Medication to help reduce pain from underlying arthritis definitely. Cosequin or Dasuquin available over the counter, gabapentin with prescription. However for the mechanics of getting up and stairs, which might be a continuing or progressive problem, google "dog support for stairs, or check with local pet shop. They make slings which go under dogs belly with handles, so you can help take some of dogs weight off legs/joints. In a pinch, a towel under dogs body and ends held above will help. Making our senior pets comfortable can be a challenge. good luck.
By the way, glucosamine for humans is not recommended for dogs. "Glucosamine is an amino sugar and should be the same regardless if it's in a human or dog supplement. However, human supplements can contain ingredients that may be unsafe for your dog. Surprisingly, some ingredients that humans use daily can be fatal to dogs."
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