Often used for:
N/A
What is ampicillin?
Ampicillin (also called Omnipen® or Principen®) is used to prevent or treat infections. It is available in 250-mg capsules, 500-mg capsules, and 50-mg/mL liquid suspension, all taken by mouth. It is also available as a clear liquid given by vein (IV).
How to take and store ampicillin
- Take ampicillin on an empty stomach, 1 hour before or 2 hours after meals.
- Shake the liquid suspension well before each dose and measure using a medicine cup or oral syringe.
- Store the liquid suspension in the refrigerator and discard after 14 days or by the expiration date on the label.
- Store capsules at room temperature in a dry place.
- Do not use the medicine past the expiration date.
Possible side effects
- Nausea and vomiting
- Diarrhea
- Rash
- Loss of appetite
- Headache
- Stomach pain
- Symptoms of an allergic reaction include: rash, hives, itching, chills, fever, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck.
- Not all patients who take ampicillin will experience these side effects. Common side effects are in bold, but there may be others. Please report all suspected side effects to your doctor or pharmacist.
Tips for patients and families
- Be sure to discuss all questions and instructions with your doctor or pharmacist.
- Tell your doctor if you have had an allergic reaction to any penicillin. Report allergic symptoms or severe or watery diarrhea right away.
- Take all doses exactly as prescribed, even if you begin to feel better.
- Tell your doctor if you are taking probenecid or methotrexate. Do not combine these medicines unless directed by your doctor.
- Birth control medicines that contain estrogen may be less effective while taking ampicillin. Use a second birth control method for at least 1 month after treatment.
- Ampicillin may cause a false-positive urine test for sugar.
