ampicillin

Binds to bacterial cell wall, resulting in cell death.

Therapeutic effects:

Bactericidal action; spectrum is broader than penicillin.

Spectrum:

Active against:
- Streptococci,
- nonpenicillinase-producing staphylococci,
- Listeria,
- Pneumococci,
- Enterococci,
- Haemophilus influenzae,
- Escherichia coli,
- Enterobacter,
- Klebsiella,
- Proteus mirabilis,
- Neisseria meningitidis,
- N. gonorrhoeae,
- Shigella,
- Salmonella.

Pharmacokinetics ⬆ ⬇

Absorption: Moderately absorbed from the duodenum (30–50%).

Distribution: Diffuses readily into body tissues and fluids. CSF penetration is ↑ in the presence of inflamed meninges. Crosses the placenta; enters breast milk in small amounts.

Metabolism/Excretion: Variably metabolized by the liver (12–50%). Renal excretion is variable (25–60% after oral dosing; 50–85% after IM administration).

Half-Life: Neonates: 1.7–4 hr; Children and Adults: 1–1.5 hr (↑ in renal impairment).

Time/Action Profile ⬆ ⬇

(blood levels)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	1.5–2 hr	4–6 hr
IM	rapid	1 hr	4–6 hr
IV	rapid	end of infusion	4–6 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to penicillins.

Use Cautiously in:

Severe renal insufficiency (dose ↓ required if CCr <10 mL/min);
Infectious mononucleosis, acute lymphocytic leukemia or cytomegalovirus infection (↑ incidence of rash);
Patients allergic to cephalosporins;
OB: Has been used during pregnancy;
Lactation: Distributed into breast milk. Can cause rash, diarrhea, and sensitization in the infant.

Adv. Reactions/Side Effects ⬆ ⬇

Derm: rash, urticaria

GI: diarrhea, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD), nausea, vomiting

Hemat: blood dyscrasias

Neuro: SEIZURES (HIGH DOSES)

Misc: ANAPHYLAXIS AND SERUM SICKNESS ALLERGIC REACTIONS INCLUDING , superinfection

Interactions ⬆ ⬇

Drug-drug:

Probenecid↓ renal excretion and ↑ blood levels of ampicillin—therapy may be combined for this purpose.
Large doses may ↑ the risk of bleeding with warfarin.
↑risk of with concurrent allopurinol therapy.
May ↓ the effectiveness of oral hormonal contraceptives.

Route/Dosage ⬆ ⬇

Respiratory and Soft-Tissue Infections

PO (Adults and Children ≥20 kg): 250–500 mg q 6 hr.
PO (Children <20 kg): 50–100 mg/kg/day in divided doses q 6–8 hr (not to exceed 2–3 g/day).
IM IV (Adults and Children ≥40 kg ): 500 mg to 3 g q 6 hr (not to exceed 14 g/day).
IM IV (Children <40 kg): 100–200 mg/kg/day in divided doses q 6–8 hr (not to exceed 12 g/day).

Bacterial Meningitis Caused by H. influenzae, Streptococcus pneumoniae, Group B streptococcus or N. meningitidis or Septicemia

IM IV (Adults ): 500 mg to 3 g q 6 hr (not to exceed 14 g/day).
IM IV (Children >1 mo): 200–400 mg/kg/day in divided doses q 6 hr (not to exceed 12 g/day).
IM IV (Neonates ≤7 days): 200 mg/kg/day divided q 8 hr.
IM IV (Neonates >7 days): 300 mg/kg/day divided q 6 hr.

GI/GU Infections other than N. gonorrhoeae

PO (Adults and Children >20 kg): 250–500 mg q 6 hr (larger doses for more serious/chronic infections).
PO (Children ≤20 kg): 50–100 mg/kg/day in divided doses q 6 hr.

N. gonorrhoeae

PO (Adults ): 3 g with 1 g probenecid.
IM IV (Adults and Children ≥40 kg ): 500 mg q 6 hr.
IM IV (Children <40 kg): 100–200 mg/kg/day in divided doses q 6–8 hr.

Urethritis Caused by N. gonorrhoeae in Men

IM IV (Adults and Children ≥40 kg ): 500 mg, repeated 8–12 hr later; additional doses may be necessary for more complicated infections (prostatitis, epididymitis).

Prevention of Bacterial Endocarditis

IM IV (Adults ): 2 g 30 min before procedure (gentamicin may be added for high-risk patients); additional 1 g may be given 6 hr later for high-risk patients.
IM IV (Children ): 50 mg/kg (not to exceed 2 g) 30 min before procedure (gentamicin may be added for high-risk patients); additional 25 mg/kg may be given 6 hr later for high-risk patients.

Renal Impairment

(Adults and Children ): CCr ≤10 mL/min: ↑dosing interval to q 12 hr.

Availability ⬆ ⬇

(Generic available)

Capsules: 250 mg; 500 mg
Suspensionwild cherry flavor: 125 mg/5 mL; 250 mg/5 mL
Powder for injection: 125 mg/vial; 250 mg/vial; 500 mg/vial; 1 g/vial; 2 g/vial; 10 g/vial

Assessment ⬆ ⬇

Assess patient for infection (vital signs, wound appearance, sputum, urine, stool, and WBC) at beginning of and throughout therapy.
Obtain a history before initiating therapy to determine previous use and reactions to penicillins or cephalosporins. Persons with a negative history of penicillin sensitivity may still have an allergic response.
Obtain specimens for culture and sensitivity before therapy. First dose may be given before receiving results.
Observe patient for signs and symptoms of anaphylaxis (rash, pruritus, laryngeal edema, wheezing). Discontinue the drug and notify health care professional immediately if these occur. Keep epinephrine, an antihistamine, and resuscitation equipment close by in the event of an anaphylactic reaction.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of Clostridioides difficile-associated diarrhea (CDAD). May begin up to several wk following cessation of therapy.
Assess skin for "ampicillin rash," a nonallergic, dull red, macular or maculopapular, mildly pruritic rash.

Lab Test Considerations:

Implementation ⬆ ⬇

Reserve IM or IV route for moderately severe or severe infections or patients unable to take oral medication. Change to PO as soon as possible.
PO: Administer around the clock on an empty stomach at least 1 hr before or 2 hr after meals with a full glass of water. Capsules may be opened and mixed with water. Reconstituted oral suspensions retain potency for 7 days at room temperature and 14 days if refrigerated. Combination with probenecid should be used immediately after reconstitution.
IM: Reconstitute for IM or IV use by adding sterile water for injection 0.9–1.2 mL to the 125-mg vial, 0.9–1.9 mL to the 250-mg vial, 1.2–1.8 mL to the 500-mg vial, 2.4–7.4 mL to the 1-g vial, and 6.8 mL to the 2-g vial.

IV Administration:

Add 5 mL of sterile water for injection to each 125-, 250-, or 500-mg vial or at least 7.4–10 mL of diluent to each 1- or 2-g vial. Solution should be used within 1 hr of reconstitution.
Rate: Doses of 125–500 mg may be given over 3–5 min (not to exceed 100 mg/min). Rapid administration may cause seizures.
Intermittent Infusion: Diluent: Reconstitute vials as per the directions above. Further dilute in 50 mL or more of 0.9% NaCl, D5W, D5/0.45% NaCl, or LR. Administer within 4 hr (more stable in NaCl).Concentration: Not to exceed 30 mg/mL.
Rate: Infuse over 10–15 min.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication around the clock and to finish the drug completely as directed, even if feeling better. Advise patients that sharing of this medication can be dangerous.
Advise patient to report the signs of superinfection (furry overgrowth on the tongue, vaginal itching or discharge, loose or foul-smelling stools) and allergy.
Caution patient to notify health care professional if fever and diarrhea occur, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care professional. May occur up to several wk after discontinuation of medication.
Instruct the patient to notify health care professional if symptoms do not improve.
Patients with a history of rheumatic heart disease or valve replacement need to be taught the importance of using antimicrobial prophylaxis before invasive medical or dental procedures.
Advise patients taking oral contraceptives to use an alternate or additional nonhormonal method of contraception while taking ampicillin and until next menstrual period.
Advise female patient to notify health care professional if breast feeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇