Factors that Change a Drug’s Efficacy

The following factors change the efficacy of a drug within a person’s system:

1. Age (often due to a decrease in GFR therefore a decrease in drug excretion)

2. Weight

3. Condition of the patient and any previous medical illnesses or conditions

4. Individual variation

5. Idiosyncratic and allergic reactions

How a drug or medication will effect a person following ingestion or injection depends of a variety of factors. These should be considered whenever a person potentially overdoses on either a single drug or has a polypharmacy overdose when determining potential effects and treatment requirements.