I absolutely endorse Buscopan, but it's not available in the USA. They have a similar, more expensive drug called Levsin, and another one called Bentyl.
US residents - make a trip to Mexico to get Buscopan. I'm not sure if Buscopan is sold in Canada, but Bentyl is.
Normally you take pills, but for complete obstruction when you're in agony and cannot take anything by mouth: injectable Buscopan. Where I live, injectable Buscopan costs $1/ampule (1 ampule=1 dose). When I was in the USA I asked about
injectable Levsin and was quoted $150/vial (a vial being good for 5 shots, but once you
open it you've got to use it up fast).
Levsin can be bought in a sublingual (under the tongue) form, an alternative to injections. Not as good as a shot, but better than nothing.
Note that these drugs should not be taken if you've got glaucoma.
Crohn's since 1988