Dacarbazine-induced photosensitivity reaction

Ex vivo model of human skin (hOSEC) for assessing the dermatokinetics of the anti-melanoma drug Dacarbazine

Alternative models to replace animals in experimental studies remain a challenge in testing the effectiveness of dermatologic and cosmetic drugs. We proposed a model of human organotypic skin explant culture (hOSEC) to assess the profile of cutaneous drug skin distribution, adopting dacarbazine as a model, and respective new methodologies for dermatokinetic analysis. The viability tests were evaluated in primary keratinocytes and fibroblasts, and skin by MTT and TTC assays, respectively. Then, dacarbazine was applied to the culture medium, and the hOSEC method was applied to verify the dynamics of skin distribution of dacarbazine and determine its dermatokinetic profile. The results of cell and tissue viability showed that both were considered viable. The dermatokinetic results indicated that dacarbazine can be absorbed through the skin, reaching a concentration of 36.36 µg/mL (18,18%) of the initial dose (200 µg/mL) after 12 h in culture. Histological data showed that the skin maintained its structure throughout the tested time that the hOSEC method was applied. No apoptotic cells were observed in the epidermal and dermal layers. No visible changes in the dermo-epidermal junction and no inflammatory processes with the recruitment of defense cells were observed. Hence, these findings suggest that the hOSEC concept as an alternative ex vivo model for assessing the dynamics of skin distribution of drugs, such as dacarbazine, and determining their respective dermatokinetic profiles.

Drug-Induced Photosensitivity-An Update: Culprit Drugs, Prevention and Management

Photosensitive drug eruptions are cutaneous adverse events due to exposure to a medication and either ultraviolet or visible radiation. In this review, the diagnosis, prevention and management of drug-induced photosensitivity is discussed. Diagnosis is based largely on the history of drug intake and the appearance of the eruption primarily affecting sun-exposed areas of the skin. This diagnosis can also be aided by tools such as phototesting, photopatch testing and rechallenge testing. The mainstay of management is prevention, including informing patients of the possibility of increased photosensitivity as well as the use of appropriate sun protective measures. Once a photosensitivity reaction has occurred, it may be necessary to discontinue the culprit medication and treat the reaction with corticosteroids. For certain medications, long-term surveillance may be indicated because of a higher risk of developing melanoma or squamous cell carcinoma at sites of earlier photosensitivity reactions. A large number of medications have been implicated as causes of photosensitivity, many with convincing clinical and scientific supporting evidence. We review the medical literature regarding the evidence for the culpability of each drug, including the results of phototesting, photopatch testing and rechallenge testing. Amiodarone, chlorpromazine, doxycycline, hydrochlorothiazide, nalidixic acid, naproxen, piroxicam, tetracycline, thioridazine, vemurafenib and voriconazole are among the most consistently implicated and warrant the most precaution by both the physician and patient.

Drug-induced photosensitivity: Photoallergic and phototoxic reactions

Drug-induced photosensitivity refers to the development of cutaneous disease due to the interaction between a given chemical agent and sunlight. Photosensitivity reactions can be classified as phototoxic or photoallergic. Sometimes, there is an overlap between these two patterns, making their distinction particularly difficult for the clinician. We review the drugs that have been implicated as photosensitizers, the involved mechanism, and their clinical presentations. The main topical agents that cause contact photosensitivity are the nonsteroidal antiinflammatory drugs, whereas the main systemic drugs inducing photosensitivity are antimicrobials, nonsteroidal antiinflammatory agents, and cardiovascular drugs. Drug-induced photosensitivity remains a common clinical problem and is often underdiagnosed.

Drug-induced photosensitivity: culprit drugs, management and prevention

Photo-induced drug eruptions are cutaneous adverse events due to exposure to a drug and either ultraviolet or visible radiation. Based on their pathogenesis, they can be classified as phototoxic or photoallergic drug eruptions, although in many cases it is not possible to determine whether a particular eruption is due to a phototoxic or photoallergic mechanism. In this review, the diagnosis, prevention and management of drug-induced photosensitivity are discussed. Diagnosis is based primarily on the history of drug intake and the clinical appearance of the eruption, primarily affecting sun-exposed areas of the skin. Phototesting and photopatch testing can be useful adjuncts in making a diagnosis. The mainstay of management is prevention, including informing patients of the possibility of increased sun sensitivity and the use of sun protective measures. However, once the eruption has occurred, it may be necessary to discontinue the culprit medication and treat the eruption with a potent topical corticosteroid. Drugs that have been implicated in causing photosensitive eruptions are reviewed. Tetracycline, doxycycline, nalidixic acid, voriconazole, amiodarone, hydrochlorothiazide, naproxen, piroxicam, chlorpromazine and thioridazine are among the most commonly implicated medications. We review the medical literature regarding evidence for the culpability of each drug, including the results of phototesting, photopatch testing and rechallenge testing.

Mechanisms of hepatotoxicity caused by dacarbazine in rats

Possible risks of fatal dacarbazine hepatotoxicity have not been studied systematically. We therefore asked whether dacarbazine hepatotoxicity is influenced by the dose or mode of application, by dacarbazine light-decay products, by prior liver damage or by an induction of dacarbazine metabolism. 22 Sprague-Dawley rats were treated with 4.5 mg and 200 mg dacarbazine/kg bodyweight i.p. and i.v., with dacarbazine light-decay products and with 4.5 mg and 200 mg dacarbazine/kg bodymass after previous galactosamine and ethanol treatment. Serum alanine aminotransferase, cholinesterase and white blood cell and platelet numbers were measured and liver histology was evaluated. Dose-dependent dacarbazine hepatotoxicity could be demonstrated by histology. The mode of application, dacarbazine light-decay products and acute liver damage did not influence dacarbazine hepatotoxicity. However 200 mg dacarbazine/kg bodymass after ethanol pretreatment caused significant serological changes and a significant leucodepression. The increased hepato- and myelotoxicity after induction of hepatic microsomal enzymes should be reason to exclude ethanol and drugs that induce hepatic microsomal enzymes prior to treatment with dacarbazine.

Mucocutaneous side effects of chemotherapy

Increasing numbers of chemotherapeutic agents are being used to treat patients with cancer. They have only a slight margin of safety between the tumoricidal and toxic doses. The skin is a frequent target for the side effects of these drugs, and the clinician should be alert to these manifestations so that needless diagnostic work up is avoid.

Cutaneous side effects of cancer chemotherapy

Chemotherapeutic agents are used with increasing frequency to treat a wide variety of neoplastic and inflammatory disorders. These drugs may inadvertently affect the skin, mucous membranes, hair, and nails, producing many undesirable reactions including alopecia, stomatitis, hyperpigmentation, hypersensitivity reactions, and photosensitivity. Awareness of these relatively common complications may help physicians caring for patients on these medications.

Cutaneous complications of chemotherapeutic agents

Increasing numbers of chemotherapeutic agents are being used to treat patients with cancer and various immunologically mediated and inflammatory disorders. Many of the drugs used have distinctive cutaneous side effects that range from relatively common ones, such as alopecia, stomatitis, and hyperpigmentation, to more unusual ones, such as radiation enhancement and recall phenomena, photosensitivity and hypersensitivity reactions, and phlebitis or chemical cellulitis. In addition, there are some rare complications such as diffuse sclerosis of the hands and feet, Raynaud's phenomenon, sterile folliculitis, and flushing reactions. By being aware of which drug may have caused a particular cutaneous reaction, dermatologists will be able to contribute to the care of patients with complex problems in a meaningful way.