Peripherally-selective drug

Peripherally-selective drugs have their primary mechanism of action outside of the central nervous system (CNS), usually because they are excluded from the CNS by the blood-brain barrier. By being excluded from the CNS, drugs may act on the rest of the body without producing side-effects related to their effects on the brain or spinal cord. For example, most opiates cause sedation when given at a sufficiently high dose, but peripherally-selective opiates can act on the rest of the body without entering the brain and are less likely to cause sedation.^[1]

References

1. Stein, C; Zöllner, C (2009). "Opioids and sensory nerves.". Handbook of experimental pharmacology (194): 495–518. PMID 19655116.