Table 3.

Parameters in Mechanistic Models

Parameter	Meaning	Units
u	Unmitigated pain level	Pain
k0	Rate of decrease of pain in the absence of drugs or disease/sources of pain
k1	Effect of drug 1 (long-acting opioid) on pain relaxation rate
k2	Effect of drug 2 (short-acting opioid) on pain relaxation rate
k3	Effect of drug 3 (nonopioid) on pain relaxation rate
	Rate of decay of drug 1 (long-acting opioid) in body due to metabolism
	Rate of decay of drug 2 (short-acting opioid) in body due to metabolism
	Rate of decay of drug 3 (nonopioid) in body due to metabolism
	Amplitude of intrinsic noise (variability) in human subjective pain reports	T1/2
Ni	Number of standard drug i doses taken	Count
	Drug i dose times (indexed by j)	T