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Ampicillin Prescribing Information

Ampicillin is a broad-spectrum antibiotic that belongs to the penicillin group of antibiotics. It is commonly used to treat a wide variety of bacterial infections. Medicine works by inhibiting the formation of the bacterial cell wall, which is essential for the structural integrity of the bacteria. This ultimately leads to the death of susceptible bacteria.

Antibiotic is effective against both Gram-positive and Gram-negative bacteria. It is commonly used to treat infections such as:

  • Respiratory tract infections
  • Urinary tract infections
  • Skin and soft tissue infections
  • Gastrointestinal infections
  • Bacterial meningitis

Drug is available in various forms, including oral capsules, tablets, and injectable formulations. It's important to note that like other antibiotics, overuse or inappropriate use of Ampicillin can lead to antibiotic resistance, where bacteria develop the ability to withstand the effects of the drug.

Ampicillin capsules

Uses of Ampicillin

Ampicillin is a versatile antibiotic with a range of medical uses. Some of the common applications include:

  • Bacterial Infections: Medicine is used to treat a wide variety of bacterial infections caused by both Gram-positive and Gram-negative bacteria. These infections include respiratory tract infections, urinary tract infections, skin and soft tissue infections, gastrointestinal infections, and intra-abdominal infections.
  • Bacterial Meningitis: Antibiotic is often used in combination with other antibiotics to treat bacterial meningitis, an infection of the membranes surrounding the brain and spinal cord.
  • Neonatal Infections: Ampicillin is commonly used in newborns and infants to treat infections such as group B Streptococcus (GBS) infections and other bacterial infections that can occur in the early days of life.
  • Endocarditis Prophylaxis: Pharmaceutical product may be prescribed as prophylaxis (preventive treatment) for individuals at risk of developing bacterial endocarditis, which is an infection of the inner lining of the heart chambers and valves.
  • Intra-abdominal Infections: Ampicillin is effective against a range of bacteria that can cause infections within the abdominal cavity, such as peritonitis (infection of the abdominal lining).
  • Gynecological Infections: It can be used to treat certain gynecological infections like pelvic inflammatory disease (PID) and other infections of the female reproductive organs.
  • Gastrointestinal Infections: Ampicillin can be used to treat infections caused by bacteria in the gastrointestinal tract, such as certain cases of gastroenteritis.
  • Syphilis: Medicament is sometimes used as an alternative treatment for syphilis, particularly in individuals who are allergic to penicillin.


The dosage of Ampicillin can vary depending on factors such as the type of infection being treated, the patient's age, weight, and overall health condition. Dosage recommendations can also vary between different countries and healthcare guidelines. Below are general dosage guidelines for common indications:

  • Adults: The typical dosage for adults is usually in the range of 250 mg to 500 mg every 6 hours. For more severe infections, the dosage may be higher, up to 1 gram every 4 to 6 hours.
  • Children: Pediatric dosages are usually based on the child's weight. Typical dosages range from 25 mg to 50 mg per kilogram of body weight, divided into several doses throughout the day.
  • Neonates and Infants: Neonatal dosages are also weight-based and vary significantly based on the specific indication and the baby's age. It's crucial to work with a pediatrician to determine the appropriate dosage.
  • Bacterial Meningitis: For bacterial meningitis treatment, higher dosages are often required. Adult dosages can range from 2 to 4 grams every 4 hours, while children and infants will have weight-based dosages.
  • Endocarditis Prophylaxis: For individuals requiring prophylaxis against bacterial endocarditis, a single dose of Ampicillin (usually 2 grams) may be administered before certain dental or medical procedures.
  • Renal Impairment: Dosage adjustments may be necessary for individuals with impaired kidney function.

Side Effects

Some people may experience mild side effects, while others may have more severe reactions. Here are some common side effects associated with ampicillin:

Common Side Effects:

  • Nausea
  • Vomiting
  • Diarrhea
  • Upset stomach
  • Skin rash or itching
  • Headache

Less Common Side Effects:

  • Allergic reactions, including rash, itching, swelling, or difficulty breathing
  • Severe skin reactions, such as Stevens-Johnson syndrome or toxic epidermal necrolysis
  • Diarrhea that is watery or bloody (may indicate a more serious intestinal infection)
  • Yeast infections (oral or genital) due to disruption of normal bacterial balance
  • White patches in the mouth or on the tongue (oral thrush)
  • Joint pain
  • Fever

Serious Side Effects (Rare):

  • Severe allergic reactions, including anaphylaxis (a life-threatening reaction)
  • Clostridium difficile-associated diarrhea (a bacterial infection that can result from antibiotic use)
  • Hepatitis (inflammation of the liver)
  • Hemolytic anemia (destruction of red blood cells)
  • Kidney problems

If you experience any severe or unusual symptoms while taking Ampicillin, such as difficulty breathing, swelling of the face or throat, severe skin reactions, or persistent diarrhea, seek medical attention immediately.

Interaction with other drugs

Ampicillin can interact with other drugs and substances, potentially affecting its effectiveness or causing adverse effects, here are some common interactions to be aware of:

  • Probenecid: Probenecid can increase the levels of Ampicillin in the body by reducing its elimination. This may lead to increased side effects or toxicity.
  • Oral Contraceptives: Medicine can reduce the effectiveness of oral contraceptives (birth control pills). It's recommended to use an additional form of contraception while taking Ampicillin and for a few days after completing the course.
  • Anticoagulants (Blood Thinners): Antibiotic can interact with anticoagulant medications like warfarin and increase the risk of bleeding. Your doctor may need to monitor your blood clotting factors and adjust your anticoagulant dosage if you are taking Ampicillin.
  • Methotrexate: The combination of Ampicillin and methotrexate can increase methotrexate levels in the blood, potentially leading to increased side effects or toxicity.
  • Allopurinol: There's a possibility of an increased risk of skin rash when Ampicillin is used with allopurinol.
  • Tetracyclines: Ampicillin and tetracycline antibiotics can interfere with each other's effectiveness when taken together. They should be administered at different times to avoid this interaction.
  • Live Bacterial Vaccines: The use of this drug can reduce the effectiveness of live bacterial vaccines. It's recommended to separate the administration of Ampicillin and live bacterial vaccines by a few weeks.
  • Certain Antacids: Some antacids containing aluminum or magnesium can decrease the absorption of Ampicillin. If you need to take an antacid, it's advisable to do so at least 2 hours before or after taking this medicine.
  • Other Antibiotics: Some antibiotics, especially those with similar mechanisms of action, can interact with Ampicillin.

What to avoid while on Ampicillin

While taking Ampicillin, there are certain things you should avoid to ensure the medication's effectiveness and to prevent potential interactions or adverse effects. Here are some guidelines to follow:

  • Avoid Alcohol: Drinking alcohol while on antibiotics like Ampicillin may interfere with the medication's effectiveness and could potentially increase the risk of side effects.
  • Avoid Dairy Products: Some dairy products, especially those high in calcium, can bind to antibiotics like Ampicillin and reduce their absorption. It's a good idea to avoid consuming large amounts of dairy products close to when you take your medication.
  • Separate Antacids: If you need to take antacids for stomach discomfort, do so at least 2 hours before or after taking Ampicillin. Some antacids can interfere with the absorption of the antibiotic.
  • Be Cautious with Oral Contraceptives: Remedy can reduce the effectiveness of oral contraceptives (birth control pills). To prevent unintended pregnancies, use an additional form of contraception (such as condoms) while taking Ampicillin and for a few days after completing the course.
  • Follow Dietary Restrictions: If you have been advised to follow certain dietary restrictions due to your medical condition or the type of infection you have, make sure to adhere to them while taking Ampicillin.
  • Consult Your Doctor Before Starting New Medications or Supplements: Before starting any new medications, supplements, or herbal products while on Ampicillin, consult your doctor. They can assess potential interactions and provide guidance.
  • Follow Dosage Instructions: Stick to the prescribed dosage and schedule. Avoid adjusting your dosage or stopping the medication without consulting your doctor.
  • Complete the Full Course: It's important to complete the entire course of Ampicillin as prescribed, even if you start feeling better before the course is finished. Stopping antibiotics prematurely can lead to incomplete eradication of the infection and potential development of antibiotic resistance.
  • Avoid Allergic Triggers: If you have a known allergy to Ampicillin or other penicillin antibiotics, avoid exposure to these substances to prevent an allergic reaction.
  • Maintain Hydration: It's important to stay hydrated while on antibiotics. Drink plenty of water.

Contraindications of Ampicillin

Ampicillin should not be used in certain situations due to potential risks and contraindications. Contraindications are specific circumstances or medical conditions that make the use of a particular medication unsafe or potentially harmful. Here are some contraindications:

  • Allergy to Penicillin or Beta-Lactam Antibiotics: If you have a known allergy to penicillin antibiotics or if you've had a severe allergic reaction (anaphylaxis) to any beta-lactam antibiotics, you should not use Ampicillin or other drugs in the same class.
  • Infectious Mononucleosis (Mono): Ampicillin use is not recommended in individuals with infectious mononucleosis, as it can cause a rash that is often mistaken for an allergic reaction. This is more likely to occur in patients with mono.
  • Severe Liver Disease: Ampicillin is metabolized in the liver. Individuals with severe liver impairment may have difficulty processing the medication, leading to potential toxicity.
  • History of Cholestatic Jaundice: If you have a history of cholestatic jaundice (a type of liver disorder), you may be at an increased risk of experiencing liver-related adverse effects from Ampicillin.
  • Colitis or Inflammatory Bowel Disease: Medicine can disturb the balance of bacteria in the intestines, which could lead to overgrowth of harmful bacteria and cause colitis (inflammation of the colon). It's generally avoided in patients with a history of colitis or inflammatory bowel disease.
  • Pre-existing Kidney Disease: Pharmaceutical preparation is excreted primarily by the kidneys. Individuals with severe kidney impairment may need dosage adjustments or alternative treatment options.
  • Certain Types of Leukemia: Ampicillin use is associated with an increased risk of skin rash in patients with certain types of leukemia.
  • Severe Bacterial Infections Without Laboratory Confirmation: Antibiotic should not be used in the treatment of severe bacterial infections unless the causative bacteria have been identified and are known to be susceptible to Ampicillin.

Pregnancy and Ampicillin

Ampicillin is generally considered safe to use during pregnancy when prescribed by a healthcare professional. However, as with any medication, it's important to weigh the potential benefits against the potential risks before using it during pregnancy. Here's what you need to know about using this drug during pregnancy:

  • Safety Category: Ampicillin is classified as a Pregnancy Category B medication by the U.S. Food and Drug Administration (FDA). This means that animal studies have not shown any significant risks to the fetus, and there are no well-controlled studies in pregnant women. However, the medication may be prescribed if the potential benefits to the mother outweigh the potential risks to the fetus.
  • Infections: In some cases, treating bacterial infections with antibiotics is important to prevent complications for both the pregnant person and the fetus. Untreated bacterial infections can lead to more serious health risks than the potential risks associated with antibiotic use.
  • Urinary Tract Infections (UTIs): UTIs are common during pregnancy and can lead to complications if not treated. Ampicillin is often used to treat UTIs during pregnancy.
  • Group B Streptococcus (GBS): Ampicillin is also used to prevent GBS infection in newborns. Pregnant individuals who test positive for GBS colonization may be given remedy during labor to reduce the risk of passing the infection to the baby.
  • Dosage and Duration: Your doctor will determine the appropriate dosage and duration of Ampicillin treatment based on your individual circumstances. It's important to follow their recommendations closely.
  • Potential Risks and Side Effects: While Ampicillin is generally considered safe during pregnancy, there is always a possibility of side effects or adverse reactions.
  • Avoid Self-Medication: Do not self-prescribe or self-medicate during pregnancy.
Drug Uses

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