Identification and determination of opipramol metabolites in plasma and urine.

In six cases of suspected opipramol overdose, commercially available immunoassays for tricyclic antidepressants (TCA) EMIT tox serum Assay and ADxR serum TCA Assay indicated arbitrarily high or toxic TCA concentrations. However, opipramol concentrations determined by high-performance liquid chromatography (HPLC) analysis were in the high-normal or low-toxic range. This finding prompted us to study opipramol metabolism by mass spectral techniques and to determine the cross-reactivity of opipramol and its metabolites in immunoassays. Three previously unknown metabolites (I, II, V) included an oxidation product of the hydroxyethyl moiety to an acetic acid group at the piperazine side chain (1), a decarboxylation product of the latter metabolite (II), and opipramol-N-oxide (V). In addition, two previously reported metabolites were identified, which included a deshydroxyethyl metabolite (III) and dibenzazepine (IV). One of the major metabolites of opipramol is the acetic acid metabolite (I), which may exceed the opipramol plasma concentration immensely and contribute to an arbitrarily high concentration in commercially available immunoassays. The cross-reactivities of the metabolite (I) were determined to be 64 and 66% with EMIT and ADx, respectively.

Prophylactic oral ganciclovir after renal transplantation-dosing and pharmacokinetics.

Ganciclovir alone or in combination with hyperimmunoglobulin is replacing other treatment modalities for the prophylactic treatment of cytomegalovirus (CMV) infections. No dose recommendations are available for oral ganciclovir therapy in children with impaired renal function after renal transplantation of a kidney from a CMV IgG-positive donor. We undertook a pharmacokinetic study in 14 pediatric renal transplant recipients who were CMV IgG negative and had received a graft from a CMV IgG-positive donor. We estimated the daily dosage of oral ganciclovir in relation to the glomerular filtration rate (GFR). Oral ganciclovir was administered at a starting dose of 3 x 1 g for children with a weight above 50 kg, 3 x 750 mg for children between 50 and 37.5 kg, and 3 x 500 mg for children between 37.5 and 24 kg. The starting dose was reduced by 50% for GFR values < or = 50 ml/min per 1.73 m2 and by 75% for GFR values < or = 25 ml/min per 1.73 m2. The daily dose was divided into three daily doses unless GFR was < 40 ml/ min per 1.73 m2, when only two daily doses were given. Doses were adjusted according to the measured plasma trough concentrations (c) using the simple formula: c(ganciclovir)(measured)/c(ganciclovir)(desired) = dosage rate(used)/dosage rate(adjusted). Mean stable plasma trough concentration was 0.91 +/- 0.68 microg/ml. The dosage rate, adjusted to a trough concentration of 1.0 microg/ml, correlated with the GFR. The dose per day could be calculated according to a simple equation for a GFR < 100 ml/min per 1.73 m2: dosage per day (mg/kg per day) = GFR. No CMV disease developed in any of the patients during oral ganciclovir, but 1 patient developed an acute rejection episode and a positive pp65 antigen 5 weeks after discontinuation of ganciclovir. The drug was well tolerated and without side effects.

Fatal poisoning with detajmium: identification of detajmium and its metabolites and artifacts by gas chromatography-mass spectrometry and quantification by high-performance liquid chromatography.

After ingestion of an unknown dose of detajmium, a 14-year-old female collapsed with asystolia. Resuscitation efforts were not successful. A medicolegal autopsy was carried out, and blood, liver and gastric content were extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). After derivatization with acetic anhydride, detajmium and twelve of its derivatives and metabolites were identified. The main metabolic pathways include hydroxylation and subsequent O-methylation of the indol ring, and oxidation as well as reduction of the C-21 hydroxyl function. Cleavage of the N-alkyl side-chain is a further, possibly non-enzymatic degradation pathway. Artifact formation induced by acetylation included dehydratation of the hydroxyl function of C-21 and the N-alkyl side-chain. The detajmium concentration in blood of the decreased was determined by high-performance liquid chromatography with fluorimetric detection (12 micrograms/ml).