Patients w/ predisposing factors of urinary retention eg, spinal cord lesion, prostatic hyperplasia; epilepsy, at risk of convulsion. Neuropsychiatric events, eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, neuropathy. Allow 3-day wash-out period prior to allergy skin tests. Avoid aspirin or NSAIDs in patients w/ known aspirin sensitivity. Concurrent use w/ alcohol. May affect ability to drive & use machines. Moderate to severe renal impairment. Pregnancy & lactation. Not recommended in paed & adolescents <18 yr.