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Ampicillin

pronounced as (am pi sil' in)

Why is this medication prescribed?

Ampicillin is used to treat certain infections that are caused by bacteria such as meningitis (infection of the membranes that surround the brain and spinal cord); and infections of the throat, sinuses, lungs, reproductive organs, urinary tract, and gastrointestinal tract. Ampicillin is in a class of medications called penicillins. It works by killing bacteria.

Antibiotics such as ampicillin will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

How should this medicine be used?

Ampicillin comes as a capsule and a suspension (liquid) to take by mouth. It is usually taken three to four times a day, either half an hour before or two hours after meals. The length of your treatment depends on the type of infection that you have. Take ampicillin at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take ampicillin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the suspension well before each use to mix the medication evenly.

The medication should be taken with a full glass of water.

You should begin to feel better during the first few days of treatment with ampicillin. If your symptoms do not improve or get worse, call your doctor.

Take ampicillin until you finish the prescription, even if you feel better. If you stop taking ampicillin too soon or skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking ampicillin,

  • tell your doctor and pharmacist if you are allergic to ampicillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin (Ancef, Kefzol), cefdinir, cefditoren, cefepime (Maxipime), cefixime (Suprax), cefotaxime (Claforan), cefotetan, cefoxitin (Mefoxin), cefpodoxime, cefprozil, ceftaroline (Teflaro), ceftazidime (Fortaz, Tazicef, in Avycaz), ceftibuten, ceftriaxone, cefuroxime (Ceftin, Zinacef), and cephalexin (Keflex); any other medications; or any of the ingredients in ampicillin capsules or suspension. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: allopurinol (Lopurin, Zyloprim), other antibiotics, oral contraceptives, and probenecid (Probalan in Col-Probenecid,). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have mononucleosis (a virus also called 'mono') and if you have or have ever had allergies, asthma, hives, or hay fever, or kidney disease,
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking ampicillin, call your doctor.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Ampicillin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • diarrhea
  • nausea
  • vomiting

Some side effects can be serious. If you experience any of the following symptoms, stop taking ampicillin and call your doctor immediately or get emergency medical treatment:

  • rash
  • itching
  • hives
  • difficulty breathing or swallowing
  • wheezing
  • severe diarrhea (watery or bloody stools) that may occur with or without fever and stomach cramps (may occur up to 2 months or more after your treatment)
  • a return of fever, cough, sore throat, chills, and other signs of infection

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the capsules at room temperature and away from excess heat and moisture (not in the bathroom). Keep the suspension in the refrigerator, tightly closed, and dispose of any unused suspension after 14 days. Do not freeze.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your response to ampicillin.

If you are diabetic and test your urine for sugar, use Clinistix or TesTape (not Clinitest) to test your urine while taking this medication.

Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms of infection after you finish the ampicillin, call your doctor.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Amcill®
  • Omnipen®
  • Penbritin®
  • Pfizerpen®
  • Polycillin®
  • Principen®
  • Totacillin®

Other names

  • Aminobenzylpenicillin

This branded product is no longer on the market. Generic alternatives may be available.

Last Revised - 04/15/2018