If a drug precipitates in the stomach, what is the effect on the CT curve?

If a drug precipitates in the stomach, what is the effect on the CT curve?

• A. CT curve shifts upward
• B. CT curve shifts downward
• C. CT curve becomes steeper
• D. CT curve is unchanged

Answer: (B)

When a drug precipitates in the stomach, less of it remains in dissolved form to be absorbed. The amount that can enter the bloodstream at each moment depends on how much is dissolved and available for uptake, so with precipitation the drug entering circulation is smaller across the entire time course. That makes the concentration-time curve lie lower at all time points, i.e., a downward shift. It wouldn’t produce a steeper curve or an upward shift, and it wouldn’t be unchanged, because the reduced dissolved fraction directly lowers systemic exposure.

When a drug precipitates in the stomach, less of it remains in dissolved form to be absorbed. The amount that can enter the bloodstream at each moment depends on how much is dissolved and available for uptake, so with precipitation the drug entering circulation is smaller across the entire time course. That makes the concentration-time curve lie lower at all time points, i.e., a downward shift. It wouldn’t produce a steeper curve or an upward shift, and it wouldn’t be unchanged, because the reduced dissolved fraction directly lowers systemic exposure.