6 Doxycycline Capsules (100mg) theratshop.com - $5.00 Product Description: Stronger than tetracycline and better absorbed. Don't use in pregnant or nursing animals. 2.5-5 mg/lb twice daily for 6 weeks or long term. (referenced from Rat Health Care by Debbie Ducommun) Please seek professional advice before administering this product to your rats. RattyRat's Review: This is a good second antibiotic to try if Amoxicillin doesn't work when your rat is starting to show signs of respiratory infections, the main indicator being noisy breathing (sounds like the rat is talking), but can also include red tears around the eyes/nose, sneezing, and in much more serious cases labored breathing. You will need "Rat Health Care" by Debbie Ducommun reviewed in the Book section of this site to administer this medicine.