MacTavish feeling puny

MacTavish has not been feeling good. Coughing and crying a lot. Took him to the vet last Thursday and he got shots and was put on Tameril (Temeril?) for a week. The vet said that if it helps, we will put him on a lower dosage for longer. MacTavish is 13 now. He's only been on dry food, so I don't think it has anything to do with the current pet food problems. Also, he hasn't lost any weight. He tends to gain weight when he feels bad. (me, too.)