Medicare supplement plans, also known as Medigap plans, are designed to help cover out-of-pocket costs of Original Medicare, such as deductibles, coinsurance, and copayments. These plans do not include prescription drug coverage. On the other hand, Medicare Part D plans are standalone prescription drug plans that provide coverage for your prescription medications. These plans are offered by private insurance companies approved by Medicare. It’s important to note that you cannot have a Medicare supplement plan and a Medicare Part D plan at the same time. If you have a Medicare supplement plan and want prescription drug coverage, you would need to enroll in a standalone Part D plan.