Usage
Cefdinir is a broad-spectrum, third-generation cephalosporin antibiotic indicated for the treatment of mild to moderate bacterial infections. It is commonly prescribed for:
- Community-Acquired Pneumonia: Caused by susceptible strains of Streptococcus pneumoniae (penicillin-susceptible strains only), Haemophilus influenzae (including beta-lactamase-producing strains), Haemophilus parainfluenzae (including beta-lactamase-producing strains), or Moraxella catarrhalis (including beta-lactamase-producing strains).
- Acute Exacerbations of Chronic Bronchitis: Caused by susceptible strains of H. influenzae (including beta-lactamase-producing strains), H. parainfluenzae (including beta-lactamase-producing strains), S. pneumoniae (penicillin-susceptible strains only), or M. catarrhalis (including beta-lactamase-producing strains).
- Acute Maxillary Sinusitis: Caused by susceptible strains of H. influenzae (including beta-lactamase-producing strains), S. pneumoniae (penicillin-susceptible strains only), or M. catarrhalis (including beta-lactamase-producing strains).
- Pharyngitis and Tonsillitis: Caused by Streptococcus pyogenes.
- Uncomplicated Skin and Skin Structure Infections: Caused by susceptible strains of Staphylococcus aureus (including beta-lactamase-producing strains) or S. pyogenes.
- Acute Bacterial Otitis Media: Caused by susceptible strains of H. influenzae (including beta-lactamase-producing strains), S. pneumoniae (penicillin-susceptible strains only), or M. catarrhalis (including beta-lactamase-producing strains).
Pharmacological Classification: Cefdinir is a third-generation cephalosporin antibiotic.
Mechanism of Action: Cefdinir exerts its bactericidal effect by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs), enzymes essential for the final transpeptidation step of peptidoglycan synthesis. This disruption weakens the cell wall, leading to bacterial cell lysis and death. Cefdinir is effective against a wide range of Gram-positive and Gram-negative bacteria, including those producing beta-lactamases.
Alternate Names
Cefdinir is also known internationally as cefdinir. It’s marketed under the brand name Omnicef.
How It Works
Pharmacodynamics: Cefdinir exerts its bactericidal action by disrupting bacterial cell wall synthesis, leading to cell lysis and death.
Pharmacokinetics:
- Absorption: Cefdinir is administered orally and is absorbed from the gastrointestinal tract. Food does not significantly affect the extent of absorption, but it may slow down the rate of absorption slightly.
- Distribution: Cefdinir is widely distributed in the body, reaching therapeutic concentrations in various tissues and fluids.
- Metabolism: Cefdinir undergoes minimal hepatic metabolism.
- Elimination: Cefdinir is primarily excreted unchanged by the kidneys. A small amount is excreted in the bile.
Mode of Action: Cefdinir binds to specific penicillin-binding proteins (PBPs) located on the bacterial cell membrane. PBPs are transpeptidases and carboxypeptidases crucial for the final steps in peptidoglycan synthesis, which forms the rigid structural component of the bacterial cell wall. By binding to PBPs, cefdinir blocks the transpeptidation and carboxypeptidation reactions, resulting in defective cell wall synthesis. This causes the bacterial cell wall to weaken and become susceptible to osmotic lysis, leading to bacterial cell death. Cefdinir’s beta-lactam ring structure is essential for its binding to PBPs.
Elimination Pathways: Primarily renal excretion.
Dosage
Standard Dosage
Adults:
The usual adult dose is 300 mg every 12 hours or 600 mg once daily for 5-10 days, depending on the infection.
Children:
The usual pediatric dose (6 months to 12 years) is 7 mg/kg every 12 hours or 14 mg/kg once daily for 5-10 days, not to exceed 600 mg/day. For children weighing 43 kg or more, the maximum dose is 600 mg/day. Safety and efficacy have not been established in infants under 6 months of age.
Special Cases:
- Elderly Patients: No dose adjustment is necessary unless renal function is impaired.
- Patients with Renal Impairment: For creatinine clearance (CrCl) < 30 mL/min, the dose should be 300 mg once daily in adults and 7 mg/kg (up to 300 mg) once daily in children. For hemodialysis patients, an initial dose of 300 mg (adults) or 7 mg/kg (children) is given every other day. A supplemental dose should be administered after each dialysis session.
- Patients with Hepatic Dysfunction: No dosage adjustment is necessary.
- Patients with Comorbid Conditions: Consideration should be given to drug interactions and the patient’s overall health status.
Clinical Use Cases
Cefdinir is not typically used in the specific clinical settings you mentioned (intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations). Its use focuses on oral administration for the specific infections mentioned in the Usage section.
Dosage Adjustments
Dosage adjustments are primarily based on renal function. See “Special Cases” above.
Side Effects
Common Side Effects
Diarrhea, nausea, vomiting, abdominal pain, vaginitis, headache, and diaper rash (in infants).
Rare but Serious Side Effects
- Allergic Reactions: Including anaphylaxis, skin rash, hives, itching, swelling of the face, throat, tongue, lips, or eyes, difficulty breathing or swallowing.
- Clostridium difficile-associated diarrhea (CDAD).
- Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): Severe skin reactions that can be life-threatening.
- Serum Sickness: An immune complex-mediated hypersensitivity reaction.
Long-Term Effects
Prolonged use of cefdinir can lead to an increased risk of CDAD and the development of antibiotic-resistant bacteria.
Adverse Drug Reactions (ADR)
See “Rare but Serious Side Effects.”
Contraindications
Cefdinir is contraindicated in patients with a known hypersensitivity to cephalosporins. Caution should be used in patients with penicillin allergy due to the potential for cross-reactivity.
Drug Interactions
Cefdinir may interact with antacids containing aluminum or magnesium, iron supplements, probenecid, and H2 antagonists, potentially reducing cefdinir absorption. It may also interact with certain oral contraceptives, although the clinical significance is not fully established. Consult a comprehensive drug interaction resource for a complete list.
Pregnancy and Breastfeeding
Cefdinir is categorized as Pregnancy Category B. Animal studies have not shown evidence of fetal harm, but there are no adequate and well-controlled studies in pregnant women. Cefdinir should be used during pregnancy only if clearly needed.
Cefdinir is excreted in breast milk in small amounts. While generally considered safe, caution should be exercised when administering to breastfeeding mothers.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial cell wall synthesis.
- Side Effects: Diarrhea, nausea, vomiting, rash, headache, abdominal pain; rarely, severe allergic reactions, CDAD, SJS/TEN.
- Contraindications: Hypersensitivity to cephalosporins.
- Drug Interactions: Antacids, iron supplements, probenecid, H2 antagonists, some oral contraceptives.
- Pregnancy & Breastfeeding: Category B; use with caution if benefits outweigh risks.
- Dosage: Adults: 300 mg q12h or 600 mg qd; Children (6 months-12 years): 7 mg/kg q12h or 14 mg/kg qd.
- Monitoring Parameters: Observe for signs of allergic reactions, CDAD, and other adverse effects. Monitor renal function in patients with renal impairment.
Popular Combinations
Cefdinir is not typically used in combination with other antibiotics.
Precautions
Screen for allergies to cephalosporins and penicillins. Assess renal function, particularly in elderly patients. Advise patients about the risk of CDAD. Monitor for adverse reactions. Caution patients about potential interactions with antacids, iron supplements, and other medications. For pregnant and breastfeeding women, carefully weigh the risks and benefits.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cefdinir?
A: Adults: 300 mg every 12 hours or 600 mg once daily. Children (6 months-12 years): 7 mg/kg every 12 hours or 14 mg/kg once daily, not to exceed 600 mg/day. Dosage adjustments are needed for renal impairment.
Q2: What infections is Cefdinir commonly used to treat?
A: Cefdinir is used to treat various bacterial infections, including community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute maxillary sinusitis, pharyngitis/tonsillitis, uncomplicated skin and skin structure infections, and acute bacterial otitis media in children.
Q3: What are the common side effects of Cefdinir?
A: Common side effects include diarrhea, nausea, vomiting, abdominal pain, vaginitis, headache, and diaper rash in infants.
Q4: What are the serious side effects of Cefdinir?
A: Serious side effects, though rare, include allergic reactions (including anaphylaxis), C. difficile -associated diarrhea (CDAD), and severe skin reactions like Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN).
Q5: Is Cefdinir safe to use during pregnancy and breastfeeding?
A: Cefdinir is a Pregnancy Category B drug. Consult with a doctor to evaluate the risks and benefits. While generally considered safe during breastfeeding, it’s essential to exercise caution.
Q6: Does Cefdinir interact with other medications?
A: Yes, Cefdinir can interact with antacids, iron supplements, probenecid, and certain H2 antagonists. It might also interact with some oral contraceptives. Consult a comprehensive drug interaction resource for details.
Q7: How does Cefdinir work?
A: Cefdinir is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs).
Q8: What should patients be advised about while taking Cefdinir?
A: Patients should be advised to complete the entire course of Cefdinir, even if they feel better. They should also be informed about the signs and symptoms of allergic reactions and C. difficile infection. Encourage them to report any unusual symptoms to their doctor.
Q9: Are there any contraindications for Cefdinir?
A: Cefdinir is contraindicated in patients with a known hypersensitivity to cephalosporin antibiotics.
Q10: How is Cefdinir eliminated from the body?
A: Cefdinir is primarily eliminated unchanged through renal excretion (by the kidneys).
