Antidiarrheal agents

Both loperamide and diphenoxylate act as opioid agonists to prevent and treat diarrhea. Which of the following best characterizes the difference between these two medications?

1: Loperamide increases phasic segmenting contractions of the colon, while diphenoxylate increases peristaltic contractions of the colon.
2: Unlike diphenoxylate, loperamide is often combined with atropine.
3: In the gastrointestinal tract, loperamide acts as an agonist at µ opioid receptors, while diphenoxylate acts at Κ opioid receptors.
4: Loperamide does not readily cross the blood-brain barrier, but, at higher doses, diphenoxylate can.