TRIMOX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIMOX (TRIMOX).
Amoxicillin is a semisynthetic penicillin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking, leading to cell lysis and death.
| Metabolism | Amoxicillin undergoes partial hepatic metabolism via hydrolysis of the beta-lactam ring to inactive penicilloic acid. The major route of elimination is renal excretion via tubular secretion and glomerular filtration, with about 60% excreted unchanged in urine. |
| Excretion | Renal: 50-85% unchanged via glomerular filtration and tubular secretion; biliary/fecal: minimal, <5%. |
| Half-life | Terminal elimination half-life: 1-1.5 hours (normal renal function); in renal impairment (CrCl <10 mL/min), extends to 6-20 hours, requiring dose adjustment. |
| Protein binding | ~18% bound, primarily to albumin. |
| Volume of Distribution | 0.2-0.4 L/kg; distributes well into interstitial fluid, with low CNS penetration unless inflamed meninges. |
| Bioavailability | Oral: 60-75% (fasting); reduced with food. IM: ~100%. |
| Onset of Action | PO: 30-60 minutes for peak serum levels; IV: immediate for therapeutic levels. |
| Duration of Action | 4-6 hours for susceptible organisms; sustained with probenecid co-administration. |
| Action Class | Cell wall active agent -Extended spectrum Penicillin |
| Brand Substitutes | Almox 500 Capsule, Cipmox 500 Capsule, Tidoxyl 500mg Capsule, Actimox 500mg Capsule, SB Mox 500mg Capsule, Amoxipen 250mg Capsule, Hipen A 250mg Capsule, Moxipal 250mg Capsule, Amoxil 250mg Capsule, Moxikem 250mg Capsule |
250-500 mg orally every 8 hours or 500-875 mg orally every 12 hours depending on infection severity.
| Dosage form | CAPSULE |
| Renal impairment | CrCl 10-30 mL/min: 250-500 mg every 12 hours; CrCl <10 mL/min: 250-500 mg every 24 hours. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment. Not studied in severe impairment; use with caution. |
| Pediatric use | 20-40 mg/kg/day in divided doses every 8 hours for mild to moderate infections; up to 80-90 mg/kg/day for severe infections. |
| Geriatric use | No specific dose adjustment based on age alone; adjust dose based on renal function as elderly often have reduced CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TRIMOX (TRIMOX).
| Breastfeeding | Amoxicillin is excreted into human breast milk in small amounts. The milk-to-plasma (M/P) ratio is approximately 0.01–0.02. The estimated daily dose received by the infant is less than 1% of the maternal weight-adjusted dose, which is well below therapeutic levels. The American Academy of Pediatrics considers amoxicillin compatible with breastfeeding. However, there is a potential for alteration of infant gut flora or allergic sensitization, though these are rare. Monitoring for diarrhea, rash, or candidiasis in the infant is advised. |
| Teratogenic Risk | Amoxicillin (TRIMOX) is a penicillin-class antibiotic classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate and well-controlled studies in pregnant women. However, amoxicillin is considered safe for use during pregnancy when clinically indicated. No specific teratogenic effects have been consistently associated with first-trimester exposure. During the second and third trimesters, use is also considered low risk, though theoretical concerns about alteration of neonatal gut microbiota exist. Overall, the benefits generally outweigh the risks for treating maternal infections. |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients on penicillin therapy. These reactions are more likely to occur in individuals with a history of penicillin hypersensitivity and/or sensitivity to multiple allergens. Before initiating therapy, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens.
| Serious Effects |
["History of allergic reaction to any penicillin","History of hypersensitivity to cephalosporins (cross-sensitivity)"]
| Precautions | ["Severe and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported","Clostridium difficile-associated diarrhea (CDAD) has been reported and may range in severity from mild diarrhea to fatal colitis","Use with caution in patients with renal impairment; dose adjustment may be necessary","Prolonged use may result in overgrowth of non-susceptible organisms, including fungi","Rashes may occur more frequently in patients with infectious mononucleosis","Serum sickness-like reactions have been reported"] |
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| Fetal Monitoring | No specific fetal monitoring is required for amoxicillin use during pregnancy. Routine prenatal care is sufficient. For maternal monitoring, assess for signs of allergic reaction (rash, urticaria, anaphylaxis) and gastrointestinal side effects. In pregnant patients, monitor renal function and consider potential interactions with other medications. No additional surveillance beyond standard obstetric care is needed. |
| Fertility Effects | No adverse effects on fertility have been reported with amoxicillin. Penicillin antibiotics are not known to impair reproductive function in males or females. There is no evidence of ovulatory dysfunction, spermatogenesis impairment, or hormonal disruption. Amoxicillin is not considered to have any significant impact on fertility in either sex. |