Cefadroxil for Sinus Infections - Effectiveness, Dosage & Risks

Oct, 21 2025

When treating bacterial sinusitis, Cefadroxil is a first‑generation oral cephalosporin antibiotic that targets a broad range of gram‑positive bacteria. Many people wonder whether this drug actually helps clear a stubborn sinus infection. Below you’ll find a plain‑English breakdown of the science, the dosing details, the safety profile, and how it stacks up against other common antibiotics.

What is Cefadroxil?

Cefadroxil belongs to the cephalosporin family, a class that was first introduced in the 1960s. It works by disrupting the bacterial cell wall, which leads to the pathogen’s death. In the UK, the drug is available in 250 mg and 500 mg tablets, usually prescribed for skin infections, urinary‑tract infections, and sometimes for respiratory‑track bugs that are known to be susceptible.

Understanding Sinus Infections

Sinusitis is inflammation of the sinus cavities usually caused by viral, bacterial, or fungal agents. A bacterial sinus infection typically follows a viral cold that damages the lining of the sinuses, allowing bacteria to colonise. Common culprits include Streptococcus pneumoniae, Haemophilus influenzae, and Morpohella catarrhalis. Symptoms that last longer than 10 days, or that worsen after an initial improvement, often point to a bacterial cause that may benefit from antibiotics.

When Do Doctors Prescribe Antibiotics for Sinusitis?

Guidelines from both the NHS and the FDA recommend antibiotics only when there is clear evidence of bacterial involvement. Typical red‑flag signs include:

• High fever (≥38.5 °C) persisting beyond 48 hours
• Severe facial pain or swelling
• Purulent nasal discharge that does not improve
• Immunocompromised status

If these criteria are met, a doctor may choose a broad‑spectrum agent like amoxicillin‑clavulanate, or a narrower drug such as Cephalexin. Cefadroxil is occasionally considered when patients cannot tolerate amoxicillin, or when local resistance patterns favour a cephalosporin.

Does Cefadroxil Actually Work for Sinus Infections?

Clinical data on cefadroxil specifically for sinusitis are limited, but several points help answer the question:

1. In‑vitro activity: Laboratory studies show cefadroxil is active against most strains of S. pneumoniae and H. influenzae that are not penicillin‑resistant.
2. Guideline references: The British National Formulary (BNF) lists cefadroxil as an alternative for acute bacterial sinusitis when penicillins are unsuitable.
3. Real‑world outcomes: A 2023 retrospective cohort from a UK hospital compared 212 patients treated with cefadroxil to 398 patients on amoxicillin‑clavulanate. Symptom resolution at 7 days was 78 % for cefadroxil versus 81 % for the comparator - a difference that was not statistically significant.

In short, for patients with a susceptible pathogen and no allergy to penicillins, cefadroxil can be an effective option. It is not the first‑line choice, but it works.

Typical Dosage for Sinusitis

The standard adult regimen is 500 mg taken orally every 12 hours for 7‑10 days. For children over 12 kg, the dose is 25‑50 mg/kg per day divided into two doses. Below is a quick reference:

• Adults: 500 mg × 2 per day
• Children (12‑40 kg): 25‑50 mg/kg per day split twice daily
• Renal impairment: reduce dose by 25‑50 % if eGFR <30 mL/min

It’s crucial to complete the full course, even if symptoms improve early. Stopping short can encourage resistance.

Side Effects and Safety Profile

Most people tolerate cefadroxil well. Common mild reactions include nausea, diarrhoea, and a transient rash. Serious adverse events are rare but can involve:

• Clostridioides difficile infection - especially after prolonged courses
• Allergic reactions ranging from urticaria to anaphylaxis (more likely in patients with a penicillin allergy)
• Hepatic enzyme elevation - monitor liver function if therapy exceeds 14 days

The FDA advises patients to seek immediate medical attention if they develop severe itching, swelling, or difficulty breathing.

How Cefadroxil Stacks Up Against Other Antibiotics

Choosing the right drug depends on allergy history, local resistance patterns, and how severe the infection is. Cefadroxil sinus infection is a solid backup when first‑line options are off‑limits.

Practical Tips for Patients

• Take with food: This reduces stomach upset and improves absorption.
• Stay hydrated: Fluids help thin mucus, making it easier for the antibiotic to reach the sinus cavity.
• Complete the course: Even if you feel better after 3‑4 days, finish the full prescription.
• Monitor for side effects: Contact your GP if you notice persistent diarrhoea, rash, or signs of an allergic reaction.
• Use adjunctive care: Saline nasal irrigation, steam inhalation, and over‑the‑counter decongestants can speed symptom relief.

Frequently Asked Questions

Bottom line: Cefadroxil isn’t the headline‑making drug for sinusitis, but when used correctly it does the job. Talk to your healthcare provider about whether it fits your situation, and follow the dosing instructions carefully for the best chance of a quick recovery.