ampicillin
(am pi sill' in)

ampicillin sodium
Oral:
Ampicin (CAN), Apo-Ampi (CAN), Marcillin, Novo-Ampicillin (CAN), Nu-Ampi (CAN), Omnipen, Penbritin (CAN), Principen, Totacillin

ampicillin sodium
Parenteral:
Omnipen-N

Pregnancy Category B

Drug classes
Antibiotic
Penicillin

Therapeutic actions
Bactericidal action against sensitive organisms; inhibits synthesis of bacterial cell wall, causing cell death.

Indications
· Treatment of infections caused by susceptible strains of Shigella, Salmonella, E. coli, H. influenzae, P. mirabilis, N. gonorrhoeae, enterococci, gram-positive organisms (penicillin G–sensitive staphylococci, streptococci, pneumococci)
· Meningitis caused by Neisseria meningitidis
· Unlabeled use: prophylaxis in cesarean section in certain high-risk patients

Contraindications and cautions
· Contraindicated with allergies to penicillins, cephalosporins, or other allergens.
· Use cautiously with renal disorders.

Available forms
Capsules--250, 500 mg; powder for oral suspension--125 mg/5 mL, 250 mg/5 mL; powder for injection--125, 250, 500 mg, 1, 2, 10 g

Dosages
Maximum recommended dosage: 8 mg/day; may be given IV, IM, or PO. Use parenteral routes for severe infections, and switch to oral route as soon as possible.
· Respiratory and soft-tissue infections:
Patients weighing > 40 kg: 250–500 mg IV or IM q 6 hr.
Patients weighing < 40 kg: 25–50 mg/kg/day IM or IV in equally divided doses at 6–8 hr intervals.
Patients weighing > 20 kg: 250 mg PO q 6 hr.
Patients weighing < 20 kg: 50 mg/kg/day PO in equally divided doses q 6–8 hr.
· GI and GU infections, including women with N. gonorrhoeae:
Patients weighing > 40 kg: 500 mg IM or IV q 6 hr.
Patients weighing < 40 kg: 50–100 mg/kg/day IM or IV in equally divided doses q 6–8 hr.
Patients weighing > 20 kg: 500 mg PO q 6 hr.
Patients weighing < 20 kg: 100 mg/kg/day PO in equally divided doses q 6–8 hr.
· Gonococcal infections: 500 mg q 6 hr for penicillin-sensitive organism or single dose of 3.5 g PO with 1 g probenecid for patients > 45 kg.
· Bacterial meningitis (adult and pediatric): 150–200 mg/kg/day by continuous IV drip and then IM injections in equally divided doses q 3–4 hr.
· Prevention of bacterial endocarditis for GI or GU surgery or instrumentation:
Adults:
2 g ampicillin IM or IV with gentamicin 1.5 mg/kg IM or IV within 30 minutes of starting procedure. Six hours later give 1 g ampicillin IM or IV or 1 g amoxicillin PO.
Pediatric patients: 50 mg/kg ampicillin IM or IV with 1.5 mg/kg gentamicin IM or IV within 30 minutes of procedure. Six hours later give 25 mg/kg ampicillin IM or IV or 25 mg/kg amoxicillin PO.
· Prevention of bacterial endocarditis for dental, oral, or upper respiratory procedures:
Adults:
2 g ampicillin IM or IV within 30 minutes of procedure.
Pediatric patients: 50 mg/kg ampicillin IM or IV within 30 minutes of procedure.
· Septicemia (adult and pediatric): 150–200 mg/kg/day IV for at least 3 days, then IM q 3–4 hr.
· Sexually transmitted diseases (adult):
Rape victims:
Prophylaxis against infection. Pregnant women and patients allergic to tetracycline: 3.5 g ampicillin PO with 1 g probenecid.
Prophylaxis in cesarean section: Single IV or IM dose of 25–100 mg/kg immediately after cord is clamped.

Pharmacokinetics
Route
Onset
Peak
Duration
Oral
30 min
2 hr
6–8 hr
IM
15 min
1 hr
6–8 hr
IV
Immediate
5 min
6–8 hr


Metabolism: T1/2: 1–2 hr
Distribution: Crosses placenta; passes into breast milk
Excretion: Unchanged in the urine

IV facts
Preparation: Reconstitute with sterile or bacteriostatic water for injection; piggyback vials may be reconstituted with sodium chloride injection; use reconstituted solution within 1 hr. Do not mix in the same IV solution as other antibiotics. Use within 1 hr after preparation because potency may decrease significantly after that.
Infusion: Direct IV administration; give slowly over 3–5 min. Rapid administration can lead to convulsions.
IV drip: dilute as above before further dilution.
IV piggyback: administer alone or further dilute with compatible solution.
Compatibility: Ampicillin is compatible with 0.9% sodium chloride, 5% dextrose in water, or 0.45% sodium chloride solution, 10% invert sugar water, M/6 sodium lactate solution, lactated Ringer's solution, sterile water for injection. Diluted solutions are stable for 2–8 hr; check manufacturer's inserts for specifics. Discard solution after allotted time period.
Incompatibility: Do not mix with lidocaine, verapamil, other antibiotics, dextrose solutions.
Y-site incompatibility: Do not give with epinephrine, hydralazine, ondansetron.

Adverse effects
· CNS: Lethargy, hallucinations, seizures
· CV: CHF
· GI: Glossitis, stomatitis, gastritis, sore mouth, furry tongue, black “hairy” tongue, nausea, vomiting, diarrhea, abdominal pain, bloody diarrhea, enterocolitis, pseudomembranous colitis, nonspecific hepatitis
· GU: Nephritis
· Hematologic: Anemia, thrombocytopenia, leukopenia, neutropenia, prolonged bleeding time
· Hypersensitivity: Rash, fever, wheezing, anaphylaxis
· Local: Pain, phlebitis, thrombosis at injection site (parenteral)
· Other: Superinfections--oral and rectal moniliasis, vaginitis

Interactions
Drug-drug
· Increased ampicillin effect with probenecid
· Increased risk of rash with allopurinol
· Increased bleeding effect with heparin, oral anticoagulants
· Decreased effectiveness with tetracyclines, chloramphenicol
· Decreased efficacy of oral contraceptives, atenolol with ampicillin
Drug-food
· Oral ampicillin may be less effective with food; take on an empty stomach
Drug-lab test
· False-positive Coombs' test if given IV
· Decrease in plasma estrogen concentrations in pregnant women
· False-positive urine glucose tests if Clinitest, Benedict's solution, or Fehling's solution is used; enzymatic glucose oxidase methods (Clinistix, Tes-Tape) should be used to check urine glucose

Nursing considerations
Assessment
· History: Allergies to penicillins, cephalosporins, or other allergens; renal disorders; lactation
· Physical: Culture infected area; skin color, lesion; R, adventitious sounds; bowel sounds; CBC, liver and renal function tests, serum electrolytes, hematocrit, urinalysis

Interventions
· Culture infected area before treatment; reculture area if response is not as expected.
· Check IV site carefully for signs of thrombosis or drug reaction.
· Do not give IM injections in the same site; atrophy can occur. Monitor injection sites.
· Administer oral drug on an empty stomach, 1 hr before or 2 hr after meals with a full glass of water--no fruit juice or soft drinks.

Teaching points
· Take this drug around the clock.
· Take the full course of therapy; do not stop taking the drug if you feel better.
· Take the oral drug on an empty stomach, 1 hr before or 2 hr after meals; the oral solution is stable for 7 days at room temperature.
· This antibiotic is specific to your problem and should not be used to self-treat other infections.
· These side effects may occur: nausea, vomiting, GI upset (small frequent meals may help), diarrhea.
· Report pain or discomfort at sites, unusual bleeding or bruising, mouth sores, rash, hives, fever, itching, severe diarrhea, difficulty breathing.

Adverse effects in Italic are most common; those in Bold are life-threatening.