You're picking up a prescription and wondering whether to mention cannabis. Maybe you don't want a lecture. Maybe you're not sure the pharmacist needs to know.
You can keep it simple: “I use cannabis. Is there anything I should know with this medicine?”
For CBD in particular, the FDA identifies medication interactions as a concern. Interactions can change how medicines work, including their side effects. It's worth asking someone who can review your actual medication list.
Bring something specific
A photo of the package helps more than a broad description like “something for sleep.” Include the ingredients if you have them. Mention other prescriptions, nonprescription medicines, and supplements, along with anything you've recently started or stopped.
If you've felt different, describe the change plainly. “I've been unusually sleepy since last week” gives the pharmacist something to work with. You don't have to decide in advance which product caused it.
Ask for a private conversation if you'd be more comfortable away from the counter. If you're unsure about a label, show it rather than guessing.
Don't change a prescription's timing or amount on your own to make the combination work. Let the pharmacist or prescribing clinician help with the next step. The point is to get advice that fits what you're actually taking.