Hello, my name isXXXXX and I have over 20 years of experience as a veterinarian.
I'm sorry to hear about Rowdy's night-time restlessness.
In some dogs as they age their organ systems don't work as well as they once did,
and waste products that their organs usually filter out build up in the blood stream and that affects brain function. They may behave much differently because their brain function isn't normal. I am glad to see that Rowdy has had some blood tests that show his organ function is normal and that is not his problem.
The other possibility given his confusion which seems to worsen at night is that he is experiencing senility, not uncommon at as dogs age although he is a little young. These dogs often forget their housebreaking, seem more confused at night when it is dark, cannot seem to remember whether they have eaten or not, and seem to pace, looking for something they cannot find. They may all of the sudden get into the garbage or chew up things when they never displayed these habits before.
If his organ function is normal there are medications that can help with senility and the associated anxiety, such as Anipryl (L-deprenyl or selegiline). There is also a diet formulated for older dogs high in the particular trace minerals and supplements needed for healthy brain function in older dogs called Hills b/d.
There are anti-anxiety drugs such as amitriptyline or fluoxetine that can be used as well if Anipryl doesn't work for him.
I must warn you that these medications and the b/d diet doesn't work for all dogs
and they may not work for long but they may allow him to rest and relax at night and help with his confusion
Because we know he has some spinal arthritis it may help to treat that as well so he is more comfortable.
Long term for joint pain/arthritis I do recommend using a combination of a glucosamine/chondroitin product (examples are Dasuquin or Cosequin) and an
omega 3 fatty acid (like 3V Caps or Derm Caps). These work synergistically and
improve cartilage health and joint fluid quality and quantity as well as reducing inflammation. They can take several weeks to see full improvement but some dogs do very well with them alone. They are available over the counter.
Another option is a product called Duralactin. This is an anti-inflammatory product derived from milk proteins and it also has omega 3 fatty acids incorporated into it which can be very helpful. See this link for further information: http://www.duralactin.com/products_canine.htm
If that's not enough his veterinarian can prescribe drugs that are more potent. Veterinary drugs we can add include a nonsteroidal like Metacam, Deramaxx, Previcox or Rimadyl. If those aren't enough we can add another drug in the opiod family called Tramadol and/or another drug called Gabapentin.
I also recommend night lights and playing soft music at night as a way to comfort him. Sometimes when vision and hearing acuity are decreasing the dark and quiet at night can be disorienting for them.
Please let me know if you have any further questions.