Maintaining Steady Antibiotic Levels

Steps:

• Antibiotics kill bacteria only above a minimum inhibitory concentration (MIC).
• Drug levels peak after dosing but decline over time due to metabolism and excretion.
• Even spacing ensures levels stay above MIC continuously.
• Irregular dosing risks sub-MIC periods, allowing bacterial regrowth.

Why B is correct:

• Antibiotics require sustained levels above the MIC to continuously inhibit or kill bacteria, as defined by pharmacokinetics.

Why the others are wrong:

• A: Concentration rises quickly post-dose, not slowly; even spacing prevents drops below lethal levels.
• C: Even spacing reduces resistance risk indirectly by fully eradicating bacteria, but primary goal is sustained lethality.
• D: Antibiotics target all susceptible bacteria; even dosing avoids selecting for resistance by ensuring complete kill.

Final answer: B