Pharmacokinetic interactions transporters

Pharmacokinetic Interactions. Remember that pharmacokinetics is the study of what the body does to the medication. This includes how the body transports, inactivates (i.e., metabolizes), and eliminates the medication. Sometimes, one medication can change the way the body handles another medication. This is known as a pharmacokinetic interaction. There are two types of pharmacokinetic interactions. One type occurs in the medication transportation system, and the other occurs in the medication elimination system. 

So far, analysis has centered on metabolic drug interactions. But there are many pharmacokinetic interactions other than those occurring at enzymatic sites, such as those involving transporters or altered physiological function. 

Treiber A, Schneiter R, Delahaye S, et al. Inhibition of organic anion transporting polypeptide-mediated hepatic uptake is the major determinant in the pharmacokinetic interaction between bosentan and cyclosporin A in the rat. J Pharmacol Exp Ther 2004 308 1121-1129. 

Adefovir is excreted by the kidneys, by a combination of glomerular filtration and active secretion via the rend transporter, human Organic Anion Transporter 1 (hOATl). The potential for pharmacokinetic interactions with co-trimoxazole, ibuprofen, lamivudine, paracetamol and tenofovir (other drugs that also undergo, or may affect tubular secretion) has been investigated. ... 

Paliperidone There was no clinically significant pharmacokinetic interaction of co-tri-moxazole, an inhibitor of organic cation transport, and paliperidone, which is an organic cation that is mainly eliminated by renal excretion paliperidone did not affect steady-state plasma concentrations of trimethoprim [195 ]. 

Aliskiren In an open, multiple-dose study in healthy subjects of the pharmacokinetic interaction of aliskiren 300 mg and keto-conazole 200 mg bed (n = 21), aliskiren AUC was significantly increased by keto-conazole (by 76%) through mechanisms that most probably involved transporters such as P glycoprotein and organic aniontransporting peptide and possibly through... 

If the unbound drug concentrations in plasma are higher than their K values on the transporters, then transporter function may be significantly affected [106], Following a pharmacokinetic analysis of the effect of probenecid on the hepatobiliary excretion of methotrexate, it has been shown the extent of an in vivo drug-drug interaction can be quantitatively predicted from the kinetic parameters for transport across the sinusoidal and bile canalicular membranes determined in vitro [107]. 

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