Enkephalin
endogenous
What it isEndogenous delta-preferring opioid peptides.
Why this oneThey explain why delta agonism has been pursued for analgesia without the mu-related respiratory depression.
What limits itEnkephalinase inhibition was tried as a way to raise them, but selectivity has been the barrier.
NO BOXED WARNINGS
Principal riskEndogenous or dietary; no boxed warning applies