The action just keeps coming $CWNM In addition, the achieved peak level may reside above the upper limit of the therapeutic range, exposing the patient to the risk of adverse reactions. Supra-therapeutic peak levels, particularly or drugs with rapid elimination characteristics, are often unavoidable in attempts to extend the duration of therapeutic concentrations and increase trough levels. Although frequent and sustained dosing may circumvent the issue of toxic peak and sub-therapeutic trough levels, the feasibility of this approach is limited by poor patient acceptance and compliance.