For pain, what else can I take besides ibuprofen if I have arrhythmia (taking anticoagulants)?

Given your situation with taking anticoagulants, it is important to be cautious with the type of pain relief medications you can take. It is advisable to avoid anti-inflammatories and opioids in the long term due to potential risks. A good initial approach for managing your back pain may involve muscle exercises and thoughtful movements tailored to your condition. Consulting a physiotherapist for personalized exercise recommendations could greatly benefit your condition without causing further issues. It is recommended to focus on exercise as a first step before considering other medication options.