What is Ampicillin: Uses, Warnings & Interactions

Updated Jan 12, 2021  •  Published Dec 30, 2020

Ampicillin overview

Generic Names:

  • Ampicillin

Uses:

  • Treats infections. This medicine is a penicillin antibiotic.

Therapeutic Classes:

  • Antibiotic

Forms:

  • Capsule, Liquid, Tablet

How it’s taken:

  • By mouth

What is Ampicillin used for?

Ampicillin is an antibiotic used to treat various bacterial infections. This drug can be given by mouth or injected into a vein (intravenous). Ampicillin is considered to be a penicillin-type antibiotic. Ampicillin is a generic drug also sold under various brand names. This drug has been available for many years. In the treatment of some bacterial infections, ampicillin use is common.

What form(s) does Ampicillin come in

  • Capsule

  • Liquid

  • Tablet

What are common Ampicillin doses?

  • Capsule 500MG

Common Ampicillin prescriptions

  • Ampicillin
    100ml of 125mg/5ml bottle

  • Ampicillin
    100ml of 250mg/5ml bottle

  • Ampicillin
    200ml of 125mg/5ml bottle

  • Ampicillin
    200ml of 250mg/5ml bottle

  • Ampicillin
    250mg capsule

  • Ampicillin
    500mg capsule

How to take Ampicillin

  • Your doctor will tell you how much to take and how often.

  • Shake the oral liquid before each use.

  • It is important that you keep taking the medicine for as long as your doctor tells you, even if you feel better.

  • 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.

  • 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.

  • 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.

What to do if you miss a dose of Ampicillin

  • You should not use two doses at the same time.

  • Take the missed dose as soon as possible.

  • Take the rest of the doses for that day at regularly spaced times.

Ampicillin contraindications

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

Ampicillin warnings

  • 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.

  • 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.

Ampicillin interactions

  • 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.

  • 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.

Ampicillin side effects

Serious 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)

Less Serious Side Effects

  • Nausea

  • Vaginal itching or discharge

  • Mild diarrhea

  • Sore mouth or tongue