Loading Dose

[neuroiscool42]

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Do low levels of albumin call for a lower loading dose or maintenance dose of a drug? One way I was thinking about it is that a lower loading dose would be required because low albumin levels may indicate a higher volume of distribution so more drug can enter the body (ie tissues) with a lower dose. However, I also learned the equation, LD= Css x Vd, which shows loading dose and volume of distribution having a directly proportional relationship, which would mean increase in Vd leads to increase in LD. This contradicts the statement I just mentioned about needing a lower dose. I would appreciate it if anybody could point out any mistakes in my understanding.

 

[funtertaining15]

So since the albumin levels are associated with whether the drug is able to get into tissues or not, less albumin would mean that more drug is easily floating around, and so for pt w/ liver dz who aren't making the albumin as much, the loading dose is unaffected, bc it just means that the 1 dose you give them will get into more cells, but other doses after that ie the maintenance dose would have to decrease b/c that equation is plasma conc times the clearance, and since the clearance would be affected especially if it is lipophilic and dep on p450, it would stay in the body longer. Not sure if this explanation helped at all...