Usage
Cefixime is a third-generation cephalosporin antibiotic prescribed for various bacterial infections. It is indicated for the treatment of:
- Upper Respiratory Tract Infections: Otitis media, pharyngitis, tonsillitis, sinusitis.
- Lower Respiratory Tract Infections: Acute exacerbations of chronic bronchitis, pneumonia.
- Urinary Tract Infections: Cystitis, cystourethritis, uncomplicated pyelonephritis.
- Uncomplicated Gonorrhea: (cervical/urethral) While effective, it is no longer a first-line treatment according to CDC guidelines.
- Typhoid Fever: (Off-label use)
Pharmacological Classification: Cefixime is classified as a beta-lactam antibiotic, specifically a third-generation cephalosporin.
Mechanism of Action: Cefixime exerts its bactericidal effect by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs), enzymes essential for cross-linking peptidoglycans in the bacterial cell wall. This disruption weakens the cell wall, leading to bacterial cell lysis and death. Cefixime is effective against a broad spectrum of gram-positive and gram-negative bacteria.
Alternate Names
Cefixime is also known internationally and regionally by the same name.
Brand Names: A common brand name for Cefixime is Suprax.
How It Works
Pharmacodynamics: Cefixime is bactericidal, disrupting bacterial cell wall synthesis, leading to cell death. It achieves high concentrations in urine and bile.
Pharmacokinetics:
- Absorption: Orally administered cefixime is absorbed approximately 40-50%, unaffected by food.
- Metabolism: Minimally metabolized in the liver.
- Elimination: Primarily excreted unchanged in urine via glomerular filtration and tubular secretion, with a small amount eliminated in bile. The elimination half-life is approximately 3-4 hours, which may be prolonged in patients with renal impairment.
Mode of Action: Cefixime inhibits bacterial cell wall synthesis by binding to and inactivating penicillin-binding proteins (PBPs).
Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: Cefixime primarily acts through enzyme inhibition (PBPs).
Elimination Pathways: Cefixime is primarily excreted unchanged by the kidneys, with minor biliary excretion.
Dosage
Standard Dosage
Adults:
- 400 mg once daily or 200 mg every 12 hours, orally.
- For uncomplicated gonorrhea, a single oral dose of 400 mg is recommended.
Children (6 months and older):
- 8 mg/kg/day orally once daily or divided into two doses of 4 mg/kg every 12 hours.
- Children weighing more than 45 kg or older than 12 years should receive the adult dose.
- For children under 6 months, safety and efficacy haven’t been established.
Special Cases:
- Elderly Patients: Dosage adjustments based on renal function.
- Patients with Renal Impairment: For creatinine clearance (CrCl) > 60 mL/min, no adjustment is needed. For CrCl 21-60 mL/min, reduce to 260 mg/day. For CrCl ≤ 20 mL/min, reduce to 200 mg/day. Hemodialysis and peritoneal dialysis do not remove significant amounts of cefixime.
- Patients with Hepatic Dysfunction: No dosage adjustment is typically required.
- Patients with Comorbid Conditions: Consider disease-specific interactions, particularly with anticoagulants and other drugs metabolized by the liver.
Clinical Use Cases
Cefixime’s dosage recommendations are based on infection type and severity, not specific clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or most emergency situations. In these cases, other cephalosporins administered intravenously are often preferred.
Dosage Adjustments
Dose adjustments are necessary in patients with renal impairment (as detailed above) and may be considered in other situations based on individual patient characteristics.
Side Effects
Common Side Effects:
- Diarrhea
- Nausea
- Abdominal pain
- Vomiting
- Skin rash
Rare but Serious Side Effects:
- Pseudomembranous colitis ( Clostridium difficile infection)
- Allergic reactions (including anaphylaxis, Stevens-Johnson syndrome)
- Seizures (especially in patients with renal impairment)
- Hepatitis, jaundice
Long-Term Effects:
Chronic complications are rare with short-term cefixime use. Prolonged use can increase the risk of C. difficile infection and select for resistant bacterial strains.
Adverse Drug Reactions (ADR):
Clinically significant ADRs include severe allergic reactions, C. difficile infection, and seizures. These require immediate medical attention.
Contraindications
- Absolute Contraindication: Known hypersensitivity to cefixime or other cephalosporins.
- Relative Contraindications: History of penicillin allergy (cross-reactivity is possible), severe renal impairment.
Drug Interactions
- Anticoagulants (warfarin): Cefixime can enhance the anticoagulant effects. Close monitoring of INR is necessary.
- Probenecid: Can increase cefixime serum concentrations.
- Antacids: May reduce cefixime absorption. Separate administration.
- Oral Contraceptives: Efficacy of oral contraceptives may be reduced.
Pregnancy and Breastfeeding
Cefixime is generally considered safe during pregnancy (Pregnancy Category B). It is excreted in breast milk in low concentrations, generally considered compatible with breastfeeding. However, observe the infant for potential side effects like diarrhea.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial cell wall synthesis.
- Side Effects: Diarrhea, nausea, abdominal pain, rash, allergic reactions.
- Contraindications: Hypersensitivity to cephalosporins.
- Drug Interactions: Warfarin, probenecid, antacids.
- Pregnancy & Breastfeeding: Generally safe.
- Dosage: Adults: 400 mg daily; Children: 8 mg/kg/day. Adjust for renal impairment.
- Monitoring Parameters: Renal function (especially in impaired patients), signs of allergic reactions, and resolution of infection symptoms.
Popular Combinations
While not a fixed combination, Cefixime is sometimes used with azithromycin for treating gonorrhea or other infections where combined coverage is beneficial.
Precautions
- General Precautions: Assess for allergies, renal and hepatic function before initiating therapy. Monitor for signs of allergic reactions and C. difficile infection.
- Specific Populations:
- Pregnant Women: Generally considered safe, but use cautiously.
- Breastfeeding Mothers: Monitor the infant for side effects.
- Children & Elderly: Age-specific dosing adjustments are necessary.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cefixime?
A: Adults: 400 mg daily or 200 mg twice daily. Children (6 months+): 8 mg/kg/day once daily or divided every 12 hours. Adjust for renal impairment.
Q2: What are the common side effects of Cefixime?
A: Common side effects include diarrhea, nausea, abdominal pain, vomiting, and skin rash.
Q3: Is Cefixime safe during pregnancy?
A: Cefixime is generally considered safe during pregnancy (Pregnancy Category B).
Q4: Can Cefixime be used in patients with renal impairment?
A: Yes, but dosage adjustments are necessary based on creatinine clearance.
Q5: What are the contraindications to Cefixime?
A: A known allergy to cefixime or other cephalosporins is a contraindication.
Q6: How does Cefixime work?
A: Cefixime inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins.
Q7: What infections does Cefixime treat?
A: Cefixime treats various bacterial infections, including respiratory, urinary tract, and some sexually transmitted infections.
Q8: What should I counsel my patients about when prescribing Cefixime?
A: Counsel patients about potential side effects, the importance of completing the full course of therapy, and to report any signs of allergic reactions or severe diarrhea.
Q9: Does food affect the absorption of Cefixime?
A: No, food does not significantly affect cefixime absorption.
Q10: Can Cefixime be used to treat strep throat?
A: Yes, Cefixime is effective against Streptococcus pyogenes, the bacteria that causes strep throat. The duration of treatment should be at least 10 days.
