Cefdinir

Uses

Cefdinir is used for the treatment of Community Acquired Pneumonia, Acute Exacerbation of Chronic Bronchitis, Acute Maxillary Sinusitis, Pharyngitis, Tonsillitis, Uncomplicated Skin and Skin Structure, Infections

Cefdinir is also used to associated treatment for these conditions: Acute Exacerbation of Chronic Bronchitis (AECB), Acute Exacerbation of Chronic Bronchitis caused by Haemophilus Influenza, Acute Exacerbation of Chronic Bronchitis caused by Streptococcus Pneumoniae, Acute exacerbation of chronic bronchitis caused by Haemophilus parainfluenzae, Acute exacerbation of chronic bronchitis caused by Moraxella catarrhalis, Acute maxillary sinusitis, Acute maxillary sinusitis caused by H. influenzae, Acute maxillary sinusitis caused by M. catarrhalis, Acute maxillary sinusitis caused by Susceptible strains of Streptococcus pneumoniae, Community Acquired Pneumonia (CAP), Community acquired pneumonia caused by Susceptible strains of Streptococcus pneumoniae, Pneumonia due to Haemophilus influenzae (H. influenzae), Streptococcal Pharyngitis, Streptococcal tonsillitis, Tonsillitis, Uncomplicated Skin and Skin Structure Infections, Uncomplicated skin and skin structure infections caused by streptococcus pyogenes, staphylococcus aureus, Acute otitis media caused by M. catarrhalis, Acute otitis media caused by S.pneumoniae, Bacterial otitis media caused by Haemophilus influenzae, Community aquired pneumonia caused by H. parainfluenzae, Community aquired pneumonia caused by M.catarrhalis

How Cefdinir works

Five-member thiazolidine rings that make up penicillins are replaced in cephalosporins by a six-member dihydrothiazine ring, conferring greater bactericidal activity. This This 6-member ring enables cefdinir and other cephalosporins to resist inactivation by certain bacterial enzymes.

With a mechanism similar to other beta-lactam antibiotics, the bactericidal activity of cefdinir is caused by the inhibition of cell wall synthesis via binding to penicillin-binding proteins (PBPs). Cefdinir, like other cephalosporins, penetrates the bacterial cell wall, combats inactivation by beta-lactamase enzymes, and inactivates penicillin-binding proteins. This interferes with the final step of transpeptidation in cell walls, eventually leading to cell lysis, which eventually leads to the death of bacteria that are susceptible to this drug. Cefdinir has shown affinity to penicillin protein binding proteins 2 and 3. It has also been shown to inhibit transpeptidase enzymes of various bacteria, which may play a role in its bactericidal action. One in vitro study suggests that cefdinir inhibits myeloperoxidase release extracellularly. The impact of this potential drug target in relation to its mechanism of action is unknown.

Dosage

Cefdinir dosage

Adult: 600 mg daily as a single or in 2 divided doses for 5-10 days.

Child: ≥6 months: 14 mg/kg daily as a single or in 2 divided doses. Max: 600 mg daily.

Side Effects

Common side effects are Diarrhea, Vaginal moniliasis, Nausea & Vomiting, Headache, Rash etc.

Toxicity

LD50 information Oral LD50 of cefdinir in the rat is >2000 mg/kg.

There are limited data regarding cefdinir overdose in the literature. In studies of rodents, one 5600-mg/kg dose administered orally did not lead to adverse effects. Signs of toxicity and overdose caused by other beta-lactam antibiotics included nausea, vomiting, diarrhea, abdominal pain, and seizures.

Precaution

Cefdinir, as with other broad-spectrum antibiotics, should be prescribed with caution in individuals with a history of colitis. In patients with transient or persistent renal insufficiency (creatinine clearance <30 ml/min), the total daily dose of Cefdinir should be reduced.

Interaction

Antacids: Cefdinir should be taken at least 2 hours interval of antacid administration.

Iron supplement: Cefdinir should be taken at least 2 hours interval of iron supplement administration.

Probencid: It inhibits the renal excretion of cefdinir.

Food Interaction

• Avoid multivalent ions. Do not take aluminum, magnesium, or iron containing products up to 2 hours before or after this medication.
• Take with or without food. The absorption is unaffected by food.

Cefdinir multivitamins interaction

[Moderate] ADJUST DOSING INTERVAL: The oral bioavailability of cefdinir may be significantly decreased by concomitant administration of iron preparations.

The proposed mechanism is chelation of cefdinir by the iron cation, forming a complex that is poorly absorbed from the gastrointestinal tract.

According to the product labeling, coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron (as ferrous sulfate) or vitamins supplemented with 10 mg of elemental iron resulted in a reduction of cefdinir absorption by 80% and 31%, respectively.

In a study of six healthy volunteers, simultaneous administration of cefdinir (200 mg single oral dose) with a sustained-release formulation of ferrous sulfate (1050 mg, equivalent to 210 mg elemental iron) led to greater than 90% decreases in mean cefdinir peak plasma concentration (Cmax) and systemic exposure (AUC) compared to administration of cefdinir alone.

Even when the iron preparation was administered 3 hours after cefdinir, cefdinir Cmax was still reduced by 25% and AUC by 36%.

To minimize potential interaction with iron, the product labeling recommends that cefdinir be taken at least 2 hours before or 2 hours after administration of iron-containing products.

However, this separation time may not be sufficient to prevent the interaction when sustained-release iron products are used, especially in higher dosages.

Patients should be advised that reddish stools may occur due to formation of a nonabsorbable complex between cefdinir or its breakdown products and iron in the gastrointestinal tract.

Cefdinir Drug Interaction

Unknown: diphenhydramine, diphenhydramine, fluticasone nasal, fluticasone nasal, guaifenesin, guaifenesin, albuterol, albuterol, montelukast, montelukast, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol, cetirizine, cetirizine

Cefdinir Disease Interaction

Major: colitisModerate: renal dysfunction, diabetes, nitroprusside tests, dialysis, liver disease, seizure disorders

Volume of Distribution

The average volume of distribution of cefdinir in adults is about 0.35 L/kg and 0.67 L/kg in children. Another resource estimates the volume of distribution in adults at 1.56–2.09 L/kg. Cefdinir is found to be distributed in various tissues at clinically effective concentrations. It may be found in the epithelial lining fluid, bronchial mucosa, tonsils, sinuses, skin blister fluid, as well as the middle ear fluid. Third-generation cephalosporins such as cefdinir cross the blood-brain barrier and are found in high concentrations in the cerebrospinal fluid, unlike their first and second generation counterparts. The wide tissue distribution of cefdinir allows it to treat a variety of infections throughout the body.

Elimination Route

Maximal plasma cefdinir concentration can be attained between 2-4 hours after an ingested dose. The bioavailability of cefdinir depends on the formulation used. The estimated bioavailability of cefdinir in the capsule form is approximately 16%-21%, depending on the dose. Absolute bioavailability after the administration of a suspension of cefdinir is 25%.. The Cmax of cefdinir is 1.60 μg/mL after a 300 mg dose with an AUC of 7.05. Cmax is 2.87 μg/mL after a 600 mg dose with an AUC of 11. A meal high in fat can reduce the absorption of cefdinir by up to 15%, however, this is not a cause for clinically significant changes, therefore cefdinir may be taken with or without food. When given with aluminum or magnesium-containing antacids or iron, cefdinir absorption may decrease. It is recommended to allow 2 hours between cefdinir administration and the administration of these agents.

Half Life

The average plasma elimination half-life is about 1.7 hours in adults. In children and healthy infants, plasma elimination half-life ranges from 1.2–1.5 hours.

Clearance

The renal clearance in healthy adults in a pharmacokinetic study was 2.0 (± 1.0) mL/min/kg and the clearance in patients with renal failure was lower, decreasing in proportion to the degree of renal impairment. Dose adjustment is required in patients with renal impairment.

Elimination Route

This drug is mainly excreted by the kidneys. Dose adjustments may be required for patients with renal impairment or patients on dialysis. Approximately 18.4% of a 300 mg dose of cefdinir was found unchanged in the urine after a 300 mg dose was administered during a pharmacokinetic study of 21 individuals. A large proportion of the administered dose is excreted in the feces, although the majority is found in the urine.

Pregnancy & Breastfeeding use

Pregnancy Category B. There are no adequate and well-controlled studies in pregnant women. This drug should be used during pregnancy only if clearly needed. Following administration of single 600 mg doses, Cefdinir was not detected in human breast milk.

Contraindication

Cefdinir is contraindicated in patients with known allergy to the cephalosporin class of antibiotics.

Acute Overdose

Symptoms: Nausea, vomiting, epigastric distress, diarrhoea, convulsions. 

Management: Haemodialysis may be useful in the event of a serious toxic reaction particularly if renal function is compromised.

Storage Condition

Store between 20-25° C.

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