Side-effect profile of fluoxetine in comparison with other SSRIs, tricyclic and newer antidepressants: a meta-analysis of clinical trial data

BACKGROUND

In the last ten years, SSRIs have increasingly replaced TCAs as comparators of newer antidepressants (ADs), because of their better tolerability profile. In particular, fluoxetine has become a reference drug for the treatment of depression, but the occurrence of individual side effects in depressed subjects treated with fluoxetine and each comparator AD have not been systematically investigated.

METHODS

This meta-analysis investigated the frequency of side effects induced by fluoxetine or alternative ADs and compared the occurrence of individual side effects in depressed subjects. All randomised clinical trials (RCTs) comparing fluoxetine with any other AD drug in patients with major depression were located by searching the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Controlled Trials Register. Two reviewers independently extracted information.

RESULTS

Significantly less percentage of patients treated with fluoxetine experienced any side effects in comparison with TCAs (50.9 % vs 60.3 %, 29 RCTs; RR = 0.84, p = 0.003), but not in comparison with other SSRIs (59.4 % vs 59.3 %, 15 RCTs; RR = 1.00, p = 0.902). In addition, fluoxetine was better tolerated in comparison with TCAs and related ADs (RR 0.61, 95 % CI 0.52, 0.71), but not in comparison with other SSRIs. Regard to individual side effects, activating (insomnia, agitation, tremor and anxiety) and gastrointestinal adverse events (nausea, vomiting, diarrhoea, weight loss and anorexia) were significantly more frequent in fluoxetine-treated patients, whereas cholinergic side effects were significantly less frequent.

CONCLUSIONS

Fluoxetine compared to other ADs had more activating and gastrointestinal adverse effects, which often require additional pharmacotherapy or other managements strategies, leading to discontinuation and non-compliance and increasing the costs. This information is relevant to base on evidence the prescription of ADs in everyday clinical practice.

Non-stimulant medications in the treatment of ADHD

BACKGROUND

Stimulants are the first-line medication in the psychopharmacological treatment of attention-deficit hyperactivity disorder (ADHD). However, 10 to 30% of all children and adults with ADHD either do not respond to or do not tolerate treatment with stimulants.

OBJECTIVE

To describe alternative treatment approaches with various non-stimulant agents, especially atomoxetine.

METHOD

General review of empirically based literature concerning efficacy and safety of the substances.

RESULTS

A large and still increasing body of data supports the usefulness of atomoxetine, a once daily dosing, and new selective noradrenalin reuptake inhibitor, with few side effects. Atomoxetine has been licensed in the US for use in ADHD across the lifespan, and is currently under consideration in Europe. Other non-stimulant substances, such as tricyclic antidepressants (TCAs) and alpha-2-adrenergic agonists, which are used to treat ADHD, are also reviewed. TCAs have been well studied and shown to be efficacious in the treatment of ADHD, but are limited by side effects. The number of studies documenting the efficacy of alpha-2-adrenergic agonists is still limited. Some experimental studies support a potential role of cholinergic drugs such as acetylcholinesterase inhibitors (tacrine, donepezil) as well as novel nicotinic analogues (ABT-418).

CONCLUSION

Non-stimulant agents have been shown to be effective in treatment of ADHD. Especially, atomoxetine seems promising and newline drugs are in development.

Antidepressants in the treatment of irritable bowel syndrome and visceral pain syndromes

Irritable bowel syndrome (IBS) is characterized by abdominal pain associated with disordered defecation, which may include urgency and altered stool frequency. Visceral pain syndromes, including IBS, may be effectively treated by a variety of therapies that modulate the interactions between the central and enteric nervous systems. Clinical observations and preliminary data suggest that antidepressants may be efficacious for the treatment of these syndromes. The tricyclic antidepressants (TCAs) have been utilized most extensively in this area, but there is a need for more rigorous efficacy data. Serotonin, an important neurotransmitter in both the central and enteric nervous systems, modifies both motility and sensation in the gut. Recognition of the importance of serotonin in digestive motility and sensation has sparked interest in the use of agents that modify serotonergic transmission in visceral pain syndromes. Pharmacological therapeutics that modulate the biological amines (serotonin, norepinephrine, dopamine and catecholamines) both peripherally and within the central nervous system may offer more effective therapies for these disorders. The selective serotonin reuptake inhibitors are commonly used in clinical practice, but more rigorous, controlled studies are needed to determine their effects beyond the treatment of psychiatric comorbidity. The newer generation antidepressants may provide additional insight into the pathophysiology of the brain-gut interactions and their relationship to functional bowel disorders, providing new therapeutic interventions.

Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?

The cardiovascular toxicity of older generation of tricyclic antidepressants (e.g. imipramine, desipramine, amitriptyline, clomipramine) and neuroleptics (e.g. haloperidol, droperidol, thioridazine, pimozide) is well established. These drugs inhibit cardiovascular Na(+), Ca(2+) and K(+) channels often leading to life-threatening arrhythmia. To overcome the toxicity of old generation of antidepressants and antipsychotics, selective serotonin reuptake inhibitor antidepressants (SSRIs: fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxin) and several new antipsychotics (e.g. clozapine, olanzapine, risperidone, sertindole, aripiprazole, ziprasidone, quetiapine) were introduced during the past decade. Although these new compounds are not more effective in treating psychiatric disorders than older medications, they gained incredible popularity since they have been reported to have fewer and more benign side effect profile (including cardiovascular) than predecessors. Surprisingly, an increasing number of case reports have demonstrated that the use of SSRIs and new antipsychotics (e.g. clozapine, olanzapine, risperidone, sertindole, aripiprazole, ziprasidone, quetiapine) is associated with cases of arrhythmias, prolonged QTc interval on electrocardiogram (ECG) and orthostatic hypotension in patients lacking cardiovascular disorders, raising new concerns about the putative cardiovascular safety of these compounds. In agreement with these clinical reports these new compounds indeed show marked cardiovascular depressant effects in different mammalian and human cardiovascular preparations by inhibiting cardiac and vascular Na(+), Ca(2+) and K(+) channels. Taken together, these results suggest that the new generation of antidepressants and antipsychotics also have clinically important cardiac as well as vascular effects. Clinicians should be more vigilant about these potential adverse reactions and ECG control may be suggested during therapy, especially in patients with cardiovascular disorders. The primary goal of this review is to shed light on the recently observed clinically important cardiovascular effects of new antidepressants and antipsychotics and discuss the mechanism beyond this phenomenon.

Mirtazepine: heir apparent to amitriptyline?

"What's new in therapeutics?" will examine and evaluate drugs that may have a place in hospice, palliative, and long-term care. Mirtazepine will be examined and evaluated. Mirtazepine is a potential alternative anti-depressant with multiple additional benefits. It is an atypical anti-depressant, which has both noradrenergic and specific serotonergic receptor antagonism (NaSSa), and a unique pharmacological profile. Mirtazepine appears to be a "designer drug" for palliative medicine with a number of benefits, but cost may be a drawback.

[The role of serotonergic system in the mechanism of action of antidepressant agents]

Thirty eight years after the successful clinical introduction of antidepressant agents, there has been an important progress in the knowledge and changes in thinking about the role of central serotonergic system in depression and in the mechanism of their therapeutic efficacy. Although it is not clear whether an increase or decrease in serotoninergic function is more important in antidepressant action of agents, there is increasing evidence that almost all antidepressant drugs can induce changes in the sensitivity of somotodendritic 5-HT1A autoreceptors and postsynaptic 5-HT2 receptors in spite of very different pharmacological profiles after a single administration. The question arises as to the causal nature of the relationship between these effects and beneficial clinical action. Further studies are still required to dispel these doubts.

Antidepressant drug selection: criteria and options

The dilemma of developing new medications rationally--as opposed to discovering them through serendipity--is to create an optimal balance between the number of mechanisms of action needed for the widest spectrum of antidepressant activity while maximizing safety and tolerability. Newer antidepressants, such as serotonin selective reuptake inhibitors (SSRIs) and venlafaxine, have a wider therapeutic index than the older tricyclic antidepressants. Fewer types of adverse effects and a reduction in the potential for pharmacodynamic interactions are the distinct benefits of all the newer targeted antidepressants, such as venlafaxine, SSRIs, and bupropion, in comparison with older drugs. However, there are important differences among the newer antidepressants in terms of effects of P450 enzymes, dose-response curves for antidepressant response and adverse effects, and dosing schedules. One of the main benefits of having a wide array of options is the evidence that there may be different forms of the illness, which respond to different mechanisms of action. More research is needed to test this concept and to develop predictors of differential responsiveness.

[Plasmatic concentrations of fluoxetine, pharmacokinetics, therapeutic response and side effects]

The kinetics of fluoxetine and possible relations between the drug's plasmatic concentration and therapeutic response and side effects were evaluated in a sample of 66 depressive patients, 26 men and 40 women, average age 46.6 years (SD = 14.1), diagnosed according to DSM-III criteria and evaluated using the Hamilton scale for depression (17-item HRSD). We found no difference between plasmatic concentration of fluoxetine in weeks 3 and 6 of treatment, nor in the sum of drug plus active principle in weeks 3 and 6. There was no significant linear correlation between plasmatic concentrations of fluoxetine, norfluoxetine, or the sum of both in weeks 3 and 6 and score on the Hamilton scale in week 6. By means of serial Chi-score calculation we found a "minimum plasmatic concentration" of about 30 ng/ml below which there was less therapeutic response.

[Integrated therapy in panic attack disorders]

For the past years or so, studies on panic attack disorders (PAD) have accounted for a large proportion of psychiatric research. In spite of the attempts to clarify the etiopathogenesis of PAD, its characteristic psychopathological aspects and the evolutionary stages of its development, its nosographic status is still controversial (despite its inclusion in DSM III-R) and the same is true of the therapeutical approach. Using these observation as their starting point, the authors have divided the present paper into four parts. In the first they attempt to classify PAD in nosographical terms, whereas the second reviews all pharmacological therapies put forward over the past ten years. The third part consists of a short summary of the most widely used psychotherapeutic approaches, and in the last the authors suggest a model of integrated PAD therapy which is still being clinically experimented. The practice of associating pharmacological therapy with a psychotherapeutic approach has certainly been widely used for some time, but the authors underline that the two methods are only fully integrated in the presence of a therapeutic project resulting in a treatment protocol with controls during the course and at the end of treatment. In this context, the psychodiagnostic stage before therapy is particularly important since it provides as precise as possible a picture of the subject's basic personality and psychopathological state. These factors can lead to a wide varation in the choice of drug therapy, and even jeopardise therapeutic success. On the other hand, an exclusively psychotherapeutic approach to PAD does not rule out the onset of recurrent episodes during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Atypical tricyclic neuroleptics for treatment of schizophrenia. Clothiapine and clozapine]

The main objective of the pharmacotherapy of schizophrenia has been, and still is, to obtain optimal therapeutic efficacy, which is seconded by the aim to restrict as far as possible the sometimes severe collateral effects which are acknowledged as being the major drawback to the regular use of neuroleptic agents. Tight from the start, some "atypical neuroleptics" were identified as being of interest for this reason; these included Clothiapine and Clozapine, a more recently discovered drug which is not yet commercially available in Italy. Both of these neuroleptics have been found to offer extremely interesting advantages. The authors now report data referring to the clinical use of these drugs during 1989-1990 in addition to those published in the literature on this subject.

Antidepressants may not assist recovery in practice: a naturalistic prospective survey

A total of 130 people attending psychiatric hospitals within 6 months of onset or relapse of an episode of depressive disorder were interviewed about their symptoms and treatment at the time of their initial contact. After a mean 4-month interval, 119 were reassessed to test the hypothesis that patients treated with antidepressants would be significantly more likely to be clinically improved compared with those untreated. Severity and duration of the episode emerged as the only significant clinical predictors of clinical improvement. Patients on treatment with antidepressants at the start of the study showed a nonsignificant trend for a lesser degree of clinical improvement, even when clinical severity and compliance were taken into account. Those who were not commenced on treatment until later in the study also fared no better than those who were never prescribed antidepressants. The effect of low doses of antidepressants (almost always a tricyclic) appeared to be less beneficial than either higher doses or clinical management without antidepressant drugs. The need for further experimental and naturalistic studies conducted over various periods of time and the implications for clinical practice, medical audit and the appropriate use of health outcome indicators are discussed.