You should consult vet. Sudafed causes increased heart rate and blood pressure rate increase. An antidote may be required or another kind of treatment.
Call your veterinarian immediately. If you can determine the approximate quantity and dosage, this will also be helpful. It is important to seek immediate care, so rush him to the vet or animal hospital.
If it was a large amount, take him or her to the vet immediately. If the amount was rather modest, watch him or her closely and make sure the dog is not in distress.
