The fastest way to get relief for your pet is to give an enema. You simply buy a fleet enema and discard the contents of the enema. You can add warm water with a teaspoon of mineral oil. Raise the rear end to be elevated above the head and insert the applicator tip and insert the contents of the enema at once. Then keep the rear raised up for about 3-5 minutes and then let it down somewhere you won't mind a mess as your pet will have a BM in about 10 minutes together with the oily water coming out.
Other options are using laxatone (hairball remedy for cats) as a laxative. It doesn't work as quickly as an enema and may take a day or two. Docusate is a stool softener and also takes a few days.
Let me know if you have more questions,
Dr. Debbie
Veterinarian
Full time practicing companion and exotic animal veterinarian