Alternative pharmacological strategies for adult ADHD treatment: a systematic review.

Adult Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent psychiatric condition associated with high disability and frequent comorbidity. Current standard pharmacotherapy (methylphenidate and atomoxetine) improves ADHD symptoms in the short-term, but poor data were published about long-term treatment. In addition a number of patients present partial or no response to methylphenidate and atomoxetine. Research into the main database sources has been conducted to obtain an overview of alternative pharmacological approaches in adult ADHD patients. Among alternative compounds, amphetamines (mixed amphetamine salts and lisdexamfetamine) have the most robust evidence of efficacy, but they may be associated with serious side effects (e.g. psychotic symptoms or hypertension). Antidepressants, particularly those acting as noradrenaline or dopamine enhancers, have evidence of efficacy, but they should be avoided in patients with comorbid bipolar disorder. Finally metadoxine and lithium may be particularly suitable in case of comorbid alcohol misuse or bipolar disorder.

Differential dopamine receptor occupancy underlies L-DOPA-induced dyskinesia in a rat model of Parkinson's disease.

Dyskinesia is a major side effect of an otherwise effective L-DOPA treatment in Parkinson's patients. The prevailing view for the underlying presynaptic mechanism of L-DOPA-induced dyskinesia (LID) suggests that surges in dopamine (DA) via uncontrolled release from serotonergic terminals results in abnormally high level of extracellular striatal dopamine. Here we used high-sensitivity online microdialysis and PET imaging techniques to directly investigate DA release properties from serotonergic terminals both in the parkinsonian striatum and after neuronal transplantation in 6-OHDA lesioned rats. Although L-DOPA administration resulted in a drift in extracellular DA levels, we found no evidence for abnormally high striatal DA release from serotonin neurons. The extracellular concentration of DA remained at or below levels detected in the intact striatum. Instead, our results showed that an inefficient release pool of DA associated with low D2 receptor binding remained unchanged. Taken together, these findings suggest that differential DA receptor activation rather than excessive release could be the underlying mechanism explaining LID seen in this model. Our data have important implications for development of drugs targeting the serotonergic system to reduce DA release to manage dyskinesia in patients with Parkinson's disease.

Restoration of dopamine release deficits during object recognition memory acquisition attenuates cognitive impairment in a triple transgenic mice model of Alzheimer's disease.

Previous findings indicate that the acquisition and consolidation of recognition memory involves dopaminergic activity. Although dopamine deregulation has been observed in Alzheimer's disease (AD) patients, the dysfunction of this neurotransmitter has not been investigated in animal models of AD. The aim of this study was to assess, by in vivo microdialysis, cortical and hippocampal dopamine, norepinephrine, and glutamate release during the acquisition of object recognition memory (ORM) in 5- and 10-mo-old triple-transgenic Alzheimer's disease mice (3xTg-AD) and to relate the extracellular changes to 24-h memory performance. Five- and 10-mo-old wild-type mice and 5-mo-old 3xTg-AD showed significant cortical but not hippocampal dopamine increase during object exploration. On a 24-h ORM test, these three groups displayed significant ORM. In contrast, 10-mo-old 3xTg-AD mice showed impaired dopamine release in the insular cortex during ORM acquisition, as well as significant impairment in ORM. In addition, cortical administration of a dopamine reuptake blocker produced an increase of dopamine levels in the 10-mo-old 3xTg-AD mice and attenuated the memory impairment. These data suggest that activation of the dopaminergic system in the insular cortex is involved in object recognition memory, and that dysfunction of this system contributes to the age-related decline in cognitive functioning of the 3xTg-AD mice.

The politics and bio-ethics of regulatory trust: case-studies of pharmaceuticals.

Drawing on case studies from the modern era of pharmaceutical regulation in the UK, US and Europe, I examine how the extent and distribution of trust between regulators, the pharmaceutical industry, and the medical profession about drug testing and monitoring influences knowledge and regulatory judgements about the efficacy and safety of prescription drugs. Introducing the concepts of 'acquiescent' and 'investigative' norms of regulatory trust, I demonstrate how investigative norms of regulatory trust-which deter pharmaceutical companies from assuming that their data analyses will be accepted without independent de-construction-drive up bioethical and regulatory standards of drug assessment in the interests of health. By contrast, acquiescent norms of regulatory trust, which are associated with industrial capture and professional closure of interests, promote permissive standards allowing patients to take pharmaceuticals with greater risks to health and less evidence of therapeutic efficacy.

Neuroprotection of MPTP-induced toxicity in zebrafish dopaminergic neurons.

Parkinson's disease is characterized by a severe loss of dopaminergic neurons resulting in a range of motor deficits. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to cause a similar loss of dopaminergic neurons in the human midbrain with corresponding Parkinsonian symptoms. Several animal species have also shown sensitivity to MPTP, including primates, mice, goldfish, and, most recently, zebrafish. This study demonstrates that the effect of MPTP on dopaminergic neurons in zebrafish larvae is mediated by the same pathways that have been demonstrated in mammalian species. MPTP-induced neurodegeneration was prevented by co-incubation with either the monoamine oxidase-B (MAO-B) inhibitor l-deprenyl or the dopamine transporter (DAT) inhibitor nomifensine. Furthermore, targeted inactivation of the DAT gene by antisense morpholinos also protected neurons from MPTP damage. Thus, the mechanism for MPTP-induced dopaminergic neuron toxicity in mammals is conserved in zebrafish larvae. Effects on swimming behavior and touch response that result from MPTP damage are partially ameliorated by both l-deprenyl and DAT knockdown.

Dopamine-independent locomotor actions of amphetamines in a novel acute mouse model of Parkinson disease.

Brain dopamine is critically involved in movement control, and its deficiency is the primary cause of motor symptoms in Parkinson disease. Here we report development of an animal model of acute severe dopamine deficiency by using mice lacking the dopamine transporter. In the absence of transporter-mediated recycling mechanisms, dopamine levels become entirely dependent on de novo synthesis. Acute pharmacological inhibition of dopamine synthesis in these mice induces transient elimination of striatal dopamine accompanied by the development of a striking behavioral phenotype manifested as severe akinesia, rigidity, tremor, and ptosis. This phenotype can be reversed by administration of the dopamine precursor, L-DOPA, or by nonselective dopamine agonists. Surprisingly, several amphetamine derivatives were also effective in reversing these behavioral abnormalities in a dopamine-independent manner. Identification of dopamine transporter- and dopamine-independent locomotor actions of amphetamines suggests a novel paradigm in the search for prospective anti-Parkinsonian drugs.

Treatment with 6-hydroxydopamine in planaria (Dugesia gonocephala s.l.): morphological and behavioral study.

Morpho-functional and behavioral effects of exposure to 6-hydroxydopamine (OHDA)-HCI (24 microg/ml per day for 24 h and 7 days) were studied in planarias (Dugesia gonocephala s.l.). Exposure to 6-OHDA-HC1 for 24 h produced hypokinesia of the specimens. These behavioral changes were more pronounced, leading to complete immobility, after 7 days of exposure to the neurotoxin. Moreover, specimens exposed to 6-OHDA-HCI for 24 h and 7 days failed to show any behavioral response to nomifensine, thus furnishing evidence of the damage of presynaptic dopamine terminals. Exposure to 6-OHDA-HCl for 24 h significantly reduced cathecolamine content in neuropil region, as demonstrated by histochemistry, and electron-dense presynaptic vesicles, as observed on electron microscopy examination. All these alterations were significantly more pronounced and were accompanied by swelling and strong increase of electron-density in cytoplasm of numerous neurons after exposure to the neurotoxin for 7 days. This appears to be the first demonstration of the neurotoxic effects of 6-OHDA-HCI in flatworms.

Acute therapy of depression.

The acute therapy (the initial 8 weeks of treatment) of depression (including the whole spectrum of "less than major," "major," and "more than major") has been reviewed comparing the old tricyclics with the new generations (especially mianserin, moclobemide, and the serotonin selective reuptake inhibitors (SSRIs), i.e., citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline). The Hamilton Rating Scale for Depression has been used to measure clinical efficacy. Statistically, the method of meta-analysis has been applied. The results showed that the SSRIs and moclobemide are equal to the tricyclics. Mianserin is inferior to tricyclics as well as to SSRIs. The antidepressive profile of the SSRIs is nonsedation but still with anxiolytic effects. The safety profile of the SSRIs is much more benign than that of the tricyclics.

Efficacy of tianeptine in comparative trials versus reference antidepressants. An overview.

The clinical properties of tianeptine have been assessed in double-blind controlled studies, which involved depressed patients fulfilling DSM-III criteria for either major depression--single episode or recurrent (without melancholia and psychotic features)--or dysthymic disorder--with or without an additional diagnosis of alcohol abuse or dependence. Five studies have compared tianeptine with reference antidepressants: its efficacy has been found to be similar to that of amitriptyline in depressed out-patients. However, these data need to be confirmed by other controlled trials v. reference drugs and by at least two placebo-controlled studies. Tianeptine does not induce sleep disorders, anticholinergic effects, or modifications of cardiovascular variables or biological parameters (renal, haematological, or hepatic). After the end of treatment, the only signs of withdrawal have been some disturbances of sleep.

[Results of using tricyclic antidepressive drugs in the treatment of endogenous depression (comparative analysis of 7 drugs)]. / Wyniki stosowania trójpierscieniowych leków przeciwdepresyjnych w terapii depresji endogennej (analiza porównawcza 7 leków).

A group of 250 patients with endogenous depression was studied. Amitriptyline proved to be the most effective drug (51% positive responses) followed by noxiptilin (50%), imipramine (42%), dibenzepin (43%). Clomipramine, desipramine, and nomifensine appeared to be the least effective. Demographic or clinical factors such as age, sex, type of affective illness, severity of depressive syndrome or its particular symptoms (depression, fear, anxiety, psychomotor impairment or biological rhythm alteration) did not show any potential for prediction of the treatment outcome. Worse therapeutic results were observed in patients who had already been given antidepressant treatment for the current depressive cycle before the assessment.

What has happened to the new antidepressant drugs?

Depression is a widespread and serious disease for which a multiplicity of antidepressant drugs is available for treatment. Although these agents are numerous, there is little to distinguish among them except for their different side-effects. This article reviews the antidepressant drugs that currently are available in Australia, the antidepressant drugs that are used in other countries and some antidepressant drugs that are likely to become available internationally in the next few years.

Striatal kinetics of [11C]-(+)-nomifensine and 6-[18F]fluoro-L-dopa in Parkinson's disease measured with positron emission tomography.

The kinetics in brain of the dopamine reuptake blocking agent [11C]-(+)-nomifensine and the L-dopa analogue 6-[18F]fluoro-L-dopa were compared in 3 patients with idiopathic Parkinson's disease and age-matched healthy volunteers using positron emission tomography. Regional uptake was analyzed and quantified according to a 3-compartment model. Retention of both tracers in striatal regions of the parkinsonian patients were reduced compared with the healthy volunteers mainly in the putamen, while the caudate nucleus was only mildly affected. The reductions were considerably less than the decrease previously reported postmortem for striatal dopamine content in the basal ganglia of patients with Parkinson's disease. A fairly constant ratio between 6-[18F]fluoro-L-dopa utilization and [11C]-(+)-nomifensine binding in the caudate nucleus and the putamen were found in both groups unrelated to the size of the estimated parameters. This indicates that a limiting factor for the utilization of exogenous levodopa in Parkinson's disease may be a reduced transport capacity for the amino acid into the dopaminergic terminals.

Nomifensine maleate in adult attention deficit disorder.

The authors studied 18 adults (8 men and 10 women) in an open trial of nomifensine maleate for the treatment of attention deficit disorder (ADD). All patients met DSM-III criteria and the Utah criteria for ADD, residual type (RT). Medication effect was measured at week 1 and week 4 of treatment using the Structured Interview for ADD-H Symptoms. Data from week 4 showed that all eight men and seven of the women responded well to nomifensine, showing a significant decrease in ADD with hyperactivity symptoms. Side effects were minimal, consisting of drowsiness, dry mouth, headache, and nausea. One responder (5%) was taken off the medicine after developing an allergic reaction. Results showed that short-term use of nomifensine was relatively free from side effects and was remarkably effective in the treatment of ADD-RT. The authors discussed the implications of the use of nomifensine and related drugs in the treatment of ADD-RT.

[A double-blind comparison study of nomifensine and imipramine in treating depressed patients].

Nomifensine was compared to imipramine in treatment of 40 patients with endogenous major depressive disorder. After one week washout, patients were randomly assigned to 5 weeks treatment with Nomifensine or Imipramine. Mean scores for HAM-D, HAM-A, GAS were significantly improved in both treatment groups (P less than 0.01). Two agents were similar in antidepressant efficacy and rapidity of action. Nomifensine treatment group had fewer side effect, whereas the Imipramine group had more adverse experiences. Effects of Nomifensine on the ECG were compared to those of imipramine. Both drugs increased heart rate. Nomifensine less than imipramine. QT measurement interval revealed a statistically significant decrease in imipramine group. Plasma Nomifensine and imipramine concentrations were not correlated with clinical response, side effects or electrocardiographic parameters. The steady-state plasma concentration 105 +/- 47ng/ml for nomifensine, 860 +/- 773ng/ml for imipramine were offaimed respectively at the fixed dose (225mg/day) during the 35 treatment day.

Effect of nomifensine on platelet monoamine oxidase activity in chronic schizophrenic patients.

1. The levels of platelet MAO activity increase and the frequency of affective symptoms diminish in the depressed chronic schizophrenics treated with nomifensine. 2. Nomifensine has no inhibitory effect in vitro on platelet MAO activity in depressed schizophrenic pellets.

Therapeutic and side-effect profile of a selective and reversible MAO-A inhibitor, brofaromine. Results of dose-finding trials in depressed patients.

Brofaromine (CGP 11 305 A), a new reversible and selective MAO-A inhibitor, was studied in two multicentre, (Trial A and Trial B) double-blind, dose-finding trials in a total of 124 depressed in-patients. Doses of 25, 50 and 75 mg bid were compared, to determine which was the most effective. The duration of the trials was four weeks. The comparative drugs were nomifensine (100 mg/day) and tranylcypromine (20 mg/day). The majority of patients in the Trial A was classified as "endogenous" depression. Diagnosis of depression was based on DSM-III or ICD-9 criteria. Conversely, most of the patients in Trial B were "non-endogenous" depressives. In "endogenous" depression, a statistically significant linear dose-response relationship was found in all the efficacy variables assessed. The most effective dose was 150 mg/day. This dose gave a mean drop of 25.3 +/- 11.9 (S.D.) points in the total Hamilton Depression Rating Scale (HAMD) scores and provided successful treatment in 83% of the patients treated, success being defined as a drop of at least 50% in the initial HAMD score at the end of the trial period. In "non-endogenous" depression, no statistical difference was found between the four treatment groups in any of the efficacy variables assessed. Response rate in all brofaromine groups averaged 59% (tranylcypromine group 60%). Tolerability was good in 90% or more of the brofaromine patients in both trials, regardless of the dose administered. The side effects reported most frequently were sleep disturbances, nausea, and headaches.

Tranylcypromine in depression resistant to cyclic antidepressions.

1. Non-responders to cyclic antidepressants were treated with the MAO-inhibitor tranylcypromine in two studies: the first study in an open comparison with L-5-hydroxytryptophan (L-5HTP), the second study in a double blind comparison with nomifensine. 2. While both L-5HTP and nomifensine appeared to be ineffective, tranylcypromine was effective in 26 out of 45 patients. 3. It is concluded that besides ECT also MAO-inhibitors such as tranylcypromine are an effective alternative for depressed patients not responding to cyclic antidepressants.

Treatment strategy in depression. II. MAO inhibitors in depression resistant to cyclic antidepressants: two controlled crossover studies with tranylcypromine versus L-5-hydroxytryptophan and nomifensine.

Antidepressants are ineffective in about 30% of the patients with major depression. Besides electroconvulsive therapy (ECT) and lithium, MAO inhibitors have been suggested as an alternative in such patients. In 2 controlled, partial crossover studies involving 47 patients with major depression who had already been treated unsuccessfully with at least 2 cyclic antidepressants, the effect of the MAO inhibitor tranylcypromine was studied. The first study was an open comparison with L-5-hydroxytryptophan (L-5HTP), the second study a double-blind comparison with nomifensine. Neither the patients treated with L-5HTP nor the patients treated with nomifensine, except one, improved. In contrast, tranylcypromine was effective in 50% of the patients. The depressions of the responders to tranylcypromine appeared to be more endogenous (according Newcastle Scale II) and of shorter duration than those of the non-responders. It is concluded that MAO inhibitors such as tranylcypromine are an effective alternative to ECT and lithium in patients with major depression who have failed to respond to cyclic antidepressants.