Thank you for your query at DoctorSpring.com
I understand your concern.
Unfortunately 3 weeks is a long time, and you will need an enema. You have already tried most medicines and now the cause has to be ascertained. Normally acute cases of constipation won't last that long. Is this the first time you're having such an issue? Or you have had episodes of constipation before?
Most of the medicines that are effective in constipation has been tried and if they have failed and also the fact that you're having so much pain warrants an enema.
I would have advised you the basic steps which normally relieve constipation in a day or two. But I'm assuming you have already tried all of them and it has not been helpful. You can go through if there is something you have missed out that you can try :
1) Drink plenty of fluids close to 5-6 liters a day, in cases of repeated constipation.
2) Bulk forming laxatives psyllium or methylcellulose to be taken with lactulose solution ( 30 ml at bed time ), helps in removing the toxins that have been accumulating for a long time, and also clears the bowel.
3) Among foods, fruits especially banana and others such as figs and prunes are helpful in relieving constipation, and also softening the stool.
4) Exercise also increases the intra abdominal pressure and improves persitalsis. Walking or jogging can be helpful.
5) Some recent studies claim wheat bran is excellent in relieving constipation.
6) Last but not least, you can try colonic secretogogue Lubiprostone, a relatively newer drug, in a dose of ( 24 mcg daily ), it has also shown some positive results in patients with no relief from constipation.
If all these methods fail, extensive evaluation and treatment with enema is required.
Also in your case, a colonoscopy will be helpful to ascertain the exact cause. In some patients, the nerves get really weak and the muscle tone is lost, also known as dyssynergic defeacation. Other causes can be thyroid dysfunction, intestinal obstruction, IBS- constipation ( e.t.c ).
You also need a medical gastro opinion, for further management. He can examine and order appropriate tests for you.
Hope this was helpful,
Let me know if i can help you further,