Ibuprofen With or Without Dexamethasone for Acute Radicular Low Back Pain.

Inclusion Criteria: * Present to ED primarily for management of acute radicular LBP, defined as pain or paresthesia originating from the lower back and radiating to the buttock and or leg in a radicular pattern. Some patients may not have prominent LBP but a radicular symptom--we will include these patients as well. * Patient is to be discharged home. * Age 18-70 Enrollment will be limited to adults \<70 years because of the increased risk of adverse medication effects in older adults. * Pain duration \<2 week * Prior to the acute attack of radicular LBP, back pain cannot occur more frequently than half of the days in the last 3 months. Patients with more frequent back pain/sciatica are at increased risk of poor pain and functional outcomes.10 * Non-traumatic cause of pain: no substantial and direct trauma to the back within the previous month * Functionally impairing radicular LBP: A baseline score of \> 5 on the Roland-Morris Disability Questionnaire Exclusion Criteria: * Not available for follow-up * Pregnant * Chronic pain syndrome defined as use of any analgesic medication on a daily or near-daily basis * Allergic to or intolerant of investigational medications * Chronic steroid use * Contra-indications to investigational medications: 1) known peptic ulcer disease, chronic dyspepsia, or history of gastrointestinal bleed 2) Severe heart failure (NYHA 2 or worse) 3) Chronic kidney disease (GFR \<60ml/min) 4) Current use of anti-coagulants 5) cirrhosis (Child Pugh A or worse) or hepatitis (transaminases 2x the upper limit of normal)