Ampicillin

Common Uses

Ampicillin is prescribed to treat a wide range of infections caused by bacteria. It is commonly used for the following conditions:

• Respiratory tract infections, such as pneumonia and bronchitis.
• Urinary tract infections (UTIs).
• Gastrointestinal infections, including those caused by Salmonella or Shigella.
• Meningitis, which is an infection of the membranes surrounding the brain and spinal cord.
• Endocarditis, an infection of the heart lining.
• Bloodstream infections, also known as sepsis.

It may also be used to treat certain ear, nose, and throat infections, as well as infections of the skin and soft tissues.

Important Considerations

Ampicillin belongs to the penicillin class of medications and works by stopping the growth of bacteria. It is important to note that this medication only treats bacterial infections. It will not work for viral infections, such as the common cold or the flu. Using antibiotics when they are not needed increases the risk of developing an infection later that resists antibiotic treatment.

Mechanism of Action

Ampicillin belongs to a class of medications known as penicillin-like antibiotics. It works by interfering with the ability of bacteria to form stable cell walls. These walls are essential for the bacteria to survive and protect themselves from the surrounding environment.

When bacteria attempt to grow or multiply, ampicillin prevents them from properly building their outer structure. This weakens the bacteria, eventually causing them to burst or preventing them from spreading further throughout the body.

Targeting Infections

Because ampicillin specifically targets structures found in bacterial cells, it is effective against a variety of bacterial infections, including those affecting the:

• Respiratory tract (such as the throat, sinuses, and lungs)
• Urinary tract
• Gastrointestinal system
• Meninges (the membranes surrounding the brain and spinal cord)

It is important to note that ampicillin only treats infections caused by bacteria. It does not work against viral infections, such as the common cold or the flu.

Common Side Effects

Some people may experience mild side effects while taking ampicillin. These often include:

• Nausea or vomiting
• Diarrhea
• Stomach pain
• Vaginal itching or discharge
• A swollen, black, or "hairy" appearance of the tongue

Serious Side Effects

Seek medical attention immediately if you experience any of the following serious symptoms:

• Signs of an allergic reaction, including skin rash, hives, itching, or swelling of the face, throat, or tongue
• Difficulty breathing, wheezing, or swallowing
• Severe diarrhea that is watery or bloody, which may occur with fever and stomach cramps (this can happen during treatment or several months after stopping the medication)
• Unusual bruising or bleeding
• Yellowing of the eyes or skin
• Seizures
• Extreme fatigue or weakness

Allergic Reactions

Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients receiving penicillin therapy. These reactions are more likely to occur in individuals with a history of penicillin hypersensitivity or sensitivity to multiple allergens. Before starting treatment, it is important to identify any previous reactions to penicillins, cephalosporins, or other allergens. If an allergic reaction occurs, the medication must be discontinued immediately.

Diarrhea and Colitis

Clostridioides difficile-associated diarrhea (CDAD) has been reported with the use of nearly all antibacterial agents, including ampicillin. This condition can range in severity from mild diarrhea to life-threatening inflammation of the colon. It occurs because the antibiotic alters the normal flora of the colon, allowing the overgrowth of C. difficile bacteria.

Patients with Mononucleosis

A high percentage of patients with infectious mononucleosis who take ampicillin develop a skin rash. Because of this, ampicillin is generally not recommended for individuals suspected of having mononucleosis.

Development of Drug-Resistant Bacteria

Using ampicillin in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit and increases the risk that bacteria will develop resistance to the drug. Additionally, prolonged use may lead to the overgrowth of non-susceptible organisms, such as fungi.

Laboratory Monitoring

For patients receiving long-term therapy, healthcare providers may perform periodic assessments of organ system functions, including the kidneys, liver, and blood-forming systems.

Pregnancy

Ampicillin is frequently used during pregnancy to treat various bacterial infections. Research in animals has not shown evidence of harm to the developing fetus. While there are no adequate and well-controlled studies in pregnant women, the long history of clinical use suggests that the risk of birth defects or other problems is low.

If you are pregnant or planning to become pregnant, discuss the potential risks and benefits with your doctor before starting this medication.

Breastfeeding

Ampicillin passes into breast milk in small quantities. It is generally considered safe to use while breastfeeding, but there are a few potential effects to monitor in the nursing infant:

• Changes in bowel habits, such as diarrhea.
• Development of a yeast infection (thrush).
• Allergic sensitization.

Consult your healthcare provider to determine if breastfeeding is appropriate while taking ampicillin.

Oral Forms

Ampicillin is commonly prescribed in oral forms for use at home. These include:

• Capsules: These are typically available in multiple strengths for oral administration.
• Oral Suspension: This is a powder that is mixed with water by a pharmacist to create a liquid medication, often used for children or individuals who have difficulty swallowing pills.

Injectable Forms

For more severe infections or when oral administration is not possible, ampicillin is available as a powder for injection. This form is reconstituted by a healthcare professional and administered in the following ways:

• Intravenous (IV) infusion: Delivered directly into a vein.
• Intramuscular (IM) injection: Injected into a large muscle.

Ampicillin is also available as a combination product with sulbactam, which is provided as a powder for injection to be administered intravenously or intramuscularly.

FDA Approval and Indications

Ampicillin was first approved by the U.S. Food and Drug Administration (FDA) in the 1960s. It is indicated for the treatment of infections caused by susceptible strains of specific microorganisms. These include infections of the urinary tract, respiratory tract, and gastrointestinal tract, as well as meningitis and endocarditis.

Regulatory Status

Ampicillin is classified as a prescription drug. It is not available over-the-counter. The FDA monitors its safety and efficacy through standard reporting mechanisms. There are currently no boxed warnings or Risk Evaluation and Mitigation Strategies (REMS) associated with this medication.

Safety Warnings

The FDA-approved labeling includes warnings regarding:

• Hypersensitivity: Serious and occasionally fatal allergic reactions (anaphylaxis) have been reported in patients on penicillin therapy.
• Clostridioides difficile-associated diarrhea (CDAD): This condition has been reported with the use of nearly all antibacterial agents, including ampicillin, and may range in severity from mild diarrhea to fatal colitis.
• Development of drug-resistant bacteria: To reduce the development of drug-resistant bacteria and maintain the effectiveness of ampicillin, it should be used only to treat infections that are proven or strongly suspected to be caused by bacteria.

Use During Pregnancy

Ampicillin is widely used during pregnancy and is not known to cause birth defects or other developmental issues. It is often the preferred treatment for various bacterial infections, such as urinary tract infections, in pregnant patients.

Healthcare providers also commonly administer ampicillin during labor and delivery. This is often done to prevent the transmission of Group B Streptococcus (GBS) from the parent to the newborn, which helps reduce the risk of the baby developing a serious infection after birth.

Breastfeeding

Ampicillin passes into breast milk in small amounts. While it is generally considered compatible with breastfeeding, you should inform your doctor if you are nursing. Potential effects on a breastfeeding infant may include:

• Changes in the infant's bowel flora, which may lead to diarrhea.
• A potential for the infant to develop a skin rash or allergic sensitivity.

Always consult with a healthcare professional to discuss the benefits and risks of using this medication while breastfeeding.