Theoph: Pharmacokinetics of theophylline

Description

The Theoph data frame has 132 rows and 5 columns of data from an experiment on the pharmacokinetics of theophylline.

Usage

Theoph

Arguments

Format

This data frame contains the following columns:

Subject: a factor with levels A, …, L identifying the subject on whom the observation was made.
Wt: weight of the subject (kg).
Dose: dose of theophylline administered orally to the subject (mg/kg).
Time: time since drug administration when the sample was drawn (hr).
conc: theophylline concentration in the sample (mg/L).

Details

Boeckmann, Sheiner and Beal (1994) report data from a study by Dr. Robert Upton of the kinetics of the anti-asthmatic drug theophylline. Twelve subjects were given oral doses of theophylline then serum concentrations were measured at 11 time points over the next 25 hours.

These data are analyzed in Davidian and Giltinan (1995) and Pinheiro and Bates (2000) using a two-compartment open pharmacokinetic model, for which a self-starting model function, SSfol, is available.

Examples

Run this code

# NOT RUN {
require(lattice)
xyplot(conc ~ Time | Subject, Theoph, aspect = 'xy',
     xlab = "Time since drug administration (hr)",
     ylab = "Theophylline concentration (mg/L)")
Theoph.D <- subset(Theoph, Subject == "D")
fm1 <- nls(conc ~ SSfol(Dose, Time, lKe, lKa, lCl),
           data = Theoph.D)
summary(fm1)
plot(conc ~ Time, data = Theoph.D,
     xlab = "Time since drug administration (hr)",
     ylab = "Theophylline concentration (mg/L)",
     main = "Observed concentrations and fitted model",
     sub  = "Theophylline data - Subject 4 only",
     las = 1, col = 4)
xvals <- seq(0, par("usr")[2], len = 55)
lines(xvals, predict(fm1, newdata = list(Time = xvals)),
      col = 4)
# }