No abstract

Harmine, harmaline, tetrahydroharmine (THH), and N,N-dimethyltryptamine (DMT) were quantitated in plasma from 15 healthy male volunteers after the ingestion of ayahuasca, a beverage that has been used for religious purposes in Brazil since pre-Columbian times. A growing awareness of the interest in this ancient shamanistic practice in modern urban cultures and the widespread popular dissemination of the inebriant effects and type and sources of the plant admixtures used to prepare the beverage have provided additional impetus for this study. The three harmala alkaloids were quantitated from protein-precipitated plasma by high-performance liquid chromatography using fluorescence detection. Recovery from blank human plasma was quantitative, and the limit of quantitation (LOQ) was below 2 ng/mL of plasma for each of the harmala alkaloids. Standard concentrations ranged from 10 to 250 ng/mL for harmine and THH and from 1.0 to 25.0 ng/mL for harmaline, respectively. Linearity was observed for harmine, harmaline, and THH within these respective ranges. The highest concentrations of harmala alkaloids in human plasma were found to be 222.3 ng/mL for harmine, 134.5 ng/mL for THH, and 9.4 ng/mL for harmaline. DMT was quantitated by gas chromatography using nitrogen-phosphorus detection after liquid-liquid extraction with diphenhydramine as an internal standard. DMT recovery was quantitative, and the limit of detection and LOQ were 0.5 and 5 ng/mL, respectively. Linearity for DMT was observed from 5 to 1000 ng/mL. The one-step extraction method for DMT and the protein precipitation method for the three harmala alkaloids afford rapid, sensitive, and quantitative analyses of these alkaloids with minimal analyte loss. The analytical methods also may be applicable to other matrices, including whole blood and urine samples and homogenized tissue specimens. These are the first reported observations of DMT and harmala alkaloids in plasma after ritual ingestion of ayahuasca.

The recent increase in reports of drug-facilitated sexual assaults has caused alarm in the general public and prompted forensic toxicologists from across North America to address the toxicological issues surrounding this matter. The authors have developed recommendations and guidelines to inform law enforcement, medical, and scientific personnel of the requirements for performing successful toxicological examinations in cases of drug-facilitated rape.

No abstract

This paper reviews the complex pharmacology of the new class of antidepressant medications exhibiting selective inhibition of serotonin reuptake. The four selective serotonin reuptake inhibitors (SSRIs) considered—fluoxetine, fluvoxamine, sertraline and paroxetine—can result in toxicity and death through contributing to serotonergic excess resulting in serotonin syndrome, inhibiting the metabolism of other centrally acting drugs, leading to accumulation of toxic concentrations, and exerting complex vasoactive effects on the vascular smooth muscle. This latter feature is of particular concern in patients with preexisting heart disease. An analytical method involving isolation of the drugs by liquid/liquid extraction at alkaline pH into n-butyl chloride, and analysis by gas chromatography/mass spectrometry (GC/MS) is described, together with some of its limitations. Toxicologic and cause and manner of death data were examined in 60 deaths involving fluoxetine, 5 involving fluvoxamine, 75 involving sertraline, and 28 involving paroxetine. Deaths involving drug toxicity were generally a result of ingestion of multiple drugs, and in only a small number of the cases was death attributed principally to the SSRI involved. The potential for drug interactions between members of this class of drugs is discussed as well as their metabolites and a variety of other therapeutic and abused drugs which can contribute to their toxicity. In the absence of other risk factors, the lowest concentrations determined to have resulted in death were 0.63 mg/L for fluoxetine, 0.4 mg/L for paroxetine, and 1.5 mg/L for sertraline. We had insufficient data to make even this crude assessment for fluvoxamine. Drug-induced elevation of serotonin concentrations may be a significant risk factor for patients with atherosclerotic cardiovascular disease (ASCVD). Other factors including preexisting disease and the presence of other drugs and their pharmacology need to be carefully considered before determining the appropriate cause and manner of death in these cases.

Trazodone is a popular antidepressant medication that has been available for approximately 30 years. It has a reputation as a safe drug with relatively few reported fatalities attributed solely to it. We review the pharmacology and forensic toxicology of trazodone and report toxicology and cause and manner of death in a series of 37 deaths in which trazodone was detected. Although the normal upper therapeutic blood concentration for trazodone is about 2 mg/L, fatalities are rarely attributed solely to it at blood concentrations below 9 mg/L. Considering the pharmacology of the drug, potential interactions between other drugs with serotonin reuptake properties need to be considered, as does the increased susceptibility to the toxic effects in patients with pre-existing heart disease. In the cases reviewed, none were attributed solely to trazodone, although trazodone was frequently present together with other serotonergic drugs, such as the selective serotonin reuptake inhibitors like fluoxetine and sertraline. Ten cases had blood trazodone concentrations above 2 mg/L. Of these cases, trazodone played a primary role in the death of three subjects, with blood concentrations all greater than 9 mg/L. We confirm the conclusions of others that trazodone is a relatively safe drug except in massive overdose, although its toxicity may be influenced by the presence of other drugs and underlying pathophysiology.

Piperidine and cyclohexyl ring homologues of the high-affinity dopamine (DA) uptake inhibitor 1-[1-(2-benzo[b]thienyl)cyclohexyl]piperidine (BTCP, 3) were each prepared in four steps from the appropriate cycloalkanones. These compounds were tested for their ability to displace [3H]BTCP and [3H]cocaine and to inhibit [3H]DA uptake in rat striatal homogenates. The ratios IC50([3H]cocaine)/IC50([3H]BTCP) ranged from 62 for BTCP to 1.5 for 1-[2-(benzo[b]thienyl)-cyclopentylamine (17); cocaine gave a ratio of 0.6. This indicates that BTCP is the most selective of all the compounds tested for sites labeled by [3H]BTCP whereas cocaine is most selective for sites labeled by [3H]cocaine. The wide differences in the relative abilities of these compounds to displace [3H]BTCP and [3H]cocaine suggests that these two radioligands are labeling different sites on the transporter. In general, the compounds structurally related to BTCP exhibited greater selectivity for sites labeled by [3H]BTCP. However, several of the BTCP-related derivatives showed greater (compared with BTCP and cocaine) ability to displace [3H]cocaine. Most notably, 1-[1-(2-benzo[b]thienyl)cyclohexyl]pyrrolidine (7) exhibited a 3.4-fold greater affinity for these sites compared with BTCP and a 9-fold greater affinity at these sites than cocaine. Most of the BTCP homologues displayed greater ability to inhibit [3H]DA uptake in rat forebrain synaptosomes than cocaine. BTCP and 7 were the most potent of all the compounds tested in terms of their ability to inhibit uptake of [3H]DA. IC50 ratios for [3H]cocaine binding/[3H]DA uptake ranged from 0.47 for 1-[1-(2-benzo[b]thienyl)cyclopentyl]homopiperidine (11) to 8.8 for 1-(2-benzo[b]thienyl)cyclohexylamine (4). The importance of this ratio remains unclear in terms of identification of potential cocaine antagonists. As for BTCP, all of the compounds tested showed Ki values > 10,000 nM for displacement of [3H]TCP from rat brain homogenates. These compounds were able to displace the highly selective sigma receptor probe [3H]-(+)-pentazocine from guinea pig brain homogenates with Ki values ranging from 125 to 9170 nM. The significance of their sigma-binding activity in light of their dopaminergic properties is unclear. The diverse binding properties of these compounds at the DA-uptake site and their spectrum of inhibitory activities for [3H]DA uptake identifies them as a useful base for the development of subtype selective probes at this site. These compounds will allow further study of the structure and function of the "cocaine" receptor as well as the development of potential cocaine antagonists.

We previously reported (J. Med. Chem. 1993, 36, 1188-1193) that changes to the ring size of the piperidine and cyclohexyl rings of the high-affinity and selective dopamine (DA)-uptake inhibitor 1-[1-(2-benzo[b]thienyl)cyclohexyl]piperidine (BTCP, 2) caused different, and in some cases opposite, changes in affinity for sites on the DA transporter labeled by [3H]BTCP and [3H]-cocaine. These results suggested that the radioligands label different sites on the transporter. In the present study, we extend the structure-activity relationships (SAR) of BTCP by studying the binding characteristics of a series of N,N-disubstituted 1-(2-benzo[b]thienyl)cyclohexylamines 7-32 at the DA transporter. Cyclohexyl was selected as opposed to other ring sizes since it corresponds to BTCP. The binding results indicate that a considerable degree of structural variation is permitted for the N-substituents, while still retaining nanomolar affinity for sites on the transporter (studied in rat forebrain homogenates). As observed in our earlier study, the differential effects of structural change on binding to sites on the DA transporter labeled by these radioligands suggests that they are different and distinct binding sites. In general, and up to a point, increasing the size and lipophilicity of the N substituents resulted in improvements in binding but appeared to have less predictable effects on DA-uptake inhibition (as measured in rat brain synaptosomes). The binding of these compounds to sites labeled by [3H]BTCP appeared to correlate best with IC50 for DA-uptake inhibition. To our surprise, the monoalkyl N-substituted BTCP derivatives displayed the highest affinity for the DA transporter of all the compounds in this series. For example, the N-(cyclopropylmethyl) derivative 14 displayed IC50's = 23 nM ([3H]cocaine) and 1 nM ([3H]-BTCP), and the N-butyl derivative 10 showed IC50's = 60 nM ([3H]cocaine) and 0.3 nM ([3H]-BTCP). BTCP exhibited IC50's of 39 nM ([3H]cocaine) and 5 nM ([3H]BTCP) in this assay. The observation that N,N-dibutyl derivative 31 exhibited low ratios of IC50 [3H]cocaine/IC50 DA reuptake and IC50 [3H]BTCP/IC50 DA reuptake suggests that it may be a potential candidate for cocaine antagonism studies. The effect of additional amino, amide, and aromatic groups on the N-substituents was examined, and the results are discussed. The failure of all of the compounds in this series to bind phenycyclidine receptors coupled with their high affinity and range of selectivities at the DA transporter identifies many of them as useful tools for probing the mode of action of BTCP at this site.