You can crush the pills and add a little water. Place in a syringe and in the rat's mouth. If it tastes good to the rat, he'll take it when you slowly empty the syringe. Or wrap your rat in a towel making sure his front legs are in the wrap with only his head visible. Again crush the pill, add a little water and slowly release in the rat's mouth. If nothing works, you may have to have the vet help you administer the medication.