The quantity reflects the rate of drug elimination divided by plasma concentration. Each download lippincott pharmacology pdf has a specific clearance that depends on its filtration characteristics.
It can refer to the amount of drug removed from the whole body per unit time, or in some cases the inter-compartmental clearances can be discussed referring to redistribution between body compartments such as plasma, muscle, fat. It is derived from a mass balance. There is an important relationship between clearance, elimination half-life and distribution volume. This means, for example, that an increase in elimination rate half-life results in an increased total clearance, provided distribution volume is constant. Derivation of these equations can be found in e. This decreases clearance compared to what would have been the case if the substance did not bind to protein. Bowman’s capsule, because the relative increases in concentrations of substance-protein and non-occupied protein are equal and therefore give no net binding or dissociation of substances from plasma proteins, thus giving a constant plasma concentration of free substance throughout the glomerulus, which also would have been the case without any plasma protein binding.
If one assumes that the volume change is not significant, i. The development of the clearance concept”. Accessed on: Sept 2, 2007. The genesis of the square meter-hour hypothesis”. Ritter J, Flower R, Henderson G, Rang H. The current place of urea kinetic modelling with respect to different dialysis modalities”.
Also, for clearance via bile please see: Estimation of Biliary Excretion of Foreign Compounds Using Properties of Molecular Structure. This page was last edited on 3 December 2017, at 18:16. This article is about lithium as a medication. Lithium is taken by mouth.
Blood level monitoring is recommended to decrease the risk of potential toxicity. How they work is not specifically known. In the United States at usual doses it costs about 0. This benefit is not seen with other medications.
The required dosage is slightly less than the toxic level, requiring close monitoring of blood levels of lithium carbonate during treatment. A limited amount of evidence suggests lithium carbonate may contribute to treatment of substance abuse for some people with bipolar disorder. High levels of naturally occurring lithium in drinking water have been associated with lower rates of suicide. Dehydration, which is compounded by heat, can result in increasing lithium levels. This causes an inability to concentrate urine, leading to consequent loss of body water and thirst.
Lithium concentrations in whole blood, plasma, serum or urine may be measured using instrumental techniques as a guide to therapy, to confirm the diagnosis in potential poisoning victims or to assist in the forensic investigation in a case of fatal overdosage. Serum lithium concentrations are usually in the 0. Doses are adjusted to achieve plasma concentrations of 0. 12 hours after the preceding dose. Sources for the following lists. Weight gain may be a source of low self-esteem for the clinically depressed.