TABLE 3

ED₅₀ estimates for hydrocodone-, hydromorphone-, and norhydrocodone-induced seizure activity

Route of Administration^{^a}	ED₅₀ (95% Cl)
Route of Administration^{^a}	HYC	HYM	NHYC
Intrathecal (μg/mouse)	19.43 (12.63–31.63)	5.25 (3.54–8.27)	4.27 (2.89–6.76)

↵^a Mice were injected intrathecally with an opioid agonist and observed for seizure activity as described in Materials and Methods.