Nifedipine plasma-concentration-time curve

The time to maximum plasma-concentration (Tmax) of coadministered soluble paracetamol and nifedipine is significantly decreased when subjects are standing or lying on their right side compared with when they lie on their leftside. These postures also resulted in a significantly higher peak plasma-concentration and area imder the plasma-concentration-time curve of nifedipine. 

The area under the plasma concentration-time curve is a useful indicator of the amount of drug that reaches the systemic circulation and of the duration resides there before it is removed. The processes of ADME influence the plasma concentration-time profile of an administered drug and the associated parameters. For example, a reduction in the rate of elimination of nifedipine will result in elevated and prolonged drug levels in plasma (Figure 5). 

Fig. 1. Frequency distribution of the area under the plasma concentration versus time curve (AUC) of nifedipine in plasma after oral administration of 20 mg nifedipine to 130 healthy subjects (from [5]). There is 10-fold interindividual variability in AUC in this...

Fig. 4. Plasma concentration versus time curves of nifedipine in an individual subject after oral intake of 20 mg nifedipine on three different oeeasions without pretreatment (o), after enzyme induction (A) with pentoharhital and inhibition ( )...

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