Tricyclic antidepressants SSRIs compared with

Arroll B, Macgillivray S, Ogston S, et al. Efficacy and tolerability of tricyclic antidepressants and SSRIs compared with placebo for treatment of depression in primary care a meta-analysis. Ann Fam Med 2005 3(5) 449 56. 

A study in 14 treatment-resistant depressed patients aged between 61 and 82 found that 7 showed eomplete improvement and 3 showed partial improvement, 3 to 21 days after lithium was added to treatment with the tricyclic or related antidepressants. Lithium adverse effects occurred in 6 patients 4 of whom stopped lithium as a result. One of them was successfully restarted at a lower dose. Tremor was the most frequent adverse effect, and reversible neurotoxicity with a stroke-like syndrome was the most severe. The antidepressants used were amitriptyline, doxepin, maprotiline and trazodone. A meta-analysis of 9 studies on the acute treatment of unipolar or bipolar depression indicated that the combined use of a mood stabiliser (lithium in 6 studies) and a tricyclic antidepressant was associated with an increased risk of switches into (hypo)mania, when compared with a mood stabiliser alone. It was suggested that monotherapy with a mood stabiliser should be tried to see if it is effective, before adding an antidepressant. Tricyclics were considered to be second-line antidepressants, with SSRIs the preferred choice. ... 

Tricyclic antidepressants are not licensed for use in the anxiety disorders, so in theory the SSRIs should not be compared with them in cost-effectiveness terms. The SSRIs and venlafaxine are supplanting benzodiazepines as the latter s long-term problems become more appreciated. The SSRIs will take an increasing proportion of the market. However, in comparison with the overall costs of the anxiety disorders, this drug expenditure can be justified. Further cost-offset and cost-effectiveness studies will help hammer this point home. 

The tricyclic antidepressant clomipramine also has been studied for PMDD. In placebo-controlled trials, both continuous daily dosing and luteal phase administration proved effective.17 Compared with the SSRIs, however, clomipramine has a less desirable side-effect profile with low tolerability. 

At first, Sapirstein and I found the equivalence between antidepressants and other drugs puzzling, to say the least. Why should drugs that are not antidepressants be as effective as antidepressants in treating depression To answer this question, we asked another. What do all these diverse drugs have in common that they do not share with inert placebos What do SSRIs have in common with the older tricyclic antidepressants, with other less common antidepressants, and even with tranquillizers, depressants and thyroid medication The only common factor that we were able to note was that they all produce easily noticeable side effects - the one thing that was lacking in Merck s new treatment for depression. Placebos can also produce side effects, but they do so to a much lesser extent than active medication. Clinical trials show that whereas the therapeutic benefits of antidepressants are relatively small when compared to placebos, the difference in side effects is substantial.7... 

In many clinical trials a positive control of a clinically established drug is often used for comparison purposes for example, a novel selective serotonin reuptake inhibitor (SSRI), may be compared with a more established tricyclic antidepressant, such as imipramine. The aim is to see whether the new SSRI is more efficacious or has fewer adverse side effects than the more established tricyclic (Chapter 12). In many such comparisons the new and older treatments are equally efficacious at relieving depression, but the newer drugs display fewer side effects this means that they are better tolerated by patients, so that they are more willing to continue taking the tablets. The high rates of compliance also mean that, in overall terms, newer drugs with fewer side effects tend to be more efficacious. 

In general, the SSRIs have a more tolerable side effect profile than the tricyclic antidepressants with their anticholinergic effects. Review of the rate that subjects in the controlled studies discontinued a SSRI because of adverse effects provides some perspective on how well tolerated the medications are, although the specifics may vary according to dosage and design (e.g., forced titration) and are not directly comparable. The rate of discontinuation was reported to be 12% (4/48) for fluoxetine (Emslie et ah, 1997), 9.7% for paroxetine (Keller et ah, 2001), 13% (12/92) for sertraline (March et ah, 1998), and 33% (19/57) (Riddle et ah, 2001) and 7.9% (5/63) for fluvoxamine (Walkup et ah, 2001). 

Fluoxetine is a selective serotonin-reuptake inhibitor (SSRI) that produces a net increase in (post-synaptic motor neuron) serotonin delivery after 4-6 weeks of use. A double-blind, randomized cross-over trial compared fluoxetine to the tricyclic antidepressant agent protriptyline and placebo in 12 patients with sleep-disordered breathing [52], The group apnea-hypopnea index (AHI) improved with fluoxetine compared to placebo, but there was great variability of response and other measures of disordered sleep did not change. These potentially beneficial results in a small number of patients need to be replicated in well-designed larger studies to support a useful role in clinical practice. 

The selective serotonin-reuptake inhibitors (SSRI) are a new group of chemically unique antidepressant drugs that specifically inhibit serotonin reuptake (see Figure 12.3). This contrasts with the tricyclic antidepressants that nonselectively inhibit the uptake of norepinephrine, and serotonin, and block muscarinic, H histaminic and a -adrenergic receptors. Compared with tricyclic antidepressants, the SSRIs cause fewer anticholinergic effects and lower cardiotoxicity. However, the newer serotonin reuptake inhibitors should be used cautiously until their long-term effects have been evaluated. 

Fergusson et al. (2005) searched the literature and found 702 randomized clinical trials (87,650 patients) comparing SSRIs with either placebo or an active non-SSRI control medication. They found a statistically significant, more than two-fold increased risk of suicide attempts on SSRIs compared to placebo. The odds ratio of suicide attempts in SSRI-treated patients versus placebo patients was 2.28 (p = 0.02) and a 95% confidence interval (Cl) of 1.14-4.55. They also found an increased suicide risk between SSRIs and other medications, excluding tricyclic antidepressants. There was no difference between the SSRIs and tricyclics in suicide risk. Overall, their results documented an association between suicide attempts and the use of SSRIs. ... 

Sertraline, at its usual effective dose of 50 mg/day, has been found to cause less pronounced modifications in plasma concentrations of tricyclic antidepressants (TCAs) as compared with other selective serotonin reuptake inhibitors (SSRIs) (mainly studies with fluoxetine, fluvoxamine, and paroxetine). However, since inhibition of the hepatic enzyme CYP2D6 is dose-dependent, significant increase in plasma concentration of TCAs may occur when higher doses of sertraline are administered. Acute liver damage possibly related to sertraline and venlafaxine ingestion has been reported. 

Future directions for research on hypericum may continue the work done in clinical efficacy. More specifically, studies may be of interest that examine its effects in treatment of more severe depression and different subtypes of depression. The comparative efficacy of different hypericum preparations could be further investigated, and optimum dosages need to be established (Linde et al. 1996). Further work is needed to compare hypericum s efficacy and side effects with those of the SSRIs or atypical antidepressants, because published studies to date have only compared it with tricyclics. 

That SSRIs are more acceptable from the patient s perspective than traditional TCAs is largely accepted by clinicians but has recently been questioned in an article by F. Song et al. [1993]. These researchers conducted a metaanalysis of 63 randomized controlled trials comparing the efficacy and acceptability of SSRIs with those of tricyclic and related antidepressants. The article has been cited widely, especially in the United Kingdom. The authors suggest that the dropout rate in patients receiving SSRIs is similar to that of patients receiving TCAs in controlled studies. They concluded that the routine use of SSRIs as the first-line treatment of depressive illness was not... 

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