1.
Valproic acid malabsorption in 30 year-old female patient - Case study.
Jopowicz, A, Piechal, A, Kurkowska-Jastrzębska, I
Neurologia i neurochirurgia polska. 2017;(3):259-262
Abstract
AIM: Valproic acid (VPA) is used in epilepsy treatment and as a stabilizer in bipolar affective disorder for over 40 years. Although, the pharmacokinetic properties of valproic acid are well known, it is often forgotten that the formulation of the drug significantly influences its gastrointestinal absorption. CASE We are describing the case of 30 year-old female patient, diagnosed at the age of 13 with juvenile myoclonic epilepsy. Complete ineffectiveness of the treatment was caused by malabsorption of sodium valproate and valproic acid in the patient. The change of the drug formulation resulted in a several times higher bioavailability of the drug and a partial improvement of the patient's clinical condition. COMMENTARY Low concentration of valproic acid after administration the slow-released tablets are usually observed. However, a low bioavailability beside the bad compliance should be considered when the minimal level is extremely low during therapy. It is known that form of the drug, beside presence of food and its components, as well as gastrointestinal tract condition or interactions with other drugs can influence the drug level. Modification of the formulation of the drug may lead to improvement of absorption and increase its effectiveness.
2.
Perspectives in cholesterol-lowering therapy: the role of ezetimibe, a new selective inhibitor of intestinal cholesterol absorption.
Bruckert, E, Giral, P, Tellier, P
Circulation. 2003;(25):3124-8
3.
A subtherapeutic international normalized ratio despite increasing doses of warfarin: could this be malabsorption?
Lara, LF, Delgado, LL, Frazee, LA, Haupt, KM, Rutecki, GW
The American journal of the medical sciences. 2000;(3):214-8
Abstract
OBJECTIVE To describe a case of warfarin resistance apparently caused by malabsorption and to review the literature regarding warfarin resistance. CASE SUMMARY A 28-year-old renal transplant patient with systemic lupus erythematosus was admitted for upper extremity thrombophlebitis. Resistance to oral warfarin was demonstrated. Potential causes were investigated. The trapezoidal rule was used to compare the area under the curve for intravenous versus oral dosing of warfarin. The usual bioavailability of warfarin should be 100%. In this patient, warfarin bioavailability after oral dosing was 1.5%. Three potential causes, malabsorption (FF), enzymatic degradation (FG), and first-pass extraction in the portal circulation (FH), are discussed. CONCLUSION This case demonstrates resistance to warfarin presumably caused by malabsorption.