Primor (sulfadimethoxine/ormetoprim) is a broad-spectrum antibiotic combination used to treat susceptible bacterial infections in dogs.
How it works: Primor is made up of two antibiotics: sulfadimethoxine and ormetoprim. Together, these antibiotics are even more powerful than when they are used alone, as they block two sequential steps in bacterial folic acid synthesis. The net effect is not only the limiting of bacterial growth, but the killing of bacteria as well.
Cautions: Do not use in pregnant or nursing animals. Your pet should be encouraged to drink plenty of water while being given Primor. Before giving Primor, be sure to tell your veterinarian what other medications or treatments your pet is receiving.
Dosage & Administration: Give this medication exactly as directed by your veterinarian. Give Primor by mouth. It may be given with food. Leave plenty of water for your pet to drink. If you do not understand the directions ask the pharmacist or veterinarian to explain them to you. Store Primor at room temperature in a tight, light-resistant container. Keep this medication away from children and pets.
Tip: If your pet shows no improvement after 2 or 3 days, have your veterinarian re-evaluate your pet’s diagnosis. Treatment should not exceed 21 consecutive days.
Possible side effects of Primor: Sulfa crystals may appear in your pet's urine. Your pet should be allowed to drink plenty of water while taking this medication. Other side effects that may occur include KCS or dry eye, anemia, fever, loss of appetite, vomiting or diarrhea, joint inflammation, kidney damage, or skin rash. Stop the medication and contact your veterinarian if any of the above symptoms occur. Other side effects may also occur. Talk to your veterinarian about any side effect that seems unusual or bothersome to your pet. If your pet experiences an allergic reaction, signs may include facial swelling, hives, scratching, and sudden onset of diarrhea, vomiting, shock, seizures, or coma. If these signs occur, contact your veterinarian immediately.
If you miss giving a dose: Give the missed dose as soon as you remember during the same day. However, if you don't remember until the next day, skip the dose you missed and give only the next regularly scheduled dose. Do not give a double dose of the medication.
If you overdose the pet: Seek emergency veterinary medical treatment. Symptoms of overdose may include side effects listed below and may also include behavioral changes.
What should I avoid while giving Primor: Antacids may decrease the effectiveness of sulfa drugs such as Primor. Give antacids 2-3 hours before or after giving a dose of Primor.
What other drugs will affect Primor: Before giving Primor, tell your veterinarian if your pet is being given methotrexate, warfarin, phenylbutazone, thiazide diuretics, aspirin, probenecid, or phenytoin.