The influence of posture on the pharmacokinetics of orally administered nifedipine.

Renwick, A. G.; Ahsan, C. H.; Challenor, V. F.; Daniels, Regina; Macklin, B. S.; Waller, Derek G.; George, C. F.

doi:10.1111/j.1365-2125.1992.tb05639.x

Cited by 40 publications

(49 citation statements)

References 19 publications

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“…Similarly, Culbertson et al also reported a mean 37% reduction of estimated hepatic blood flow in the standing compared to supine position [36]. Changes in splanchnic-hepatic blood flow may substantially affect the absorption and metabolism of orally administered drugs, especially of those with a high firstpass metabolism [1,18]. In cases of partial saturation of first-pass metabolism, overall systemic bioavailability can depend on the rate of absorption [37] and, therefore, on posture as well.…”

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

“…In the case of saturable absorption kinetics (e.g. amoxycillin [17]) and if there is a small "absorption window", accelerated gastric emptying may decrease overall systemic bioavailability [1,18]. Usually, as has been shown for a solution of acetaminophen (20 mg/kg), the first-order rate constant for drug transfer from the intestinal lumen into the systemic circulation is greater than the first-order rate constant for gastric emptying [19].…”

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

“…As shown in Table 2, several studies, for example, with paracetamol [18,20,21], nifedipine [18], amoxycillin [22] and theophylline [23], have found an increase in the time to reach the maximum serum drug concentration (t max )/mean residence time (MRT) and/or a decrease in maximum plasma drug concentration (C max )/ (early) AUC for left lateral and supine position compared to other positions (right lateral, prone, sitting, standing). The effects of the respective postures on pharmacokinetics correspond to their effects on gastric emptying, as discussed above (left lateral and supine positions tend to decrease the rate of gastric emptying).…”

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

“…standing, sitting and recumbent right) may cause a transient saturation of first-pass metabolism due to the more rapid delivery of the agent to the metabolizing enzymes in the gut wall and liver. This is especially true if the administered drugs are absorbed rapidly after gastric emptying and undergo extensive presystemic elimination, as faster gastric emptying may increase the overall bioavailability of drugs with saturable first-pass metabolism, such as propranolol [39], nifedipine [18] and ethanol [51]. On the other hand, slower absorption may decrease overall systemic availability [37].…”

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

“…Consequently, gastric emptying, which is predominantly pulsatile, is the ratelimiting step in the early phase of absorption of orally administered drugs (provided the drug is well absorbed/ highly soluble according to the Biopharmaceutics Classification System classification and given as a solution or rapidly dissolving dosage form; if dissolution is slow, it is rate-limiting). As posture is known to influence gastric emptying [1,5,18], in many cases the rate-limiting step for absorption can be influenced by posture. Moreover, in addition to the factors discussed above, it may also depend on posture as to whether the rate-limiting step is dissolution or gastric emptying, with respective consequences for the pharmacokinetic profile.…”

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

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Influence of posture on pharmacokinetics

Queckenberg

Fuhr

2008

Eur J Clin Pharmacol

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Introduction Body position may influence physiological characteristics, such as perfusion, gastrointestinal function and plasma volume. These characteristics may interact with key factors determining the pharmacokinetics of drugs (dissolution, absorption, distribution, metabolism, excretion). Objectives Based on a systematic literature search, current data on the effect of posture on physiological characteristics and/or pharmacokinetics are summarized, and the relevance of possible effects, such as those presenting in clinical practice and clinical pharmacokinetic studies, is assessed. Results Postures which favour rapid gastric emptying (sitting, standing, recumbent right) accelerate the absorption of orally administered drugs. Consequently, these postures favour a shorter time to reach peak plasma drug concentration (t max ) and a higher maximum plasma drug concentration (C max ) and-in the case of transient saturation of first-pass metabolism-total exposure (area under the concentration-time curve, AUC) in comparison to recumbent left and supine positions (e.g. nifedipine: AUC 30 and 38% higher in standing and right lateral position vs. left lateral position; C max 149 and 80% higher, respectively). The magnitude of these postural effects depends strongly on the nature and amount of liquids and food ingested before drug administration and is most pronounced in the fasting state and after administration with a nonnutrient liquid. Changes in splanchnic-hepatic blood flow (e.g. reduction of estimated hepatic perfusion by 37% in standing vs. supine position) may substantially affect the metabolism of orally administered drugs, especially of those with a high/saturable first-pass metabolism. For highly protein-bound drugs (e.g. phenytoin, imipramine), the total plasma concentration has been found to be approximately 10% higher in standing than lying subjects due to changes in plasma volume. Conclusions Positioning of a patient may be an effective method of enhancing or retarding absorption of some drugs in appropriate clinical situations (e.g. toxic ingestions, bedridden patients). In clinical pharmacokinetic trials, such as bioequivalence studies, defining and maintaining posture precisely is a useful approach for reducing within-and between-subject variability.Keywords Absorption . Gastric emptying . Pharmacokinetics . Posture IntroductionThe influence of body position on physiological characteristics and pharmacokinetics has been investigated for several decades. The first study on this topic (effects of posture on gastric emptying) was reported to have been performed as early as 1918 [1] when it was observed that barium was emptied faster when subjects lay on the right side compared to other positions. Since then, a multitude of studies has addressed various aspects of postural effects, especially those on gastrointestinal motility, haematological parameters/perfusion and the pharmacokinetics of orally administered drugs.

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Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

Section: Effects Of Posture On the Absorption Of Orally Administered mentioning

confidence: 99%

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Influence of posture on pharmacokinetics

Queckenberg

Fuhr

2008

Eur J Clin Pharmacol

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Oral Paracetamol Bioavailability in Rats Subjected to Experimental Spinal Cord Injury

Garcı́a-López

Pèrez‐Urizar

Madrazo

et al. 1997

Biopharm. Drug Dispos.

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Additional Factors Affecting Plasma Concentrations

2016

Introduction to Drug Disposition and Pharmacokinetics

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The influence of posture on the pharmacokinetics of orally administered nifedipine.

Cited by 40 publications

References 19 publications

Influence of posture on pharmacokinetics

Influence of posture on pharmacokinetics

Oral Paracetamol Bioavailability in Rats Subjected to Experimental Spinal Cord Injury

Additional Factors Affecting Plasma Concentrations

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