Amoxicillin is a penicillin derivative used to treat infections caused by gram-positive bacteria, especially streptococci, which cause upper respiratory tract infections.
Amoxicillin is rapidly and well absorbed from the gastrointestinal tract. Bioavailability is about 70% (orally). The time to reach maximum plasma concentration is approximately 1-2 hours (orally). Amoxicillin is easily distributed in the gallbladder, abdominal tissues, lungs, liver, prostate gland, middle ear effusion, maxillary sinus secretions, skin, adipose, bone, muscle tissues, peritoneum and synovial fluid, bile, pus. Poor permeability of the brain and cerebrospinal fluid (except in cases of inflammation of the meninges). Penetrates through the placenta and passes into breast milk (in small amounts). The volume of distribution is approximately 0.3–0.4 l/kg. Plasma protein binding is about 20%. Amoxicillin is metabolized (in small amounts) to inactive penicillazole by hydrolysis. Excreted in the urine (60% in the original dosage form). The half-life is about 1 hour.
Amoxicillin may have side effects such as upset stomach, nausea and vomiting, rash, loose stools, taste changes, and headache.
Amoxicillin is available in India, USA, Canada, Malaysia, Japan, Switzerland, Germany, France, Russia, China, Italy, Spain and Australia.
Amoxicillin competitively inhibits penicillin-binding protein 1 and other high molecular weight penicillin-binding proteins. Penicillin-binding proteins are responsible for the glycosyltransferase and transpeptidase reactions that lead to the cross-linking of D-alanine and D-aspartate in the bacterial cell wall. Without the action of penicillin-binding proteins, bacteria would activate autolysozymes, unable to build and repair cell walls, which would lead to a bactericidal effect.
Amoxicillin is an antibiotic. It is used to treat various types of bacterial infections of the throat, lungs, ears, nose, urinary tract, and skin. Amoxicillin is also used with other medicines to stop the growth of Helicobacter pylori, which causes stomach ulcers.
Amoxicillin inhibits bacterial cell wall synthesis by binding to one or more penicillin-binding proteins (PBPs), thereby inhibiting the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall, thereby inhibiting cell wall biosynthesis. Due to the continued activity of cell wall autolysins (autolysins and murein hydrolases), the bacteria eventually lyse while cell wall assembly is prevented.
Oral: 500 mg 3-4 times daily or 1 g 3 times daily; case reports have used higher doses of 4–6 g/day in divided doses. The optimal duration has not been determined; some experts suggest a total duration of 2 to 6 months for mild infections and 6 to 12 months for severe or widespread infections.
Oral: 1 g every 8 hours; duration depends on anthrax vaccine status and series completion, age, immunization status, and pregnancy/lactation status. For people not previously vaccinated against anthrax, the duration is 42 to 60 days.
Oral: 1 gram every 8 hours; the duration is 7 to 10 days after natural contamination and 60 days after a biological weapons incident.
Oral: 60 days after exposure, 75 mg/kg/day in divided doses every 8 hours; maximum dose: 1000 mg/dose.
Oral: 75 mg/kg/day in divided doses every 8 hours; maximum dose: 1000 mg/dose. Duration of treatment: 7 to 10 days for naturally acquired infections and up to 60 days for contact with biological weapons.
Oral: 75 mg/kg/day in divided doses every 8 hours as part of appropriate combination therapy to complete a 60-day course; maximum dose: 1000 mg/dose.
Oral: According to experts: 500 mg twice a day. The duration varies depending on individual factors.
Treatment of pulmonary exacerbations in patients without β-lactamase-positive Haemophilus influenzae or Pseudomonas aeruginosa
Oral: 2 g 30–60 minutes before surgery; if accidentally not taken before surgery, can be given within 2 hours after surgery.
Oral: 50 mg/kg/day divided into doses every 8 hours; maximum dose: 500 mg/dose. The duration of treatment depends on the clinical symptoms: 14 days for erythema migrans and borreliosis lymphoma, 14–21 days for carditis, 28 days for arthritis (initial, recurrent or refractory), 28 days for chronic atrophic dermatitis of the extremities, 21–28 days.
Oral: 500 mg every 8 hours plus metronidazole for 14 days or until clinical remission, whichever is longer; used in addition to periodontal sanitation.
Oral: single dose of 50 mg/kg 30–60 minutes before dental procedures; maximum dose: 2000 mg/dose.
Empiric outpatient therapy (patients without comorbidities or risk factors for developing antibiotic-resistant pathogens)
Orally: 1 g 3 times a day; some experts use lower doses (500 mg 3 times a day or 875 mg 3 times a day 2 times a day).
Children and adolescents over 2 years of age: Oral: 80–90 mg/kg/day in divided doses every 12 hours; maximum dose: 2000 mg/dose.
Oral: 500 mg 3 times a day or 875 mg 2 times a day; the total duration is 5 days, which can be extended to 14 days for slow response, severe infection, or immunosuppression.
Oral: 50 mg/kg/day once a day or in divided doses every 12 hours for 10 days; maximum daily dose: 1000 mg/day.
Oral: 50 to 100 mg/kg/day in divided doses every 8 hours; maximum dose: 500 mg/dose; in uncomplicated cystitis, 30 mg/kg per day in divided doses every 8 hours may be considered.
Amoxicillin has various specifications such as 250mg; 500 mg; 125 mg/5 ml; 50 mg/ml; 250 mg/5 ml; 125 mg; 200 mg; 400 mg; 875 mg; 200 mg/5 ml; 400 mg/5 ml; 600 mg; 775 mg.
Serious and sometimes fatal allergic reactions have been reported in patients treated with penicillins, including amoxicillin. Hypersensitivity reactions have also been observed in patients treated with oral penicillin, although anaphylaxis is more common after parenteral treatment. These reactions are more likely to occur in individuals with a history of penicillin allergy and/or hypersensitivity to multiple allergens. Serious reactions to cephalosporins have been reported in individuals with a history of penicillin allergy. Before initiating amoxicillin therapy, prior allergic reactions to penicillins, cephalosporins, or other allergens should be carefully investigated.
Clostridium difficile associated diarrhea (CDAD) has been reported with virtually all antimicrobials, including amoxicillin, and can range in severity from mild diarrhea to fatal colitis. Antimicrobial therapy alters the normal flora of the colon, leading to overgrowth of C. difficile. Clostridium difficile produces toxins A and B, which contribute to the development of CDAD. High toxin strains of C. difficile are associated with increased morbidity and mortality because these infections may not respond to antimicrobial therapy and may require colectomy. CDAD should be considered in all patients with diarrhea following antimicrobial use. Careful history taking is essential, as CDAD has been reported 2 months after antibiotic use. If CDAD is suspected or confirmed, continuous non-C. difficile antibiotics may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, C. difficile antibiotic therapy, and surgical examination should be performed as clinically indicated.
Prescribing amoxicillin without a proven or strongly suspected bacterial infection is unlikely to benefit patients and increase the risk of developing resistant bacteria.
Erythematous rashes develop in a significant proportion of patients with mononucleosis receiving amoxicillin. Therefore, people with mononucleosis should not take amoxicillin.
Amoxicillin chewable tablets contain aspartame, which contains phenylalanine. Each 200 mg chewable tablet contains 1.82 mg phenylalanine; each 400 mg chewable tablet contains 3.64 mg of phenylalanine. Amoxicillin oral suspension does not contain phenylalanine and can be used in patients with phenylketonuria.
Penicillin has been shown to be excreted in breast milk. The use of amoxicillin by nursing mothers can cause allergic reactions in infants. Caution should be exercised when prescribing amoxicillin to lactating women.
Reproduction studies have been performed in mice and rats at doses up to 2000 mg/kg (3 and 6 times the human dose of 3 g based on body surface area). There is no evidence that amoxicillin can harm a fetus. However, there are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, amoxicillin should only be used during pregnancy if clearly needed.
Probenecid reduces tubular secretion of amoxicillin. The simultaneous use of amoxicillin and probenecid can lead to an increase and prolongation of the concentration of amoxicillin in the blood.
Abnormally prolonged prothrombin time (increased international normalized ratio [INR]) has been reported in patients treated with amoxicillin and oral anticoagulants. With the simultaneous use of anticoagulants, appropriate monitoring should be carried out. To maintain the desired level of anticoagulants, dose adjustment of oral anticoagulants may be required.
Co-administration of allopurinol and amoxicillin increased the incidence of rash in patients treated with both drugs compared with patients treated with amoxicillin alone. It is unclear whether the exacerbation of the amoxicillin rash was caused by allopurinol or by the hyperuricemia present in these patients.
Amoxicillin may affect the gut microbiota, leading to a decrease in estrogen reabsorption and a decrease in the effectiveness of combined oral estrogen/progesterone contraceptives.
Chloramphenicol, macrolides, sulfonamides and tetracyclines may interfere with the bactericidal action of penicillin. This has been demonstrated in vitro; however, the clinical significance of this interaction has not been well documented.
Teratogenicity: Reproductive studies have been conducted in mice and rats at doses up to 2000 mg/kg (3 and 6 times the human dose of 3 g based on body surface area). There is no evidence that amoxicillin can harm a fetus. However, there are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, amoxicillin should only be used during pregnancy if clearly needed.
Penicillin has been shown to be excreted in breast milk. The use of amoxicillin by nursing mothers can cause allergic reactions in infants. Caution should be exercised when prescribing amoxicillin to lactating women.
Elimination of amoxicillin may be delayed due to incomplete kidney development in neonates and young children. For children aged 12 weeks and younger (< 3 months), the dose of amoxicillin should be adjusted.
Clinical trials of amoxicillin were analyzed to determine if subjects aged 65 years and older responded differently than younger subjects. These analyzes did not reveal differences in response between older and younger patients, but higher sensitivity in some older patients cannot be ruled out.
Symptoms: Nausea, vomiting, diarrhea, violation of water and electrolyte balance; crystalluria leading to renal failure (in some cases) and convulsions.
Treatment: Symptomatic and supportive therapy. Keep track of the water and electrolyte balance. Maintain adequate fluid intake and diuresis. Hemodialysis may be considered to remove it from the circulation.
Competitive inhibition of penicillin-binding proteins by amoxicillin results in upregulation of autolysozymes and inhibition of cell wall synthesis. Amoxicillin lasts longer and is usually taken twice a day. Amoxicillin has a wide therapeutic window because mild overdose does not cause significant toxicity. Patients should be informed of the risks of allergic reactions, Clostridium difficile infection and bacterial resistance.
Amoxicillin is rapidly and well absorbed from the gastrointestinal tract. Bioavailability is about 70% (orally). The time to reach maximum plasma concentration is approximately 1-2 hours (orally).
Amoxicillin is easily distributed in the gallbladder, abdominal tissues, lungs, liver, prostate gland, middle ear effusion, maxillary sinus secretions, skin, adipose, bone, muscle tissues, peritoneum and synovial fluid, bile, pus. Poor permeability of the brain and cerebrospinal fluid (except in cases of inflammation of the meninges). Penetrates through the placenta and passes into breast milk (in small amounts). The volume of distribution is approximately 0.3–0.4 l/kg. Plasma protein binding is about 20%.
Amoxicillin is metabolized (in small amounts) to inactive penicillazole by hydrolysis. Excreted in the urine (60% in the original dosage form). The half-life is about 1 hour.
Post time: Sep-07-2023