7-yr old Chihuahua retching/cant keep food down

Question
Our Chihuahua Lola has been vomiting frequently in the past week, usually a whitish foam, but sometimes a viscuous puddle. We took her to our vet, who has successfully diagnosed and treated a number of ailments.  He drew blood and said the results were all normal.  He recommended a bland diet of boiled chicken and rice but after eating even that, it comes back up.  She does a lot of unproductive retching between feedings and is very sluggish and lethargic.  She will quickly eat the chicken and rice and seems ok, but then she goes to get a drink and the retching immediately starts.  The vet said the next step is X-ray to look for some kind of blockage or foreign object, or even a mass (Cancerous perhaps).  We tried to give her a piece of Pepcid earlier but she coughed that up, although it was partially digested so perhaps she got a little bit in her.  Our plan as of now is just to try to give her more frequent feedings of smaller portions with a sliver of Pepcid 2x daily.  Today is only the first day after the Vet saw her, so I know it could take a few days to calm her tummy down.  Any suggestions/experience/advice?

Answer
The first thing to always do when a dog is vomiting (or has severe diarrhea) is to fast it for 24 hours, only letting it drink *small* amounts of water on a more frequent basis so that it doesn't dehydrate. (Letting it drink at will can cause more vomiting.)

Check for dehydration by lifting the skin on the back of the dog's neck. In a hydrated dog, the skin will quickly return to normal, but if a dog is dehydrating, the skin will go down slowly, or not at all. If a dog is dehydrating, it may need sub-q fluids from the vet as dehydration can kill a dog if not remedied.

After 24 hours of fasting, I start the dog back on solid food using Gerber Strained Chicken (yes, the baby food). The dog is given only a SMALL amount of this (with my miniature schnauzers, this would initially be about 1/2 tsp.), and I repeat this every two hours or so throughout the day, increasing the amount slightly later in the day. Water is still kept to a small amount, but, again, frequently. (You will probably have to get up a couple times during the night to give it water.) If the dog continues to hold down water, I start to leave a *small* amount in the water bowl, and once it starts to leave water in the bowl, I stop regulating its water intake. If at any point the dog vomits, it is again fasted for 24 hours, and then the above is repeated.

Each day that passes without vomiting, the amount of food is slowly increased and gradually changed to something more resembling the dog's normal diet. At any sign of vomiting, the dog is fasted for 24 hours, and everything is repeated.

Good luck with your dog!