Before using Victoza pen, it is essential to inform your doctor if you have a history of thyroid cancer, pancreatitis, or any liver or kidney problems. You should avoid using Victoza if you or a family member has had medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2. Additionally, disclose any other medical conditions, such as slow digestion or heart issues, to ensure the medication is safe for you.