Evidence lacking on adherence to combination drugs
Reliable evidence about the impact of combination drugs on patient adherence is lacking, say researchers, providing companies with little incentive to invest in such products.
The researchers searched electronic databases and identified 15 studies in which the use of a combination pill or a unit-of-use packaging system was compared with more traditional presentations. A combination pill is defined as two or more drugs in fixed proportions in the same formulation and unit-of-use packaging system is, for example, medicines to be taken together being blister- packaged together.
The studies all included at least one outcome measure relating to adherence, the pharmacological goal of medication or the cost of therapy.
Although the researchers found a statistically significant trends towards improved adherence in seven out of 13 trials (53 per cent), they say that differences in the methodology used by different researchers cloud interpretation and that almost all of the studies were too small or had inadequate follow-up time.
They point out that fixed-dose combination pills and unit doses can reduce medicines wastage, lower shipping costs, prevent short supply of individual components and avoid under-treatment of diseases in both developing and developed countries. However, they describe the lack of reliable evidence about these strategies as “extraordinary” given the investment in assessing the efficacy of separate medicines and the number of people taking multiple medicines (Bulletin of the World Health Organization 2004;82:935).
Citation: The Pharmaceutical Journal URI: 10018204
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