Final answer:
Naloxone should be available to reduce postnatal effects of Demerol to the neonate as it can reverse the respiratory depression caused by opioids.
Step-by-step explanation:
The medication that should be available to reduce postnatal effects of Demerol to the neonate is Naloxone. Demerol is an opioid agonist that can cause respiratory depression in neonates if administered to the mother before birth. Naloxone is an opiate antagonist that can reverse the respiratory depression caused by opioids without producing analgesia, euphoria, or respiratory depression in individuals not dependent on narcotics. Therefore, it is the appropriate drug to have on hand to treat the neonate for any opioid-related side effects post birth.