Xasten (dexamethasone) 0.5mg is indicated for the treatment of various inflammatory and autoimmune conditions, contraindicated in patients with systemic fungal infections or hypersensitivity to dexamethasone, may cause side effects such as increased appetite, weight gain, and mood changes, and can interact with drugs like nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants, and certain vaccines.