Duricef (Cefadroxil)

Cefadroxil (Duricef): Overview

Cefadroxil is an oral, first-generation cephalosporin (a beta-lactam antibiotic) used to treat mild to moderate infections caused by susceptible bacteria. It is closely related to cefalexin, but usually gives more sustained plasma concentrations after dosing.

Duricef: What it is used for

Duricef for strep throat

In Australia, Duricef (cefadroxil) may be prescribed for streptococcal pharyngitis/tonsillitis (strep throat) when the infection is confirmed or strongly suspected to be bacterial. Because many sore throats are caused by viruses, clinicians often use rapid testing or a throat culture before choosing an antibiotic. For strep throat, it is important to complete the full prescribed course to help reduce complications and recurrence.

Duricef for skin infection

Duricef is commonly used for uncomplicated skin and soft tissue infections caused by susceptible staphylococci and streptococci, such as mild cellulitis, infected dermatitis, or other superficial bacterial skin infections. If an abscess has formed, drainage and local treatment may also be needed as well as antibiotics.

Duricef for sinus infection

Sinus symptoms are often caused by viruses and may not need antibiotics. Duricef is not a universal first choice for sinus infections, but it may be used in selected cases of bacterial sinusitis when the suspected or confirmed bacteria are susceptible and a clinician considers it appropriate. Seek medical advice if symptoms are severe, last more than 10 days without improvement, or get worse after initially improving.

Duricef for tooth infection

Dental (odontogenic) infections are often polymicrobial and commonly need source control (for example, dental drainage, root canal treatment, or extraction) alongside any antibiotic. In Australian dental practice, cefadroxil has been used in some orofacial/odontogenic infections, but the choice of antibiotic depends on the severity, the suspected bacteria (including anaerobes), and the patient's allergy history. Urgent dental or emergency assessment is needed if there is facial swelling, fever, spreading redness, difficulty swallowing, or breathing problems.

Cefadroxil: Uses and Administration

Duricef 250mg, 500mg Tablets

Cefadroxil is a first-generation cephalosporin antibacterial that is the parahydroxy derivative of cefalexin and is used in a similar way to treat mild to moderate susceptible infections. It is taken orally, and doses are expressed in terms of the anhydrous substance; 1.04 g of cefadroxil monohydrate is equivalent to about 1 g of anhydrous cefadroxil. The usual adult dose is 1 to 2 g daily as a single dose or in two divided doses. The following doses are used in children weighing less than 40 kg: 500 mg twice daily for those over 6 years of age, 250 mg twice daily for those aged 1 to 6 years, and 25 mg/kg/day in divided doses for infants under 1 year. For details of reduced doses of cefadroxil [Duricef 250mg, 500mg Tablets] in patients with renal impairment, see below. Cefadroxil [Duricef 250mg, 500mg Tablets] has also been used as the lysine derivative.

Administration in renal impairment

After an initial loading dose of 0.5 to 1 g, the dosage of cefadroxil should be adjusted in patients with renal impairment according to creatinine clearance (CC):

• CC 26 to 50 mL/minute per 1.73 m2: 0.5 to 1 g every 12 hours
• CC 11 to 25 mL/minute per 1.73 m2: 0.5 to 1 g every 24 hours
• CC 10 mL/minute per 1.73 m2 or less: 0.5 to 1 g every 36 hours

Adverse Effects and Precautions

Common adverse effects

Cefadroxil is generally well tolerated. The most commonly reported side effects affect the gastrointestinal tract, such as nausea, vomiting, abdominal discomfort, and diarrhoea, as well as hypersensitivity reactions such as rash, pruritus, and urticaria. As with other antibiotics, cefadroxil may rarely cause antibiotic-associated colitis, including C. difficile-associated diarrhoea.

Precautions

Use cefadroxil with caution in patients with a history of hypersensitivity to cephalosporins. Cross-reactivity may occur in patients with penicillin allergy. In Australian clinical practice, dose adjustment is required in renal impairment (see above), and patients receiving prolonged therapy should be monitored clinically.

Breast feeding

Although higher concentrations of cefadroxil have been reported in breast milk compared with cefalexin, cefalotin, cefapirin and cefotaxime, clinically significant exposure in breastfed infants would not be expected, and no adverse effects have been reported in infants whose mothers were taking cefadroxil. Accordingly, cefadroxil is generally considered compatible with breastfeeding in Australian clinical practice.

Cefadroxil: Interactions

Probenecid may increase and prolong cefadroxil plasma concentrations by reducing renal tubular secretion. In Australia, anticoagulants (for example, warfarin) may have stronger effects when used with some antibiotics; consider clinical monitoring (for example, INR) when cefadroxil is started or stopped in patients on anticoagulation. As with other antibacterials, cefadroxil may reduce the effectiveness of live bacterial vaccines (where applicable) if given at the same time.

Duricef and Alcohol

There is no well-known "disulfiram-like" reaction with cefadroxil. However, alcohol can make side effects such as stomach upset or dizziness worse and may slow recovery if you drink heavily. A cautious approach is to avoid or limit alcohol while you are unwell and taking antibiotics, and to follow your prescriber's advice.

Storage

• Tablets/capsules: Store at room temperature in a tightly closed container, away from heat, moisture, and direct light. Do not freeze.
• Oral suspension (liquid): Store in the refrigerator. Do not freeze. Discard any unused portion after 14 days (or as directed on the label).

Antimicrobial Action

Cefadroxil is a bactericidal beta-lactam antibiotic that inhibits bacterial cell-wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking and leading to cell lysis. Its activity is typical of first-generation cephalosporins: good activity against susceptible Gram-positive organisms (including streptococci and methicillin-susceptible staphylococci) and limited Gram-negative coverage (commonly including E. coli, Proteus mirabilis, and Klebsiella spp.). Cefadroxil is not reliably active against MRSA, enterococci, or Pseudomonas spp.

Pharmacokinetics

Cefadroxil is almost completely absorbed from the gastrointestinal tract. After oral doses of 500 mg and 1 g, peak plasma concentrations of about 16 and 30 micrograms/mL respectively are reached after 1.5 to 2 hours. Although peak concentrations are similar to those of cefalexin, plasma concentrations are more sustained. Taking cefadroxil with food does not appear to affect absorption. About 20% of cefadroxil is reported to be bound to plasma proteins. The plasma half-life of cefadroxil is about 1.5 hours and is prolonged in patients with renal impairment. Cefadroxil [Duricef 250mg, 500mg Tablets] is widely distributed to body tissues and fluids. It crosses the placenta and appears in breast milk. More than 90% of a dose of cefadroxil may be excreted unchanged in the urine within 24 hours by glomerular filtration and tubular secretion; peak urinary concentrations of 1.8 mg/mL have been reported after a dose of 500 mg. Cefadroxil is removed by haemodialysis.

Cefadroxil (Duricef) is a convenient oral first-generation cephalosporin commonly used for susceptible skin infections and streptococcal throat infections, and it may be considered in selected cases of other bacterial infections when appropriate. For best results, take it exactly as prescribed and complete the full course. Patients with beta-lactam allergy, renal impairment, or those taking anticoagulants should seek medical advice and appropriate monitoring where needed.