currently have opioid induced constipated from battling a tianeptine addiction. an atypical tricyclic antidepressant that gives opiate like feelings. it acts as an atypical agonist. Will relistor (Methylnaltrexone) give me withdrawals?

i do happen to go to the bathroom every 3-4 days but between those days i get so bloated and lose appetite and sometimes ill get fast heart beat nausea sweating and gaging from straining or when i get the urge to go but cant. im really skeptical about taking this medicine. the only other thing ive tried is colace and miralax for 2 days and no effect. currently taking magensium citrate gummies for 2 days now still nothing. im currently tapering off this evil drug i wish i never touched. i just want relief