This question confused me bc I thought loperamide could not cross the BBB and therefore could not cause respiratory depression (mu-opioid agonism at the brainstem results in CNS/respiratory depression, 1). But @dr.xx is correct in noting that ↓ RR and CNS depression in the Pt should call for an mu-opioid antagonist rather than bethanchol (cholinomimetic) to treat constipation.

1. https://anesthesiology.pubs.asahq.org/article.aspx?articleid=2675905

I looked at it this way:

A ten month girl receiving adult doses of a mu agonist (which has POOR CNS penetration not zero) could probably have some adverse effects

I then read that the kid has a decreased RR (10/min) and marked abdominal dissension (prob due to the fact that opioids slow peristalsis; sketchy pharm also says opioids can lead to biliary colic)

Figured naloxone would reverse these symptoms

Loperamide is a Mu opioid agonist that can be used to tx diarrhea. It doesn't cross the BBB so theres no chance of addiction but you can still see the effects of opioid overdose I believe. So tx opioid overdose with naloxone.

Normal respiratory rate for a 10 month old > 50 breaths per minute.

Naloxone should be given in the presence of respiratory depression and may require repeated dosing.

https://www.ncbi.nlm.nih.gov/pubmed/28506439