (2.5 J/cm2) in the presence of the 8-F and then injected subcutaneously into guinea pigs, the animals produced IgG class antibody specific to the 8-F and its UVA-irradiation product. No such phenomenon, however, was observed when the parent compound, i.e. , BLFX which possesses a methoxy group at the 8-position, was used instead of the 8-F. In a subsequent experiment, the 8-F was administered either orally or topically to the shaved neck of guinea pigs and then irradiated with UVA (5 J/cm2) once daily for 5 days. When the treated animals were challenged by a combination of UVA irradiation (5 J/cm2) and either an oral or intradermal administration of the 8-F, 2 and 3 of the 5 animals showed redness and erythema on the irradiated area, respectively. However, no change was observed when BLFX was used instead of the 8-F. These results suggest that the introduction of a fluorine substituent to the 8-position of quinoline ring of fluoroquinolones induces photoallergic responses in which the fluoroquinolone or its photo-denatured product(s) act as an allergen.

Lymphocyte stimulation test with drug-photomodified cells in patients with quinolone photosensitivity

Quinolone antibacterial agents, known to elicit photosensitive dermatitis as an adverse effect, have both phototoxicity and photoallergenicity. The latter potency is mainly derived from their photohaptenic moiety; quinolones covalently bind to protein and cells upon exposure to ultraviolet A (UVA) light. Our previous study has shown the in vivo and in vitro antigenicity of quinolone-photomodified cells in mice. Here, we examined the presence of sensitized lymphocytes that react with quinolone-photomodified autologous cells in patients with photosensitivity to quinolones. A flow cytometric analysis using a monoclonal antibody specific to quinolone photoadducts demonstrated that peripheral blood mononuclear cells (PBMC) were successfully photomodified with quinolones upon exposure to UVA. PBMC from quinolone-photosensitive patients were cocultured with autologous PBMC photomodified with the causative drug. Modest but significant proliferative responses of responder lymphocytes were found in patients photosensitive to lomefloxacin, fleroxacin, and enoxacin, indicating photoallergic mechanism in these patients. On the other hand, sparfloxacin-photosensitive patients exhibited negative lymphocyte stimulation test, suggesting that its photosensitivity is mainly phototoxic. When UVA-preirradiated quinolones were used as stimulators, only fleroxacin exceptionally stimulated patients' PBMC, indicating its prohaptenic as well as photohaptenic properties. These findings suggest the presence of circulating sensitized T cells in patients with photosensitivity to certain quinolones.

Grepafloxacin: a review of its safety profile based on clinical trials and postmarketing surveillance

The safety profile of grepafloxacin has been characterized in a number of preclinical and clinical studies. Preclinical investigations have shown that its toxicologic profile is similar to that of other fluoroquinolones, and phase I studies in humans have confirmed these data. A photosensitivity study demonstrated equivalence with ciprofloxacin, and a study in elderly patients taking the highest clinical dose of grepafloxacin indicated that prolongation of the QTc interval by grepafloxacin was less than 2 ms, 15 times less than that observed in a study of erythromycin. In phase II and III clinical investigations conducted in the United States and the United Kingdom, safety data have been gathered from more than 3000 patients with either community-acquired pneumonia or acute bacterial exacerbations of chronic bronchitis. The most common adverse events with grepafloxacin 400 or 600 mg were gastrointestinal, such as nausea, vomiting, and diarrhea. The frequency of these adverse events was similar to that seen with ciprofloxacin. Significantly more patients reported a mild, unpleasant metallic taste with grepafloxacin than with ciprofloxacin, but <1% of patients withdrew from therapy because of this. Headache was observed significantly more often in ciprofloxacin-treated patients than in grepafloxacin-treated patients. Recent postmarketing data confirm the good tolerability and safety profile of grepafloxacin. These data, from a case-report study of more than 9000 patients in Germany, demonstrated that only 2.3% of patients reported adverse events when grepafloxacin was used in routine clinical practice. The most frequently reported events were nausea (0.8%) and gastrointestinal symptoms (0.4%). Dizziness was reported by only 0.3% of patients, and only 4 patients (0.04%) reported photosensitization. Adverse events did not appear to be either dose dependent or related to diagnosis. More than 400,000 patients world-wide have received grepafloxacin treatment. No new safety issues have arisen from the spontaneous-report data and, with the exception of rare reports of an unpleasant taste, the most commonly reported events have been the same as those seen in clinical studies. These data support grepafloxacin as a well-tolerated fluoroquinolone suitable for the treatment of community-acquired respiratory tract infections.

Quinolone photoallergy: photosensitivity dermatitis induced by systemic administration of photohaptenic drugs

Quinolone antibacterial agents are well known to elicit photosensitivity as a side effect. The photoallergenicity of fluoroquinolones, the representative quinolone derivatives, is mainly derived from their photohaptenic moiety. When epidermal cells are irradiated with ultraviolet A light in the presence of fluoroquinolones, quinolone photoadducts are formed in the treated cells. This photomodification is thought to be an initial step for sensitization and elicitation of this photoallergy, and quinolone-photoderivatized Langerhans cells are capable of stimulating immune T cells in mice. In the murine model, fluoroquinolone photoallergy is mediated by Th1 cells bearing T cell receptor Vbeta 13. There is a broad photoantigenic cross-reactivity among fluoroquinolones in recognition by T cells and immunoglobulins. Therefore, it is most likely that fluoroquinolones carry the same photoantigenic epitope, which is recognized by Vbetal3+ T cells, leading to fluoroquinolone photosensitivity and cross-reactivity.

A controlled trial of levofloxacin and lomefloxacin in the treatment of complicated urinary tract infection

OBJECTIVES

The efficacy and safety of levofloxacin and lomefloxacin in complicated urinary tract infections (UTIs) were compared in a randomized, open-label, multicenter study.

METHODS

Outpatients were randomized to receive levofloxacin (250 mg once daily) for 7 to 10 days or lomefloxacin (400 mg once daily) for 14 days. Three hundred thirty-six patients (171 with levofloxacin, 165 with lomefloxacin) were evaluable for microbiologic efficacy, and 461 patients (232 with levofloxacin, 229 with lomefloxacin) for safety.

RESULTS

The overall microbiologic eradication rate of pathogens was 95.5% (168 of 176) for levofloxacin and 91.7% (154 of 168) for lomefloxacin. Eradication rates with respect to patients were 95.3% (163 of 171) and 92.1% (152 of 165) for levofloxacin and lomefloxacin, respectively. At the 5 to 9-day post-therapy visit, symptoms were completely resolved in 84.8% of levofloxacin-treated patients and were decreased in 8.2% (93.0% clinical success). Among the lomefloxacin-treated patients, complete resolution was seen in 82.4%, with decreased symptoms in 6.1% (88.5% clinical success). Drug-related adverse events (AEs) were reported by 10 (2.6%) and 18 (5.2%) levofloxacin- and lomefloxacin-treated patients, respectively. Compared with levofloxacin-treated patients, more lomefloxacin-treated patients experienced photosensitivity reactions (3 [1.3%] versus 0) and dizziness (2 [0.9%] versus 0). Nausea (3 [1.3%] versus 1 [0.4%]) was more frequent in the levofloxacin-treated group. Six patients in each treatment group had a gastrointestinal AE (1.7%); rash was reported more frequently with lomefloxacin (4 patients [0.4%]) than with levofloxacin (1 patient [0.4%]). Discontinuation because of AEs was observed in 8 (3.4%) levofloxacin- and 14 (6.1%) lomefloxacin-treated patients.

CONCLUSIONS

Once-daily levofloxacin is as effective as and has a superior tolerability profile than lomefloxacin in the treatment of complicated UTIs.

Proposed mechanism for the photodynamic generation of 8-oxo-7,8-dihydro-2'-deoxyguanosine produced in cultured cells by exposure to lomefloxacin

In this study, lomefloxacin (LMX), a widely used quinolone antibiotic with a high frequency of clinical phototoxicity, was investigated by measuring the effects of several antioxidants on its ability to form of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in cultured adult rat liver cells after exposure to UVA. In the current study the observed DNA damage, reflected by the formation of 8-oxo-dG, was almost completely inhibited by co-incubation of LMX and cultured cells with sodium azide (NaN3) that specifically quenches singlet oxygen. Vitamin E (alpha-tocopherol), known to quench both superoxide and singlet oxygen, inhibited 8-oxo-dG formation by approximately 54%. Mannitol, a hydroxyl radical scavenger, inhibited 8-oxo-dG formation by 64%. Butylated hydroxyanisole (BHA), a scavenger of hydroxyl, peroxy and alkoxy radicals, showed no inhibition of 8-oxo-dG formation but in fact enhanced levels of 8-oxo-dG by 169%. The results of this study suggest that the mechanism for the photodynamic generation of 8-oxo-dG by LMX is mediated, at least in part, by both singlet oxygen and hydroxyl radical and involves both type I and type II photosensitization.

Photohaptenic properties of fluoroquinolones

Although quinolone antibacterial agents have both phototoxicity and photoallergenicity, the latter's potency has been poorly investigated compared with the former's. Some of the photoallergic chemicals serve as photohaptens, which lead to T-cell-mediated immune reactions after photobinding to protein by UVA radiation. We examined the photohaptenic potential of fluoroquinolones, including lomefloxacin (LFLX), ciplofloxacin, norfloxacin, ofloxacin, levofloxacin, fleroxacin, enoxacin and sparfloxacin (SPFX). The absorption spectra of the quinolones were altered by UVA irradiation, with an exception of SPFX that seems to be photostable toward UVA. Bovine serum albumin and murine epidermal cells were coupled with these fluoroquinolones other than SPFX by exposure to UVA. Subcutaneous inoculation of fluoroquinolone-photomodified epidermal cells induced and elicited a delayed-type hypersensitivity reaction in mice. However, epidermal cells incubated with LFLX without UVA exposure also induced and elicited a significant hypersensitivity reaction to a lesser degree than LFLX-photomodified epidermal cells. Furthermore, there was cross-reactivity between LFLX-photomodified epidermal cells and simply LFLX-incubated cells. This suggests that cells can be weakly modified with LFLX even in the dark and that UVA irradiation promotes this modification. Our study demonstrated that fluoroquinolones have photohaptenic properties to which their photoallergenicity is probably ascribed.