Generic Name: Ampicillin Brand Name(s): .

Know the basics

What is ampicillin used for?

Ampicillin is used to treat a wide variety of bacterial infections. It is a penicillin-type antibiotic. Ampicillin works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or overuse of any antibiotic can lead to its decreased effectiveness.

How should I take ampicillin?

Take Ampicillin by mouth usually 4 times a day (every 6 hours), or as directed by your doctor. Take ampicillin on an empty stomach (1 hour before or 2 hours after a meal) with a full glass of water. Drink plenty of fluids while using this medication unless your doctor tells you otherwise.

The dosage is based on your medical condition and response to therapy.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals.

Continue to take this medication until the full-prescribed amount is finished even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, which may result in a relapse of the infection.

Inform your doctor if your condition persists or worsens.

How do I store ampicillin?

Ampicillin is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store ampicillin in the bathroom or the freezer. There may be different brands of ampicillin that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

 

Know the precautions & warnings

What should I know before using ampicillin?

Before taking ampicillin:

  • Tell your doctor and pharmacist if you are allergic to ampicillin, penicillin, or any other drugs.
  • Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other antibiotics, allopurinol (lopurin), anticoagulants (‘blood thinners’) such as warfarin (coumadin), atenolol (tenormin), oral contraceptives, probenecid (benemid), rifampin, sulfasalazine, and vitamins.
  • Tell your doctor if you have or have ever had kidney or liver disease, allergies, asthma, blood disease, colitis, stomach problems, or hay fever.
  • Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking ampicillin, call your doctor.
  • If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking ampicillin.

Is it safe to take ampicillin during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown.

Know the side effects

What are the side effects of ampicillin?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • Fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;
  • Diarrhea that is watery or bloody;
  • Fever, chills, body aches, flu symptoms;
  • Easy bruising or bleeding, unusual weakness;
  • Urinating less than usual or not at all;
  • Agitation, confusion, unusual thoughts or behavior; or
  • Seizure (black-out or convulsions).

Less serious side effects may include

  • Nausea, vomiting, stomach pain;
  • Vaginal itching or discharge;
  • Headache;
  • Swollen, black, or “hairy” tongue;
  • Thrush (white patches or inside your mouth or throat).

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with ampicillin?

Ampicillin may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval, especially if you are using:

  • Allopurinol (Zyloprim);
  • Methotrexate (Rheumatrex, Trexall);
  • Probenecid (Benemid);
  • A sulfa drug (such as Bactrim or Septra);
  • A tetracycline antibiotic such as demeclocycline (Declomycin), doxycycline (Adoxa, Doryx, Oracea, Vibramycin), minocycline (Dynacin, Minocin, Solodyn, Vectrin), or tetracycline (Brodspec, Panmycin, Sumycin, Tetracap)

Does food or alcohol interact with ampicillin?

Ampicillin may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with ampicillin?

Ampicillin may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Asthma;
  • Kidney disease;
  • A bleeding or blood clotting disorder;
  • Mononucleosis (also called “mono”);
  • A history of diarrhea caused by taking antibiotics;
  • A history of any type of allergy.

Understand the dosage

The information provided is not a substitute for medical advice. Always consult your doctor or pharmacist before using this medication.

What is the dose of Ampicillin for an adult?

Usual Adult Dose for Bacterial Infection: 250 to 500 mg orally every 6 hours.

Usual Adult Dose for Endocarditis: Ampicillin 2 g intravenous every 4 hours plus gentamicin or streptomycin (if gentamicin resistant).

Usual Adult Dose for Meningitis: 200 mg/kg/day intravenous in equally divided doses every 4 hours, in combination with other parenteral antibiotics.
Intrathecal or intraventricular: 10 to 50 mg/day in addition to intravenous antibiotics.

Usual Adult Dose for Septicemia: intravenous 150 to 200 mg/kg/day.

Usual Adult Dose for Bacterial Endocarditis Prophylaxis: 2 g intravenous or intramuscular as a single dose 30 to 60 minutes before procedure.

Usual Adult Dose for Gastroenteritis: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Intraabdominal Infection: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Skin or Soft Tissue Infection: 250 to 500 mg intravenous or intramuscular every 6 hours.

Usual Adult Dose for Pharyngitis: 250 to 500 mg intravenous or intramuscular every 6 hours. Or 250 mg orally every 6 hours.

Usual Adult Dose for Sinusitis: 250 to 500 mg intravenous or intramuscular every 6 hours. Or 250 mg orally every 6 hours.

Usual Adult Dose for Upper Respiratory Tract Infection: 250 to 500 mg intravenous or intramuscular every 6 hours. Or 250 mg orally every 6 hours.

Usual Adult Dose for Pneumonia: 250 to 500 mg intravenous or intramuscular every 6 hours. Or 250 mg orally every 6 hours

Usual Adult Dose for Bronchitis: 250 to 500 mg intravenous or intramuscular every 6 hours. Or 250 mg orally every 6 hours

Usual Adult Dose for Urinary Tract Infection: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Pyelonephritis: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Shigellosis: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Typhoid Fever: 500 mg orally or intravenous or intramuscular every 6 hours.

Usual Adult Dose for Prevention of Perinatal Group B Streptococcal Disease: 2 g intravenous initial dose, then 1 g intravenous every 4 hours until delivery.

Usual Adult Dose for Surgical Prophylaxis: Liver transplant: Ampicillin 1 g intravenous plus cefotaxime 1 g intravenous at induction of anesthesia, then every 6 hours during procedure and for 48 hours after final surgical closure.

Usual Adult Dose for Leptospirosis: Mild: 500 to 750 mg orally every 6 hours
Moderate to severe: 0.5 to 1 g intravenous every 6 hours.

Usual Adult Dose for Otitis Media: 500 mg orally or 1 to 2 g intravenous or intramuscular every 6 hours, depending on the nature and severity of the infection.

What is the dose of Ampicillin for a child?

Usual Pediatric Dose for Bacterial Infection:

Neonates:
7 days or less, 2000 g or less: 50 mg/kg intravenous or intramuscular every 12 hours.
7 days or less, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 8 hours.
8 to 28 days, 2000 g or less: 50 mg/kg intravenous or intramuscular every 8 hours.
8 to 28 days, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 6 hours.
1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg intravenous or intramuscular every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day.

Usual Pediatric Dose for Bacteremia:

Neonates:
7 days or younger, 2000 g or less: 100 mg/kg intravenous or intramuscular every 12 hours.
7 days or younger, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 8 hours or 100 mg/kg intravenous or intramuscular  every 12 hours.
8 to 28 days, 2000 g or less: 50 mg/kg intravenous or intramuscular every 8 hours.
8 to 28 days, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 6 hours.

Usual Pediatric Dose for Septicemia:

Neonates:

7 days or younger, 2000 g or less: 100 mg/kg intravenous or intramuscular every 12 hours
7 days or younger, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 8 hours or 100 mg/kg intravenous or intramuscular  every 12 hours
8 to 28 days, 2000 g or less: 50 mg/kg intravenous or intramuscular every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg intravenous or intramuscular every 6 hours.

Usual Pediatric Dose for Meningitis:

Children: 150 to 200 mg/kg/day intravenous in equally divided doses every 3 to 4 hours.

Usual Pediatric Dose for Endocarditis:

Maximum dose: 12 g/day.

Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis:

Children: 50 mg/kg intravenous or intramuscular as a single dose 30 to 60 minutes before procedure.

Usual Pediatric Dose for Upper Respiratory Tract Infection:

Less than 40 kg: 25 to 50 mg/kg/day intravenous or intramuscular in equally divided doses every 6 to 8 hours.
40 kg or more: 250 to 500 mg intravenous or intramuscular every 6 hours.
20 kg or less: 50 mg/kg/day orally in equally divided doses every 6 to 8 hours.
Greater than 20 kg: 250 mg orally every 6 hours.

Usual Pediatric Dose for Pneumonia:

Parenteral:
Less than 40 kg: 25 to 50 mg/kg/day intravenous or intramuscular in equally divided doses every 6 to 8 hours.
40 kg or more: 250 to 500 mg intravenous or intramuscular every 6 hours.
20 kg or less: 50 mg/kg/day orally in equally divided doses every 6 to 8 hours.
Greater than 20 kg: 250 mg orally every 6 hours.

Usual Pediatric Dose for Skin or Soft Tissue Infection:

Less than 40 kg: 25 to 50 mg/kg/day intravenous or intramuscular in equally divided doses every 6 to 8 hours.
40 kg or more: 250 to 500 mg intravenous or intramuscular every 6 hours.

Usual Pediatric Dose for Urinary Tract Infection:

Parenteral:
Less than 40 kg: 50 mg/kg/day intravenous or intramuscular in equally divided doses every 6 to 8 hours.
40 kg or more: 500 mg intravenous or intramuscular every 6 hours.
20 kg or less: 25 mg/kg orally every 6 hours.
Greater than 20 kg: 500 mg orally every 6 hours.

Usual Pediatric Dose for Surgical Prophylaxis:

Liver transplant:
1 month or older: Ampicillin 50 mg/kg intravenous plus cefotaxime 50 mg/kg intravenous at induction of anesthesia and every 6 hours for 48 hours after final surgical closure.

How is ampicillin available?

Ampicillin is available in the following dosage forms and strengths:

Powder for solution, Injection: 10 g  in 100 ml.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

Overdose symptoms may include confusion, behavior changes, a severe skin rash, urinating less than usual, or seizure (black-out or convulsions).

What should I do if I miss a dose?

If you miss a dose of ampicillin, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 11, 2017 | Last Modified: January 11, 2017

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