Final answer:
The physiologic change that puts Mr. Szwerinski at greater risk of drug toxicity is decreased adipose tissue.
Step-by-step explanation:
The physiologic change that puts Mr. Szwerinski at a greater risk of drug toxicity when prescribed Zocor and Lopressor is decreased adipose tissue. Adipose tissue, also known as body fat, plays an important role in drug distribution and metabolism. Drugs that are highly lipophilic, meaning they dissolve in fat, tend to accumulate in adipose tissue. In older individuals like Mr. Szwerinski, who have reduced adipose tissue due to age-related changes, drug levels can accumulate faster and reach toxic levels.