Co‐prescribing of SSRIs and TCAs in Australia: how often does it occur and who is doing it?

Abstract

Aims To determine the frequency with which the selective serotonin re-uptake inhibitor (SSRI) antidepressants are used as add-on therapy to the tricyclic antidepressants (TCA) rather than as replacement therapy. Methods The data analysed were pro®les of prescription records by date of supply to the patient. From within the national administrative dispensing claims database, the subset eligible for social security entitlements was identi®ed as individuals by means of their coded permanent identi®cation numbers (PINs). Following the initial supply of an SSRI in January 1996, the subsequent 6 months dispensing of SSRI and TCA antidepressants to these individuals was examined. The main outcome measure was the proportion of individuals to whom SSRIs and TCAs were dispensed concurrently, as an indirect measure of coprescription. In instances where a patient was receiving prescriptions for SSRIs and TCAs that had been written by the one doctor only, the major specialty of the doctor was investigated.Results 55 271 PINs were dispensed 63 865 SSRI prescriptions in January 1996 which represented over half (52%) of the total community SSRI prescriptions dispensed in that month. The number of these patients meeting the criteria for coprescription of SSRIs and TCAs over the next 6 months was 2773 (5%). The coprescribing instances were highest in Queensland and the prescribers most frequently involved had psychiatry major specialty codes. Conclusions Among SSRI users there is a cohort of patients who, within the same time frame, are receiving supplies of a TCA, the nonselective drug that the SSRIs were designed to replace. This is indirect evidence of probable coprescription. Such combination use is of uncertain clinical and cost effectiveness, and carries additional risks. The SSRIs were included on the subsidy list in Australia on the basis of reasonable cost effectiveness as monotherapy compared with the TCAs. Our data imply that for some patients, antidepressant prescribing is inconsistent with the basis on which government subsidy was approved.

The Risk of Hip Fracture Due to Mirtazapine Exposure When Switching Antidepressants or Using Other Antidepressants as Add-On Therapy

“…In practice, the use of multiple antidepressants is infrequent [17–19]. Two studies set in Australia estimated that two or more antidepressants were used by 5 and 3% of patients, respectively [17, 18].…”

“…Two studies set in Australia estimated that two or more antidepressants were used by 5 and 3% of patients, respectively [17, 18]. A Canadian study identified that, of 17,622 adults prescribed at least one antidepressant, 3842 (22%) were co-prescribed multiple antidepressants [19].…”

Adjunctive pharmacotherapy and treatment patterns among initiators of SSRI therapy for major depressive disorder: A cohort study using a primary care database

“…A study of 12 European countries, including the UK, found the prevalence of adjunctive antidepressant therapy to be less than 7% [16]. Similarly, a study in Spain found the prevalence of adjunctive antidepressant therapy to be 8.3% among patients treated for MDD [17]; several other studies have reported a range of adjunctive therapy prevalence of between 2% to 25% [16,18,19]. Reflecting a different health care system, a study based on a US insurance claims database found that 38% of patients who initiated on SSRI monotherapy received adjunctive treatment in the year following the initial index prescription [20].…”

The Strategy of Combining Antidepressants in the Treatment of Major Depression: Clinical Experience in Spanish Outpatients

“…Though it is closer to the primary care reality, sometimes the combination's indication is unknown (since the studies aim to detect polypharmacy), and results are also very varied: 2–5% [27, 28], 5% [38], 10% [39], and 24-25% [29, 30]. …”