Dried Blood Spot Sampling for Tacrolimus and Mycophenolic Acid in Children: Analytical and Clinical Validation.

Background: Tacrolimus and mycophenolic acid (MPA) are the backbone of immunosuppressive therapy after pediatric kidney transplantation. Dosing of these drugs is individualized by therapeutic drug monitoring. Dried blood spot (DBS) sampling may prove beneficial over conventional venous sampling.

Quantitative analysis of morphine in dried blood spots by using morphine-d3 pre-impregnated dried blood spot cards.

Two different internal standard dried blood spot (DBS) pre-impregnation procedures (prior to blood spotting) were investigated. In the first procedure DBS pre-impregnation is performed by immersing the DBS card fully into an internal standard solution. In the second procedure pre-impregnation is performed by pipetting a certain volume of an internal standard solution onto the DBS card.

Effect of mild diarrhea on tacrolimus exposure.

Background: Diarrhea is a frequent adverse event in patients treated with the combination of tacrolimus and mycophenolate mofetil (MMF). In case of severe diarrhea, the total exposure to tacrolimus can substantially increase, which is reflected in a rise of the predose trough level (C0). In mild diarrhea (two to three stools per day), an increased exposure might occur without trough levels exceeding the target range, resulting in "silent" chronic tacrolimus overexposure.