MOXATAG
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MOXATAG (MOXATAG).
Amoxicillin (extended-release) inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation and autolysin inhibitors, leading to cell lysis and death via activation of autolytic enzymes.
| Metabolism | Amoxicillin is primarily metabolized by hydrolysis to penicilloic acid, which is then excreted renally. Minor metabolism via hepatic pathways. |
| Excretion | Approximately 60% of the dose is excreted unchanged in urine via glomerular filtration and tubular secretion; about 20% is excreted in feces via biliary elimination. |
| Half-life | The terminal elimination half-life is 1.0–1.5 hours in healthy adults; however, with the extended-release formulation (Moxatag), the effective half-life is prolonged to support once-daily dosing. |
| Protein binding | Approximately 20% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.2–0.3 L/kg, indicating distribution primarily into extracellular fluid; clinical meaning: low Vd reflects limited tissue penetration. |
| Bioavailability | Oral bioavailability of amoxicillin is about 95% (range 74–92% for immediate-release); Moxatag ER has similar overall absorption but with extended-release characteristics. |
| Onset of Action | Oral: Peak serum concentrations are achieved in 1–2 hours for standard immediate-release; Moxatag extended-release reaches peak at approximately 3 hours. |
| Duration of Action | The extended-release formulation provides therapeutic concentrations for 24 hours, allowing once-daily administration for the treatment of pharyngitis/tonsillitis due to Streptococcus pyogenes. |
775 mg orally once daily for 7 days.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | For CrCl 30-60 mL/min: 775 mg orally once daily; for CrCl <30 mL/min: no data available, use with caution. For hemodialysis: not recommended. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B); no data for severe impairment (Child-Pugh C). |
| Pediatric use | Not approved for pediatric patients under 18 years. Safety and efficacy not established. |
| Geriatric use | No specific dose adjustment; however, consider renal function due to age-related decline. Use same dose as adults if normal renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MOXATAG (MOXATAG).
| Breastfeeding | Excreted in human milk in low amounts; M/P ratio unknown. Caution advised; consider risk of diarrhea, candidiasis, or allergic sensitization in infant. |
| Teratogenic Risk | Teratogenic risk category B. No evidence of fetal harm in animal studies; no adequate human studies. Potential risk cannot be ruled out. Use only if clearly needed. |
| Fetal Monitoring | Monitor for maternal gastrointestinal disturbances, hypersensitivity reactions, and signs of superinfection. Fetal monitoring not routinely required. |
■ FDA Black Box Warning
None
| Common Effects | Nausea Diarrhea Skin rash Vomiting |
| Serious Effects |
["History of serious hypersensitivity reaction (e.g., anaphylaxis, Stevens-Johnson syndrome) to amoxicillin, other penicillins, or cephalosporins.","Known hypersensitivity to any component of the formulation (e.g., clavulanate if combination product)."]
| Precautions | ["Serious hypersensitivity reactions (anaphylaxis) reported; contraindicated in patients with known hypersensitivity to penicillins or cephalosporins.","Clostridium difficile-associated diarrhea (CDAD) may occur; evaluate if diarrhea develops.","Prolonged use may result in bacterial or fungal superinfection.","Use with caution in patients with renal impairment; dose adjustment recommended for CrCl <30 mL/min.","Not recommended for patients with mononucleosis due to high incidence of maculopapular rash."] |
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| Fertility Effects | No known adverse effects on fertility based on animal studies; human data lacking. |