Does an individuals body weight account for determining a beginning dose of xanax (alprazolam)?

No: No, body weight is not the primary factor in determining xanax (alprazolam) dose. One would need to know what other medications are also being prescribed, any ongoing other illnesses, whether the person has been habituated to other benzodiazepines, whether s/he uses alcohol, what the intensity of anxiety is, etc. For any of these or other reasons, xanax (alprazolam) may not be the most appropriate treatment at all.