Dehydration is one reason many people get constipated, and opioids can make it worse. Plus, it can be tough to get the amount of fluids your body needs when you’re in pain. Try to drink more H2O throughout the day, even if you sip a little at a time. Hot liquids, like coffee, tea, or broth, can get things moving, too. You can also suck on ice chips, or snack on foods with a lot of water, like watermelon or berries.