Summary
Displacement of one drug by another from blood and/or tissue protein will alter the pharmacokinetic behaviour of the displaced drug. For restrictively cleared drugs, displacement from blood proteins will cause only a transient change in free drug concentration and hence in pharmacodynamic response, so that dosage adjustments are rarely necessary. Total drug concentrations, however, are decreased and must be appropriately interpreted. Binding displacement from blood and/or tissue will also shorten the half-lives of these drugs, thus magnifying peak-trough differences during a dosage interval. These theoretical expectations are supported by examples of drug displacement interactions involving warfarin and phenytoin.
Although total drug concentrations in blood will be unchanged, free drug concentrations will be increased and drug response enhanced for non-restrictively cleared drugs as a result of displacement from blood protein, possibly necessitating a dosage reduction.
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References
Breckenridge, A. and Orme, M.: Clinical implications of enzyme induction. Annals of the New York Academy of Sciences 170: 421–431 (1971).
Cheng, Y. and Prusoff, W.H.: Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reaction. Biochemical Pharmacology 22: 3099–3108 (1973).
Evans, G.H. and Shand, D.G.: Disposition of propranolol. VI. Independent variation in steady-state circulating drug concentration and half-life as a result of plasma drug binding in man. Clinical Pharmacology and Therapeutics 14: 494–500 (1973).
Gibaldi, M.; Levy, G. and McNamara, P.J.: Effect of plasma protein and tissue binding on the biologic half-life of drugs. Clinical Pharmacology and Therapeutics 24: 1–4 (1978).
Gibaldi, M. and McNamara, P.J.: Apparent volumes of distribution and drug binding to plasma proteins and tissues. European Journal of Clinical Pharmacology 13: 373–380 (1978).
Gillette, J.R.: Factors affecting drug metabolism. Annals of the New York Academy of Sciences 179: 43–66 (1971).
Klotz, U.; Antonin, K.H. and Bieck, P.R.: Pharmacokinetics and plasma binding of diazepam in man, dog, rabbit, guinea pig and rat. Journal of Pharmacology and Experimental Therapcutics 199: 67–73 (1976).
Koch-Weser, J. and Sellers, E.M.: Drug therapy. Binding of drugs to serum albumin. Part I. New England Journal of Medicine 294: 311–316 (1976).
Komhauser, D.M.; Wood, A.J.J.; Vestal, R.E.; Wilkinson, G.R.; Branch, R.A. and Shand, D.G.: Biological determinants of propranolol disposition in man. Clinical Pharmacology and Therapeutics 23: 165–174 (1978).
Lewis, R.J.; Trager, W.F.; Chan, K.K.; Breckenridge, A.; Orme, M.; Rowland, M. and Senary, W.: Warfarin. Stereochemical aspects of its metabolism and the interaction with phenyl-butazone. Journal of Clinical Investigation 53: 1607–1617 (1974).
Leonard, R.F.; Knott, P.J.; Rankin, G.O.; Robinson, D.S. and Melnick, D.E.: Phenytoin-salicylate interaction. Clinical Pharmacology and Therapeutics 29: 56–60 (1981).
Lima, J.J.; Boudoulas, H. and Blanford, M.F.: Concentration dependence of disopyramide binding to serum protein and its influence on kinetics and dynamics. Journal of Pharmacology and Experimental Therapeutics 219: 741–747 (1981).
MacKichan, J.J.; Jusko, W.J.; Duffner, P.K. and Cohen, M.E.: Liquid Chromatographie assay of diazepam and its major metabolites in plasma. Clinical Chemistry 25: 856–859 (1979).
MacKichan, J. and Zola, E.M.: Carbamazepine binding to plasma, albumin and alpha-1-acid glycoprotein. Clinical Pharmacology and Therapeutics 31: 246–247 (1982).
McDevitt, D.G.; Frisk-Holmberg, M.; Hollinfield, J.W. and Shand, D.G.: Plasma binding and the affinity of propranolol for beta-receptors in man. Clinical Pharmacology and Therapeutics 20: 152–157 (1976).
McNamara, P.J.; Slaughter, R.L.; Pieper, J.A.; Wyman, M.G. and Lalka, D.: Factors influencing serum protein binding of lidocaine in humans. Anesthesia and Analgesia 60: 395–400 (1981).
Monks, A. and Richens, A.: Effect of single doses of sodium val-proate on serum phenytoin levels and protein binding in epileptic patients. Clinical Pharmacology and Therapeutics 27: 89–86 (1980).
O’Reilly, R.A. and Levy, G.: Pharmacokinetic analysis of potentiating effect of phenylbutazone on anticoagulant action of warfarin in man. Journal of Pharmaceutical Sciences 59: 1258–1261 (1970).
Orr, J.M.; Abbott, F.S.; Farrell, K.; Ferguson, S.; Sheppard, I. and Godolphin, W.: Interaction between valproic acid and aspirin in epileptic children: Serum protein binding and metabolic effects. Clinical Pharmacology and Therapeutics 31: 642–649 (1982).
Paxton, J.W.: Effects of aspirin on salivary and serum phenytoin kinetics in healthy subjects. Clinical Pharmacology and Therapeutics 27: 170–178 (1980).
Perucca, E.; Hebdige, S.; Frigo, G.M.; Gatti, G.; Lecchini, S. and Crema, A.: Interaction between phenytoin and valproic acid: Plasma protein binding and metabolic effects. Clinical Pharmacology and Therapeutics 28: 779–780 (1980).
Piafsky, K.M.: Disease-induced changes in the plasma binding of basic drugs. Clinical Pharmacokinetics 5: 246–262 (1980).
Sellers, E.M.: Plasma protein displacement interactions are rarely of clinical significance. Pharmacology 18: 225–227 (1979).
Sellers, E.M. and Koch-Weser, J.: Potentiation of warfarin induced hypoprothrombinemia by chloral hydrate. New England Journal of Medicine 283: 827–831 (1970).
Sellers, E.M.; Lang, M.; Koch-Weser, J. and Colman, R.W.: Enhancement of warfarin-induced hypoprothrombinemia by triclofos. Clinical Pharmacology and Therapeutics 13: 911–915 (1972).
Shand, D.G.; Colham, R.H. and Wilkinson, G.R.: Perfusion-limited effects of plasma drug binding on hepatic drug extraction. Life Sciences 19: 125–130 (1976).
Sudlow, G.; Birkett, D.J. and Wade, D.N.: The characterization of two specific drug binding sites on human serum albumin. Molecular Pharmacology 11: 824–832 (1975).
Udall, J.A.: Drug interference with warfarin therapy. Clinical Medicine 77: 20–15 (1970).
Udall, J.A.: Warfarin-chloral hydrate interaction. Pharmacological activity and clinical significance. Annals of Internal Medicine 81: 341–344 (1974).
Wilkinson, G.R. and Shand, D.G.: Commentary. A physiologic approach to hepatic drug clearance. Clinical Pharmacology and Therapeutics 18: 377–390 (1975).
Yacobi, A.; Udall, J.A. and Levy, G.: Serum protein binding as a determinant of warfarin body clearance and anticoagulant effect. Clinical Pharmacology and Therapeutics 19: 552–558 (1975).
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MacKichan, J.J. Pharmacokinetic Consequences of Drug Displacement from Blood and Tissue Proteins. Clin Pharmacokinet 9 (Suppl 1), 32–41 (1984). https://doi.org/10.2165/00003088-198400091-00005
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DOI: https://doi.org/10.2165/00003088-198400091-00005