Which of the following statements about naloxone is true?

The statement regarding naloxone that is true is that it is not effective if taken orally. Naloxone is an opioid antagonist that works by reversibly binding to opioid receptors in the central nervous system, thus blocking the effects of opioids. Its bioavailability is low when taken orally due to extensive first-pass metabolism in the liver, meaning it is quickly broken down and rendered ineffective by the liver enzymes before it can exert its pharmacologic effects. As a result, naloxone is typically administered through routes such as intravenous, intramuscular, or intranasal to ensure adequate levels in the bloodstream.

The other statements do not accurately describe naloxone's characteristics. It does not have a longer half-life than most opioids; in fact, its half-life is much shorter than many opioids, which can lead to a return of opioid effects if the opioid is still present in the system. Naloxone also does not cause sedation in newborns; instead, it can counteract sedation caused by opioids. Lastly, naloxone is not a GABA agonist; it specifically targets opioid receptors, while GABA agonists work on GABA receptors to provide sedative effects.