No. It's a matter of both good medical practice and of state & federal laws.
The time since last exam may vary by state, but a valid Veterinarian-Client-Patient Relationship (VCPR) must be established, and be current enough that the doctor is comfortably knowledgeable about your pet’s health. No exam ever = no prescriptions. The doctor can’t even give you advice.
Oregon (and many states) establish one year as the allowable elapsed time since the last exam to prescribe any medication for an ongoing condition for which the doctor has seen your pet. For a new problem? A new exam is required, both legally and medically.