Amoxicillin


Generic Medicine Info
Indications and Dosage
Intramuscular, Intravenous
Bacterial meningitis
Adult: In combination with another antibiotic if needed: 1,000-2,000 mg 4-6 hourly via slow IV inj over 3-4 minutes or IV infusion over 20-60 minutes. Doses may also be given via IM inj if IV route is impossible or less appropriate for the patient. Max: 12,000 mg daily (IV); 4,000 mg daily (IM); 1,000 mg (single IM dose). Consideration must be given to local treatment guidelines.

Intramuscular, Intravenous
Endocarditis
Adult: Treatment: 1,000-2,000 mg 4-6 hourly via slow IV inj over 3-4 minutes or IV infusion over 20-60 minutes. Doses may also be given via IM inj if IV route is impossible or less appropriate for the patient. Max: 12,000 mg daily (IV); 4,000 mg daily (IM); 1,000 mg (single IM dose). Prophylaxis in patients at highest risk of infective endocarditis: 2,000 mg as a single IV dose 30-60 minutes prior to the procedure. Consideration must be given to local treatment guidelines.
Child: Treatment: ≥40 kg: Same as adult dose. Prophylaxis in patients at highest risk of infective endocarditis: >3 months <40 kg: 50 mg/kg as a single IV dose 30-60 minutes prior to the procedure; ≥40 kg: Same as adult dose.

Intramuscular, Intravenous
Acute cystitis, Acute exacerbations of chronic bronchitis, Acute pyelonephritis, Community-acquired pneumonia, Dental abscess with spreading cellulitis, Ear, nose and/or throat infections, Prosthetic joint infection
Adult: 750-2,000 mg 8 hourly or 2,000 mg 12 hourly via slow IV inj over 3-4 minutes or IV infusion over 20-60 minutes. Doses may also be given via IM inj if IV route is impossible or less appropriate for the patient. Max: 12,000 mg daily (IV); 4,000 mg daily (IM); 1,000 mg (single IM dose). Consideration must be given to local treatment guidelines.
Child: 1-3 months 20-150 mg/kg daily given in 3 equally divided doses of up to 25 mg/kg or infusion of up to 50 mg/kg; >3 months <40 kg: 20-200 mg/kg daily given in 2-4 equally divided doses of up to 25 mg/kg or infusions of up to 50 mg/kg. Max: 120 mg/kg daily in 2-6 equally divided doses (IM); ≥40 kg: Same as adult dose.

Intravenous
Lyme disease
Adult: In late stage (systemic involvement): 2,000 mg 8 hourly via slow IV inj over 3-4 minutes or IV infusion over 20-60 minutes. Consideration must be given to local treatment guidelines.
Child: >3 months <40 kg: In early stages: 25-50 mg/kg daily given in 3 divided doses for 10 days (range: 10-21 days). In late stages (systemic involvement): 50 mg/kg daily given in 3 divided doses; ≥40 kg: Same as adult dose.

Oral
Acute streptococcal pharyngitis, Acute streptococcal tonsillitis
Adult: 500 mg 8 hourly or 750-1,000 mg 12 hourly. For severe infections: 750-1,000 mg 8 hourly for 10 days. Consideration must be given to local treatment guidelines.
Child: <40 kg: 40-90 mg/kg daily in divided doses; ≥40 kg: Same as adult dose.

Oral
Community-acquired pneumonia
Adult: 500-1,000 mg 8 hourly. Consideration must be given to local treatment guidelines.
Child: <40 kg: 20-90 mg/kg daily in divided doses; ≥40 kg: Same as adult dose.

Oral
Prophylaxis of endocarditis
Adult: 2,000 mg as a single dose 30-60 minutes prior to the procedure. Consideration must be given to local treatment guidelines.
Child: <40 kg: 50 mg/kg as a single dose 30-60 minutes prior to the procedure; ≥40 kg: Same as adult dose.

Oral
Acute bacterial sinusitis, Acute cystitis, Acute otitis media, Acute pyelonephritis, Dental abscess with spreading cellulitis, Ear, nose and/or throat infections, Genitourinary infections, Skin and soft tissue infections
Adult: 250-500 mg 8 hourly or 750-1,000 mg 12 hourly. For severe infections: 750-1,000 mg 8 hourly. Consideration must be given to local treatment guidelines.
Child: <40 kg: 20-90 mg/kg daily in divided doses; ≥40 kg: Same as adult dose.

Oral
Acute exacerbations of chronic bronchitis, Asymptomatic bacteriuria in pregnancy
Adult: 250-500 mg 8 hourly or 750-1,000 mg 12 hourly. For severe infections: 750-1,000 mg 8 hourly. Consideration must be given to local treatment guidelines.

Oral
Lyme disease
Adult: In early stages: 500-1,000 mg 8 hourly for 14 days (range: 10-21 days). Max: 4,000 mg daily in divided doses. In late stages (systemic involvement): 500-2,000 mg 8 hourly for 10-30 days. Max: 6,000 mg daily in divided doses. Consideration must be given to local treatment guidelines.
Child: <40 kg: In early stages: 25-50 mg/kg daily in 3 divided doses for 10-21 days. In late stages (systemic involvement): 100 mg/kg daily in 3 divided doses for 10-30 days. ≥40 kg: Same as adult dose.

Oral
Eradication of Helicobacter pylori associated with peptic ulcer disease
Adult: In combination with PPI (e.g. omeprazole, lansoprazole) and another antibiotic (e.g. clarithromycin, metronidazole): 750-1,000 mg bid for 7-14 days depending on therapy regimen. Consideration must be given to local treatment guidelines.

Oral
Paratyphoid fever, Typhoid fever
Adult: 500-2,000 mg 8 hourly. Consideration must be given to local treatment guidelines.
Child: <40 kg: 100 mg/kg daily in 3 divided doses; ≥40 kg: Same as adult dose.

Oral
Uncomplicated gonorrhoea
Adult: In patients with susceptible non-penicillinase-producing Neisseria gonorrhoeae strains: 3 g as a single dose in combination with probenecid. Consideration must be given to local treatment guidelines.
Renal Impairment
Oral:
Patients undergoing haemodialysis: Adults and children ≥40 kg: 250 mg or 500 mg 24 hourly, and give an additional dose prior to and after dialysis; Children <40 kg: 15 mg/kg (Max of 500 mg) once daily, and give an additional 15 mg/kg dose prior to and after dialysis. GFR <10 mL/min and/or patients on peritoneal dialysis: Adults and children ≥40 kg: Max: 500 mg daily; Children <40 kg: 15 mg/kg (Max of 500 mg) daily. GFR 10-30 mL/min: Adults and children ≥40 kg: Max: 500 mg bid; Children <40 kg: 15 mg/kg bid (Max of 500 mg bid).

Intravenous/Intramuscular:
Patients undergoing haemodialysis: Adults and children ≥40 kg: 1,000 mg at the end of dialysis, then 500 mg 24 hourly via IV. Alternatively, 500 mg during and at the end of dialysis, then 500 mg 24 hourly via IM; Children <40 kg: 25 mg/kg as an IV loading dose and an additional 12.5 mg/kg dose at the end of dialysis, followed by 25 mg/kg daily via IV. Alternatively, 15 mg/kg during and at the end of dialysis, then 15 mg/kg 24 hourly via IM. GFR <10 mL/min and patients on peritoneal dialysis: Adults and children ≥40 kg: 1,000 mg as an IV loading dose then 500 mg daily via IV, or 500 mg daily as a single IM dose; Children <40 kg: 25 mg/kg daily as single IV dose, or 15 mg/kg daily as single IM dose. GFR 10-30 mL/min: Adults and children ≥40 kg: 1,000 mg as an IV loading dose followed by 500-1,000 mg bid via IV. Alternatively, 500 mg 12 hourly via IM; Children <40 kg: 25 mg/kg bid via IV. Alternatively, 15 mg/kg 12 hourly via IM.
Administration
May be taken with or without food. May be taken w/ meals for better absorption & to reduce GI discomfort.
Reconstitution
Powder for oral susp: Reconstitute with the appropriate volume of water as indicated on the label. Shake vigorously until suspended. Powder for solution for inj or infusion: IV inj: Reconstitute a vial labelled as 250 mg with 5 mL, 500 mg with 10 mL, and 1,000 mg with 20 mL of sterile water for inj to make a final volume of 5.2 mL, 10.4 mL, and 20.8 mL, respectively. IV infusion: Further dilute the reconstituted solution with compatible IV infusion fluids (e.g. NaCl 0.9% inj). IM inj: Reconstitute a vial labelled as 250 mg with 1.5 mL and 500 mg with 2.5 mL of sterile water for inj to make a final volume of 1.7 mL and 2.9 mL, respectively. Shake the vial vigorously. Refer to local detailed product guidelines for compatible infusion fluids and their stability.
Incompatibility
Powder for solution for inj or infusion: Incompatible with blood products, other proteinaceous fluids (e.g. protein hydrolysates), IV lipid emulsions, infusions containing dextran or bicarbonate, ciprofloxacin, and aminoglycosides (in the same syringe or IV fluid container).
Contraindications
Hypersensitivity or history of severe allergic reactions (e.g. anaphylaxis, Stevens-Johnson syndrome) to amoxicillin or other β-lactams (e.g. penicillins, cephalosporins, carbapenems, monobactams). Suspected or confirmed infectious mononucleosis.
Special Precautions
Patient with reduced urine output, history of seizures, treated epilepsy or meningeal disorders; lymphatic leukaemia. Atopic individuals. Renal and hepatic impairment. Neonates and children. Pregnancy and lactation.
Adverse Reactions
Significant: Erythematous or morbilliform rash (particularly in patients with infectious mononucleosis), Jarisch-Herxheimer reaction (in treatment of Lyme disease); aseptic meningitis, convulsion (during high doses or in renal impairment), gastrointestinal effects (e.g. diarrhoea, nausea, vomiting), fungal or bacterial superinfection (prolonged use). Rarely, prolonged prothrombin time; crystalluria (mostly with high parenteral doses in patients with reduced urine output).
Blood and lymphatic system disorders: Anaemia, neutropenia, thrombocytopenia, leucopenia, agranulocytosis.
Gastrointestinal disorders: Tooth discolouration (brown, yellow, or grey staining) particularly in children. Rarely, black hairy tongue.
Hepatobiliary disorders: Cholestatic jaundice, hepatitis.
Infections and infestations: Very rarely, mucocutaneous candidiasis.
Investigations: Moderately increased AST and ALT.
Nervous system disorders: Dizziness. Rarely, hyperkinesia.
Psychiatric disorders: Insomnia, reversible hyperactivity, anxiety, confusion, behavioural changes.
Renal and urinary disorders: Very rarely, interstitial nephritis.
Respiratory, thoracic and mediastinal disorders: Bronchospasm, acute severe dyspnoea and allergic pneumonitis (large IV doses).
Skin and subcutaneous tissue disorders: Rash, urticaria, pruritus.
Potentially Fatal: Hypersensitivity reactions including anaphylaxis, anaphylactoid and severe cutaneous adverse reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalised exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms); Clostridioides difficile-associated diarrhoea, Clostridioides difficile colitis.
Monitoring Parameters
Perform culture and susceptibility tests; consult local institutional recommendations before treatment initiation due to antibiotic resistance risks. Evaluate the patient's allergy history before treatment initiation. Monitor renal, hepatic, and haematologic (e.g. CBC with differential) functions periodically with prolonged therapy; electrolyte balance. Assess the patient for opportunistic infection throughout therapy; signs and symptoms of anaphylaxis (during initial dose), skin rash, and antibiotic-associated diarrhoea.
Overdosage
Symptoms: Nausea, vomiting, diarrhoea, and disturbance in fluid and electrolyte balances; crystalluria leading to renal failure (in some cases). Management: Symptomatic and supportive treatment. Monitor water or electrolyte balance. Maintain adequate fluid intake and diuresis to decrease the risk of crystalluria. May consider haemodialysis for removal from the circulation.
Drug Interactions
Decreased renal tubular secretion resulting in increased and prolonged serum concentration with probenecid. Increased risk of allergic reactions (e.g. rashes) with allopurinol. Tetracyclines, chloramphenicol, macrolides, and sulfonamides may interfere with the bactericidal effect of amoxicillin. May prolong prothrombin time or increase INR when used with oral anticoagulants (e.g. warfarin, acenocoumarol). May reduce the excretion and increase the toxicity of methotrexate. May reduce the efficacy of oral contraceptives (e.g. estrogen/progesterone combination).
Lab Interference
May result in false-positive reactions with urinary glucose tests using Benedict's solution or Fehling's solution. May interfere with the result of the assay for estriol in pregnant women.
Action
Description:
Mechanism of Action: Amoxicillin, an aminopenicillin, is a semisynthetic β-lactam antibiotic that inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls by binding to 1 or more of the penicillin-binding proteins (PBPs), thereby inhibiting cell wall biosynthesis and causing eventual bacterial lysis.
Pharmacokinetics:
Absorption: Rapidly and well absorbed from the gastrointestinal tract. Well absorbed after IM administration. Bioavailability: Approx 70% (oral). Time to peak plasma concentration: 1-2 hours (cap, conventional and dispersible tab, oral susp); 1 hour (chewable tab).
Distribution: Readily distributed in the middle ear effusions, maxillary sinus secretions, lungs, gall bladder, bile, liver, prostate, abdominal tissue, skin, fat, muscle tissues, bone, pus, peritoneal and synovial fluids; poor penetration into the brain and CSF (except when meninges are inflamed). Crosses the placenta; enters breast milk (small amounts). Volume of distribution: Approx 0.3-0.4 L/kg. Plasma protein binding: Approx 20%.
Metabolism: Metabolised via hydrolysis (small amount) to inactive penicilloic acid.
Excretion: Via urine (60% as unchanged drug). Elimination half-life: Approx 1 hour.
Chemical Structure

Chemical Structure Image
Amoxicillin

Source: National Center for Biotechnology Information. PubChem Database. Amoxicillin, CID=33613, https://pubchem.ncbi.nlm.nih.gov/compound/Amoxicillin (accessed on Jan. 20, 2020)

Storage
Cap, conventional/chewable tab, powder for oral susp: Store between 20-25°C. Protect from light. Reconstituted oral susp is stable for 14 days when stored between 2-8°C (preferred) or below 30°C. Dispersible tab: Store below 25°C. Protect from moisture. Powder for inj or infusion: Store below 25°C. Protect from moisture and light. Use the reconstituted IV or IM solution immediately after preparation. Storage and stability recommendations may vary between individual products or countries (refer to detailed product guidelines).
MIMS Class
Penicillins
ATC Classification
J01CA04 - amoxicillin ; Belongs to the class of penicillins with extended spectrum. Used in the systemic treatment of infections.
References
Amoxicillin 1,000 mg Dispersible Tablets (Special Concept Development [UK] Limited). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Amoxicillin 250 mg Film-coated Tablets (Vivalabs Europe Limited). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Amoxicillin 250 mg/5 mL Oral Suspension (Bristol Laboratories Ltd). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Amoxicillin 500 mg Hard Capsules (Gaelic Laboratories Limited). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Amoxicillin Sodium 500 mg Powder for Solution for Injection (Wockhardt UK Ltd). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Amoxicillin Tablet, Film Coated; Amoxicillin Powder, for Suspension; Amoxicillin Tablet, Chewable; Amoxicillin Capsule (Teva Pharmaceuticals USA, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 12/04/2023.

Amoxicillin. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 12/04/2023.

Anon. Amoxicillin (Pediatric and Neonatal Lexi-Drugs). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 12/04/2023.

Anon. Amoxicillin. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 12/04/2023.

Anon. Amoxicillin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 12/04/2023.

Buckingham R (ed). Amoxicillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 12/04/2023.

Douglas Pharmaceuticals Ltd. Ibiamox 250 mg, 500 mg and 1,000 mg Powder for Injection data sheet 07 June 2022. Medsafe. http://www.medsafe.govt.nz. Accessed 12/04/2023.

Himox (Asian Antibiotics, Inc.). MIMS Philippines. http://www.mims.com/philippines. Accessed 12/04/2023.

Joint Formulary Committee. Amoxicillin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 12/04/2023.

Respillin 3 g Sachet Sugar Free (Athlone Laboratories). MHRA. https://products.mhra.gov.uk. Accessed 12/04/2023.

Viatris Ltd. Alphamox 125 and 250 data sheet 18 September 2022. Medsafe. http://www.medsafe.govt.nz. Accessed 12/04/2023.

Z Mox Capsules 500 mg and 250 mg; Z Mox Oral Suspension 250 mg/5 mL (UNIMED SDN BHD). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 12/04/2023.

Disclaimer: This information is independently developed by MIMS based on Amoxicillin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by MIMS.com
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