Dosing and uses of Amoxil, Moxatag (amoxicillin)
Adult dosage forms and strengths
oral solution
- 125mg/5mL
- 200mg/5mL
- 250mg/5mL
- 400mg/5mL
capsule
- 250mg
- 500mg
tablet
- 500mg
- 875mg
tablet, chewable
- 125mg
- 250mg
extended-release (Moxatag)
- 775mg
Ear, Nose, & Throat Infections
Mild to moderate infections
- 500 mg PO q12hr or 250 mg PO q8hr for 10-14 days
Severe infections
- 875 mg PO q12hr or 500 mg PO q8hr for 10-14 days
Tonsillitis/pharyngitis
- Moxatag: 775 mg PO qDay for 10 days, taken within 1 hour after finishing a meal
Spectrum of action
- α- and β-hemolytic Strep, S pneumoniae, Staph spp, H influenzae
Genitourinary Tract Infections
Mild to moderate infections
- 500 mg PO q12hr or 250 mg PO q8hr
Severe infections
- 875 mg PO q12hr or 500 mg PO q8hr
Spectrum of action
- E coli, P mirabilis, or E faecalis
Skin & Skin Structure Infections
Mild to moderate infections
- 500 mg PO q12hr or 250 mg PO q8hr
Severe infections
- 875 mg PO q12hr or 500 mg PO q8hr
Spectrum of action
- α- and β-hemolytic Strep, Staph spp, E coli
Tonsilitis
775 mg (ER tabs) PO qDay for 10 days
Lower Respiratory Tract Infections
875 mg PO q12hr or 500 mg PO q8hr for 10-14 days
Spectrum of action
- α- and β-hemolytic Strep, S pneumoniae, Staph spp, H influenzae
Helicobacter Pylori
H pylori infection and active or 1-year history of duodenal ulcer
Triple therapy
- 1 g PO q12hr for 14 days with lansoprazole (30 mg) and clarithromycin (500 mg)
Dual therapy
- 1 g PO q8hr for 14 days with lansoprazole (30 mg) in patients intolerant of, or resistant to, clarithromycin
Anthrax
Postexposure inhalational prophylaxis
500 mg PO q8hr
Infective Endocarditis
Prophylaxis
2 g PO 30-60 min before procedure
Dosing considerations
- AHA guidelines recommend prophylaxis only in high-risk patients undergoing invasive procedures who have a history of cardiac conditions that predispose them to a risk of infection
Lyme Disease (Off-label)
Erythema migrans and other symptoms of early dissemination
500 mg PO q8hr (depending on size of patient) for 3-4wk
50 mg/kg/day q8hr in divided doses; maximum 500 mg/dose
Chlamydial Infection in Pregnant Women (Off-label)
First trimester: 500 mg PO q8hr for 7 days
Dosing considerations
- First trimester: Test to document chlamydial eradication and retest for infection 3 months after treatment
- Second or third trimester: Test to document chlamydial eradication
Administration
Take without regard to meals
Dosing Modifications
Renal impairment: Patients with impaired renal function do not generally require dose reduction unless impairment is severe; do not administer extended-release product in patients with CrCl <30 mL/min
GFR <30 mL/min: Should not receive 875 mg (immediate release) or 775 mg (extended release)
GFR 10-30 mL/min: 250-500 mg q12hr, depending on severity of infection
GFR <10 mL/min: 250-500 mg q24hr depending on severity of infection
Hemodialysis patients: 250-500 mg q24hr, depending on severity of infection; patients should receive additional dose during and at completion of dialysis; do not administer extended-release product or 875 mg immediate release
Pediatric dosage forms and strengths
oral solution
- 50mg/5mL
- 125mg/5mL
- 200mg/5mL
- 250mg/5mL
capsule
- 250mg
- 500mg
tablet
- 500mg
- 875mg
tablet, chewable
- 125mg
- 250mg
tablet, extended release (Moxatag)
- 775mg
Ear, Nose, & Throat Infections
Mild to moderate infections
- <3 months: ≤30 mg/kg/day PO divided q12hr for 48-72 hours; for ≥10 days for S pyogenes infections
- >3 months and <40 kg: 25 mg/kg/day PO divided q12hr or 20 mg/kg/day PO divided q8hr
- >40 kg: 500 mg PO q12hr or 250 mg PO q8hr for 10-14 days
Severe infections
- <3 months: ≤30 mg/kg/day PO divided q12hr for 48-72 hours; for ≥10 days for S pyogenes infections
- >3 months and <40 kg: 45 mg/kg/day PO divided q12hr or 40 mg/kg/day PO divided q8hr
- >40 kg: 875 mg PO q12hr or 500 mg PO q8hr for 10-14 days
Tonsillitis/Streptococcal pharyngitis
- 50 mg/kg PO qDay for 10 days, not to exceed 1 g/day, OR 25 mg/kg PO BID for 10 days, not to exceed 500 mg/dose
- >12 years: 775 mg (Moxatag) PO qDay for 10 days, taken within 1 hour after meal (swallow tablet whole; do not crush or chew)
Spectrum of action
- α- and β-hemolytic Streptococcus, S pneumoniae, Staphylococcus, H influenzae
Acute Otitis Media
>3 months and <40kg: 80-90 mg/kg/day PO divided q8-12hr
>40 kg: 500 mg PO q12hr or 250 mg PO q8hr for 10-14 days
Lower Respiratory Tract Infections
Mild, moderate, or severe infections
- <3 months: ≤30 mg/kg/day PO divided q12hr for 48-72 hours; for ≥10 days for S pyogenes infections
- >3 months and <40 kg: 45 mg/kg/day PO divided q12hr or 40 mg/kg/day PO divided q8hr
- >40kg: 875 mg PO q12hr or 500 mg PO q8hr for 10-14 days
Spectrum of action
- α- and β-hemolytic Streptococcus, S pneumoniae, Staphylococcus, H influenzae
Anthrax
Postexposure inhalational prophylaxis
<40 kg: 15 mg/kg PO q8hr (minimum recommended dose; should not be <45 mg/kg/day or >q8hr
>40 kg: 500 mg PO q8hr
80 mg/kg/day PO divided q8hr for 4 weeks (with concomitant vaccine) or for 60 days (without vaccine)
Infective Endocarditis
Prophylaxis
50 mg/kg PO 30-60 min before procedure
Dosing considerations
- AHA guidelines recommend prophylaxis only in high-risk patients undergoing invasive procedures with history of cardiac conditions that predispose them to infection
Lyme Disease
Erythema migrans and other symptoms of early dissemination
<3 months: Safety and efficacy not established
>3 months and 40 kg: 25-50 mg/kg/day divided q8hr; not to exceed 500 mg
Administration
Take without regard to meals
Mixing oral suspension: Tap bottle until all powder flows freely; add approximately one third of the total amount of water for reconstitution and shake vigorously to wet powder; add remainder of water and shake vigorously again
After reconstitution, place required amount of suspension directly on child’s tongue for swallowing; if taste is unacceptable, required amount of suspension can be added to formula, milk, fruit juice, water, ginger ale, or other cold drinks; preparation must be taken immediately
Shake suspension well before using; any unused portion must be discarded after 14 days
Amoxil, Moxatag (amoxicillin) adverse (side) effects
Frequency not defined
Anaphylaxis
Anemia
AST/ALT elevation
Mucocutaneous candidiasis
Diarrhea
Headache
Nausea
Vomiting
Rash
Pseudomembranous colitis
Serum sickness-like reactions
Postmarketing Reports
Mucocutaneous candidiasis
Gastrointestinal (eg, black hairy tongue and hemorrhagic/pseudomembranous colitis, which may occur during or after treatment)
Hypersensitivity reactions (eg, anaphylaxis, serum sickness–like reactions, erythematous maculopapular rashes, erythema multiforme, Stevens-Johnson syndrome, exfoliative dermatitis, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, hypersensitivity vasculitis, urticaria)
Moderate increase in AST and/or ALT; hepatic dysfunction (eg, cholestatic jaundice, hepatic cholestasis and acute cytolytic hepatitis have been reported)
Renal (eg, crystalluria)
Anemia (eg, hemolytic anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, agranulocytosis)
CNS reactions (eg, reversible hyperactivity, agitation, anxiety, insomnia, confusion, convulsions, behavioral changes, dizziness)
Tooth discoloration (brown, yellow, or gray staining); may be reduced or eliminated with brushing or dental cleaning
Warnings
Contraindications
Documented hypersensitivity to penicillins, cephalosporins, imipenem
Cautions
Anaphylaxis has been reported rarely but is more likely to occur following parenteral therapy with penicillins
Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents; severity may range from mild diarrhea to fatal colitis; CDAD may occur over 2 months after discontinuation of therapy; if CDAD is suspected or confirmed, discontinue immediately and begin appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C difficile, and surgical evaluation
Do not administer in patients with infectious mononucleosis because of risk of development of erythematous skin rash
Do not administer to patients in the absence of a proven or suspected bacterial infection because of risk of development of drug-resistant bacteria
Superinfections with bacterial or fungal pathogens may occur during therapy; if suspected, discontinue immediately and begin appropriate treatment
Chewable tablets contain aspartame, which contains phenylalanine
Use caution in patients with allergy to cephalosporins, carbapenems
Endocarditis prophylaxis: use for only high-risk patients, as per recent AHA guidelines
High doses may cause false urine glucose test by some methods
Pregnancy and lactation
Pregnancy category: B
Lactation: Excreted in breast milk, use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Amoxil, Moxatag (amoxicillin)
Mechanism of action
Derivative of ampicillin and has similar antibacterial spectrum (certain gram-positive and gram-negative organisms); similar bactericidal action as penicillin; acts on susceptible bacteria during multiplication stage by inhibiting cell wall mucopeptide biosynthesis; superior bioavailability and stability to gastric acid and has broader spectrum of activity than penicillin; less active than penicillin against Streptococcus pneumococcus; penicillin-resistant strains also resistant to amoxicillin, but higher doses may be effective; more effective against gram-negative organisms (eg, N meningitidis, H influenzae) than penicillin
Absorption
Rapidly absorbed
Bioavailability: 74-92%
Peak plasma time: 2hr (capsule); 3.1 hr (extended release tab); 1 hr (suspension)
Distribution
Most body fluids and bone, CSF <1%
Protein bound: 17-20%
Metabolism
Hepatic
Elimination
Excretion: Urine
Half-life: 3.7 hr (full-term neonates); 1-2 hr (infants and children); 0.7-1.4 hr (adults)
