This article reviews dried blood spot (DBS) sampling in therapeutic drug monitoring. The DBS method involves applying whole blood obtained via a fingerprick to a sampling paper. After drying and transportation, the blood spot is extracted and analyzed in the laboratory. Assays of many medicines in DBS have already been reported in the literature and are reviewed here. The technique involved in and factors that may influence the accuracy and reproducibility of DBS methods are also discussed. DBS sampling ultimately seems to be a useful technique for therapeutic drug monitoring that could have many advantages in comparison with conventional venous sampling. However, its benefits must be weighed against the degree of potential errors introduced via the sampling method; there is evidently a need for more standardization, quality assurance, basic research, and assay development.
SUMMARYPurpose: Psychogenic nonepileptic seizures (PNES) have long been considered as paroxysmal dissociative symptoms characterized by an alteration of attentional functions caused by severe stress or trauma. Although interpersonal trauma is common in PNES, the proposed relation between trauma and attentional functions remains under explored. We examined the attentional processing of social threat in PNES in relation to interpersonal trauma and acute psychological stress. Methods: A masked emotional Stroop test, comparing color-naming latencies for backwardly masked angry, neutral, and happy faces, was administered to 19 unmedicated patients with PNES and 20 matched healthy controls, at baseline and in a stress condition. Stress was induced by means of the Trier Social Stress Test and physiologic stress parameters, such as heart rate variability (HRV) and cortisol, were measured throughout the experiment. Results: No group differences related to the acute stress induction were found. Compared to controls, however, patients displayed a positive attentional bias for masked angry faces at baseline, which was correlated to self-reported sexual trauma. Moreover, patients showed lower HRV at baseline and during recovery. Discussion: These findings are suggestive of a state of hypervigilance in patients with PNES. The relation with self-reported trauma, moreover, offers the first evidence linking psychological risk factors to altered information processing in PNES.
The authors describe 12 pregnancies in women with epilepsy using lamotrigine (LTG) monotherapy. A seizure increase in nine pregnancies was probably related to a gradual decline of LTG level-to-dose ratio to 40% of baseline. After delivery, LTG kinetics returned swiftly to baseline, causing toxic side effects in some women. Frequent LTG level monitoring and appropriate dose adjustments are advised in the period before and during pregnancy and after delivery, especially in women on LTG monotherapy.
Summary:Purpose: Overexpression of multidrug transporters such as P-glycoprotein (P-gp) may play a significant role in pharmacoresistance, by preventing antiepileptic drugs (AEDs) from reaching their targets in the brain. Until now, many studies have described increased P-gp expression in epileptic tissue or have shown that several AEDs act as substrates for P-gp. However, definitive proof showing the functional involvement of P-gp in pharmacoresistance is still lacking. Here we tested whether P-gp contributes to pharmacoresistance to phenytoin (PHT) by using a specific P-gp inhibitor in a model of spontaneous seizures in rats.Methods: The effects of PHT on spontaneous seizure activity were investigated in the electrical post-status epilepticus rat model for temporal lobe epilepsy, before and after administration of tariquidar (TQD), a selective inhibitor of P-gp.Results: A 7-day treatment with therapeutic doses of PHT suppressed spontaneous seizure activity in rats, but only partially.However, an almost complete control of seizures by PHT (93 ± 7%) was obtained in all rats when PHT was coadministered with TQD. This specific P-gp inhibitor was effective in improving the anticonvulsive action of PHT during the first 3-4 days of the treatment. Western blot analysis confirmed P-gp upregulation in epileptic brains (140-200% of control levels), along with ∼20% reduced PHT brain levels. Inhibition of P-gp by TQD significantly increased PHT brain levels in chronic epileptic rats.Conclusions: These findings show that TQD significantly improves the anticonvulsive action of PHT, thus establishing a proof-of-concept that the administration of AEDs in combination with P-gp inhibitors may be a promising therapeutic strategy in pharmacoresistant patients.
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