Pre-treatment With Azithromycin to Reduce Immunogenicity to to Anti-TNF Agents in Patients With Crohn's Disease

This study tests whether taking an antibiotic called azithromycin before starting a biologic medication (anti-TNF agent) for Crohn's disease helps reduce the chance the body develops antibodies against the medication. When the immune system targets the biologic drug, it stops working — a major problem in Crohn's management. **You may be eligible if...** - You are age 18 to 80 - You have been diagnosed with Crohn's disease - You are about to start a new anti-TNF medication (such as infliximab or adalimumab) and have not taken these before - You are willing to attend all study visits and follow the study procedures **You may NOT be eligible if...** - You have already taken an anti-TNF medication for Crohn's disease - You have a known allergy to azithromycin or similar antibiotics - You are pregnant or planning to become pregnant - You have serious liver disease or abnormal heart rhythm (QT prolongation) Talk to your doctor to see if this trial is right for you.