Chapter 17 - Page 2 - Java 1

Linear Plot of Morphine Concentration versus Time after Codeine Administration


Try simulating morphine concentration versus time after oral codeine administration. Select individuals with low, intermediate or high CYP2D6 activity. Add additional lines with different parameter values using the Add Line button.

Figure 1701a A Simplified Pharmacokinetic Model for Codeine Transformation into Morphine

The model in Figure 1701a is a simplification of codeine and morphine pharmacokinetics. Codeine is metabolized to a variety of compounds including morphine. Also, both codeine and morphine are probably better described using a two compartment model.

The lines in the plot above were calculated using Equation 1701a, derived from the model, Figure 1701a, for codeine metabolism using Laplace transforms.

Equation 1701a Concentration of Morphine after Oral Administration of Codeine

Table 1701a Some Parameters Describing Codeine Metabolism

Parameter Value Units
Dose 30 mg
F 0.51
ka 2.282 hr-1
kel (codeine) 0.211 hr-1
Vd (morphine) 701 L
kel (morphine) 0.31 hr-1
km (high) 0.0135 hr-1
km (intermediate) 0.00659 hr-1
km (low) 0.000610 hr-1
References and Notes

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