Which information is essential to collect when planning pharmacotherapy?

• A. Pregnancy status
• B. Renal and hepatic function
• C. Family medical history
• D. Exercise routine

Answer: (B)

Assessing how the body handles drugs is the key idea. Planning pharmacotherapy hinges on renal and hepatic function because the liver metabolizes most medications and the kidneys excrete them. When these organs are impaired, drug clearance drops, leading to higher blood levels and potential toxicity. This directly influences dosing, dosing interval, and even drug selection to keep therapy both safe and effective. For drugs that are primarily renally excreted, reduced kidney function often requires lower doses or longer intervals; for drugs heavily dependent on hepatic metabolism, liver impairment can necessitate dose adjustments or avoidance. While factors like pregnancy status, family history, or exercise can be relevant in specific situations, they do not universally determine safe dosing and drug choice as foundationally as renal and hepatic function.