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% IN PLASTIC CONTAINER
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. Theophylline acts as a non-selective phosphodiesterase inhibitor, increasing intracellular cyclic AMP levels, leading to bronchodilation. It also blocks adenosine receptors, stimulates catecholamine release, and enhances diaphragmatic contractility. The ethylenediamine component increases solubility.
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 symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases (e.g., emphysema, chronic bronchitis),Adjunctive therapy in acute bronchial asthma and status asthmaticus,Off-label: Treatment of apnea of prematurity
1-2 g IV every 6-8 hours. Maximum 12 g/day.
Loading dose: 5-6 mg/kg IV over 20-30 minutes (if not on theophylline). Maintenance: 0.5-0.7 mg/kg/h IV continuous infusion.
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: 3-12 hours in adults (mean 5-6 hours); prolonged in hepatic impairment, heart failure, COPD, and neonates (up to 30 hours). Smoking reduces half-life by 30-50%.
Cefoxitin is not significantly metabolized; primarily excreted unchanged in urine via glomerular filtration and tubular secretion.
Theophylline is metabolized primarily in the liver by cytochrome P450 isoenzymes, predominantly CYP1A2, with minor contributions from CYP2E1 and CYP3A4. Metabolism involves N-demethylation and oxidation. In neonates, metabolism is immature; in adults, ~90% is hepatically cleared. Ethylenediamine is minimally metabolized.
Renal: ~85% unchanged; biliary/fecal: ~15% as active metabolite and unchanged drug.
Renal excretion of unchanged drug (about 10-20%) and metabolites (primarily 1,3-dimethyluric acid, 1-methyluric acid, 3-methylxanthine). Billary/fecal excretion is negligible.
73% (primarily albumin).
Theophylline (active moiety): approximately 40% bound to plasma proteins, primarily albumin. Protein binding decreases in neonates, hepatic cirrhosis, and uremia.
0.13–0.22 L/kg; indicates distribution mainly into extracellular fluid.
Apparent volume of distribution: approximately 0.4-0.6 L/kg (average 0.45 L/kg). Indicates distribution into total body water; slightly higher in neonates and premature infants.
IM: ~100%.
Oral: 96-100% for immediate-release tablets; 50-70% for some sustained-release formulations depending on formulation. Rectal: 70-80% (variable). IV: 100%.
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 dose adjustment required for GFR >30 m L/min. For GFR 10-30 m L/min: reduce maintenance dose by 50% and monitor serum theophylline levels. For GFR <10 m L/min: reduce maintenance dose by 50% and extend dosing interval or use with caution.
No adjustment required for hepatic impairment.
Child-Pugh A: reduce dose by 50%. Child-Pugh B: reduce dose by 75%. Child-Pugh C: contraindicated or use with extreme caution, reduce dose by 80% and monitor levels.
3 months to 12 years: 80-160 mg/kg/day IV divided every 6-8 hours. Maximum 12 g/day.
Loading dose: 1 mg/kg IV (if not on theophylline). Maintenance: Continuous infusion: age 6 months-1 year: 0.5 mg/kg/h; age 1-9 years: 0.8 mg/kg/h; age 9-12 years: 0.7 mg/kg/h; age 12-16 years: 0.6 mg/kg/h. Maximum daily dose: 24 mg/kg/day.
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.
Consider lower initial doses due to decreased clearance. Use ideal body weight. Start at lower maintenance infusion rate (e.g., 0.3 mg/kg/h) and titrate based on serum levels and clinical response. Monitor for toxicity.
No FDA black box warning.
None
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; serum theophylline levels must be monitored to avoid toxicity. Risk of seizures, cardiac arrhythmias, and death, especially at high serum concentrations. Caution in patients with hepatic impairment, congestive heart failure, cor pulmonale, fever, and in the elderly. Drug interactions with cimetidine, fluoroquinolones, macrolides, oral contraceptives, and other CYP1A2 inhibitors can increase toxicity.
Hypersensitivity to cefoxitin or other cephalosporins,Porphyria
Absolute: Hypersensitivity to theophylline, ethylenediamine, or any component; use in patients with active seizure disorder (unless receiving appropriate anticonvulsant therapy); use in patients with a history of ventricular arrhythmias (except under close supervision). Relative: Peptic ulcer disease, hyperthyroidism, hypertension, and renal impairment.
No significant food interactions. However, alcohol should be avoided to prevent disulfiram-like reactions (rare). Maintain adequate hydration.
Avoid large amounts of caffeine-containing foods and beverages (coffee, tea, cola, chocolate) as they can potentiate theophylline effects and increase risk of toxicity. A high-protein diet may increase theophylline clearance; maintain consistent dietary habits.
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.
Pregnancy Category C. First trimester: Limited human data; animal studies show no teratogenicity but some developmental delays at high doses. Second and third trimesters: Use only if benefit outweighs risk; may cause fetal tachycardia or irritability due to adenosine receptor blockade. Avoid near term due to potential neonatal irritability.
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.
Not recommended unless essential. Aminophylline is excreted into breast milk; M/P ratio approximately 0.6–0.8. Monitor infant for irritability or insomnia. Consider alternative therapies if breastfeeding.
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 may decrease protein binding and increase clearance of theophylline; monitor serum levels closely. Dose may need to be increased by 10–30% to maintain therapeutic levels. Postpartum, doses may need reduction.
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 used primarily for asthma and COPD exacerbations. Monitor serum theophylline levels closely due to narrow therapeutic index (10-20 mcg/m L). Administer IV infusion over 30 minutes to avoid hypotension. Caution in patients with cardiac arrhythmias, hyperthyroidism, or seizure disorders. Drug interactions include cimetidine, fluoroquinolones, and macrolides which 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.
Take this medication exactly as prescribed; do not stop or change dose without consulting your doctor.,Avoid excessive caffeine intake (coffee, tea, chocolate, cola) as it may increase side effects like jitteriness and palpitations.,Report any symptoms of toxicity such as nausea, vomiting, insomnia, rapid heart rate, or seizures immediately.,Inform your healthcare provider of all other medications, especially antibiotics, heart medications, or seizure drugs.,Do not chew or crush the solution; it is for intravenous use only under medical supervision.
"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% IN PLASTIC CONTAINER, 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% IN PLASTIC CONTAINER is a Electrolyte that works by Aminophylline is a complex of theophylline and ethylenediamine. Theophylline acts as a non-selective phosphodiesterase inhibitor, increasing intracellular cyclic AMP levels, leading to bronchodilation. It also blocks adenosine receptors, stimulates catecholamine release, and enhances diaphragmatic contractility. The ethylenediamine component increases solubility.. 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% IN PLASTIC CONTAINER 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% IN PLASTIC CONTAINER is: Loading dose: 5-6 mg/kg IV over 20-30 minutes (if not on theophylline). Maintenance: 0.5-0.7 mg/kg/h IV continuous infusion.. 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% IN PLASTIC CONTAINER. 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% IN PLASTIC CONTAINER is classified as Category A/B. Pregnancy Category C. First trimester: Limited human data; animal studies show no teratogenicity but some developmental delays at high doses. Second and third trimesters: Use only . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.