The diagnosis of ADRs is highly subjective and imprecise. Complaints such as fatigue, inability to concentrate, and excessive sleepiness have been reported by healthy individuals not taking medications. It is also well known that patients receiving a placebo report ADRs. However, drugs as disease and symptom producing agents should always be considered in the formulation of a differential diagnosis and the following step-wise process can be helpful in assessing possible drug-related adverse reactions:
Step 1 – Identify the drug(s) taken by the patient.
Step 2 – Verify that the onset of signs and symptoms was after the initiation of pharmacological intervention.
Step 3 – Determine the time-interval between the initiation of drug therapy and the onset of signs and symptoms.
Step 4 – Stop drug therapy and monitor signs and symptoms.
Step 5 – In rare instances it may be appropriate to restart drug therapy and monitor for recurrence of signs and symptoms.