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Ampicillin (By mouth)

Ampicillin (am-pi-SIL-in)

Treats infections. This medicine is a penicillin antibiotic.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use ampicillin if you have had an allergic reaction to any type of penicillin.

How to Use This Medicine:

Capsule, Liquid, Tablet

  • Your doctor will tell you how much to take and how often.
  • It is important that you keep taking the medicine for as long as your doctor tells you, even if you feel better.
  • Shake the oral liquid before each use.
  • Take the medicine on an empty stomach, 1 hour before or 2 hours after meals with a full glass of water.
  • Measure your medicine with a marked measuring spoon or medicine cup.

If a dose is missed:

  • Take the missed dose as soon as possible.
  • Take the rest of the doses for that day at regularly spaced times.
  • You should not use two doses at the same time.

How to Store and Dispose of This Medicine:

  • Store the capsules or tablets in a tightly closed container at room temperature away from heat, moisture, and light. Store the oral liquid in the refrigerator. Throw away any medicine that is left after 14 days. Do not freeze.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are taking estrogen, probenecid, blood thinners (such as Coumadin®), cholestyramine (Questran®), or colestipol (Colestid®).
  • Birth control pills may not work as well while taking penicillin. Use another kind of birth control while you are taking this medicine.
  • Ampicillin may cause incorrect results with some urine sugar tests used by people with diabetes.

Warnings While Using This Medicine:

  • If you have severe diarrhea, check with your doctor before taking any medicine to stop the diarrhea.
  • Make sure your doctor knows if you have ever had an allergic reaction to any cephalosporin antibiotic such as Keflex® or Ceclor® before you take ampicillin.
  • If your symptoms do not improve in a few days or become worse, call your doctor.
  • If you are pregnant or breastfeeding, talk to your doctor before taking ampicillin.
  • Make sure your doctor knows if you have mononucleosis ("mono"), stomach or intestinal disease, asthma, liver disease, hay fever, or other allergies before you take this medicine.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Rash, hives, or blistering or peeling skin
  • Swelling of the face, throat, or lips
  • Wheezing or trouble breathing
  • Severe diarrhea (watery, possibly with blood)

If you notice these less serious side effects, talk with your doctor:

  • Mild diarrhea
  • Nausea
  • Sore mouth or tongue
  • Vaginal itching or discharge

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 5/1/2020

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

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