When used for a next appointment, it means that you should contact the doctor or clinic if you need to be seen again before your scheduled appointment. This is often used for:
* Follow-up on a specific issue: The doctor may want to check in on your progress with a particular condition or treatment.
* Sudden changes or worsening symptoms: If your condition suddenly worsens or you experience new symptoms, you should contact the clinic as soon as possible.
* Concerns or questions: You can always contact the doctor if you have any questions or concerns about your health between appointments.
It's important to remember that "prn" doesn't mean you can schedule your next appointment whenever you like. It means you should contact the clinic for instructions or to schedule a new appointment if your condition requires it.