How can diseases influence adverse drug reactions?

• A. Disease states can affect the rate and extent of drug metabolism in the body; liver, heart, or thyroid disease.
• B. Diseases always decrease drug absorption.
• C. Only genetic factors influence ADRs.
• D. ADRs are unaffected by disease.

Answer: (A)

Diseases can change how drugs move through and are cleared from the body, which directly affects adverse drug reactions. The amount of drug that reaches and stays in the body depends a lot on metabolism. When the liver is diseased, metabolism often slows, leading to higher drug levels and a greater chance of ADRs. Thyroid disorders alter the body's overall metabolic rate and enzyme activity, changing how quickly drugs are cleared. Heart disease can change organ perfusion and blood flow, affecting distribution and clearance, which can also raise or lower drug exposure and ADR risk.

So, disease states influence ADRs by altering drug metabolism and overall exposure, not just by changing absorption or being irrelevant to ADRs.