I have a benign brain tumor, but I've been off meds for a good 5 days now. Is it safe for me to drink alcohol?

Maybe. Alcohol in moderation should not complicate a "benign" brain tumor such as a meningioma or schwannoma. If you have a low grade glioma, then the tumor is not really benign. Whether your liver can tolerate the alcohol may depend on what drugs you have been on which were just stopped. Consult your doctors before drinking.