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Related to Trimox: Amoxil

amoxicillin, amoxicillin trihydrate

Amix (UK), Amox (CA), Amoxident (UK), Amoxil, Apo-Amoxil (CA), Moxatag (CA), Novamoxin (CA), Nu-Amoxil (CA), Trimox

Pharmacologic class: Aminopenicillin

Therapeutic class: Anti-infective

Pregnancy risk category B


Inhibits cell-wall synthesis during bacterial multiplication, leading to cell death. Shows enhanced activity toward gram-negative bacteria compared to natural and penicillinase-resistant penicillins.


Capsules: 250 mg, 500 mg

Powder for oral suspension: 50 mg/ml and 125 mg/5 ml (pediatric), 200 mg/5 ml, 250 mg/5 ml, 400 mg/5 ml

Tablets: 500 mg, 875 mg

Tablets for oral suspension: 200 mg, 400 mg

Tablets (chewable): 125 mg, 200 mg, 250 mg, 400 mg

Indications and dosages

Uncomplicated gonorrhea

Adults and children weighing at least 40 kg (88 lb): 3 g P.O. as a single dose

Children ages 2 and older weighing less than 40 kg (88 lb): 50 mg/kg P.O. given with probenecid 25 mg/kg P.O. as a single dose

Bacterial endocarditis prophylaxis for dental, GI, and GU procedures

Adults: 2 g P.O. 1 hour before procedure

Children: 50 mg/kg P.O. 1 hour before procedure

Lower respiratory tract infections caused by streptococci, pneumococci, non-penicillinase-producing staphylococci, and Haemophilus influenzae

Adults and children weighing more than 20 kg (44 lb): 875 mg P.O. q 12 hours or 500 mg P.O. q 8 hours

Children weighing less than 20 kg (44 lb): 45 mg/kg/day P.O. in divided doses q 12 hours or 40 mg/kg/day P.O. in divided doses q 8 hours

Ear, nose, and throat infections caused by streptococci, pneumococci, non-penicillinase-producing staphylococci, and H. influenzae; GU infections caused by Escherichia coli, Proteus mirabilis, and Streptococcus faecalis

Adults and children weighing more than 20 kg (44 lb): 500 mg P.O. q 12 hours or 250 mg P.O. q 8 hours

Children weighing less than 20 kg (44 lb): 45 mg/kg/day P.O. in divided doses q 12 hours or 20 to 40 mg/kg P.O. in divided doses q 8 hours

Eradication of Helicobacter pylori to reduce risk of duodenal ulcer recurrence

Adults: 1 g P.O. q 12 hours for 14 days in combination with clarithromycin and lansoprazole, or in combination with lansoprazole alone as 1 g t.i.d. for 14 days

Postexposure anthrax prophylaxis

Adults: 500 mg P.O. t.i.d. for 60 days

Children: 80 mg/kg/day P.O. t.i.d. for 60 days

Skin and skin-structure infections caused by streptococci (alpha- and beta-hemolytic strains), staphylococci, and E. coli

Adults: 500 mg P.O. q 12 hours to 250 mg P.O. q 8 hours. For severe infections, 875 mg P.O. q 12 hours or 500 mg P.O. q 8 hours.

Children older than age 3 months: 25 mg/kg/day P.O. in divided doses q 12 hours or 20 mg/kg/day P.O. in divided doses every 8 hours. For severe infections, 45 mg/kg/day P.O. in divided doses q 12 hours or 40 mg/kg/day P.O. in divided doses every 8 hours.

Dosage adjustment

• Renal impairment

• Hemodialysis

• Infants ages 3 months and younger

Off-label uses

Chlamydia trachomatis infection in pregnant patients


• Hypersensitivity to drug or any penicillin


Use cautiously in:

• severe renal insufficiency, infectious mononucleosis, hepatic dysfunction

• pregnant patients.


Ask about history of penicillin allergy before giving.

• Give with or without food.

• Store liquid form in refrigerator when possible.

• Know that maximum dosage for infants ages 3 months and younger is 30 mg/kg/day divided q 12 hours.

Adverse reactions

CNS: lethargy, hallucinations, anxiety, confusion, agitation, depression, dizziness, fatigue, hyperactivity, insomnia, behavioral changes, seizures (with high doses)

GI: nausea, vomiting, diarrhea, bloody diarrhea, abdominal pain, gastritis, stomatitis, glossitis, black "hairy" tongue, furry tongue, enterocolitis, pseudomembranous colitis

GU: vaginitis, nephropathy, interstitial nephritis

Hematologic: eosinophilia, anemia, thrombocytopenia, thrombocytopenic purpura, leukopenia, hemolytic anemia, agranulocytosis, bone marrow depression

Hepatic: cholestatic jaundice, hepatic cholestasis, cholestatic hepatitis, nonspecific hepatitis

Respiratory: wheezing

Skin: rash

Other: superinfections (oral and rectal candidiasis), fever, anaphylaxis


Drug-drug. Allopurinol: increased risk of rash

Chloramphenicol, macrolides, sulfonamides, tetracycline: decreased amoxicillin efficacy

Hormonal contraceptives: decreased contraceptive efficacy

Probenecid: decreased renal excretion

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, eosinophils, lactate dehydrogenase: increased levels

Granulocytes, hemoglobin, platelets, white blood cells: decreased values Direct Coombs' test, urine glucose, urine protein: false-positive results

Drug-food. Any food: delayed or reduced drug absorption

Drug-herbs. Khat: decreased antimicrobial efficacy

Patient monitoring

• Monitor for signs and symptoms of hypersensitivity reaction.

Evaluate for seizures when giving high doses.

• Monitor patient's temperature and watch for other signs and symptoms of superinfection (especially oral or rectal candidiasis).

Patient teaching

Instruct patient to immediately report signs and symptoms of hypersensitivity reactions, such as rash, fever, or chills.

• Tell patient he may take drug with or without food.

• Tell patient not to chew or swallow tablets for suspension, because they're not meant to be dissolved in mouth.

• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.

• Tell patient taking hormonal contraceptives that drug may reduce contraceptive efficacy. Suggest she use alternative birth control method.

• Inform patient that drug lowers resistance to other types of infections. Instruct him to report new signs and symptoms of infection, especially in mouth or rectum.

• Tell parents they may give liquid form of drug directly to child or may mix it with foods or beverages.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


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Therapeutic: anti infectives
Pharmacologic: aminopenicillins
Pregnancy Category: B


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.Lyme disease in children <8 yr.


Binds to bacterial cell wall, causing cell death.

Therapeutic effects

Bactericidal action; spectrum is broader than penicillins.
Active against:
  • Streptococci,
  • Pneumococci,
  • Enterococci,
  • Haemophilus influenzae,
  • Escherichia coli,
  • Proteus mirabilis,
  • Neisseria meningitidis,
  • N. gonorrhoeae,
  • Shigella,
  • Chlamydia trachomatis,
  • Salmonella,
  • Borrelia burgdorferi,
  • H. pylori.


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)

PO30 min 1–2 hr8–12 hr


Contraindicated in: Hypersensitivity to penicillins (cross-sensitivity exists to cephalosporins and other beta-lactams).
Use Cautiously in: Severe renal insufficiency (↓ dose if CCr <30 mL/min);Infectious mononucleosis, acute lymphocytic leukemia, or cytomegalovirus infection (↑ risk of rash); Obstetric / Lactation: Has been used safely.

Adverse Reactions/Side Effects

Central nervous system

  • seizures (high doses) (life-threatening)


  • pseudomembranous colitis (life-threatening)
  • diarrhea (most frequent)
  • nausea
  • vomiting
  • ↑ liver enzymes


  • rash (most frequent)
  • urticaria


  • blood dyscrasias


  • allergic reactions including anaphylaxis (life-threatening)
  • serum sickness (life-threatening)
  • superinfection


Drug-Drug interaction

Probenecid ↓ renal excretion and ↑ blood levels of amoxicillin—therapy may be combined for this purpose.May ↑ effect of warfarin.May ↓ effectiveness of oral contraceptives.Allopurinol may ↑ frequency of rash.


Most Infections
Oral (Adults) 250–500 mg q 8 hr or 500–875 mg q 12 hr (not to exceed 2–3 g/day).
Oral (Adults and Children ≥12 yr) Extended-release tablets (for Strep throat)—775 mg once daily for 10 days.
Oral (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.
Oral (Infants ≤3 mo and neonates) 20–30 mg/kg/day in divided doses q 12 hr.
H. Pylori
Oral (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
Oral (Adults) 2 g 1 hr prior to procedure.
Oral (Children) 50 mg/kg 1 hr prior to procedure (not to exceed adult dose).
Oral (Adults and Children ≥40 kg) single 3 g dose.
Oral (Children >2 yr and <40 kg) 50 mg/kg with probenecid 25 mg/kg as a single dose.

Renal Impairment

Oral (Adults CCr 10–30 mL/min) 250–500 mg q 12 hr.

Renal Impairment

Oral (Adults CCr <10 mL/min) 250–500 mg q 24 hr.

Availability (generic available)

Chewable tabletscherry, 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 suspensionstrawberry [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 combination drugs.

Nursing implications

Nursing assessment

  • Assess for infection (vital signs; appearance of wound, sputum, urine, and stool; WBC) at beginning of and throughout therapy.
  • Obtain a history before initiating therapy to determine previous use of and reactions to penicillins or cephalosporins. Persons with a negative history of penicillin sensitivity may still have an allergic response.
  • Observe for signs and symptoms of anaphylaxis (rash, pruritus, laryngeal edema, wheezing). Notify health care professional immediately if these occur.
  • Obtain specimens for culture and sensitivity prior to therapy. First dose may be given before receiving results.
  • Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of pseudomembranous colitis. May begin up to several weeks following cessation of therapy.
  • Lab Test Considerations: May cause ↑ serum alkaline phosphatase, LDH, AST, and ALT concentrations.
    • May cause false-positive direct Coombs’ test result.

Potential Nursing Diagnoses

Risk for infection (Indications,  Side Effects)
Noncompliance (Patient/Family Teaching)


  • Oral: Administer around the clock. May be given without regard to meals or with meals to decrease GI side effects. Capsule contents may be emptied and swallowed with liquids. Extended-release tablets should be swallowed whole; do not crush, break, or chew. Chewable tablets should be crushed or chewed before swallowing with liquids.
    • Shake oral suspension before administering. Suspension may be given straight or mixed in formula, milk, fruit juice, water, or ginger ale. Administer immediately after mixing. Discard refrigerated reconstituted suspension after 10 days.

Patient/Family Teaching

  • Instruct patients 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 may be dangerous.
  • Pediatric: Teach parents or caregivers to calculate and measure doses accurately. Reinforce importance of using measuring device supplied by pharmacy or with product, not household items.
  • Advise patient to report the signs of superinfection (furry overgrowth on the tongue, vaginal itching or discharge, loose or foul-smelling stools) and allergy.
  • Instruct patient to notify health care professional immediately if diarrhea, abdominal cramping, fever, or bloody stools occur and not to treat with antidiarrheals without consulting health care professional.
  • Instruct the patient to notify health care professional if symptoms do not improve.
  • Teach patients with a history of rheumatic heart disease or valve replacement the importance of using antimicrobial prophylaxis before invasive medical or dental procedures.
  • Instruct female patients taking oral contraceptives to use an alternate or additional nonhormonal method of contraception during therapy with amoxicillin and until next menstrual period.

Evaluation/Desired Outcomes

  • Resolution of the signs and symptoms of infection. Length of time for complete resolution depends on the organism and site of infection.
  • Endocarditis prophylaxis.
  • Eradication of H. pylori with resolution of ulcer symptoms.
  • Prevention of inhalational anthrax (postexposure).
Drug Guide, © 2015 Farlex and Partners
References in periodicals archive ?
The oral suspensions involved are Polymox, Trimox, Betapen V/K, Veetids, Principen and Polycillin, Polycillin V/K, Prostaphin, Dynapen and Tegopen.
These pharmaceuticals include Desyrel (trazodone HCl, an antidepressant), Amikin (amikacin sulfate), Naldecon (an O-T-C cough/cold remedy), atenolol and diltiazem (antihypertensives) and Trimox (a leading brand of amoxicillin).