CNS exposure
- The ring left of the decagon reads CNS access: no ring = enters freely (or unassessed); stub = enters but effluxed; then largely excluded, limited, kept out; "gut only" = never systemic.
- The label gives the REASON — size, charge, H₂O, P-gp / BCRP — not the intensity.
Not a mechanism or drug peg. This card explains the ballicule’s CNS-access ring and applies wherever that ring is drawn.
Self-check
- What does a stub on the CNS-access ring mean?
Enters the CNS but is effluxed. - Does the CNS-access label describe the reason or intensity of exclusion?
The reason.