Dothiepin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depressive illness

The Application of Green Solvents in the Synthesis of S-Heterocyclic Compounds-A Review

Cyclic organic compounds containing sulfur atoms constitute a large group, and they play an important role in the chemistry of heterocyclic compounds. They are valuable intermediates for the synthesis of other compounds or biologically active compounds themselves. The synthesis of heterocyclic compounds poses a major challenge for organic chemists, especially in the context of applying the principles of "green chemistry". This work is a review of the methods of synthesis of various S-heterocyclic compounds using green solvents such as water, ionic liquids, deep eutectic solvents, glycerol, ethylene glycol, polyethylene glycol, and sabinene. The syntheses of five-, six-, and seven-membered heterocyclic compounds containing a sulfur atom or atoms, as well as those with other heteroatoms and fused-ring systems, are described. It is shown that using green solvents determines the attractiveness of conditions for many reactions; for others, such use constitutes a real compromise between efficiency and mild reaction conditions.

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

Challenges of the pharmacological management of benzodiazepine withdrawal, dependence, and discontinuation

BACKGROUND

Benzodiazepines (BZDs) are among the most prescribed sedative hypnotics and among the most misused and abused medications by patients, in parallel with opioids. It is estimated that more than 100 million Benzodiazepine (BZD) prescriptions were written in the United States in 2009. While medically useful, BZDs are potentially dangerous. The co-occurring abuse of opioids and BZD, as well as increases in BZD abuse, tolerance, dependence, and short- and long-term side effects, have prompted a worldwide discussion about the challenging aspects of medically managing the discontinuation of BZDs. Abrupt cessation can cause death. This paper addresses the challenges of medications suggested for the management of BZD discontinuation, their efficacy, the risks of abuse and associated medical complications. The focus of this review is on the challenges of several medications suggested for the management of BZD discontinuation, their efficacy, the risks of abuse, and associated medical complications.

METHODS

An electronic search was performed of Medline, Worldwide Science, Directory of Open Access Journals, Embase, Cochrane Library, Google Scholar, PubMed Central, and PubMed from 1990 to 2017. The review includes double-blind, placebo-controlled studies for the most part, open-label pilot studies, and animal studies, in addition to observational research. We expand the search to review articles, naturalistic studies, and to a lesser extent, letters to the editor/case reports. We exclude abstract and poster presentations, books, and book chapters.

RESULTS

The efficacy of these medications is not robust. While some of these medicines are relatively safe to use, some of them have a narrow therapeutic index, with severe, life-threatening side effects. Randomized studies have been limited. There is a paucity of comparative research. The review has several limitations. The quality of the documents varies according to whether they are randomized studies, nonrandomized studies, naturalistic studies, pilot studies, letters to the editors, or case reports.

CONCLUSIONS

The use of medications for the discontinuation of BZDs seems appropriate. It is a challenge that requires further investigation through randomized clinical trials to maximize efficacy and to minimize additional risks and side effects.

Bio-sample preparation and analytical methods for the determination of tricyclic antidepressants

An extended and comprehensive review is presented herein, focusing on sample preparation (pretreatment and extraction) and different analytical methods applied for the quantification of tricyclic antidepressants. These procedures are relevant tools in clinical and forensic toxicology. It is revealed that SPE, for sample preparation, and HPLC, using reversed-phase alkyl (C18) or cyanopropyl-bonded silica columns for the analytes separation, are effective and versatile methods for assay of tricyclic antidepressants. These methods enable achievable detection limits using UV/diode array detection, readily available in most laboratories, down to 1–8 ng ml-1, and using electron capture detection better than 1 ng ml-1, which is lower than that for nitrogen–phosphorus detector. MS interfaced with electrospray ionization offered similar sensitivity, whilst sonic spray ionization provided detection down to 0.03 ng ml-1. A brief discussion on chemical structures, metabolism and mechanism of action of this group of drugs is also presented.

Review: Pharmacogenetic aspects of the effect of cytochrome P450 polymorphisms on serotonergic drug metabolism, response, interactions, and adverse effects

The field of pharmacogenetics contains a wealth of potential for the enhancement of clinical practice by providing a more effective match between patient and drug, consequently reducing the probability of an adverse drug reaction. Although a relatively novel concept in the forensic context, pharmacogenetics has the capability to assist in the interpretation of drug related deaths, particularly in unintentional drug poisonings where the cause of death remains unclear. However, the complex pharmacology of the drugs when subjected to genetic variations in metabolism makes interpretation of the expected response and adverse events difficult. Many possess multiple metabolic pathways, narrow therapeutic indices and active metabolites or enantiomers which may be eliminated via different pathways to the parent drug. A number of these drugs, which are metabolised primarily by the CYP450 system, are also associated with serotonin syndrome, or serotonin toxicity, especially when used concomitantly with other serotonin active drugs which rely on the same metabolic pathways for drug elimination. A comprehensive understanding of polymorphic drug metabolism and its expected outcomes is therefore essential when interpreting the involvement of drugs in adverse reactions. This review examines the genetically variable CYP450-mediated metabolism of a number of serotonin-active drugs that are often implicated in cases of serotonin toxicity, to assess the impact of pharmacogenetics on drug metabolism, response, interactions and adverse effects.

Pharmacokinetics and interactions of headache medications, part II: prophylactic treatments

The present part II review highlights pharmacokinetic drug-drug interactions (excluding those of minor severity) of medications used in prophylactic treatment of the main primary headaches (migraine, tension-type and cluster headache). The principles of pharmacokinetics and metabolism, and the interactions of medications for acute treatment are examined in part I. The overall goal of this series of two reviews is to increase the awareness of physicians, primary care providers and specialists regarding pharmacokinetic drug-drug interactions (DDIs) of headache medications. The aim of prophylactic treatment is to reduce the frequency of headache attacks using beta-blockers, calcium-channel blockers, antidepressants, antiepileptics, lithium, serotonin antagonists, corticosteroids and muscle relaxants, which must be taken daily for long periods. During treatment the patient often continues to take symptomatic drugs for the attack, and may need other medications for associated or new-onset illnesses. DDIs can, therefore, occur. As a whole, DDIs of clinical relevance concerning prophylactic drugs are a limited number. Their effects can be prevented by starting the treatment with low dosages, which should be gradually increased depending on response and side effects, while frequently monitoring the patient and plasma levels of other possible coadministered drugs with a narrow therapeutic range. Most headache medications are substrates of CYP2D6 (e.g., beta-blockers, antidepressants) or CYP3A4 (e.g., calcium-channel blockers, selective serotonin re-uptake inhibitors, corticosteroids). The inducers and, especially, the inhibitors of these isoenzymes should be carefully coadministered.

Effects of 5 weeks of administration of fluoxetine and dothiepin in normal volunteers on sleep, daytime sedation, psychomotor performance and mood

This was a placebo-controlled, double-blind randomized crossover study of long-term (5 weeks) administration of fluoxetine (20 mg/day) and dothiepin (75 mg/day for 1 week followed by 150 mg/day for 4 weeks) in 12 healthy male volunteers. Subjects were studied on day 10 and day 36 of treatment, with tests of nocturnal sleep, driving performance, continuous electroencephalogram (EEG), sleep during scheduled naps, computerized visual attention tasks, saccadic eye movement measurement and visual analogue ratings of mood. Both drugs had a marked suppressive effect on nocturnal rapid eye movement (REM) sleep; these effects were less at 36 days than at 10 days, and fluoxetine decreased and dothiepin increased REM in daytime naps. Sleep fragmentation after fluoxetine is similar to that reported in the literature. We found no sleep-promoting effects of dothiepin, in contrast to our previous single-dose study, and no subjective sleep effects of either drug. Subjects were less sleepy after both antidepressants than placebo at 5 weeks measured by sleep latencies and EEG. Saccadic eye movement measures were significantly faster after 5 weeks of fluoxetine than after 5 weeks of placebo. Reaction times to a peripheral stimulus during computerized tracking task were shorter after 10 days of dothiepin compared with placebo. Driving performance, visual attention and mood ratings showed no treatment effects. Subjective health reports during each 5 weeks of treatment were similar in number for the two drugs but showed a different profile of side-effects.

Sleep and daytime sleepiness the next day following single night-time dose of fluvoxamine, dothiepin and placebo in normal volunteers

To explore the effects of sedating and non-sedating antidepressants, we conducted a placebo-controlled, double-blind cross-over study in 12 normal subjects of the effects of a single night-time dose of fluvoxamine 100 mg, dothiepin 100 mg or placebo on night-time sleep recorded at home, and sleepiness and performance the following day. Night-time sleep was altered significantly by both drugs, with main effects on rapid eye movement (REM) sleep and sleep continuity. Dothiepin increased total sleep time, REM latency and stage 2 sleep and decreased arousals, wake after sleep onset and stage 1, whereas fluvoxamine decreased total sleep time and REM time and increased wake after sleep onset. Sleep latencies in daytime naps were significantly shorter for dothiepin and longer for fluvoxamine, showing that subjects were more sleepy when taking dothiepin. Electroencephalograms (EEG) performed during performance tasks failed to distinguish significantly between drugs. There were no significant differences between groups on our measures of tracking performance or reaction time; however, these tasks were designed primarily to provide a standard setting in which to monitor continuous EEG, and were unsuitable to detect sleepiness effects themselves. Saccadic eye movement velocity, acceleration and deceleration showed small non-significant changes after both drugs. Mood self ratings showed no significant differences among the groups. Subjective measures of night-time sleep reflected the objective measures of sleep continuity, and the items for difficulty and speed of wakening in the morning were significantly higher (i.e. more difficulty and slower) in the dothiepin group. The home-recorded sleep findings after fluvoxamine in this study were very similar to sleep laboratory studies with other antidepressant drugs, thus providing more validation of the home recording method.

Fatal intoxication due to dothiepin

An ingestion of an unknown quantity of Harmomed (dothiepin and diazepam) capsules in a suicide is described. The authors report a new and fast method of analysing and determining the dothiepin concentration in postmortem specimens. Quantitation of dothiepin, and its metabolite desmethyldothiepin was performed by ethyl acetate extraction from alkalinized body fluids before GC-MS analysis. The analyses were performed without any complex sample clean-up steps and with little sample material. Postmortem concentrations of dothiepin, desmethyldothiepin, diazepam and desmethyldiazepam in body fluids are given. The proposed method is a rapid procedure for analysis in cases of deliberate poisoning with the antidepressant drug dothiepin.

Association between selective serotonin reuptake inhibitors and upper gastrointestinal bleeding: population based case-control study

OBJECTIVE

To examine the association between selective serotonin reuptake inhibitors and risk of upper gastrointestinal bleeding.

DESIGN

Population based case-control study.

SETTING

General practices included in the UK general practice research database.

SUBJECTS

1651 incident cases of upper gastrointestinal bleeding and 248 cases of ulcer perforation among patients aged 40 to 79 years between April 1993 and September 1997, and 10 000 controls matched for age, sex, and year that the case was identified.

INTERVENTIONS

Review of computer profiles for all potential cases, and an internal validation study to confirm the accuracy of the diagnosis on the basis of the computerised information.

MAIN OUTCOME MEASURES

Current use of selective serotonin reuptake inhibitors or other antidepressants within 30 days before the index date.

RESULTS

Current exposure to selective serotonin reuptake inhibitors was identified in 3.1% (52 of 1651) of patients with upper gastrointestinal bleeding but only 1.0% (95 of 10 000) of controls, giving an adjusted rate ratio of 3.0 (95% confidence interval 2.1 to 4.4). This effect measure was not modified by sex, age, dose, or treatment duration. A crude incidence of 1 case per 8000 prescriptions was estimated. A small association was found with non-selective serotonin reuptake inhibitors (relative risk 1.4, 1.1 to 1.9) but not with antidepressants lacking this inhibitory effect. None of the groups of antidepressants was associated with ulcer perforation. The concurrent use of selective serotonin reuptake inhibitors with non-steroidal anti-inflammatory drugs increased the risk of upper gastrointestinal bleeding beyond the sum of their independent effects (15.6, 6.6 to 36.6). A smaller interaction was also found between selective serotonin reuptake inhibitors and low dose aspirin (7.2, 3.1 to 17.1).

CONCLUSIONS

Selective serotonin reuptake inhibitors increase the risk of upper gastrointestinal bleeding. The absolute effect is, however, moderate and about equivalent to low dose ibuprofen. The concurrent use of non-steroidal anti-inflammatory drugs or aspirin with selective serotonin reuptake inhibitors greatly increases the risk of upper gastrointestinal bleeding.

Metabolism of tricyclic antidepressants

1. Despite the considerable advances in the treatments available for mood disorders over the past generation, tricyclic antidepressants (TCAs) remain an important option for the pharmacotherapy of depression. 2. The pharmacokinetics of TCAs are characterized by substantial presystemic first-pass metabolism, a large volume of distribution, extensive protein binding, and an elimination half-life averaging about 1 day (up to 3 days for protriptyline). 3. Clearance of tricyclics is dependent primarily on hepatic cytochrome P450 (CYP) oxidative enzymes. Although the activities of some P450 isoenzymes are largely under genetic control, they may be influenced by external factors, such as the concomitant use of other medications or substances. Patient variables, such as ethnicity and age, also affect TCA metabolism. The impact of gender and related reproductive issues is coming under increased scrutiny. 4. Metabolism of TCAs, especially their hydroxylation, results in the formation of active metabolites, which contribute to both the therapeutic and the adverse effects of these compounds. 5. Renal clearance of the polar metabolites of TCAs is reduced by normal aging, accounting for much of the increased risk of toxicity in older patients. 6. Knowledge of factors affecting the metabolism of TCAs can further the development and understanding of newer antidepressant medications.

Erythema multiforme-like reaction associated with radiotherapy

Generalized cutaneous reactions in association with radiotherapy have in the past been grouped into erythema multiforme (EM) and erythema multiforme-like reactions, the latter being reactions that do not strictly fit the accepted clinical and/or histological criteria for EM, yet have similar findings or presentations. Though usually benign and self-limiting, the progression to Stevens-Johnson syndrome, a potentially fatal form of erythema multiforme, has been reported. Presented here is a case study of a less severe radiation-induced erythema-like reaction.

The effects of antidepressant drugs on salivary flow and content of sodium and potassium ions in human parotid saliva

Stimulated parotid saliva was collected, using the Carlson-Crittenden cup, from normal controls and patients on antidepressant drugs. The saliva from patients using amitriptyline, dothiepin (tricyclics), fluoxetine and paroxetine (selective serotonin re-uptake inhibitors; SSRI) was analysed for flow rate, [Na+] and [K+], and was compared with that from unmedicated, non-depressed volunteers for all variables. The tricyclic antidepressants produced a significant reduction in flow (amitriptyline, p < 0.01; dothiepin, p < 0.05), and consequent decrease in [Na+] and increase in [K+]. These effects were presumably due to muscarinic receptor blockade. The SSRIs produced no significant change in these variables. A prospective study of dothiepin in non-depressed patients confirmed that it decreases stimulated parotid flow. This finding also suggested that depression itself contributed little to the oral dryness observed in and reported by the depressed patients. The patients' subjective rating of oral dryness related well to a reduction in stimulated flow. This applied to those taking either tricyclics or SSRI, both showing a reduced flow rate relative to control (p < 0.001 and p < 0.05, respectively). This amounted to a 58% reduction in flow rate in the tricyclic group. The data suggest that measurement of stimulated parotid salivary flow is a reliable indicator of drug-induced oral dryness.

The tolerability of dothiepin: a review of clinical studies between 1963 and 1990 in over 13,000 depressed patients

1. A total of 13,834 depressed patients were exposed to dothiepin most frequently at a dose of 150 mg/day and over 6 weeks, in 116 clinical studies between 1963 and 1990. 2. Overall, 2,066 (15%) patients were withdrawn prematurely from dothiepin for a variety of reasons, the most commonly specified reason being due to drug-related events in 500 (4%) patients. 3. In the remaining 11,768 patients, there were 9,312 reports of unwanted events most typically associated with the pharmacological effects of a tricyclic antidepressant although no serious sequelae were reported. 4. This review indicates that the incidence of serious adverse events associated with dothiepin at therapeutic doses is very low.

Greater toxicity in overdose of dothiepin than of other tricyclic antidepressants

Epidemiological studies have implicated dothiepin in a greater number of self-poisoning deaths than would be expected from its use. We have prospectively assessed the clinical toxicity of dothiepin and other tricyclic antidepressants (TCAs) in overdose. We followed-up consecutively admitted patients with TCA poisoning managed by our department between January, 1987, and August, 1992. 75 patients had taken dothiepin, 101 amitriptyline, 83 doxepin, and 61 other TCAs. Death after TCA poisoning is rare nowadays, so we used intermediate outcome measures--general seizures, tachyarrhythmias, sedation, and QRS width on the electrocardiogram. 15 patients had seizures and 7 tachyarrhythmias. When we excluded patients who had taken more than one TCA, general seizures were more likely after dothiepin than after other TCAs (9/67 vs 5/220) as were arrhythmias (4/67 vs 3/220). Rates of other complications were similar. The dothiepin group had ingested a larger dose, attributable to the larger average tablet strength, than patients who took other TCAs. The odds ratio for seizures with dothiepin versus other TCAs was 6.7 (95% Cl 2.2-20.7) unadjusted and 7.1 (2.2-23.2) after adjustment for sex, age, and ingested dose. The corresponding odds ratios for arrhythmias were 4.6 (1.0-21.1) and 3.4 (0.7-16.3). Dothiepin in overdose seems to be proconvulsant. Patients with only minor sedation and normal limb-lead QRS width may still have major complications. Consideration should be given to the use of other antidepressants in patients at risk of seizures or suicide. Regulatory authorities should review the need for a 75 mg strength tablet of any TCA.

Effects of dothiepin on nociceptive flexion reflex and diffuse noxious inhibitory controls in humans

The analgesic activity of dothiepin (an antidepressant interacting with serotonin receptors) was studied (double-blind) in humans. A significant increase in nociceptive flexion reflex threshold and subjective pain threshold was observed after a 14-day dothiepin treatment. The effects of dothiepin on diffuse noxious inhibitory controls were also investigated using the cold-pressor test as conditioning stimuli. After dothiepin a reduced inhibition of nociceptive flexion reflex during the cold-pressor test and a significant facilitation immediately after the cold-pressor test were observed, while the subjective pain perception was normally inhibited. Our data suggest a serotonergic modulation of diffuse noxious inhibitory controls in humans.

The excretion of dothiepin and its primary metabolites in breast milk

1. The excretion of dothiepin, nordothiepin, dothiepin-S-oxide and nordothiepin-S-oxide into breast milk was studied in eight women. Exposure to drug was measured in five of their infants, and possible drug-related effects were assessed in all eight infants. 2. Using pre-feed milk samples mean (+/- s.e. mean) milk:plasma (M:P) ratios were 0.78 +/- 0.12, 0.85 +/- 0.16, 1.18 +/- 0.29 and 1.86 +/- 0.29 for dothiepin, nordothiepin, dothiepin-S-oxide and nordothiepin-S-oxide, respectively. In post-feed milk samples, the mean M:P ratio for dothiepin (1.59 +/- 0.32) was significantly greater (P less than 0.05) but M:P ratios for the metabolites were similar. 3. Mean total calculated infant daily doses, (in dothiepin equivalents and as a percent of the maternal dose) were 0.58% for dothiepin, 0.23% for nordothiepin, 2.47% for dothiepin-S-oxide, and 1.17% for nordothiepin-S-oxide. 4. Plasma samples were obtained from five infants. In one, both dothiepin and nordothiepin were below their minimum quantifiable levels (2 micrograms l-1) while in four others both dothiepin-S-oxide and nordothiepin-S-oxide were below their minimum quantifiable levels (10 micrograms l-1). No adverse effects were found in any of the eight infants. 5. Use of dothiepin by depressed mothers is unlikely to be a significant hazard to their breast-feeding infants.

Drug treatment of depression in medically ill patients

Depressive symptoms are common in medically ill patients although depressive disorders are considerably underdiagnosed and undertreated. Drug treatments for depression are reviewed in terms of a risk/benefit analysis. The main benefit is approximately to double the chance of recovery (from about 30 to 65%), with possible associated improvements in physical condition. The risks of treatment are considerable and include overdose, unwanted effects at therapeutic dose and interaction with other drugs. Among the risks associated with specific medical conditions are orthostatic hypotension, cardiotoxicity, deterioration of seizure control in epileptic patients and increased side effects in patients with renal and hepatic impairment. The available data suggest that there is relatively little to choose between antidepressants in terms of efficacy (although the quantity and quality of these data vary). It is therefore primarily the risks which should determine the choice of antidepressant, and these must be separately evaluated for each patient.

Tricyclic antidepressant poisoning

OBJECTIVE

To review poisoning with tricyclic antidepressants.

DATA SOURCE

English language literature search using Australian Medlars Service (1977-1989), manual search of journals and review of bibliographies in identified articles.

STUDY SELECTION

Approximately 250 articles, abstracts and book chapters were selected for analysis.

DATA EXTRACTION

The literature was reviewed and 93 articles were selected as representative of important advances.

DATA SYNTHESIS

The major features of overdose are neurological, cardiac, respiratory and anticholinergic. Life-threatening complications develop within six hours of overdose or not at all. All patients seen within six hours of overdose should have their stomachs emptied. All patients should receive activated charcoal. Coma, convulsions, respiratory depression and hypotension are treated with standard resuscitation techniques and drugs. Treat patients with significant cardiotoxicity or cardiac arrest with alkalinisation by sodium bicarbonate or hyperventilation, aiming for an arterial pH of 7.45-7.55. Lignocaine is used for ventricular arrhythmias. Other antiarrhythmic drugs are contraindicated (Class 1A, Class 1C), potentially lethal (Class II), of no benefit (phenytoin) or of unproven efficacy (Class III and Class IV). Physostigmine has no role at all. Haemodialysis and haemoperfusion are of no benefit.

CONCLUSION

The death rate of those who reach hospital is 2%-3%. Most of these deaths are cardiac in origin, and are caused by direct depression of myocardial function rather than cardiac arrhythmias.