Thanks for the answers to my questions although I'm sorry about the nonsense text (I seem to be having a problem with the site).
Some patients with anal gland issues will continue to act uncomfortable and might strain after their glands are emptied but this doesn't sound like his problem for two reasons:
1. It's been five days and he should be back to normal by now and
2. His stools should be a normal consistency.
Even if he was reluctant to have a bowel movement because his anal glands were causing discomfort/pain (therefore more water was extracted from his feces), I would have this to have resolved after his glands were emptied.
And, if the drugs he was taking were responsible, I would expect the stools to return to normal as well once the offending drug had been discontinued.
In many cases, we're not entirely sure why the stools for some patients are firmer and harder than they should be but the goal is to soften the stools so they're easier to pass but not to the point where they're loose.
Increasing fluid as you did by adding canned food is always a good first step.
I wasn't familiar with this particular product that you've been giving him (Stool Ease) but looked up the ingredient list online. It would appear to have basically a lot of fiber in it which isn't necessarily a bad thing but may not be as effective as an actual oral laxative might be.
The following list of options is what I typically suggest for my owners whose dogs are having this problem:
1. Laxatone or Laxaire (or similar products) which are hairball laxatives for cats. These products will work very well on a smaller dog. They are available at pet or grain stores. You would give 1-3 inches 2-3 times a day.
2. Canned pumpkin (NOT the pie mix); ½ -1 tsp daily in food
3. Over the counter, human Miralax 1/4-1/2th tsp twice daily is quite an effective laxative for dogs (and cats) as well as humans.
4. Oral Docusate Sodium (Colace) 25 mg once or twice a day for small dogs.
There are other products such as Lactulose or Cisapride but I typically only suggest them for dogs with chronic constipation issues; they would also have to be dispensed or prescribed by your vet.
I'm not certain if I would continue the Stool Ease since additional fiber can actually cause constipation issues for some dogs. You'll have to decide if you think it was helping or making the problem worse.
I hope this helps and that he receives relief soon. Kind regards, Deb