Welcome to Justanswer! I am Dr. Altman and happy to assist you both todayPseudoephedrine (in sudafed) can cause some serious side-effects including vomiting, diarrhea, loss of appetite, any agitation/heavy panting. http://www.petplace.com/drug-library/pseudoephedrine/page1.aspxNow, as you can see from the above link, worse side-effects can include even tremors or seizures
. Sudafed also comes in different strengths. An example, a dog 16 pounds should not ingest more than about 3-4mg of product. Sudafed usually comes in 30mg tablets, or even 60mg or higher. If this occurred in the last hour it would be advised to induce vomiting with hydrogen peroxide:To induce vomiting at home, give 1 teaspoon for every 10 pounds of body weight of 3% hydrogen peroxide and walk Gypsy around to mix it in the stomach
. If no vomiting within 15 minutes, the dose can be repeated. It is an irritant to the stomach lining, and that is why it causes vomiting. I hope this information makes sense but if it occurred in the last hour please induce vomiting. If more than an hour please monitor for earliest signs of ingestion listed (vomiting, diarrhea, panting, agitation) and seek a veterinary er in your area. If you have more questions or if I can help in any other way, please do not hesitate to ask! If you would like to accept my answer, please press RATE OUR CONVERSATION (I am not compensated in any other way). Bonuses are always welcome. Thanks!If you have additional questions after you rate the question, you are welcome to request me for additional conversations if I am on-line or by beginning your question "Dr. Altman..." or "Dogdoc4u..." and others will leave the questions for me. Good luck to you both!!!