Phenoxymethylpenicillin
Phenoxymethylpenicillin is the first-choice oral antibiotic in NICE guidance for adults with uncomplicated acute sinusitis when antibiotic treatment is indicated. NICE lists 500 mg four times daily for 5 days.
Antibiotics are not routinely required for most acute sinusitis. Requires review of penicillin allergy, symptom duration, severity and risk of complications. Severe or high-risk illness may require a different treatment pathway.