My partner is having severe constipation due to morphine. Depending how bad your constipation is, there are several possibilities you might try.
He is taking Sena three times a day. (Natural laxative.)
He was taking Ducolax, but it didn't help.
There is something called Magneisum Citrate which is over the counter which was very strong. When he hadn't gone for 5 days they gave him Laxolose, which is prescribed at the Cancer Center. Also very strong.
Talk to your doctor before you try any of these things.