When considering if an insulin pen works with specific insulin types like Tresiba (Insulin Degludec) and Fiasp (Insulin Aspart), it's important to know that insulin pens are usually designed for specific insulin formulations.

• Tresiba is a long-acting insulin and typically requires a pen designed specifically for it or compatible with long-acting insulin cartridges.

• Fiasp is a rapid-acting insulin and usually comes with its own pen or requires a pen compatible with rapid-acting insulin.

Using the correct pen ensures accurate dosing and proper insulin delivery. If you have a pen that is not specifically made for Tresiba or Fiasp, it may not be compatible.

It's best to check the pen's instructions or consult your doctor or pharmacist to confirm compatibility. They can guide you on the right pen to use with these insulins to ensure safe and effective treatment.