Did my k-9, who has insipidus diabetes and is now taking desmopressin, have a seizure?

Appproximately 20 – 30 minutes after receiving her third dosage (in the eye), she had what appeared to be a seizure. Her back hunched over, her body became very rigid while yet trembling, and she was unable to stand unassisted. Episode lasted about 15 – 20 minutes. Does this sound like a seizure? Were the meds and/or the number of dosages perhaps the problem?