ABSTRACT
Pure mu-opioid-receptor agonists do not have ceiling doses in the conventional sense; their “ceiling” is dened mainly by their toxicity (VellaBrincat and Macleod 2007). As a general rule, opioid toxicity is dose related (Ripamonti et al. 1997). Partial mu-opioid-receptor agonists and kappa-opioid-receptor agonists do possess a dose ceiling (Vella-Brincat and Macleod 2007) and may also have treatment-limiting toxicities.
