Acute Sinusitis - Antibiotic Prescribing

Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Authority (HPRA) website for detailed drug information (summary of product characteristics and patient information leaflets). Dosing details, contraindications and drug interactions can also be found in the Irish Medicines Formulary (IMF) or other reference sources such as British National Formulary (BNF) / BNF for children (BNFC). See guidance on dosing in children for quick reference dosage/weight guide. Refer to drug interactions table for detailed drug interactions for all antimicrobials. Note extensive drug interactions for clarithromycin, fluoroquinolones, azole antifungals and rifampicin. Many antibiotics increase the risk of bleeding with anticoagulants.

Note additional warnings for clarithromycin and fluoroquinolones

Comments from Expert Advisory Committee

  1. Many are viral. Symptomatic benefit of antibiotics is small.
  2. 80% resolve in 14 days without antibiotics and they only offer marginal benefit after 7 days (NNT 15). A+
  3. Reserve for severe cases B+ or symptoms >10 days.
  4. Cochrane review concludes that amoxicillin and phenoxymethylpenicillin have similar efficacy to the other recommended antibiotics.
  5. In persistent infection use an agent with anti-anaerobic activity e.g. co-amoxiclav. B+

Symptomatic relief

  • Use NSAID or paracetamol B+
  • Systemic decongestants, e.g. pseudoephedrine, improve air circulation and mucus drainage
  • Saline preparations for local irrigation (e.g. nasal rinses, sprays, drops)
  • Topical decongestants, e.g. oxymetazoline, xylometazoline, suitable for most patient groups (hypertensive, diabetes, pregnant women post first trimester)
  • Topical route should not be used >7 days due to rebound congestion


Consider a no or delayed antibiotic strategy. A+

If antibiotics deemed clinically indicated:

See guidance on dosing in children for quick reference dosage/weight guide.

Treatment Dose TX Duration
First line amoxicillin A+ 500 mg TDS 7-10 days
OR doxycycline if allergic to penicillin 200 mg stat/100 mg OD 7-10 days
OR clarithromycin if allergic to penicillin 250-500mg BD 7-10 days
Second line co-amoxiclav 625 mg TDS 7-10 days

Patient Information

We recommend patients use the website developed by HSE/ICGP/IPU partnership for tips on how to get better from common infections without using antibiotics, what you can do for yourself or a loved one and when to seek help.

Reviewed Dec 2019

antibiotics banner