Ampicillin

Ampicillin is a penicillin-type of antibiotic used to treat a variety of bacterial infections. It is effective in infections of the throat, ear, nasal sinuses, respiratory tract (e.g. pneumonia), urinary tract, skin and soft tissue, and typhoid fever. Ampicillin is also used to prevent infection of the heart valves (bacterial endocarditis) in people with pre-existing heart disease.

This medicine should be taken on an empty stomach (1 hour before or 2 hours after meals). Use it regularly at evenly spaced intervals as per the schedule prescribed by your doctor. Complete the full course of treatment even if you feel better - stopping early may lead to the infection returning or worsening.

Ampicillin kills bacteria by preventing them from forming the bacterial protective covering (cell wall) which is needed for their survival. Rash, vomiting, allergic reactions, nausea and diarrhea may be seen as side effects. This medicine is generally regarded as safe to use during pregnancy under doctor's supervision.

• Respiratory tract infections (pneumonia, bronchitis)
• Ear, nose and sinus infections (otitis media, sinusitis)
• Urinary tract infections (UTI)
• Gastrointestinal infections (shigellosis, typhoid)
• Skin and soft tissue infections
• Gonorrhea
• Meningitis
• Listeriosis
• Peritonitis
• Endocarditis prophylaxis
• Perinatal group B streptococcal infection prevention

Ampicillin is a broad-spectrum penicillin antibiotic effective against both Gram-positive and Gram-negative bacteria. It binds to penicillin-binding proteins (PBPs) and inhibits the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall. Bacteria undergo lysis due to ongoing activity of cell wall autolytic enzymes.

Ampicillin's spectrum includes S. pneumoniae, other Streptococci, L. monocytogenes, M. catarrhalis, N. gonorrhoea, N. meningitidis, E. coli, P. mirabilis, Salmonella, Shigella, and H. influenzae.

Ampicillin inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls by binding to penicillin-binding proteins. It inactivates transpeptidase enzymes required for cell wall formation. When the cell wall becomes weak, bacteria undergo lysis and are destroyed.

Adult Oral Dosage:

• Biliary tract infections, bronchitis, endocarditis, gastroenteritis, listeriosis, otitis media, peritonitis: 0.25-1 g every 6 hours
• Typhoid and paratyphoid fever (acute): 1-2 g every 6 hours (2 weeks)
• Typhoid carriers: 1-2 g every 6 hours (4-12 weeks)
• Uncomplicated gonorrhea: 2 g + probenecid 1 g (single dose), repeat recommended in females
• Urinary tract infections: 500 mg every 8 hours

Adult Parenteral Dosage:

• Susceptible infections: 500 mg every 6 hours (IM or slow IV injection)
• Meningitis: 2 g every 6 hours (IV)
• Septicemia: 150-200 mg/kg/day, IV for at least 3 days, then IM every 3-4 hours
• Perinatal group B streptococcal infection prophylaxis: Initial 2 g IV, then 1 g every 4 hours until delivery

Pediatric Oral Dosage:

• Under 10 years: Half of adult routine dosage
• Weight-based: 50-100 mg/kg/day (every 6 hours), if >20 kg: 1-2 g/day (every 6 hours)

Pediatric Parenteral Dosage:

• Susceptible infections: 50-200 mg/kg/day (every 6 hours)
• Endocarditis/meningitis: 300-400 mg/kg/day (every 4-6 hours)

Intra-articular/Intraperitoneal/Intrapleural:

• Adult: 500 mg daily
• Child (under 10 years): Half of adult routine dosage

Renal Dose: Reduce dose or increase interval if CrCl <10 mL/min.

Group A β-hemolytic streptococci: At least 10 days treatment (to prevent acute rheumatic fever or glomerulonephritis).

Take on an empty stomach (1 hour before or 2 hours after meals). Take in the dose and duration as advised by your doctor. Do not chew, crush or break capsules/tablets.

Reconstitution:

• Intramuscular: Add 1.5 mL water for injection to 500 mg vial
• Intravenous: Dissolve 500 mg in 10 mL water for injection
• Intra-articular: Dissolve 500 mg in up to 5 mL water for injection
• Intraperitoneal: Dissolve 500 mg in up to 10 mL water for injection
• Intrapleural: Dissolve 500 mg in 5-10 mL water for injection

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not double the dose.

• Rash (Erythematous maculo-papular rashes)
• Vomiting
• Allergic reactions
• Nausea
• Diarrhea
• Sore mouth
• Black/hairy tongue
• Fever
• Joint pains
• Hemolytic anemia, thrombocytopenia, leukopenia, neutropenia
• Interstitial nephritis, hepatitis, cholestatic jaundice
• Anaphylaxis, Clostridium difficile-associated diarrhea (CDAD)
• Stevens-Johnson syndrome, toxic epidermal necrolysis

Important Precautions:

• Inform your doctor if allergic to penicillin or cephalosporin antibiotics - serious anaphylactic reactions may occur
• Complete the full course - do not stop even if you feel better
• Stop and inform your doctor immediately if you develop allergic reactions (rash, swelling of face/throat/tongue, breathing difficulties)
• Inform your doctor if you notice bloody stools or develop abdominal cramps
• Caution in infectious mononucleosis
• Caution in kidney disease
• Caution during pregnancy and lactation
• Caution in patients with β-lactam allergy history

• Hypersensitivity to penicillin
• Hypersensitivity to ampicillin
• Infectious mononucleosis

• Oral contraceptives: May reduce contraceptive efficacy
• Warfarin/Phenindione: May alter INR
• Oral typhoid vaccines: May reduce vaccine efficacy
• Methotrexate: May reduce methotrexate excretion
• Probenecid/Sulfinpyrazone: Reduce excretion, increasing toxicity risk
• Allopurinol: Increases ampicillin-induced skin reactions
• Chloroquine: Reduces ampicillin absorption
• Bacteriostatic antibacterials (erythromycin, chloramphenicol, tetracycline): May interfere with ampicillin's bactericidal action

[SAFE] Consuming alcohol with Ampicillin does not cause any harmful side effects. However, alcohol may reduce immune function.

[SAFE IF PRESCRIBED] Ampicillin is generally considered safe to use during pregnancy (Pregnancy Category B). Animal studies have shown low or no adverse effects on the developing baby; however, there are limited human studies. Use under doctor's supervision.

[SAFE IF PRESCRIBED] Ampicillin is safe to use during breastfeeding. Human studies suggest that the drug does not pass into breastmilk in a significant amount and is not harmful to the baby. However, caution is advised.

Pediatric dosage: 50-100 mg/kg/day (every 6 hours), if >20 kg: 1-2 g/day. Under 10 years: Half of adult routine dosage.

Elderly patients may have decreased renal function, so dose adjustment may be needed.

[CAUTION] Use with caution in kidney disease. If CrCl <10 mL/min, reduce dose or increase interval.

[CONSULT YOUR DOCTOR] Limited information is available on use in liver disease. Please consult your doctor.

Symptoms: Nausea, vomiting, and diarrhea.

Management: Symptomatic and supportive treatment. May be removed from circulation by hemodialysis.

Store between 20-25°C. Reconstituted oral suspension: Store between 2-8°C (discard after 14 days).