Here is a review of this subject for antibacterial drugs:

Article The Effects of Hypoalbuminaemia on Optimizing Antibacterial ...

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Low serum albumin levels are very common in critically ill patients, with reported incidences as high as 40-50%. This condition appears to be associated with alterations in the degree of protein binding of many highly protein-bound antibacterials, which lead to altered pharmacokinetics and pharmacodynamics, although this topic is infrequently considered in daily clinical practice. The effects of hypoalbuminaemia on pharmacokinetics are driven by the decrease in the extent of antibacterial bound to albumin, which increases the unbound fraction of the drug. Unlike the fraction bound to plasma proteins, the unbound fraction is the only fraction available for distribution and clearance from the plasma (central compartment). Hence, hypoalbuminaemia is likely to increase the apparent total volume of distribution (Vd) and clearance (CL) of a drug, which would translate to lower antibacterial exposures that might compromise the attainment of pharmacodynamic targets, especially for time-dependent antibacterials. The effect of hypoalbuminaemia on unbound concentrations is also likely to have an important impact on pharmacodynamics, but there is very little information available on this area. The objectives of this review were to identify the original research papers that report variations in the highly protein-bound antibacterial pharmacokinetics (mainly Vd and CL) in critically ill patients with hypoalbuminaemia and without renal failure, and subsequently to interpret the consequences for antibacterial dosing. All relevant articles that described the pharmacokinetics and/or pharmacodynamics of highly protein-bound antibacterials in critically ill patients with hypoalbuminaemia and conserved renal function were reviewed.

Thank you Zaim Gashi , Adam B Shapiro and Asemoloye Micheal Dare for you response. But how can we modify the dose w.r.t to the protein level in the body?

Wonderful question, I guess there are no as such guidelines for said above question. Even I am curious to know the answer, even one can choose this as a research area.

Thank you @manik. I have got few more clarification regarding this perticular problem.

1. If we know the amount of free drug present in the body, we can adjust the dose. But problem is financial constraints w.r.t TDM process.

2. Develop a PK model for individual drugs and extrapolation. Accuracy will be a concern here.

Let us know if you got anymore details

Thank you

It's very important to consider this in practice particularly for narrow therapeutic index drugs but as Dr. Subeesh has mentioned practically its not that much easy as it will increase the financial burden. In my opinion, at least for critically ill patients, it should be considered as a small increased and a decreased level of free drug concentration could result in the death of the patients.

Recently, in our lab, we have conducted binding studies of some molecules with BSA (more than 70% similar to serum albumin) by using spectroscopic and in silico techniques. The free drug concentration and the binding mechanism were determined but we have not considered hypoalbuminemia condition. In further experiments, we will consider this one also. Thanks, Dr. Subeesh and Dr. Manik for discussing such an important question.