amoxicillin, Amoxil, Moxatag, Novamoxin, Trimox

Indications

Treatment of: Skin and skin structure infections, Otitis

media, Sinusitis, Respiratory infections, Genitourinary

infections. Endocarditis prophylaxis. Postexposure inhalational

anthrax prophylaxis. Management of ulcer

disease due to Helicobacter pylori. Unlabeled Use:

Lyme disease in children 8 yr.

Action

Binds to bacterial cell wall, causing cell death. Therapeutic

Effects: Bactericidal action; spectrum is

broader than penicillins. Spectrum: Active against:

Streptococci, Pneumococci, Enterococci, Haemophilus

influenzae, Escherichia coli, Proteus mirabilis,

Neisseria meningitidis, N. gonorrhoeae, Shigella,

Chlamydia trachomatis, Salmonella, Borrelia burgdorferi,

H. pylori.

Pharmacokinetics

Absorption: Well absorbed from duodenum (75–

90%). More resistant to acid inactivation than other

penicillins.

Distribution: Diffuses readily into most body tissues

and fluids. CSF penetration increased when meninges

are inflamed. Crosses placenta; enters breast milk in

small amounts.

Metabolism and Excretion: 70% excreted unchanged

in the urine; 30% metabolized by the liver.

Half-life: Neonates: 3.7 hr; Infants and Children: 1–

2 hr; Adults: 0.7–1.4 hr.

TIME/ACTION PROFILE (blood levels)

ROUTE ONSET PEAK DURATION

PO 30 min 1–2 hr 8–12 hr

Contraindications/Precautions A

Contraindicated in: Hypersensitivity to penicillins

(cross-sensitivity exists to cephalosporins and other

beta-lactams).

Use Cautiously in: Severe renal insufficiency (p

dose if CCr 30 mL/min); Infectious mononucleosis,

acute lymphocytic leukemia, or cytomegalovirus infection

(qrisk of rash); OB, Lactation: Has been used

safely.

Adverse Reactions/Side Effects

CNS: SEIZURES (high doses). GI: CLOSTRIDIUM DIFFICILE-

ASSOCIATED DIARRHEA (CDAD), diarrhea, nausea,

vomiting,qliver enzymes. Derm: rash, urticaria.

Hemat: blood dyscrasias. Misc: allergic reactions

including ANAPHYLAXIS, SERUM SICKNESS, superinfection.

Interactions

Drug-Drug: Probenecidprenal excretion andq

blood levels of amoxicillin—therapy may be combined

for this purpose. Mayqeffect of warfarin. Maypeffectiveness

of oral contraceptives. Allopurinol mayq

frequency of rash.

Route/Dosage

Most Infections

PO (Adults): 250–500 mg q 8 hr or 500–875 mg q

12 hr (not to exceed 2–3 g/day).

PO (Adults and Children 12 yr): Extended-release

tablets (for Strep throat)—775 mg once daily

for 10 days.

PO (Children 3 mo): 25–50 mg/kg/day in divided

doses q 8 hr or 25–50 mg/kg/day individual doses q

12 hr; Acute otitis media due to highly resistant

strains of S. pneumoniae—80–90 mg/kg/day divided

q 12 hr; Postexposure inhalational anthrax

prophylaxis—40 kg: 45 mg/kg/day in divided doses

q 8 hr; 40 k g: 500 mg q 8 hr.

PO (Infants 3 mo and neonates): 20–30 mg/kg/

day in divided doses q 12 hr.

H. Pylori

PO (Adults): Triple therapy—1000 mg amoxicillin

twice daily with lansoprazole 30 mg twice daily and clarithromycin

500 mg twice daily for 14 days or 1000 mg

amoxicillin twice daily with omeprazole 20 mg twice

daily and clarithromycin 500 mg twice daily for 14 days

or amoxicillin 1000 mg twice daily with esomeprazole

40 mg daily and clarithromycin 500 mg twice daily for

10 days. Dual therapy—1000 mg amoxicillin three

times daily with lansoprazole 30 mg three times daily

for 14 days. 

Endocarditis Prophylaxis

PO (Adults): 2 g 1 hr prior to procedure.

PO (Children): 50 mg/kg 1 hr prior to procedure

(not to exceed adult dose).

Gonorrhea

PO (Adults and Children 40 kg): single 3 g dose.

PO (Children 2 yr and 40 kg): 50 mg/kg with

probenecid 25 mg/kg as a single dose.

Renal Impairment

PO (Adults CCr 10–30 mL/min): 250–500 mg q 12

hr.

Renal Impairment

PO (Adults CCr 10 mL/min): 250–500 mg q 24

hr.

Availability (generic available)

Chewable tablets (cherry, banana, peppermint

flavors): 125 mg, 200 mg, 250 mg, 400 mg. Cost: Generic—

250 mg $15.89/30. Tablets: 500 mg, 875 mg.

Cost: Generic—875 mg $9.53/30. Extended-release

tablets: 775 mg. Cost: $524.90/30. Capsules:

250 mg, 500 mg. Cost: Generic—250 mg $5.90/30,

500 mg $5.90/30. Suspension (pediatric drops)

(bubblegum flavor): 50 mg/mL. Powder for oral

suspension (strawberry [125 mg/5 mL] and bubblegum

[200 mg/5 mL, 250 mg/5 mL, 400 mg/5

mL] flavors): 125 mg/5 mL, 200 mg/5 mL, 250 mg/5

mL, 400 mg/5 mL. Cost: Generic—125 mg/5 mL

$4.11/150 mL, 200 mg/5 mL $6.84/75 mL, 250 mg/5

mL $6.09/100 mL, 400 mg/5 mL $7.33/75 mL. In

combination with: clarithromycin and lansoprazole

in a compliance package (Prevpac). See Appendix B.