The relationship between drug dose and clinical outcome has not been established for many medications used to treat chronic disease. Evidence is emerging that chronic diseases can be treated effectively with low doses.

Adverse drug reactions account for significant morbidity and mortality and are generally dose related.

Optimal drug dose — the best balance of benefit and risk — varies between individuals and may change over time. When treating chronic disease it is important to establish and maintain the optimal dose for each patient by close clinical monitoring.