For the concentration-effect curve, increasing dose from 1x to 10x to 100x does not change the curve shape for the same route.

For the concentration-effect curve, increasing dose from 1x to 10x to 100x does not change the curve shape for the same route.

• A. True
• B. Not enough information
• C. False
• D. Depends on tissue

Answer: (C)

The concentration-effect curve shows how a drug’s effect relates to the concentration at the site of action, governed by receptor binding and downstream signaling (Emax, EC50, and slope). Dose determines the amount of drug reaching that site, and thus the concentration-time profile. Because of this, simply increasing the dose does not guarantee an unchanged shape of the curve across a broad range. In real systems, nonlinear pharmacokinetics (for example, saturable absorption or metabolism) or pharmacodynamic factors (like receptor desensitization or different pathways engaged at higher concentrations) can alter potency or maximum effect, changing the observed curve. So the statement isn’t universally true; the curve can change with dose under many conditions, making the correct choice false.

The concentration-effect curve shows how a drug’s effect relates to the concentration at the site of action, governed by receptor binding and downstream signaling (Emax, EC50, and slope). Dose determines the amount of drug reaching that site, and thus the concentration-time profile. Because of this, simply increasing the dose does not guarantee an unchanged shape of the curve across a broad range. In real systems, nonlinear pharmacokinetics (for example, saturable absorption or metabolism) or pharmacodynamic factors (like receptor desensitization or different pathways engaged at higher concentrations) can alter potency or maximum effect, changing the observed curve. So the statement isn’t universally true; the curve can change with dose under many conditions, making the correct choice false.