"an opiate"? You do not get constipation from one pill that is "so bad".
Plus it depends on the opioid. Hydrocodone and oxycodone for example leaves the system pretty quickly (ER, too), and once it does, you can defecate without issues. Morphine on the other hand causes awful constipation but can be treated with proper diet. Hydrate, plum jam, magnesium citrate, or laxatives if serious. You can skip a dose or two so you can defecate.
Plus it depends on the opioid. Hydrocodone and oxycodone for example leaves the system pretty quickly (ER, too), and once it does, you can defecate without issues. Morphine on the other hand causes awful constipation but can be treated with proper diet. Hydrate, plum jam, magnesium citrate, or laxatives if serious. You can skip a dose or two so you can defecate.