International Journal of Psychiatry in Clinical Practice
ISSN: 1365-1501 (Print) 1471-1788 (Online) Journal homepage: http://www.tandfonline.com/loi/ijpc20
Use and misuse: Antidepressants in general practice N M Kosky & J G C Rasmussen To cite this article: N M Kosky & J G C Rasmussen (1999) Use and misuse: Antidepressants in general practice, International Journal of Psychiatry in Clinical Practice, 3:2, 121-128 To link to this article: http://dx.doi.org/10.3109/13651509909024772
Published online: 12 Jul 2009.
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Article views: 16
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ijpc20 Download by: [Chinese University of Hong Kong]
Date: 06 November 2015, At: 12:06
8 1999 Martin Dunitz Ltd
International Journal of Psychiatry in Clinical Practice 1999 Volume 3 Pages 121- 128
121
Use and misuse: Antidepressants in general practice NM KOSKY’ AND JGC RASMUSSEN’
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
‘Dorset Community NHS Trust and ’Leacroft Medical Practice, Crawley, UK
Correspondence Address Dr N. M. Kosky, Blackdown Hospital, 34 Blocton Road, Weymouth, Dorset DT3 4ER, UK Tel: +44 (0) 1305 786905 F a : +44 (0) 1305 766807 E-mail: [email protected]
Received 23 October 1998, revised 26 January 1999, accepted for publication 27 January 1999
Depressive disorders are the most common psychiatric illnesses encountered in general practice. The majority of cases are managed exclusively by GPs, prescribing antidepressant medications with or without concurrent counselling or other treatments. There is persistent evidence that in relation to existing treatment guidelines, GPs prescribe antidepressants at inadequate doses for inadequate periods. The Dorset Antidepressant Side-Effects Initiative was designed to discover some of the issues that influence GPs’ prescribing of antidepressants. Whilst results indicate that GPs have reasonably good understanding of the characteristics of the two main classes of antidepressant medications, they are much more likely to underprescribe older tricyclics than SSRls. The differing side-effect profiles of these classes of antidepressant play a significant role in prescribing behaviour. However, the choice of antidepressant is also influenced by the age of the GP, and the type of drug prescribed influences the way in which the GP manages complaints of adverse effects. (Int J Psych Clin Pract 1999; 3: 121- 128) Keywords depression adverse effects selective serotonin re-uptake inhibitors
INTRODUCTION
B
0th depressive symptoms and depressive illness are very common in the adult population. For example, the DEPRES study found a 6-month prevalence rate of 6.9%.’ The vast majority of cases of depressive illness are managed in primary care by general practitioners (GPs) without input from a psychiatrist.* Consequently, it is important that management in general practice should be as effective as possible. For most GPs in the United Kingdom, antidepressants are the backbone of treatment, and the Royal College of General Practitioners set out guidelines for drug treatment of depressive illness in 1992. Those guidelines emphasize the importance of adequate doses of antidepressant treat men^^ The present study was prompted by the experiences of one of the authors (NK) during the provision of a general adult psychiatry service in West Dorset, England. It was noted that patients diagnosed by GPs as suffering from a major depressive illness were often referred to secondary care, having been prescribed the older antidepressants at lower doses, and for shorter periods, than recommended by available guidelines. This observation has been supported by previously published w ~ r k . ~ . ~
antidepressants tricyclic antidepressants
DASI (Dorset Antidepressant Side-Effects Initiative) was designed to find out more about GPs’ reported use of antidepressants by examining their understanding of antidepressants and the expected effects of these drugs. In particular, we sought to explore the general usage of antidepressants among a group of GPs and then to discover the issues that influenced GPs’ prescribing of antidepressants. DASI was a postal questionnaire (see Appendix); here we outline the results and try to interpret them.
METHODS QUESTIONNAIRE DESIGN In the design of DASI, several points were considered. First, it should allow fairly rapid completion, or busy GPs would not respond; second, it should permit free expression of the respondents’ views; i.e. the questions should, as far as possible, avoid leading respondents to a particular conclusion; third, it should yield information about: 0 the GP: age, years since qualification and whether or not the GP was a fundholder, used a practice formulary, had a particular interest in mental health or had been
122
0
0
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
0
NM Kosky andJGC Rasmussen
involved with any antidepressant clinical trials in the past 5 years; the antidepressants they commonly used: usual dosage, side-effects and the management of those side-effects; symptomatic and medical factors that might influence the choice of antidepressant; the expected effects of stopping antidepressant treatment, and the time course of antidepressant withdrawal.
It was decided to distribute and collect DASI by post, partly because this would allow respondents to remain anonymous, and might thereby elicit more candour than might have been the case with personal interviews. In any event, resource constraints would have seriously limited the size of the sample if interviews had been used. The original version of the DASI questionnaire was sent to 10 GPs, to assess its acceptability. This pilot showed that it would take 12- 18 minutes to complete the questionnaire, and few problems were encountered. No significant changes were made to the questionnaire following this pilot trial.
TARGET POPULATION The target population for this study was GPs who were served by mental health services from one West Dorset Community Health Trust. It was felt that by making the study local, we would increase the response rate.
DATACOLLECTION The questionnaire was sent to all 132 GPs in West Dorset; if there was no response, the questionnaire was sent again, up to three times. Data collection was completed over 4 months in the early part of 1997. Once the questionnaires were returned, each was scrutinized. Free-text responses to questions about the recognition of side-effects, the management of those sideeffects, and the physical factors influencing drug choice, were coded and then grouped by common theme to allow statistical analysis. Respondents could list up to five antidepressants, and it was assumed that the first two listed represented the first and second choices for drug therapy. The remainder of the form concentrated on these two drugs. For these, the questionnaire asked the usual daily dose, and many respondents gave a range of doses. When evaluating whether the suggested doses were therapeutic or sub-therapeutic, only the highest dose mentioned was considered. The drugs themselves were classified either as tricyclic antidepressants (TCAs) or selective serotonin re-uptake inhibitors (SSRIs). Subsequent comparisons of prescribing and management styles were generally based upon these two major classes of drug. Consequently, calculations of the significance of differences were obtained using Fisher’s Exact Test or x2 analyses. To see whether newer TCAs were used differently from the older drugs, data for lofepramine were compared with other TCAs in some cases.
RESULTS From the 132 GPs in West Dorset, 100 (76%) returned completed questionnaires (including the 10 from the pilot group). All of these were used in our analysis, and the great majority were completely filled in. One GP returned a blank questionnaire, declining to take part. Another expressed concern over “having my practice scrutinised by an expert”.
GENERALPRACTITIONERS Among the respondents, 22% GPs were younger than 35, 44% were between 35 and 45, while 34% were over 45 years. On average, they had been in practice for 17 years (range 5 - 39) and 35% were fundholders. Overall 53% of the GPs had a practice formulary (79%of fundholders) and 22%had a special interest in mental health. Only one doctor had taken part in a relevant clinical trial in the past 5 years.
THEDRUGS Each doctor had an opportunity to list up to five antidepressants. There were 389 responses to this section of DASI, and the results are given in Table 1. The DASI questionnaire did not specifically ask GPs to list drugs in order of preference or frequency of prescribing, but it is reasonable to assume that this was generally, if not always, the case. This assumption is implicit in the general design of DASI, where other information about the use of antidepressants concentrated on the first two drugs listed. Consequently, for the purposes of this report, the first and
Table I Drugs used as antidepressants
Drug Fluoxetine Dothiepin Paroxetine Lofepramine Amitryptiline Sertraline Flupenthixol Trazodone Clomipramine Nefazodone Imipramine Citalopram Chlorpromazine Doxepin Fluvoxamine Trimipramine Venlafaxine
No. ojtimes listed
% of total lists
87 80 57 55 38 36 10 6 5 5 3 2 1 1 1 1 1
22.4 20.6 14.7 14.1 9.8 9.3 2.6 1.5 1.3 1.3 0.8 0.5 0.3 0.3 0.3 0.3 0.3
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
Antidepressants in general practice
second drugs listed are considered to be the first and second choices of respondents. Overall, fluoxetine was most often mentioned, but dothiepin was mentioned first by more GPs (see Table 2). Tricyclic antidepressants (TCAs), among which lofepramine was included, were listed most often. The vast majority of antidepressants mentioned were either TCAs or selective serotonin re-uptake inhibitors (SSRIs). Venlafaxine was included in the SSRI group, as this is its predominant action at the dosages mentioned in our study, and nefazodone was treated in the same way, its main site of action being on the serotonergic system. There was only one mention of a nonantidepressant drug being used as an antidepressant; chlorpromzine was included on one list. This and one other drug mentioned - flupenthixol- were not included in analyses, on the basis that they could not be reasonably classified
Table 2 Antidepressants listed first
Drug Dothiepin Fluoxetine Amitryptiline Paroxetine Sertraline Lofepramine Flupenthixol Nefazodone Trazodone Trimipramine Total
No. of times listed first
No. of times listed second
36 25 15
17 37 8 17 7 11 1 1 1
7 7 5 2 1 1 1
100
100
123
as either an SSRI or TCA and were mentioned too infrequently to warrant analysis on their own account. Flupenthixol was mentioned twice as a first choice and once as a second choice. Chlorpromazine was mentioned once as the third, and last, choice of one respondent. There was no relationship between choice of drug and interest in mental health, fundholding status or existence of a practice formulary. There was a relationship between age of the GPs and their choice of antidepressant, particularly their second choice (Figure 1). Older GPs tended to prescribe TCAs whilst younger GPs were significantly more likely to list an SSRI as their second choice (P
ISSN: 1365-1501 (Print) 1471-1788 (Online) Journal homepage: http://www.tandfonline.com/loi/ijpc20
Use and misuse: Antidepressants in general practice N M Kosky & J G C Rasmussen To cite this article: N M Kosky & J G C Rasmussen (1999) Use and misuse: Antidepressants in general practice, International Journal of Psychiatry in Clinical Practice, 3:2, 121-128 To link to this article: http://dx.doi.org/10.3109/13651509909024772
Published online: 12 Jul 2009.
Submit your article to this journal
Article views: 16
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ijpc20 Download by: [Chinese University of Hong Kong]
Date: 06 November 2015, At: 12:06
8 1999 Martin Dunitz Ltd
International Journal of Psychiatry in Clinical Practice 1999 Volume 3 Pages 121- 128
121
Use and misuse: Antidepressants in general practice NM KOSKY’ AND JGC RASMUSSEN’
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
‘Dorset Community NHS Trust and ’Leacroft Medical Practice, Crawley, UK
Correspondence Address Dr N. M. Kosky, Blackdown Hospital, 34 Blocton Road, Weymouth, Dorset DT3 4ER, UK Tel: +44 (0) 1305 786905 F a : +44 (0) 1305 766807 E-mail: [email protected]
Received 23 October 1998, revised 26 January 1999, accepted for publication 27 January 1999
Depressive disorders are the most common psychiatric illnesses encountered in general practice. The majority of cases are managed exclusively by GPs, prescribing antidepressant medications with or without concurrent counselling or other treatments. There is persistent evidence that in relation to existing treatment guidelines, GPs prescribe antidepressants at inadequate doses for inadequate periods. The Dorset Antidepressant Side-Effects Initiative was designed to discover some of the issues that influence GPs’ prescribing of antidepressants. Whilst results indicate that GPs have reasonably good understanding of the characteristics of the two main classes of antidepressant medications, they are much more likely to underprescribe older tricyclics than SSRls. The differing side-effect profiles of these classes of antidepressant play a significant role in prescribing behaviour. However, the choice of antidepressant is also influenced by the age of the GP, and the type of drug prescribed influences the way in which the GP manages complaints of adverse effects. (Int J Psych Clin Pract 1999; 3: 121- 128) Keywords depression adverse effects selective serotonin re-uptake inhibitors
INTRODUCTION
B
0th depressive symptoms and depressive illness are very common in the adult population. For example, the DEPRES study found a 6-month prevalence rate of 6.9%.’ The vast majority of cases of depressive illness are managed in primary care by general practitioners (GPs) without input from a psychiatrist.* Consequently, it is important that management in general practice should be as effective as possible. For most GPs in the United Kingdom, antidepressants are the backbone of treatment, and the Royal College of General Practitioners set out guidelines for drug treatment of depressive illness in 1992. Those guidelines emphasize the importance of adequate doses of antidepressant treat men^^ The present study was prompted by the experiences of one of the authors (NK) during the provision of a general adult psychiatry service in West Dorset, England. It was noted that patients diagnosed by GPs as suffering from a major depressive illness were often referred to secondary care, having been prescribed the older antidepressants at lower doses, and for shorter periods, than recommended by available guidelines. This observation has been supported by previously published w ~ r k . ~ . ~
antidepressants tricyclic antidepressants
DASI (Dorset Antidepressant Side-Effects Initiative) was designed to find out more about GPs’ reported use of antidepressants by examining their understanding of antidepressants and the expected effects of these drugs. In particular, we sought to explore the general usage of antidepressants among a group of GPs and then to discover the issues that influenced GPs’ prescribing of antidepressants. DASI was a postal questionnaire (see Appendix); here we outline the results and try to interpret them.
METHODS QUESTIONNAIRE DESIGN In the design of DASI, several points were considered. First, it should allow fairly rapid completion, or busy GPs would not respond; second, it should permit free expression of the respondents’ views; i.e. the questions should, as far as possible, avoid leading respondents to a particular conclusion; third, it should yield information about: 0 the GP: age, years since qualification and whether or not the GP was a fundholder, used a practice formulary, had a particular interest in mental health or had been
122
0
0
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
0
NM Kosky andJGC Rasmussen
involved with any antidepressant clinical trials in the past 5 years; the antidepressants they commonly used: usual dosage, side-effects and the management of those side-effects; symptomatic and medical factors that might influence the choice of antidepressant; the expected effects of stopping antidepressant treatment, and the time course of antidepressant withdrawal.
It was decided to distribute and collect DASI by post, partly because this would allow respondents to remain anonymous, and might thereby elicit more candour than might have been the case with personal interviews. In any event, resource constraints would have seriously limited the size of the sample if interviews had been used. The original version of the DASI questionnaire was sent to 10 GPs, to assess its acceptability. This pilot showed that it would take 12- 18 minutes to complete the questionnaire, and few problems were encountered. No significant changes were made to the questionnaire following this pilot trial.
TARGET POPULATION The target population for this study was GPs who were served by mental health services from one West Dorset Community Health Trust. It was felt that by making the study local, we would increase the response rate.
DATACOLLECTION The questionnaire was sent to all 132 GPs in West Dorset; if there was no response, the questionnaire was sent again, up to three times. Data collection was completed over 4 months in the early part of 1997. Once the questionnaires were returned, each was scrutinized. Free-text responses to questions about the recognition of side-effects, the management of those sideeffects, and the physical factors influencing drug choice, were coded and then grouped by common theme to allow statistical analysis. Respondents could list up to five antidepressants, and it was assumed that the first two listed represented the first and second choices for drug therapy. The remainder of the form concentrated on these two drugs. For these, the questionnaire asked the usual daily dose, and many respondents gave a range of doses. When evaluating whether the suggested doses were therapeutic or sub-therapeutic, only the highest dose mentioned was considered. The drugs themselves were classified either as tricyclic antidepressants (TCAs) or selective serotonin re-uptake inhibitors (SSRIs). Subsequent comparisons of prescribing and management styles were generally based upon these two major classes of drug. Consequently, calculations of the significance of differences were obtained using Fisher’s Exact Test or x2 analyses. To see whether newer TCAs were used differently from the older drugs, data for lofepramine were compared with other TCAs in some cases.
RESULTS From the 132 GPs in West Dorset, 100 (76%) returned completed questionnaires (including the 10 from the pilot group). All of these were used in our analysis, and the great majority were completely filled in. One GP returned a blank questionnaire, declining to take part. Another expressed concern over “having my practice scrutinised by an expert”.
GENERALPRACTITIONERS Among the respondents, 22% GPs were younger than 35, 44% were between 35 and 45, while 34% were over 45 years. On average, they had been in practice for 17 years (range 5 - 39) and 35% were fundholders. Overall 53% of the GPs had a practice formulary (79%of fundholders) and 22%had a special interest in mental health. Only one doctor had taken part in a relevant clinical trial in the past 5 years.
THEDRUGS Each doctor had an opportunity to list up to five antidepressants. There were 389 responses to this section of DASI, and the results are given in Table 1. The DASI questionnaire did not specifically ask GPs to list drugs in order of preference or frequency of prescribing, but it is reasonable to assume that this was generally, if not always, the case. This assumption is implicit in the general design of DASI, where other information about the use of antidepressants concentrated on the first two drugs listed. Consequently, for the purposes of this report, the first and
Table I Drugs used as antidepressants
Drug Fluoxetine Dothiepin Paroxetine Lofepramine Amitryptiline Sertraline Flupenthixol Trazodone Clomipramine Nefazodone Imipramine Citalopram Chlorpromazine Doxepin Fluvoxamine Trimipramine Venlafaxine
No. ojtimes listed
% of total lists
87 80 57 55 38 36 10 6 5 5 3 2 1 1 1 1 1
22.4 20.6 14.7 14.1 9.8 9.3 2.6 1.5 1.3 1.3 0.8 0.5 0.3 0.3 0.3 0.3 0.3
Downloaded by [Chinese University of Hong Kong] at 12:06 06 November 2015
Antidepressants in general practice
second drugs listed are considered to be the first and second choices of respondents. Overall, fluoxetine was most often mentioned, but dothiepin was mentioned first by more GPs (see Table 2). Tricyclic antidepressants (TCAs), among which lofepramine was included, were listed most often. The vast majority of antidepressants mentioned were either TCAs or selective serotonin re-uptake inhibitors (SSRIs). Venlafaxine was included in the SSRI group, as this is its predominant action at the dosages mentioned in our study, and nefazodone was treated in the same way, its main site of action being on the serotonergic system. There was only one mention of a nonantidepressant drug being used as an antidepressant; chlorpromzine was included on one list. This and one other drug mentioned - flupenthixol- were not included in analyses, on the basis that they could not be reasonably classified
Table 2 Antidepressants listed first
Drug Dothiepin Fluoxetine Amitryptiline Paroxetine Sertraline Lofepramine Flupenthixol Nefazodone Trazodone Trimipramine Total
No. of times listed first
No. of times listed second
36 25 15
17 37 8 17 7 11 1 1 1
7 7 5 2 1 1 1
100
100
123
as either an SSRI or TCA and were mentioned too infrequently to warrant analysis on their own account. Flupenthixol was mentioned twice as a first choice and once as a second choice. Chlorpromazine was mentioned once as the third, and last, choice of one respondent. There was no relationship between choice of drug and interest in mental health, fundholding status or existence of a practice formulary. There was a relationship between age of the GPs and their choice of antidepressant, particularly their second choice (Figure 1). Older GPs tended to prescribe TCAs whilst younger GPs were significantly more likely to list an SSRI as their second choice (P
