What is Primor?

Primor (sulfadimethoxine/ormetoprim) is a broad-spectrum antibiotic combination used to treat susceptible bacterial infections in dogs. Primor is sold per tablet and requires a prescription from your veterinarian.

For:

Dogs

Benefits:

• Treats skin and soft tissue infections (wounds and abscesses)
• Also effective against urinary tract infections caused by susceptible bacteria
• Single, comparatively low dose provides rapid and sustained therapeutic blood levels
• Sold per tablet

How does Primor work?

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 pets. 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.

Brand Name:

Primor Tablets (Pfizer Animal Health)

Generic Name:

Sulfadimethoxine/Ormetoprim

What is the most important thing I should know about Primor?

Primor is a potentiated sulfa drug used in dogs for the treatment of skin and soft tissue infections (wounds and abscesses), and urinary tract infections caused by susceptible bacteria. Primor may also be used for other conditions not listed.Primor is a prescription medication FDA-approved for veterinary use in dogs. Primor is available as scored tablets in two strengths: Primor 240 which contains 200 mg sulfadimethoxine and 40 mg ormetoprim, and Primor 1200 which contains 1000 mg sulfadimethoxine and 200 mg ormetoprim. Primor is not for use in pets allergic to it or other sulfa drugs.

What should I discuss with my veterinarian before giving Primor to my pet?

Tell your veterinarian if your pet is allergic to Primor or other sulfonamides (sulfa drugs). Tell your veterinarian if your pet has liver disease or blood dyscrasias, is dehydrated, or is pregnant or lactating. Also tell your veterinarian what other medication, including vitamins and supplements, that you are giving your pet while giving Primor.

How should Primor be given?

The usual initial starting dose is 25 mg/lb on the first day of treatment followed by 12.5 mg/lb given once a day. Treatment should continue for 2 days after symptoms disappear. However, treatment should not exceed 21 consecutive days. Give Primor by mouth. It may be given with food. Leave plenty of water for your pet to drink. Always follow the dosage instructions provided by your veterinarian. Do not give Primor to any pet other than the pet for whom it was prescribed. If you do not understand the directions ask your 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. 

What are the potential 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.

What happens if I miss giving a dose of Primor?

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.

What happens if I overdose my pet on Primor?

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 to my pet?

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.