Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER vs AMINOPHYLLINE IN SODIUM CHLORIDE 0.45%
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Cefoxitin is a cephamycin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
Aminophylline is a complex of theophylline and ethylenediamine, acting as a phosphodiesterase inhibitor, increasing intracellular c AMP levels; nonselective adenosine receptor antagonist; enhances cardiac inotropy, bronchodilation, and CNS stimulation.
Treatment of serious infections caused by susceptible Gram-positive and Gram-negative bacteria including intra-abdominal infections, pelvic inflammatory disease, diabetic foot infections, and prophylaxis in colorectal surgery,Off-label: Treatment of aspiration pneumonia, perioperative prophylaxis in cesarean section
Treatment of acute bronchospasm in asthma and COPD,Reversal of dipyridamole-induced adverse effects during stress testing,Apnea of prematurity (off-label),Status asthmaticus (off-label)
1-2 g IV every 6-8 hours. Maximum 12 g/day.
Loading dose: 5-6 mg/kg IV over 20-30 minutes, then continuous infusion: 0.5-0.7 mg/kg/hour IV.
Terminal elimination half-life: 0.7–1.1 hours in normal renal function; prolonged to 5–10 hours in severe renal impairment (Cr Cl <10 m L/min).
Terminal elimination half-life is 6-12 hours in adults, 1-5 hours in children (due to faster clearance), 20-30 hours in premature neonates, and 10-15 hours in patients with hepatic cirrhosis or heart failure. Clinical context: dosing interval adjustment required based on half-life; prolonged half-life in hepatic impairment or cardiac decompensation increases risk of toxicity.
Cefoxitin is not significantly metabolized; primarily excreted unchanged in urine via glomerular filtration and tubular secretion.
Hepatic via cytochrome P450 enzymes (CYP1A2, CYP3A4, CYP2E1); saturable kinetics; extensive first-pass metabolism.
Renal: ~85% unchanged; biliary/fecal: ~15% as active metabolite and unchanged drug.
Renal excretion of unchanged theophylline (10-20%) and metabolites (80-90%). In neonates, renal excretion of unchanged drug is higher (up to 50%). Biliary/fecal excretion is negligible.
73% (primarily albumin).
Approximately 40% bound to plasma proteins, mainly albumin. In neonates, preterm infants, and patients with hepatic cirrhosis, protein binding is reduced (free fraction increases). Binding is also saturable at high theophylline concentrations.
0.13–0.22 L/kg; indicates distribution mainly into extracellular fluid.
Volume of distribution is approximately 0.45 L/kg (range 0.3-0.7 L/kg) in adults. In neonates, Vd is larger (~0.6-0.8 L/kg). Clinical meaning: Vd indicates extensive distribution into body water; loading doses are calculated using Vd (e.g., 1 mg/kg raises serum concentration by ~2 mcg/m L).
IM: ~100%.
Oral immediate-release: 100% (well absorbed). Rectal: 80-100% (absorption may be erratic). IV: 100%. No significant first-pass metabolism.
Cr Cl 30-50 m L/min: 1-2 g every 8 hours; Cr Cl 10-29 m L/min: 1-2 g every 12 hours; Cr Cl <10 m L/min: 1-2 g every 24-48 hours.
No specific dose adjustment required for GFR >10 m L/min. For GFR <10 m L/min, reduce infusion rate by 50%.
No adjustment required for hepatic impairment.
Child-Pugh Class A: reduce dose by 25%; Class B: reduce dose by 50%; Class C: reduce dose by 75%.
3 months to 12 years: 80-160 mg/kg/day IV divided every 6-8 hours. Maximum 12 g/day.
Loading dose: 5-6 mg/kg IV over 20-30 minutes; continuous infusion: 0.5-0.7 mg/kg/hour (age-dependent, with lower doses for younger children).
Based on renal function; Cr Cl 30-50 m L/min: 1-2 g every 8 hours; Cr Cl 10-29 m L/min: 1-2 g every 12 hours; Cr Cl <10 m L/min: 1-2 g every 24-48 hours.
Elderly patients may have reduced clearance; consider starting at the lower end of dosing range (e.g., 0.3-0.5 mg/kg/hour) and titrate based on serum levels.
No FDA black box warning.
Theophylline toxicity is dose-related and can be fatal; monitor serum theophylline levels closely; use with caution in patients with risk factors for reduced clearance (e.g., hepatic impairment, heart failure, elderly).
Hypersensitivity reactions including anaphylaxis,Clostridium difficile-associated diarrhea (CDAD),Prolonged use may result in superinfection,Dose adjustment required in renal impairment,May cause false-positive urine glucose tests with copper reduction methods,Use with caution in patients with history of gastrointestinal disease
Narrow therapeutic index; severe toxicity can occur at levels >20 mcg/m L,Seizures and arrhythmias may occur without preceding symptoms,Variable clearance due to drug interactions, disease states, age, and smoking,Use with caution in peptic ulcer disease, seizure disorders, hyperthyroidism, and cardiac disease
Hypersensitivity to cefoxitin or other cephalosporins,Porphyria
Hypersensitivity to aminophylline or any component,Hypersensitivity to theophylline or ethylenediamine,Cardiac arrhythmias requiring immediate therapy (relative)
No significant food interactions. However, alcohol should be avoided to prevent disulfiram-like reactions (rare). Maintain adequate hydration.
Avoid high-dose caffeine (coffee, tea, energy drinks, chocolate) as it may increase risk of side effects like nausea, anxiety, and tachycardia. Charcoal-broiled foods and a high-protein diet may increase theophylline clearance. Consistent dietary intake is recommended.
Cefoxitin is a second-generation cephalosporin classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Inadequate human data; risk cannot be ruled out. First trimester: unlikely to cause major malformations based on limited data. Second and third trimesters: no documented fetal harm. However, use only if clearly needed.
First trimester: Limited data; no increased risk of major malformations observed in human studies. Second and third trimesters: Risk of fetal tachycardia and jitteriness with high maternal doses; may cause transient neonatal tachycardia with chronic use. No documented teratogenicity.
Cefoxitin is excreted into human breast milk in low concentrations (M/P ratio approximately 0.04-0.3). Likely compatible with breastfeeding due to poor oral bioavailability in infants. Caution with theoretical risk of diarrhea or allergic sensitization.
Aminophylline/theophylline is excreted into breast milk with an M/P ratio of approximately 0.6-0.7. Infant exposure is low (about 1-10% of maternal dose). Irritability and insomnia reported rarely. Use with caution, monitor infant for signs of theophylline toxicity.
Pregnancy increases glomerular filtration rate (GFR) and volume of distribution, potentially reducing cefoxitin peak concentrations and elimination half-life. However, no specific dose adjustments recommended for pregnancy-induced pharmacokinetic changes. Standard dosing for adults is 1-2 g every 6-8 hours; use lower end if renal impairment.
Pregnancy decreases theophylline clearance by approximately 20-30% during third trimester. Dosing adjustments may be required: monitor serum levels and adjust dose to maintain therapeutic levels. Postpartum clearance returns rapidly, requiring downward dose adjustment.
MEFOXIN (cefoxitin) is a cephamycin antibiotic with activity against anaerobes, including Bacteroides fragilis. Use for surgical prophylaxis, intra-abdominal infections, and pelvic inflammatory disease. Note that it has poor activity against Pseudomonas and Enterococci. Administer 1-2 g IV every 6-8 hours; dose adjustment required in renal impairment (Cr Cl <50 m L/min). May cause false-positive urine glucose with Clinitest but not with glucose oxidase methods. Can prolong prothrombin time; monitor INR in patients on warfarin.
Aminophylline is a bronchodilator that releases theophylline. Monitor serum theophylline levels (therapeutic range 5-15 mcg/m L). Avoid in patients with active peptic ulcer disease, seizure disorders, or hypersensitivity to xanthines. Caution in hepatic impairment, heart failure, and elderly due to reduced clearance. Drug interactions with cimetidine, ciprofloxacin, and macrolides increase theophylline levels.
Complete the full course of antibiotics even if you feel better.,Report any severe diarrhea, rash, or difficulty breathing to your healthcare provider.,This medication is given intravenously; do not mix with other drugs in the same IV line without consulting a pharmacist.,If you have a history of allergic reactions to penicillins or cephalosporins, inform your doctor.,Monitor for signs of bleeding (easy bruising, dark stools) if you are taking blood thinners.
Do not exceed prescribed dose. Take exactly as directed.,Avoid caffeine-containing products (coffee, tea, cola, chocolate) as they may increase side effects.,Report symptoms of toxicity: nausea, vomiting, insomnia, rapid heart rate, palpitations, or seizures.,Do not crush or chew extended-release forms; take with food if gastric upset occurs.,Do not stop abruptly without consulting your healthcare provider.
"Lithium cation may increase the excretion rate of Sodium chloride which could result in a lower serum level and potentially a reduction in efficacy."
"The risk or severity of adverse effects can be increased when Sodium chloride is combined with Tolvaptan."
"Concurrent administration of aminophylline, a xanthine derivative bronchodilator that is metabolized primarily by CYP1A2 and to a lesser extent CYP3A4, may reduce the clearance of ranolazine, an antianginal agent predominantly metabolized by CYP3A4 and to a lesser extent CYP2D6. Aminophylline can inhibit CYP3A4 activity, leading to increased ranolazine plasma concentrations, which elevates the risk of dose-dependent adverse effects such as QTc prolongation, dizziness, and syncope. This interaction is clinically significant and may necessitate dose adjustment or alternative therapy."
"Asunaprevir, a potent inhibitor of the drug transporter OATP1B1, can significantly decrease the serum concentration of aminophylline, a theophylline salt, likely by reducing its intestinal absorption or increasing its hepatic clearance. This interaction may lead to reduced therapeutic efficacy of aminophylline, potentially worsening respiratory symptoms in patients with asthma or COPD. Close monitoring and dose adjustment of aminophylline are recommended during coadministration with asunaprevir."
"Aminophylline, a bronchodilator, inhibits the metabolism of tibolone, a synthetic steroid hormone used for hormone replacement therapy, primarily through competitive inhibition of cytochrome P450 (CYP) 3A4 isoenzyme. This results in increased plasma concentrations of tibolone and its active metabolites, potentiating its hormonal effects and increasing the risk of adverse events such as thromboembolism, endometrial hyperplasia, or breast tenderness. Clinically, coadministration may require dose adjustments and careful monitoring for signs of estrogenic excess."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER vs AMINOPHYLLINE IN SODIUM CHLORIDE 0.45%, answered by our medical review team.
MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER is a Electrolyte that works by Cefoxitin is a cephamycin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.. AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is a Electrolyte that works by Aminophylline is a complex of theophylline and ethylenediamine, acting as a phosphodiesterase inhibitor, increasing intracellular c AMP levels; nonselective adenosine receptor antagonist; enhances cardiac inotropy, bronchodilation, and CNS stimulation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER and AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% depend on the specific clinical indication. These are both Electrolyte agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER is: 1-2 g IV every 6-8 hours. Maximum 12 g/day.. The standard adult dose of AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is: Loading dose: 5-6 mg/kg IV over 20-30 minutes, then continuous infusion: 0.5-0.7 mg/kg/hour IV.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
A moderate-severity drug interaction has been identified when combining MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER and AMINOPHYLLINE IN SODIUM CHLORIDE 0.45%. The risk or severity of adverse effects can be increased when Sodium chloride is combined with Tolvaptan. Consult your prescriber before combining these medications.
The maternal-fetal safety profiles differ. MEFOXIN IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER is classified as Category A/B. Cefoxitin is a second-generation cephalosporin classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Inadequate human data; risk cannot be ruled . AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is classified as Category A/B. First trimester: Limited data; no increased risk of major malformations observed in human studies. Second and third trimesters: Risk of fetal tachycardia and jitteriness with high . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.