Respiratory infection

Question

John&Stevie   Yesterday I noticed my 12month old dumbo rat John was breathing very heavily and showing signs of respiratory problems. First thing this morning my partner took him to our local vet where he confirmed that John has a respiratory infection and sadly that he doesn't seem hopeful for our little fella.
The vet gave John a injection and antibiotics, I can't read the vets writing so I'm unsure of which antibiotic it is. I'm really struggling to administrate the medicine to him, I've tried yogurt which is his favourite, other foods which he likes and syringing it straight into his mouth but no luck!
Could the injection the vet gave him already be making him feel better? Because he seems a lot more social and wanting more attention than previous days.
I have another rat of the same age(Stevie) together with John and I am reluctant to separate them both as they are very close. The vet checked him over as well and said Stevie is fine but I just wanted to check that they will be ok together in the same cage?
The last thing is that I have noticed what I think are lice on both boys skin and fur. I have purchased this product and I would like some advice on how to administer and if its safe with John being poorly already?
http://www.amazon.co.uk/Beaphar-Anti-Parasite-Spot--Small-Animals/dp/B001UALNX2/
Sorry for such a long email and I appreciate your help.
Thank you, Charlie.

Answer
Hi Charlie,
Yes, it is possible that the shot is already helping John feel better. You really need to call your vet to find out exactly what shot he got and what antibiotic he is on, although probably it is Baytril as apparently vets in the UK must prescribe Baytril for rats first. If you put only 0.1 ml of the medicine in the back of his mouth at a time, that is too small to spit out.

You do not need to separate him from Stevie unless Stevie is picking on him.

Yes, the Beaphar Anti-Parasite Spot is a safe good treatment for lice. Are you seeing silvery blobs on their fur? Those are lice eggs (nits).
Deb