The influence of body posture on lithium clearance

Kamper, Anne-Lise; Strandgaard, Svend; Nh, Holstein-Rathlou; Munck, O.; Pp, Leyssac

doi:10.3109/00365518809085765

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…T o avoid the adverse renal effects of exogenous lithium endogenous trace levels of lithium in plasma and urine has been used for clearance measurements (Miller et al 1989, Durr et al 1990). These studies found a fractional lithium excretion of about 23% in normal humans, which is similar to values reported for exogenous lithium in humans (Holstein-Rathlou et al 1985, Kamper et al 1988, Hla et al 1989, Bruun et a!. 1989, Bruun et al 1990Niutta et al 1991;Olsen et al 1993;Dieperink et al 1993) and rats (Thomsen & Shalmi 1990).…”

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confidence: 76%

A comparison between endogenous and exogenous lithium clearance in the anaesthetized rat

Leyssac

Christensen

1994

Acta Physiologica Scandinavica

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The present study tests whether the endogenous renal lithium clearance (CLi) may be used as an alternative to the conventional method in order to avoid the adverse effects of exogenous lithium on renal function. Endogenous CLi) was measured by flameless atomic absorption spectrometry (AAS) in halothane anaesthetized, laparotomized rats and compared with values obtained after subsequent intravenous (i.v.) administration of LiCl. Endogenous plasma lithium concentration (PLi) was 0.30 +/- 0.06 mumol l-1. When measured by both conventional flame emission AAS and flameless AAS on the same samples, values for PLi did not differ significantly. Endogenous CL1/GFR was 0.195 +/- 0.01 (mean +/- SEM). Amiloride caused on significant change in either the endogenous CLi or 51Cr-EDTA clearance, a measure of glomerular filtration rate (GFR), but it caused a significant increase in CNa. Administration of exogenous Li+ had no significant effect on CLi (230 +/- 33 vs. 234 +/- 35 microliters min-1 gKW-1); both urine flow and CNa increased significantly (P < 0.01) (5.4 +/- 0.4 vs. 9.6 +/- 1.3, and 2.4 +/- 0.5 vs. 10.7 +/- 2.4 microliters min-1 gKW-1, respectively). GFR and calculated proximal tubular reabsorption rate (APR) both decreased by approximately 100 microliters min-1 gKW-1 (both P < or = 0.025), suggesting a moderate inhibition of APR after the acute elevation of plasma Li+ concentration. It is concluded that the endogenous CLi may be used as an alternative to the conventional method.

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confidence: 76%

A comparison between endogenous and exogenous lithium clearance in the anaesthetized rat

Leyssac

Christensen

1994

Acta Physiologica Scandinavica

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“…After oral administration of lithium to volunteers who adopted either a supine or sitting position or walked around, lithium and sodium clearance tended fell in the sitting position and fell significantly while the subjects were walking around (30, 29 and 26 ml/min, respectively) [42]. The decreased lithium clearance was not associated with any significant change in glomerular filtration rate, indicating an increase in both the absolute and the fractional proximal tubular reabsorptive rate (APR: walking 92, supine 83 ml/min; p<0.005.…”

Section: Effects On Renal Elimination/clearancementioning

confidence: 99%

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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“…In humans, reflex maneuvers that suppress the activity of the sympathetic nervous system (e.g., change of posture from upright to supine postion or water immersion) produces an increase in CLi (Kamper et al 1988;Rabelink et al 1989). The diuretic response to loop diuretics is markedly attenuated in the upright position compared to responses in the supine position (Ring-Larsen et al 1986;Okaniwa et al 1990).…”

Section: J0rgen S0berg Petersenmentioning

confidence: 99%

Interactions Between Furosemide and the Renal Sympathetic Nerves

Petersen¹

1999

Pharmacology & Toxicology

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The influence of body posture on lithium clearance

Cited by 9 publications

References 8 publications

A comparison between endogenous and exogenous lithium clearance in the anaesthetized rat

A comparison between endogenous and exogenous lithium clearance in the anaesthetized rat

Influence of posture on pharmacokinetics

Interactions Between Furosemide and the Renal Sympathetic Nerves

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