Final answer:
The nurse should have naloxone available to counteract the effects of meperidine on the newborn, as it is an opiate antagonist that can reverse opioid-induced respiratory depression.
Step-by-step explanation:
The medication that the nurse should have available to counteract the effects of meperidine on the newborn is naloxone. Meperidine is an opioid analgesic, and naloxone is an opiate antagonist that counteracts the effects of opioids, including the potential respiratory depression in newborns whose mothers received opioids before delivery. Naloxone works by reversing the effects of morphine and similar drugs at all their receptors, which includes alleviating narcotic-induced respiratory depression in newborns.