DESCRIPTION: 
  - PK one compartment model with Tlag
  - effect compartment
  - PD model for ordered categorical data 

[LONGITUDINAL]
input = {Tlag, ka, V, Cl, ke0, alpha, beta, gamma}

EQUATION:
{Cc,Ce}= pkmodel(Tlag,ka,V,Cl,ke0)
lp1 = alpha + beta*Ce
lp2 = lp1+ gamma         ; gamma >= 0

DEFINITION:
Level = {
	type=categorical
	categories={1,2,3}
	logit(P(Level<=1)) = lp1
	logit(P(Level<=2)) = lp2
}

