What medications can help my pug with enlarged heart and arthritis?

I am so very sorry to hear about Troy. You don't mention if his enlarged heart is causing any symptoms yet (coughing, weakness) or if your vet has him on any medication, or if there is a heart murmur present causing enlargement or if he has something like a dilated cardiomyopathy. If you are interested in discussing his heart issue more, you can consider a personal consultation with a veterinarian. As far as his arthritis goes, we often do a combination of medications. We usually start with a joint supplement containing glucosamine and chondroitin. The more common ones we use include Dasuquin or Cosequin. You can find these online and in some pet stores. A fatty acid supplement is also a good idea (such as Welactin) because the fatty acids can help decrease inflammation in the joints. These products must be given daily for a month or more before we can see results. If those are not enough, then pain medications such as a canine NSAID (nonsteroidal anti-inflammatory) are usually started. Some popular types used in dogs are Carprofen, Deracoxib, and grapiprant- these are generic names of the drug but the trade names may vary by country- here in the US they would be Rimadyl, Deramax, and Galliprant). In cases that are still having trouble we may add on secondary drugs such as Gabapentin, Tramadol, or Amantadine.