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Consumption of antidepressants in Denmark in the primary health sector in the period 1994-2003

11 June 2004

Introduction

Antidepressants is the designation for medicinal products for depression. At some point in life, approximately 15 per cent of the Danish population will be diagnosed with depression (The Danish Medicinal Product catalogue 2003) - women twice as often as men. Depressive patients are often treated with medicinal products. In Denmark, the use of medicinal products for depression has increased greatly over the last years. Also, there has been a large debate on the use of antidepressants, and this debate has included subjects such as overtreatment and undertreatment, dependency/discontinuation, adverse drug reactions, diagnosis of depression and treatment of children.

In this study, the consumption during the last 10 years is therefore examined, and it has been investigated whether, on the basis of the Danish Medicines Agency’s Register of Medicinal Product Statistics, any factors exist which may help to explain the great increase in the use of antidepressants. As the increase is almost exclusively seen among newer preparations, the tricyclic antidepressants and other older preparations are only included in some parts of this study.

In appendix 4 (see fact box on the right in the top of this page), you may see an overview of the primary preparations that are included in this study and which are characterised as newer antidepressants. SSRI preparations are Selective Serotonin Reuptake Inhibitors. In the ATC group N06AX are primarily included mirtazapine (Remeron® etc.) and venlafaxine (Efexor® etc.). The name "Other" is used about mirtazapine and venlafaxine, and "SSRI" is used about the group of medicinal products called SSRI. The name "newer antidepressants" includes SSRI, mirtazapine and venlafaxine. On 1 January 2002, the ATC code for Zyban® was changed from N06AX12 to N07BA02, so that Zyban® is no longer classified as an antidepressant but as a product against nicotine dependency. Zyban® is therefore not included in the study.

Summary

The consumption and number of people undergoing treatment with antidepressants has increased since 1994 and is still increasing rapidly. However, the turnover has declined over the last couple of years because of Cipramil®’s patent expiry. This has also lead to a decline in the total turnover of all antidepressants in 2003. The increase in the use of newer antidepressants is both due to the fact that more people receive treatment but also that each person undergoes treatment for a larger part of the year and/or uses larger daily doses. The increase in the number of people undergoing treatment with newer antidepressants can be explained by the fact that an increasingly large proportion of people undergo longer or repeated treatments but also by an increasing number of new users of these medicinal products, especially among the younger age groups. Furthermore, many of the newer antidepressants have become authorised for other indications than depression and some preparations have also become authorised for preventive treatment.

Approximately 20 per cent of all new users of antidepressants only use one prescription throughout the entire period, whereas 19 per cent of users have used one or more prescriptions for at least 5 consecutive years. Five per cent of the users used one or more prescriptions every year in the period 1994-2003, i.e. they have more or less been under continuous treatment for 10 years.

In 2003, the most preferred first line agent for the treatment of depression was medicinal products with the constituent citalopram and in second place preparations with the constituent escitalopram.

There is a significantly larger number of users of antidepressants who use products against dementia than in the population as a whole. The reason for this may be that depression in older people may be mistaken for dementia and vice versa. Merely saying that older people are the primary users of antidepressants does not explain the difference in the use of dementia medication.

You can read the entire analysis in Danish Forbruget af antidepressiva i Danmark 1994 - 2003