Let's try to be mature about this, as funny as it may seem, this is a very serious issue that left untreated can lead to life threatening conditions such as narcotic bowel syndrome, partial or complete intestinal blockage/obstruction, etc. If you think opioid induced constipation is bad, do not wait for it to progress into something much MUCH worse.
There's this drug called methylnaltrexone which is basically a specialized kind of opioid antagonist, but I have NEVER heard of anyone getting it prescribed, and I'm sure it has some side effects, if it's anything even remotely like naltrexone, but I won't waste any more time speculating.
Some laxatives are better than others, although everyone's body will react differently due to unique body chemistry. A lot of people like Sennakot, some people swear by docusate sodium (Colace), drinking warm prune juice, various forms of magnesium, god forbid you require PEG, and enemas aren't exactly known for being fun.
Unfortunately, some people have to resort to combining various of the aforementioned treatment options, although it is EXTREMELY important to consult your physician prior to selecting a laxative, especially if you believe your constipation is a result of drug abuse. Laxatives, especially the stimulant laxatives, are pretty serious drugs that can have profound consequences when misused and many laxatives are habit-forming or cause rebound constipation upon discontinuation after regular use.
Regular use of laxatives is definitely not something to consider lightly. It's something that sometimes must be done, usually by Chronic Pain Patients under the supervision of their prescribing healthcare professional, due to the constipating nature of certain medications, most infamous being the opioid analgesics. I definitely would advise the OP to contact their doctor prior to commencing regular use of laxatives, there are things you need to know about how each laxative will react in your body, and the effect they may have on the digestion / absorption of nutrients.
Every day, I take coconut oil capsules, peppermint oil capsules (which also contain Ginger and Fennel oils), magnesium supplements, (not just for constipation though, Mg has a wide range of therapeutic values) in combination with a strictly regulated dietary intake and increased hydration and physical exercise. Albeit controversial, I also rely heavily on high-dose high-potency cannabinoids daily to help regulate my GI health, and promote bowel movements and reduce some pain, cramping, spasms, and bloating (I have chronic GI conditions).
When it gets worse, I will add in warm prune juice and 100mg docusate sodium per day until I have a bowel movement. When in combination with my daily peppermint oil, coconut oil, magnesium, extra water, strict food intake, increased physical exertion in the abdominal area (I prefer sex for this, doggystyle works your core very well), and I STILL CANT GO TO THE BATHROOM, then I'll give myself a micro-enema using 10mL syringes, you can mix warm water with coconut oil and PEG. I usually start by
- plugging 10mL of raw coconut oil at anywhere between 75-100 degrees Fahrenheit, then
- plugging 10mL PEG/H20, and
- finishing with 10mL more of warm water, to ensure the above coconut oil, water/PEG gets up into your bowels.
Don't expel the enema right away, it needs a little bit of time to do it's work, but like I said earlier, consult your doctor.