Usage
Amoxycillin + Sulbactam is prescribed for a variety of bacterial infections. It is classified as a beta-lactam antibiotic. The combination combats bacteria by inhibiting bacterial cell wall synthesis. Amoxycillin, a penicillin-like antibiotic, disrupts the formation of the bacterial cell wall. Sulbactam, a beta-lactamase inhibitor, safeguards amoxycillin from degradation by enzymes produced by certain bacteria, thereby broadening its effectiveness against resistant strains.
Alternate Names
Sultamox, Unasyn.
How It Works
Pharmacodynamics: Amoxycillin, a beta-lactam antibiotic, inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). Sulbactam, although possessing weak antibacterial activity, primarily acts as a beta-lactamase inhibitor, irreversibly binding and inhibiting these enzymes commonly found in bacteria resistant to penicillins and cephalosporins. This inhibition extends amoxycillin’s spectrum of activity.
Pharmacokinetics: Amoxycillin and sulbactam, when administered intravenously or intramuscularly, demonstrate good absorption. Both are distributed widely throughout the body. Metabolism of amoxycillin is minimal, whereas sulbactam undergoes some metabolism. Elimination is primarily renal, with a half-life necessitating dosing every 6-8 hours typically. Dosage adjustment is crucial for patients with renal impairment.
Mode of Action: The combination targets bacterial cell wall synthesis, an essential process for bacterial survival and proliferation. Amoxycillin’s binding to PBPs disrupts peptidoglycan cross-linking, a fundamental step in cell wall formation. This structural weakening leads to bacterial cell lysis and death. Sulbactam’s beta-lactamase inhibition prevents amoxycillin degradation, extending its antibacterial activity.
Elimination Pathways: Both drugs are eliminated predominantly through renal excretion.
Dosage
Standard Dosage
Adults:
1.5 to 3 g (1-2 g amoxycillin/0.5-1 g sulbactam) every 6 hours intravenously or intramuscularly. Total daily sulbactam dose should not exceed 4g.
Children:
Neonates (first week): 75 mg/kg/day (50 mg/kg/day amoxycillin + 25 mg/kg/day sulbactam), divided every 12 hours.
Infants and children 1 month and older: 150 mg/kg/day, in divided doses every 6-8 hours. (100 mg/kg/day amoxycillin and 50 mg/kg/day sulbactam)
Children 1 year and older (skin infections): 300 mg/kg/day, in divided doses every 6 hours. (200 mg/kg/day amoxycillin and 100 mg/kg/day sulbactam)
Special Cases:
- Elderly Patients: Dosage adjustment based on renal function.
- Patients with Renal Impairment: Dose and frequency reduction necessary depending on creatinine clearance. If creatinine clearance is 15-29 mL/min, administer every 12 hours, or even 24 hours if clearance is 5-14 ml/min.
- Patients with Hepatic Dysfunction: Caution advised, monitor liver function.
Clinical Use Cases
Dosage follows standard adult guidelines, adjusted for renal function and infection severity, for all scenarios.
Dosage Adjustments
Modifications are essential for renal impairment, as outlined above. Monitor for adverse events and adjust accordingly for other specific conditions.
Side Effects
Common Side Effects
Diarrhea, nausea, vomiting, rash, itching, pain at injection site.
Rare but Serious Side Effects
Severe allergic reactions (anaphylaxis, angioedema), Clostridioides difficile -associated diarrhea, Stevens-Johnson syndrome.
Adverse Drug Reactions (ADR)
As above, focusing on severe allergic reactions and C. difficile infections.
Contraindications
Hypersensitivity to penicillins, cephalosporins or sulbactam. History of cholestatic jaundice or hepatic dysfunction associated with the drug.
Drug Interactions
Probenecid reduces amoxycillin excretion. Allopurinol may increase rash risk. May decrease efficacy of oral contraceptives. Monitor INR with warfarin. Aminoglycosides and methotrexate may interact. Avoid alcohol.
Pregnancy and Breastfeeding
Relatively safe during pregnancy, excreted in breast milk in low levels. Monitor infant for diarrhea.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial cell wall synthesis, extended spectrum by beta-lactamase inhibition.
- Side Effects: Diarrhea, nausea, vomiting, rash, injection site pain; rarely severe allergic reactions or C. difficile infection.
- Contraindications: Penicillin or cephalosporin allergy; prior drug-related cholestatic jaundice or hepatic dysfunction.
- Drug Interactions: Probenecid, allopurinol, oral contraceptives, warfarin, aminoglycosides, methotrexate.
- Pregnancy & Breastfeeding: Generally safe, monitor infant.
- Dosage: 1.5-3g IV/IM q6h for adults; pediatric dosage based on weight and age. Adjust for renal impairment.
- Monitoring Parameters: Renal function, liver function, signs of allergic reactions, signs of superinfection (e.g. candidiasis).
Popular Combinations
Frequently used alone. May be used in combination with other antibiotics for specific infections based on culture and sensitivity results.
Precautions
Standard precautions apply, including monitoring for allergy and organ dysfunction. Monitor infants of breastfeeding mothers for diarrhea or thrush.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Amoxycillin + Sulbactam?
A: Adults: 1.5-3 g IV/IM every 6 hours. Pediatric dosages are weight-based and vary by age.
Q2: How should I adjust the dosage for patients with renal impairment?
A: Adjust dose and frequency based on creatinine clearance.
Q3: What are the most common side effects?
A: Diarrhea, nausea, vomiting, and rash are common.
Q4: Is Amoxycillin + Sulbactam safe during pregnancy?
A: It’s generally considered safe, but consult with an obstetrician.
Q5: Can I use this drug if I’m allergic to penicillin?
A: No, it’s contraindicated.
Q6: What should I monitor in breastfed infants whose mothers are taking this drug?
A: Monitor the infant for diarrhea or thrush.
Q7: Does this drug interact with other medications?
A: Yes, interactions with probenecid, allopurinol, oral contraceptives, warfarin, and some others are known.
Q8: What is the mechanism of action of Amoxycillin + Sulbactam?
A: It inhibits bacterial cell wall synthesis and has an extended spectrum due to beta-lactamase inhibition.
Q9: How is this drug administered?
A: Intravenously (IV) or intramuscularly (IM).
Q10: What are the signs of an allergic reaction?
A: Rash, itching, hives, swelling, difficulty breathing, and anaphylaxis. Seek immediate medical attention if these occur.
