Which of the following statements about the biodisposition of penicillins and cephalosporins is NOT accurate?
**Core Concept**
The biodisposition of penicillins and cephalosporins involves their absorption, distribution, metabolism, and excretion (ADME) properties. These properties are crucial in determining their pharmacokinetic profiles and clinical efficacy.
**Why the Correct Answer is Right**
Penicillins and cephalosporins are primarily eliminated by the kidneys, and their plasma half-lives are typically in the range of 0.5 to 2 hours. This rapid elimination is due to their low protein binding and the presence of renal tubular secretion mechanisms. The primary metabolites of these antibiotics are inactive, and their excretion is not significantly affected by the liver.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option may be incorrect if it implies that penicillins and cephalosporins are primarily eliminated by the liver. While some metabolism does occur in the liver, the kidneys are the primary route of elimination for these antibiotics.
* **Option B:** This option may be incorrect if it suggests that the plasma half-lives of penicillins and cephalosporins are typically longer than 2 hours. While some cephalosporins have longer half-lives, most penicillins and cephalosporins have half-lives in the range of 0.5 to 2 hours.
* **Option C:** This option may be incorrect if it implies that the primary metabolites of penicillins and cephalosporins are active. In fact, the primary metabolites of these antibiotics are usually inactive and do not contribute significantly to their pharmacological effects.
**Clinical Pearl / High-Yield Fact**
To remember the primary route of elimination for penicillins and cephalosporins, recall that "penicillins go to the kidneys."
**Correct Answer:** A.