Combining drugs acting on different pathological mechanisms of the same disease
Simultaneous administration of a prefixed combination of different drugs that act on different aspects of the disease pathology is designed to achieve the following advantages:
1. Additive or synergistic therapeutic effect
There are typically multiple mechanisms and pathways involved in the pathology of a given disease. Even in an apparently simple condition such as a local infection, there are not only multiplying microorganisms such as bacteria that can in principle be suppressed with antibiotics, but also consequences to the body’s cellular defense mechanisms, such as neutrophils, macrophages and dendritic cells, which may function sub-optimally in the infected environment. If their function is improved e.g. by supplying the stimulatory cytokine GM-CSF, as well as providing antibiotic to kill the bacteria, a double action to clear the infection is obtained. The actions may be additive or even multiplicative (synergistic). Substances may also be added to the pharmaceutical preparation which potentiate the effects of the active ingredients, e.g. by preventing breakdown and prolonging their action.
2. Convenience for the patient and clinician
At the same time, it is convenient for both the patient and the clinician not to have to apply several different medications at once to treat a single condition, but to use the preparation that has been developed to provide the best generally applicable combination. While this practice was at first criticized for hindering the clinicians from tailoring dosage ratios to suit individual patients and circumstances, it has long since become widely accepted as offering convenient solutions, as clinicians rarely had the means of initiating and adequately following up the individual tailoring principle. The use of ready-made drug combinations is particularly well accepted in the treatment of high blood pressure.