A general practitioner double-blind study of dothiepin hydrochloride ('Prothiaden') and amitriptyline in depression

Amitriptyline for depression

BACKGROUND

For many years amitriptyline has been considered one of the reference compounds for the pharmacological treatment of depression. However, new tricyclic drugs, heterocyclic compounds and selective serotonin reuptake inhibitors have been introduced on the market with the claim of a more favourable tolerability/efficacy profile.

OBJECTIVES

The aim of the present systematic review was to investigate the tolerability and efficacy of amitriptyline in comparison with the other tricyclic/heterocyclic antidepressants and with the selective serotonin reuptake inhibitors.

SEARCH STRATEGY

The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR-Studies) was searched on 28-11-2005. Reference lists of all included studies were checked.

SELECTION CRITERIA

Only randomised controlled trials were included. Study participants were of either sex and any age with a primary diagnosis of depression. Included trials compared amitriptyline with another tricyclic/heterocyclic antidepressant or with one of the selective serotonin reuptake inhibitors.

DATA COLLECTION AND ANALYSIS

Data were extracted using a standardised form. The number of patients undergoing the randomisation procedure, the number of patients who completed the study and the number of improved patients were extracted. In addition, group mean scores at the end of the trial on Hamilton Depression Scale or any other depression scale were extracted. In the tolerability analysis, the number of patients failing to complete the study and the number of patients complaining of side-effects were extracted.

MAIN RESULTS

A total number of 194 studies were included in the review. The estimate of the overall odds ratio (OR) for responders showed that more subjects responded to amitriptyline in comparison with the control antidepressant group (OR 1.12 to 95% confidence interval (CI) 1.02 to 1.23, number needed to treat to benefit (NNTB) = 50). The estimate of the efficacy of amitriptyline and control agents on a continuous outcome revealed an effect size which also significantly favoured amitriptyline (Standardised Mean Difference (SMD) 0.13, 95% CI 0.04 to 0.23). Whilst these differences are statistically significant, their clinical significance is less clear. When the efficacy analysis was stratified by drug class, no difference in outcome emerged between amitriptyline and either tricyclic or selective serotonin reuptake inhibitor comparators. The dropout rate in patients taking amitriptyline and control agents was similar; however, the estimate of the proportion of patients who experienced side-effects significantly favoured control agents in comparison with amitriptyline (OR 0.66, 95% CI 0.59 to 0.74). When the tolerability analysis was stratified by drug class, the dropout rate in patients taking amitriptyline and the selective serotonin reuptake inhibitors significantly favoured the latter (OR 0.84, 95% CI 0.75 to 0.95, number needed to treat to harm (NNTH) = 40). When the responder analysis was stratified by study setting amitriptyline was more effective than control antidepressants in inpatients (OR 1.22, 95% CI 1.04 to 1.42, NNTB = 24), but not in outpatients (OR 1.01, 95%CI 0.88 to 1.17, NNTB = 200).

AUTHORS' CONCLUSIONS

This present systematic review indicates that amitriptyline is at least as efficacious as other tricyclics or newer compounds. However, the burden of side-effects in patients receiving it was greater. In comparison with selective serotonin reuptake inhibitors amitriptyline was less well tolerated, and although counterbalanced by a higher proportion of responders, the difference was not statistically significant.

Amitriptyline versus other types of pharmacotherapy for depression

BACKGROUND

For many years amitriptyline has been considered one of the reference compounds for the pharmacological treatment of depression. However, new tricyclic drugs, heterocyclic compounds and the selective serotonin reuptake inhibitors have been introduced on the market with the claim of a more favourable tolerability/efficacy profile.

OBJECTIVES

The aim of the present systematic review was to investigate the tolerability and efficacy of amitriptyline in comparison with the other tricyclic/heterocyclic antidepressants and with the selective serotonin reuptake inhibitors.

SEARCH STRATEGY

The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (2002-3) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched. Key journals and conference abstracts were handsearched. Pharmaceutical companies were contacted for information on unpublished materials.

SELECTION CRITERIA

Only randomised controlled trials were included. Study participants were of either sex and any age with a primary diagnosis of depression. Included trials compared amitriptyline with another tricyclic/heterocyclic antidepressant or with one of the selective serotonin reuptake inhibitors.

DATA COLLECTION AND ANALYSIS

Data were extracted using a standardised form. The number of patients undergoing the randomisation procedure, the number of patients who completed the study and the number of improved patients were extracted. In addition, group mean scores at the end of the trial on Hamilton Depression Scale or any other depression scale were extracted. In the tolerability analysis, the number of patients failing to complete the study and the number of patients complaining of side-effects was extracted.

MAIN RESULTS

The estimate of the overall odds ratio for responders showed that more subjects responded to amitriptyline in comparison with the control antidepressant group (odds ratio 1.12, 95% confidence interval 1.01, 1.23, number needed to treat 50). The estimate of the efficacy of amitriptyline and control agents on a continuous outcome revealed an effect size which also significantly favoured amitriptyline (Standardised Mean Difference 0.13, 95% confidence interval 0.04, 0.23). Whilst these differences are statistically significant, their clinical significance is less clear. When the efficacy analysis was stratified by drug class, no difference in outcome emerged between amitriptyline and either tricyclic or selective serotonin reuptake inhibitor comparators. The dropout rate in patients taking amitriptyline and control agents was similar; however, the estimate of the proportion of patients who experienced side-effects significantly favoured control agents in comparison with amitriptyline (odds ratio 0.63, 95% confidence interval 0.56, 0.71). When the tolerability analysis was stratified by drug class, the dropout rate in patients taking amitriptyline and the selective serotonin reuptake inhibitors significantly favoured the latter (odds ratio 0.84, 95% confidence interval 0.75,0.95, number needed to harm 40). When the responder analysis was stratified by study setting amitriptyline was more effective than control ADs in inpatients (odds ratio 1.22, 95% confidence interval 1.04, 1.42, number needed to treat 24), but not in outpatients (odds ratio 1.01, 95% confidence interval 0.88, 1.17, number needed to treat = 200).

REVIEWER'S CONCLUSIONS

This present systematic review indicates that amitriptyline is at least as efficacious as other tricyclics or newer compounds. However, the burden of side-effects in patients receiving it was greater. In comparison with the selective serotonin reuptake inhibitors amitriptyline was less well tolerated, and although counterbalanced by a higher proportion of responders, the difference was not statistically significant.

Amitriptyline v. the rest: still the leading antidepressant after 40 years of randomised controlled trials

BACKGROUND

Tricyclic antidepressants have similar efficacy and slightly lower tolerability than selective serotonin reuptake inhibitors (SSRIs). However, there are no systematic reviews assessing amitriptyline, the reference tricyclic drug, v. other tricyclics and SSRIs directly.

AIMS

To review the tolerability and efficacy of amitriptyline in the management of depression.

METHOD

A systematic review of randomised controlled trials (RCTs) comparing amitriptyline with other tricyclics/heterocyclics or with an SSRI.

RESULTS

We reviewed 186 RCTs. The overall estimate of the efficacy of amitriptyline revealed a standardised mean difference of 0.147 (95% CI 0.05-0.243), significantly favouring amitriptyline. The overall OR for dropping out was 0.99 (95% CI 0.91-1.08) and that for side-effects was 0.62 (95% CI 0.54-0.70), favouring the control drugs. With drop-outs included as treatment failures, the estimate of the effectiveness of amitriptyline v. tricyclics/heterocyclics and SSRIs showed a 2.5% difference in the proportion of responders in favour of amitriptyline (number needed to treat 40, CI 21-694; OR 1.12 (95% CI 1.01-1.24)).

CONCLUSIONS

Amitriptyline is less well tolerated than tricyclics/heterocyclics and SSRIs, but slightly more patients treated on it recover than on alternative antidepressants.

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.

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

Dothiepin is a tricyclic antidepressant that is structurally related to amitriptyline. It appears that the antidepressant activity of dothiepin is mediated through facilitation of noradrenergic neurotransmission by uptake inhibition and possibly also by enhancement of serotoninergic neurotransmission. The overall therapeutic efficacy of dothiepin is very similar to that of amitriptyline. In addition, dothiepin appears to be comparable to imipramine, doxepin, maprotiline, mianserin, fluoxetine, fluvoxamine and trazodone. Dry mouth is the most commonly reported side effect of therapeutic doses but the incidence of this and other anticholinergic side effects is less among patients treated with dothiepin than with amitriptyline. However, the sedative/anxiolytic activity of dothiepin is similar to that of amitriptyline. Dothiepin has not been associated with cardiotoxicity at therapeutic doses. Thus, many years of extensive clinical use have shown that dothiepin is now an established and effective antidepressant in both inpatients and outpatients with depressive symptoms of varying severity and coexisting anxiety. Its therapeutic equivalence to other tricyclics ensures its place as a treatment alternative in these disorders.

Clinical trial comparison of a sustained release form of amitriptyline with dothiepin

A double-blind between-group trial was undertaken in fifty depressed patients to compare the efficacy of a sustained release form of amitriptyline (Lentizol) with dothiepin (Prothiaden) over a 5-week period. Patients fulfilling defined admission criteria were randomly allocated to treatment with evening dosage of either 50 mg of the sustained release preparation or 75 mg of dothiepin for the first week of the trial. Subject to review as necessary, these dosages were doubled at the end of the first week. Both drugs effected significant and appreciable improvement over the 5-week period, with the mean responses at the end of the trial retaining the same relative positions as at the beginning.